From 9570cd46de7567b27aa122a9aaf947c23abf0ae2 Mon Sep 17 00:00:00 2001
From: CJ Bryan and Matt Olenick <pair+cj+matto@ministryofvelocity.com>
Date: Fri, 2 Feb 2018 17:52:07 -0800
Subject: [PATCH] Use a join table to link Blocks and Transactions.

---
 lib/explorer/block.ex                         |  13 +-
 lib/explorer/block_transaction.ex             |  24 ++
 lib/explorer/fetcher.ex                       |  23 +-
 lib/explorer/forms/block_form.ex              |  18 +-
 lib/explorer/forms/transaction_form.ex        |  48 ++--
 lib/explorer/from_address.ex                  |   7 +-
 .../importers/transaction_importer.ex         |  95 +++++++
 lib/explorer/to_address.ex                    |   7 +-
 lib/explorer/transaction.ex                   |  14 +-
 .../controllers/block_controller.ex           |   8 +-
 .../controllers/chain_controller.ex           |  19 +-
 .../controllers/transaction_controller.ex     |  16 +-
 .../templates/transaction/show.html.eex       |   2 +-
 priv/gettext/default.pot                      |  47 +++-
 priv/gettext/en/LC_MESSAGES/default.po        |  47 +++-
 ...180202195342_create_block_transactions.exs |  14 ++
 ...5933_remove_block_id_from_transactions.exs |   9 +
 test/explorer/block_transaction_test.exs      |  17 ++
 test/explorer/fetcher_test.exs                |  52 +++-
 test/explorer/forms/block_form_test.exs       |   4 +-
 test/explorer/forms/transaction_form_test.exs |  56 ++++-
 .../importers/transaction_importer_test.exs   | 235 ++++++++++++++++++
 test/explorer/transaction_test.exs            |   9 +-
 .../controllers/chain_controller_test.exs     |  26 +-
 .../transaction_controller_test.exs           |  25 +-
 .../features/contributor_browsing_test.exs    |   6 +-
 .../factories/block_transaction_factory.ex    |   9 +
 test/support/factories/transaction_factory.ex |  21 +-
 test/support/factory.ex                       |   1 +
 ...ction_importer_creates_a_from_address.json |  30 +++
 ...saction_importer_creates_a_to_address.json |  30 +++
 ...ter_creates_a_to_address_from_creates.json |  30 +++
 ...saction_importer_download_transaction.json |  30 +++
 ..._download_transaction_with_a_bad_hash.json |  30 +++
 ...importer_import_saves_the_transaction.json |  30 +++
 ...action_importer_saves_the_association.json |  30 +++
 ...ransaction_importer_txn_without_block.json |  30 +++
 ...tion_importer_updates_the_association.json |  30 +++
 38 files changed, 989 insertions(+), 153 deletions(-)
 create mode 100644 lib/explorer/block_transaction.ex
 create mode 100644 lib/explorer/importers/transaction_importer.ex
 create mode 100644 priv/repo/migrations/20180202195342_create_block_transactions.exs
 create mode 100644 priv/repo/migrations/20180202215933_remove_block_id_from_transactions.exs
 create mode 100644 test/explorer/block_transaction_test.exs
 create mode 100644 test/explorer/importers/transaction_importer_test.exs
 create mode 100644 test/support/factories/block_transaction_factory.ex
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_creates_a_from_address.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address_from_creates.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_download_transaction.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_download_transaction_with_a_bad_hash.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_import_saves_the_transaction.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_saves_the_association.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_txn_without_block.json
 create mode 100644 test/support/fixture/vcr_cassettes/transaction_importer_updates_the_association.json

diff --git a/lib/explorer/block.ex b/lib/explorer/block.ex
index 3c56533909..d67aaf1b07 100644
--- a/lib/explorer/block.ex
+++ b/lib/explorer/block.ex
@@ -1,8 +1,9 @@
 defmodule Explorer.Block do
-  use Ecto.Schema
+  alias Explorer.Block
+  alias Explorer.BlockTransaction
   import Ecto.Changeset
+  use Ecto.Schema
   import Ecto.Query
-  alias Explorer.Block
 
   @moduledoc false
 
@@ -10,6 +11,8 @@ defmodule Explorer.Block do
                     autogenerate: {Timex.Ecto.DateTime, :autogenerate, []}]
 
   schema "blocks" do
+    has_many :block_transactions, BlockTransaction
+    has_many :transactions, through: [:block_transactions, :transaction]
     field :number, :integer
     field :hash, :string
     field :parent_hash, :string
@@ -22,19 +25,15 @@ defmodule Explorer.Block do
     field :gas_used, :integer
     field :timestamp, Timex.Ecto.DateTime
     timestamps()
-
-    has_many :transactions, Explorer.Transaction
   end
 
   @required_attrs ~w(number hash parent_hash nonce miner difficulty
                      total_difficulty size gas_limit gas_used timestamp)a
-  @optional_attrs ~w()a
 
   @doc false
   def changeset(%Block{} = block, attrs) do
     block
-    |> cast(attrs, @required_attrs, @optional_attrs)
-    |> cast_assoc(:transactions)
+    |> cast(attrs, @required_attrs)
     |> validate_required(@required_attrs)
     |> update_change(:hash, &String.downcase/1)
     |> unique_constraint(:hash)
diff --git a/lib/explorer/block_transaction.ex b/lib/explorer/block_transaction.ex
new file mode 100644
index 0000000000..73c94e8592
--- /dev/null
+++ b/lib/explorer/block_transaction.ex
@@ -0,0 +1,24 @@
+defmodule Explorer.BlockTransaction do
+  @moduledoc false
+  alias Explorer.BlockTransaction
+  import Ecto.Changeset
+  use Ecto.Schema
+
+  @timestamps_opts [type: Timex.Ecto.DateTime,
+                    autogenerate: {Timex.Ecto.DateTime, :autogenerate, []}]
+
+  @primary_key false
+  schema "block_transactions" do
+    belongs_to :block, Explorer.Block
+    belongs_to :transaction, Explorer.Transaction, primary_key: true
+    timestamps()
+  end
+
+  @required_attrs ~w(block_id transaction_id)a
+
+  def changeset(%BlockTransaction{} = block_transaction, attrs \\ %{}) do
+    block_transaction
+    |> cast(attrs, @required_attrs)
+    |> validate_required(@required_attrs)
+  end
+end
diff --git a/lib/explorer/fetcher.ex b/lib/explorer/fetcher.ex
index 2bf4112bc5..393ad0fce9 100644
--- a/lib/explorer/fetcher.ex
+++ b/lib/explorer/fetcher.ex
@@ -2,6 +2,7 @@ defmodule Explorer.Fetcher  do
   @moduledoc false
   alias Explorer.Address
   alias Explorer.Block
+  alias Explorer.BlockTransaction
   alias Explorer.FromAddress
   alias Explorer.Repo.NewRelic, as: Repo
   alias Explorer.ToAddress
@@ -52,13 +53,30 @@ defmodule Explorer.Fetcher  do
   def create_transaction(block, changes) do
     transaction = Repo.get_by(Transaction, hash: changes["hash"]) || %Transaction{}
     transaction
-    |> Transaction.changeset(extract_transaction(block, changes))
+    |> Transaction.changeset(extract_transaction(changes))
     |> Repo.insert_or_update!
     |> create_from_address(changes["from"])
     |> create_to_address(changes["to"] || changes["creates"])
+    |> create_block_transaction(block)
   end
 
-  def extract_transaction(block, transaction) do
+  def create_block_transaction(transaction, block) do
+    if block do
+      block_transaction =
+        Repo.get_by(BlockTransaction, transaction_id: transaction.id) ||
+          %BlockTransaction{}
+
+      changes = %{block_id: block.id, transaction_id: transaction.id}
+
+      block_transaction
+      |> BlockTransaction.changeset(changes)
+      |> Repo.insert_or_update!
+    end
+
+    transaction
+  end
+
+  def extract_transaction(transaction) do
     %{
       hash: transaction["hash"],
       value: transaction["value"] |> decode_integer_field,
@@ -72,7 +90,6 @@ defmodule Explorer.Fetcher  do
       standard_v: transaction["standardV"],
       transaction_index: transaction["transactionIndex"],
       v: transaction["v"],
-      block_id: block.id,
     }
   end
 
diff --git a/lib/explorer/forms/block_form.ex b/lib/explorer/forms/block_form.ex
index dd3e70b11f..c0a0ef80bc 100644
--- a/lib/explorer/forms/block_form.ex
+++ b/lib/explorer/forms/block_form.ex
@@ -1,9 +1,9 @@
 defmodule Explorer.BlockForm do
-  import Ecto.Query
-  alias Explorer.Transaction
-  alias Explorer.Repo
-
   @moduledoc false
+  alias Explorer.Block
+  alias Explorer.BlockTransaction
+  alias Explorer.Repo
+  import Ecto.Query
 
   def build(block) do
     block |> Map.merge(%{
@@ -14,10 +14,12 @@ defmodule Explorer.BlockForm do
   end
 
   def get_transactions_count(block) do
-    Transaction
-      |> where([t], t.block_id == ^block.id)
-      |> Repo.all
-      |> Enum.count
+    query = from block_transaction in BlockTransaction,
+      join: block in Block,
+        where: block.id == block_transaction.block_id,
+      where: block.id == ^block.id,
+      select: count(block_transaction.block_id)
+    Repo.one(query)
   end
 
   def calculate_age(block) do
diff --git a/lib/explorer/forms/transaction_form.ex b/lib/explorer/forms/transaction_form.ex
index 60043dbb49..24a43b5c1d 100644
--- a/lib/explorer/forms/transaction_form.ex
+++ b/lib/explorer/forms/transaction_form.ex
@@ -1,40 +1,56 @@
 defmodule Explorer.TransactionForm do
-  @moduledoc false
+  alias Cldr.Number
   alias Explorer.Address
   alias Explorer.Block
+  alias Explorer.BlockTransaction
   alias Explorer.FromAddress
   alias Explorer.Repo
   alias Explorer.ToAddress
   alias Explorer.Transaction
   import Ecto.Query
 
+  @moduledoc "Format a Block and a Transaction for display."
+
   def build(transaction) do
+    block = with_block(transaction)
+
     transaction
     |> Map.merge(%{
-      block_number: transaction |> block_number,
-      age: transaction |> block_age,
-      formatted_timestamp: transaction |> format_timestamp,
-      cumulative_gas_used: transaction |> cumulative_gas_used,
+      block_number: block |> block_number,
+      age: block |> block_age,
+      formatted_timestamp: block |> format_timestamp,
+      cumulative_gas_used: block |> cumulative_gas_used,
       to_address: transaction |> to_address,
       from_address: transaction |> from_address,
-      confirmations: transaction |> confirmations,
+      confirmations: block |> confirmations,
     })
   end
 
-  def block_number(transaction) do
-    transaction.block.number
+  def with_block(transaction) do
+    Repo.one(
+      from block in Block,
+        join: block_transaction in BlockTransaction,
+          where: block_transaction.block_id == block.id,
+        join: transaction in Transaction,
+          where: transaction.id == block_transaction.transaction_id,
+        where: transaction.id == ^transaction.id
+    )
+  end
+
+  def block_number(block) do
+    block && block.number || ""
   end
 
-  def block_age(transaction) do
-    transaction.block.timestamp |> Timex.from_now
+  def block_age(block) do
+    block && block.timestamp |> Timex.from_now || ""
   end
 
-  def format_timestamp(transaction) do
-    transaction.block.timestamp |> Timex.format!("%b-%d-%Y %H:%M:%S %p %Z", :strftime)
+  def format_timestamp(block) do
+    block && block.timestamp |> Timex.format!("%b-%d-%Y %H:%M:%S %p %Z", :strftime) || ""
   end
 
-  def cumulative_gas_used(transaction) do
-    transaction.block.gas_used
+  def cumulative_gas_used(block) do
+    block && block.gas_used |> Number.to_string! || ""
   end
 
   def to_address(transaction) do
@@ -59,8 +75,8 @@ defmodule Explorer.TransactionForm do
     Repo.one(query).hash
   end
 
-  def confirmations(transaction) do
+  def confirmations(block) do
     query = from block in Block, select: max(block.number)
-    Repo.one(query) - transaction.block.number
+    block && Repo.one(query) - block.number || 0
   end
 end
diff --git a/lib/explorer/from_address.ex b/lib/explorer/from_address.ex
index c09f051fe4..960d4c8791 100644
--- a/lib/explorer/from_address.ex
+++ b/lib/explorer/from_address.ex
@@ -1,9 +1,8 @@
 defmodule Explorer.FromAddress do
-  use Ecto.Schema
-  import Ecto.Changeset
-  alias Explorer.FromAddress
-
   @moduledoc false
+  alias Explorer.FromAddress
+  import Ecto.Changeset
+  use Ecto.Schema
 
   @timestamps_opts [type: Timex.Ecto.DateTime,
                     autogenerate: {Timex.Ecto.DateTime, :autogenerate, []}]
diff --git a/lib/explorer/importers/transaction_importer.ex b/lib/explorer/importers/transaction_importer.ex
new file mode 100644
index 0000000000..4d4c72be27
--- /dev/null
+++ b/lib/explorer/importers/transaction_importer.ex
@@ -0,0 +1,95 @@
+defmodule Explorer.TransactionImporter do
+  @moduledoc "Imports a transaction given a unique hash."
+
+  import Ethereumex.HttpClient, only: [eth_get_transaction_by_hash: 1]
+
+  alias Explorer.Address
+  alias Explorer.Block
+  alias Explorer.BlockTransaction
+  alias Explorer.Repo
+  alias Explorer.FromAddress
+  alias Explorer.ToAddress
+  alias Explorer.Transaction
+
+  def import(hash) do
+    raw_transaction = download_transaction(hash)
+    changes = extract_attrs(raw_transaction)
+
+    transaction = Repo.get_by(Transaction, hash: changes.hash) || %Transaction{}
+    transaction
+    |> Transaction.changeset(changes)
+    |> Repo.insert_or_update!
+    |> create_from_address(raw_transaction["from"])
+    |> create_to_address(raw_transaction["to"] || raw_transaction["creates"])
+    |> create_block_transaction(raw_transaction["blockHash"])
+  end
+
+  def download_transaction(hash) do
+    {:ok, payload} = eth_get_transaction_by_hash(hash)
+    payload
+  end
+
+  def extract_attrs(raw_transaction) do
+    %{
+      hash: raw_transaction["hash"],
+      value: raw_transaction["value"] |> decode_integer_field,
+      gas: raw_transaction["gas"] |> decode_integer_field,
+      gas_price: raw_transaction["gasPrice"] |> decode_integer_field,
+      input: raw_transaction["input"],
+      nonce: raw_transaction["nonce"] |> decode_integer_field,
+      public_key: raw_transaction["publicKey"],
+      r: raw_transaction["r"],
+      s: raw_transaction["s"],
+      standard_v: raw_transaction["standardV"],
+      transaction_index: raw_transaction["transactionIndex"],
+      v: raw_transaction["v"],
+    }
+  end
+
+  def create_block_transaction(transaction, block_hash) do
+    block = Repo.get_by(Block, hash: block_hash)
+
+    if block do
+      block_transaction =
+        Repo.get_by(BlockTransaction, transaction_id: transaction.id) ||
+        %BlockTransaction{}
+
+      changes = %{block_id: block.id, transaction_id: transaction.id}
+
+      block_transaction
+      |>BlockTransaction.changeset(changes)
+      |> Repo.insert_or_update!
+    end
+
+    transaction
+  end
+
+  def create_from_address(transaction, hash) do
+    address = Address.find_or_create_by_hash(hash)
+    changes = %{transaction_id: transaction.id, address_id: address.id}
+
+    from_address = Repo.get_by(FromAddress, changes) || %FromAddress{}
+    from_address
+    |> FromAddress.changeset(changes)
+    |> Repo.insert_or_update!
+
+    transaction
+  end
+
+  def create_to_address(transaction, hash) do
+    address = Address.find_or_create_by_hash(hash)
+    changes = %{transaction_id: transaction.id, address_id: address.id}
+
+    to_address = Repo.get_by(ToAddress, changes) || %ToAddress{}
+    to_address
+    |> ToAddress.changeset(changes)
+    |> Repo.insert_or_update!
+
+    transaction
+  end
+
+  def decode_integer_field(hex) do
+    {"0x", base_16} = String.split_at(hex, 2)
+    String.to_integer(base_16, 16)
+  end
+end
diff --git a/lib/explorer/to_address.ex b/lib/explorer/to_address.ex
index f20460fd6f..66ddc5e453 100644
--- a/lib/explorer/to_address.ex
+++ b/lib/explorer/to_address.ex
@@ -1,9 +1,8 @@
 defmodule Explorer.ToAddress do
-  use Ecto.Schema
-  import Ecto.Changeset
-  alias Explorer.ToAddress
-
   @moduledoc false
+  alias Explorer.ToAddress
+  import Ecto.Changeset
+  use Ecto.Schema
 
   @timestamps_opts [type: Timex.Ecto.DateTime,
                     autogenerate: {Timex.Ecto.DateTime, :autogenerate, []}]
diff --git a/lib/explorer/transaction.ex b/lib/explorer/transaction.ex
index 6c5a32236d..aefcd419f9 100644
--- a/lib/explorer/transaction.ex
+++ b/lib/explorer/transaction.ex
@@ -1,14 +1,16 @@
 defmodule Explorer.Transaction do
   @moduledoc false
-
-  use Ecto.Schema
-  import Ecto.Changeset
+  alias Explorer.BlockTransaction
   alias Explorer.Transaction
+  import Ecto.Changeset
+  use Ecto.Schema
 
   @timestamps_opts [type: Timex.Ecto.DateTime,
                     autogenerate: {Timex.Ecto.DateTime, :autogenerate, []}]
 
   schema "transactions" do
+    has_one :block_transaction, BlockTransaction
+    has_one :block, through: [:block_transaction, :block]
     field :hash, :string
     field :value, :decimal
     field :gas, :decimal
@@ -22,10 +24,6 @@ defmodule Explorer.Transaction do
     field :transaction_index, :string
     field :v, :string
     timestamps()
-
-    belongs_to :block, Explorer.Block
-
-    many_to_many :to_address, Explorer.Address, join_through: "to_addresses", unique: true
   end
 
   @required_attrs ~w(hash value gas gas_price input nonce public_key r s
@@ -35,7 +33,7 @@ defmodule Explorer.Transaction do
   @doc false
   def changeset(%Transaction{} = transaction, attrs \\ %{}) do
     transaction
-    |> cast(attrs, [:block_id | @required_attrs], @optional_attrs)
+    |> cast(attrs, @required_attrs, @optional_attrs)
     |> validate_required(@required_attrs)
     |> foreign_key_constraint(:block_id)
     |> update_change(:hash, &String.downcase/1)
diff --git a/lib/explorer_web/controllers/block_controller.ex b/lib/explorer_web/controllers/block_controller.ex
index 98c6580d85..06bc0170a0 100644
--- a/lib/explorer_web/controllers/block_controller.ex
+++ b/lib/explorer_web/controllers/block_controller.ex
@@ -8,9 +8,11 @@ defmodule ExplorerWeb.BlockController do
   alias Explorer.Repo.NewRelic, as: Repo
 
   def index(conn, params) do
-    blocks = from b in Block,
-      order_by: [desc: b.number],
-      preload: :transactions
+    blocks = from block in Block,
+      left_join: block_transaction in assoc(block, :block_transactions),
+      left_join: transactions in assoc(block_transaction, :transaction),
+      preload: [transactions: transactions],
+      order_by: [desc: block.number]
 
     render(conn, "index.html", blocks: Repo.paginate(blocks, params))
   end
diff --git a/lib/explorer_web/controllers/chain_controller.ex b/lib/explorer_web/controllers/chain_controller.ex
index 43b25e6e04..f23db58563 100644
--- a/lib/explorer_web/controllers/chain_controller.ex
+++ b/lib/explorer_web/controllers/chain_controller.ex
@@ -4,8 +4,10 @@ defmodule ExplorerWeb.ChainController do
   import Ecto.Query
 
   alias Explorer.Block
+  alias Explorer.BlockForm
   alias Explorer.Repo.NewRelic, as: Repo
   alias Explorer.Transaction
+  alias Explorer.TransactionForm
 
   def show(conn, _params) do
     blocks = from b in Block,
@@ -13,17 +15,20 @@ defmodule ExplorerWeb.ChainController do
       preload: :transactions,
       limit: 5
 
-    transactions = from t in Transaction,
-      join: b in Block, on: b.id == t.block_id,
-      order_by: [desc: b.number],
-      preload: :block,
-      limit: 5
+    transactions = from transaction in Transaction,
+      left_join: block_transaction in assoc(transaction, :block_transaction),
+      left_join: block in assoc(block_transaction, :block),
+      preload: [block_transaction: block_transaction, block: block],
+      limit: 5,
+      order_by: [desc: block.number]
 
     render(
       conn,
       "show.html",
-      blocks: Repo.all(blocks),
-      transactions: Repo.all(transactions)
+      blocks: blocks |> Repo.all |> Enum.map(&BlockForm.build/1),
+      transactions: transactions
+        |> Repo.all
+        |> Enum.map(&TransactionForm.build/1)
     )
   end
 end
diff --git a/lib/explorer_web/controllers/transaction_controller.ex b/lib/explorer_web/controllers/transaction_controller.ex
index f32b5ec537..ea8f957bfa 100644
--- a/lib/explorer_web/controllers/transaction_controller.ex
+++ b/lib/explorer_web/controllers/transaction_controller.ex
@@ -3,18 +3,20 @@ defmodule ExplorerWeb.TransactionController do
 
   import Ecto.Query
 
-  alias Explorer.Block
   alias Explorer.Repo.NewRelic, as: Repo
   alias Explorer.Transaction
   alias Explorer.TransactionForm
 
   def index(conn, params) do
-    transactions = from t in Transaction,
-      join: b in Block, on: b.id == t.block_id,
-      order_by: [desc: b.number],
-      preload: :block
+    query = from transaction in Transaction,
+      left_join: block_transaction in assoc(transaction, :block_transaction),
+      left_join: block in assoc(block_transaction, :block),
+      preload: [block_transaction: block_transaction, block: block],
+      order_by: [asc: block.inserted_at]
 
-    render(conn, "index.html", transactions: Repo.paginate(transactions, params))
+    transactions = Repo.paginate(query, params)
+
+    render(conn, "index.html", transactions: transactions)
   end
 
   def show(conn, params) do
@@ -22,8 +24,8 @@ defmodule ExplorerWeb.TransactionController do
       |> where(hash: ^params["id"])
       |> first
       |> Repo.one
-      |> Repo.preload(:block)
       |> TransactionForm.build
+
     render(conn, "show.html", transaction: transaction)
   end
 end
diff --git a/lib/explorer_web/templates/transaction/show.html.eex b/lib/explorer_web/templates/transaction/show.html.eex
index 16f0e5be91..dff848ee0b 100644
--- a/lib/explorer_web/templates/transaction/show.html.eex
+++ b/lib/explorer_web/templates/transaction/show.html.eex
@@ -63,7 +63,7 @@
           </div>
           <div class="transaction__item">
             <dt class="transaction__item-key"><%= gettext "Cumulative Gas Used" %></dt>
-            <dd class="transaction__item-value"><%= @transaction.cumulative_gas_used |> Cldr.Number.to_string! %></dd>
+            <dd class="transaction__item-value"><%= @transaction.cumulative_gas_used %></dd>
           </div>
           <div class="transaction__item">
             <dt class="transaction__item-key"><%= gettext "Nonce" %></dt>
diff --git a/priv/gettext/default.pot b/priv/gettext/default.pot
index 096747c43e..19b8a591e4 100644
--- a/priv/gettext/default.pot
+++ b/priv/gettext/default.pot
@@ -1,14 +1,18 @@
-#: lib/explorer_web/templates/page/index.html.eex:11
-#: lib/explorer_web/templates/page/index.html.eex:39
+#: lib/explorer_web/templates/block/index.html.eex:12
+#: lib/explorer_web/templates/chain/show.html.eex:11
+#: lib/explorer_web/templates/chain/show.html.eex:39
+#: lib/explorer_web/templates/transaction/index.html.eex:13
 #: lib/explorer_web/templates/transaction/show.html.eex:33
 msgid "Age"
 msgstr ""
 
-#: lib/explorer_web/templates/page/index.html.eex:38
+#: lib/explorer_web/templates/chain/show.html.eex:38
+#: lib/explorer_web/templates/transaction/index.html.eex:12
 msgid "Block"
 msgstr ""
 
-#: lib/explorer_web/templates/page/index.html.eex:4
+#: lib/explorer_web/templates/chain/show.html.eex:4
+#: lib/explorer_web/templates/layout/_header.html.eex:16
 msgid "Blocks"
 msgstr ""
 
@@ -16,17 +20,20 @@ msgstr ""
 msgid "Copyright %{year} POA"
 msgstr ""
 
+#: lib/explorer_web/templates/block/index.html.eex:14
 #: lib/explorer_web/templates/block/show.html.eex:53
-#: lib/explorer_web/templates/page/index.html.eex:13
+#: lib/explorer_web/templates/chain/show.html.eex:13
 msgid "Gas Used"
 msgstr ""
 
 #: lib/explorer_web/templates/block/show.html.eex:25
-#: lib/explorer_web/templates/page/index.html.eex:37
+#: lib/explorer_web/templates/chain/show.html.eex:37
+#: lib/explorer_web/templates/transaction/index.html.eex:11
 msgid "Hash"
 msgstr ""
 
-#: lib/explorer_web/templates/page/index.html.eex:10
+#: lib/explorer_web/templates/block/index.html.eex:11
+#: lib/explorer_web/templates/chain/show.html.eex:10
 msgid "Height"
 msgstr ""
 
@@ -35,13 +42,16 @@ msgstr ""
 msgid "POA Network Explorer"
 msgstr ""
 
+#: lib/explorer_web/templates/block/index.html.eex:13
 #: lib/explorer_web/templates/block/show.html.eex:21
-#: lib/explorer_web/templates/page/index.html.eex:12
-#: lib/explorer_web/templates/page/index.html.eex:31
+#: lib/explorer_web/templates/chain/show.html.eex:12
+#: lib/explorer_web/templates/chain/show.html.eex:31
+#: lib/explorer_web/templates/layout/_header.html.eex:12
 msgid "Transactions"
 msgstr ""
 
-#: lib/explorer_web/templates/page/index.html.eex:40
+#: lib/explorer_web/templates/chain/show.html.eex:40
+#: lib/explorer_web/templates/transaction/index.html.eex:14
 #: lib/explorer_web/templates/transaction/show.html.eex:37
 #: lib/explorer_web/templates/transaction/show.html.eex:49
 msgid "Value"
@@ -55,6 +65,7 @@ msgstr ""
 msgid "Difficulty"
 msgstr ""
 
+#: lib/explorer_web/templates/block/index.html.eex:15
 #: lib/explorer_web/templates/block/show.html.eex:57
 #: lib/explorer_web/templates/transaction/show.html.eex:57
 msgid "Gas Limit"
@@ -105,6 +116,7 @@ msgstr ""
 msgid "Gas"
 msgstr ""
 
+#: lib/explorer_web/templates/block/index.html.eex:16
 #: lib/explorer_web/templates/transaction/show.html.eex:61
 msgid "Gas Price"
 msgstr ""
@@ -155,7 +167,20 @@ msgid "Balance"
 msgstr ""
 
 #: lib/explorer_web/templates/address/show.html.eex:11
-#: lib/explorer_web/templates/page/index.html.eex:53
+#: lib/explorer_web/templates/chain/show.html.eex:53
+#: lib/explorer_web/templates/transaction/index.html.eex:25
 #: lib/explorer_web/templates/transaction/show.html.eex:38
 msgid "POA"
 msgstr ""
+
+#: lib/explorer_web/templates/block/index.html.eex:24
+msgid "%{count} transactions"
+msgstr ""
+
+#: lib/explorer_web/templates/block/index.html.eex:3
+msgid "Showing #%{start_block} to #%{end_block}"
+msgstr ""
+
+#: lib/explorer_web/templates/transaction/index.html.eex:3
+msgid "Showing %{count} Transactions"
+msgstr ""
diff --git a/priv/gettext/en/LC_MESSAGES/default.po b/priv/gettext/en/LC_MESSAGES/default.po
index df3366f810..d579d0c9d3 100644
--- a/priv/gettext/en/LC_MESSAGES/default.po
+++ b/priv/gettext/en/LC_MESSAGES/default.po
@@ -10,17 +10,21 @@ msgid ""
 msgstr ""
 "Language: en\n"
 
-#: lib/explorer_web/templates/page/index.html.eex:11
-#: lib/explorer_web/templates/page/index.html.eex:39
+#: lib/explorer_web/templates/block/index.html.eex:12
+#: lib/explorer_web/templates/chain/show.html.eex:11
+#: lib/explorer_web/templates/chain/show.html.eex:39
+#: lib/explorer_web/templates/transaction/index.html.eex:13
 #: lib/explorer_web/templates/transaction/show.html.eex:33
 msgid "Age"
 msgstr "Age"
 
-#: lib/explorer_web/templates/page/index.html.eex:38
+#: lib/explorer_web/templates/chain/show.html.eex:38
+#: lib/explorer_web/templates/transaction/index.html.eex:12
 msgid "Block"
 msgstr "Block"
 
-#: lib/explorer_web/templates/page/index.html.eex:4
+#: lib/explorer_web/templates/chain/show.html.eex:4
+#: lib/explorer_web/templates/layout/_header.html.eex:16
 msgid "Blocks"
 msgstr "Blocks"
 
@@ -28,17 +32,20 @@ msgstr "Blocks"
 msgid "Copyright %{year} POA"
 msgstr "%{year} POA Network Ltd. All rights reserved"
 
+#: lib/explorer_web/templates/block/index.html.eex:14
 #: lib/explorer_web/templates/block/show.html.eex:53
-#: lib/explorer_web/templates/page/index.html.eex:13
+#: lib/explorer_web/templates/chain/show.html.eex:13
 msgid "Gas Used"
 msgstr "Gas Used"
 
 #: lib/explorer_web/templates/block/show.html.eex:25
-#: lib/explorer_web/templates/page/index.html.eex:37
+#: lib/explorer_web/templates/chain/show.html.eex:37
+#: lib/explorer_web/templates/transaction/index.html.eex:11
 msgid "Hash"
 msgstr "Hash"
 
-#: lib/explorer_web/templates/page/index.html.eex:10
+#: lib/explorer_web/templates/block/index.html.eex:11
+#: lib/explorer_web/templates/chain/show.html.eex:10
 msgid "Height"
 msgstr "Height"
 
@@ -47,13 +54,16 @@ msgstr "Height"
 msgid "POA Network Explorer"
 msgstr "POA Network Explorer"
 
+#: lib/explorer_web/templates/block/index.html.eex:13
 #: lib/explorer_web/templates/block/show.html.eex:21
-#: lib/explorer_web/templates/page/index.html.eex:12
-#: lib/explorer_web/templates/page/index.html.eex:31
+#: lib/explorer_web/templates/chain/show.html.eex:12
+#: lib/explorer_web/templates/chain/show.html.eex:31
+#: lib/explorer_web/templates/layout/_header.html.eex:12
 msgid "Transactions"
 msgstr "Transactions"
 
-#: lib/explorer_web/templates/page/index.html.eex:40
+#: lib/explorer_web/templates/chain/show.html.eex:40
+#: lib/explorer_web/templates/transaction/index.html.eex:14
 #: lib/explorer_web/templates/transaction/show.html.eex:37
 #: lib/explorer_web/templates/transaction/show.html.eex:49
 msgid "Value"
@@ -67,6 +77,7 @@ msgstr "Block #%{number} Details"
 msgid "Difficulty"
 msgstr "Difficulty"
 
+#: lib/explorer_web/templates/block/index.html.eex:15
 #: lib/explorer_web/templates/block/show.html.eex:57
 #: lib/explorer_web/templates/transaction/show.html.eex:57
 msgid "Gas Limit"
@@ -117,6 +128,7 @@ msgstr "Cumulative Gas Used"
 msgid "Gas"
 msgstr "Gas"
 
+#: lib/explorer_web/templates/block/index.html.eex:16
 #: lib/explorer_web/templates/transaction/show.html.eex:61
 msgid "Gas Price"
 msgstr "Gas Price"
@@ -167,7 +179,20 @@ msgid "Balance"
 msgstr "Balance"
 
 #: lib/explorer_web/templates/address/show.html.eex:11
-#: lib/explorer_web/templates/page/index.html.eex:53
+#: lib/explorer_web/templates/chain/show.html.eex:53
+#: lib/explorer_web/templates/transaction/index.html.eex:25
 #: lib/explorer_web/templates/transaction/show.html.eex:38
 msgid "POA"
 msgstr "POA"
+
+#: lib/explorer_web/templates/block/index.html.eex:24
+msgid "%{count} transactions"
+msgstr "%{count} transactions"
+
+#: lib/explorer_web/templates/block/index.html.eex:3
+msgid "Showing #%{start_block} to #%{end_block}"
+msgstr "Showing #%{start_block} to #%{end_block}"
+
+#: lib/explorer_web/templates/transaction/index.html.eex:3
+msgid "Showing %{count} Transactions"
+msgstr "Showing %{count} Transactions"
diff --git a/priv/repo/migrations/20180202195342_create_block_transactions.exs b/priv/repo/migrations/20180202195342_create_block_transactions.exs
new file mode 100644
index 0000000000..e95111f038
--- /dev/null
+++ b/priv/repo/migrations/20180202195342_create_block_transactions.exs
@@ -0,0 +1,14 @@
+defmodule Explorer.Repo.Migrations.CreateBlockTransactions do
+  use Ecto.Migration
+
+  def change do
+    create table(:block_transactions, primary_key: false) do
+      add :block_id, references(:blocks)
+      add :transaction_id, references(:transactions), primary_key: true
+      timestamps null: false
+    end
+
+    create unique_index(:block_transactions, :transaction_id)
+    create unique_index(:block_transactions, [:block_id, :transaction_id])
+  end
+end
diff --git a/priv/repo/migrations/20180202215933_remove_block_id_from_transactions.exs b/priv/repo/migrations/20180202215933_remove_block_id_from_transactions.exs
new file mode 100644
index 0000000000..aab2d83479
--- /dev/null
+++ b/priv/repo/migrations/20180202215933_remove_block_id_from_transactions.exs
@@ -0,0 +1,9 @@
+defmodule Explorer.Repo.Migrations.RemoveBlockIdFromTransactions do
+  use Ecto.Migration
+
+  def change do
+    alter table(:transactions) do
+      remove :block_id
+    end
+  end
+end
diff --git a/test/explorer/block_transaction_test.exs b/test/explorer/block_transaction_test.exs
new file mode 100644
index 0000000000..f9da5e6c8e
--- /dev/null
+++ b/test/explorer/block_transaction_test.exs
@@ -0,0 +1,17 @@
+defmodule Explorer.BlockTransactionTest do
+  use Explorer.DataCase
+  alias Explorer.BlockTransaction
+
+  describe "changeset/2" do
+    test "with empty attributes" do
+      changeset = BlockTransaction.changeset(%BlockTransaction{}, %{})
+      refute(changeset.valid?)
+    end
+
+    test "with valid attributes" do
+      attrs = %{block_id: 4, transaction_id: 3}
+      changeset = BlockTransaction.changeset(%BlockTransaction{}, attrs)
+      assert(changeset.valid?)
+    end
+  end
+end
diff --git a/test/explorer/fetcher_test.exs b/test/explorer/fetcher_test.exs
index fd187cf413..80e65037da 100644
--- a/test/explorer/fetcher_test.exs
+++ b/test/explorer/fetcher_test.exs
@@ -8,6 +8,7 @@ defmodule Explorer.FetcherTest do
   alias Explorer.Address
   alias Explorer.ToAddress
   alias Explorer.FromAddress
+  alias Explorer.BlockTransaction
 
   @raw_block %{
     "difficulty" => "0xfffffffffffffffffffffffffffffffe",
@@ -69,7 +70,6 @@ defmodule Explorer.FetcherTest do
     standard_v: "0x11",
     transaction_index: "0x12",
     v: "0x13",
-    block_id: 100,
   }
 
   describe "fetch/1" do
@@ -143,9 +143,12 @@ defmodule Explorer.FetcherTest do
 
   describe "extract_transactions/2" do
     test "that it creates a list of transactions" do
-      block = insert(:block, %{id: 100})
-      transactions = Fetcher.extract_transactions(block, [@raw_transaction])
-      assert List.first(transactions).block_id == 100
+      raw_transactions = [%{@raw_transaction | "hash" => "0xlimon"}, %{@raw_transaction | "hash" => "0xpepino"}]
+      block = insert(:block)
+      Fetcher.extract_transactions(block, raw_transactions)
+      transaction_hashes = Repo.all(from transaction in Transaction, select: transaction.hash)
+
+      assert(transaction_hashes == ["0xlimon", "0xpepino"])
     end
   end
 
@@ -158,6 +161,41 @@ defmodule Explorer.FetcherTest do
       assert last_transaction.hash == "0xab1"
     end
 
+    test "that it creates a block transaction when there is a block" do
+      block = insert(:block)
+      transaction_attrs = %{@raw_transaction | "hash" => "0xab1"}
+      Fetcher.create_transaction(block, transaction_attrs)
+
+      transaction = Transaction |> Repo.get_by(hash: "0xab1")
+      block_transaction = BlockTransaction |> Repo.get_by(block_id: block.id, transaction_id: transaction.id)
+      assert block_transaction
+    end
+
+    test "that it updates the block transaction when it is called multiple times" do
+      first_block = insert(:block)
+      second_block = insert(:block)
+      transaction_attrs = %{@raw_transaction | "hash" => "0xsabzi"}
+      Fetcher.create_transaction(first_block, transaction_attrs)
+
+      transaction = Transaction |> Repo.get_by(hash: "0xsabzi")
+      block_transaction = BlockTransaction |> Repo.get_by(transaction_id: transaction.id)
+      assert block_transaction.block_id == first_block.id
+
+      Fetcher.create_transaction(second_block, transaction_attrs)
+      block_transaction = BlockTransaction |> Repo.get_by(transaction_id: transaction.id)
+      assert block_transaction.block_id == second_block.id
+      refute block_transaction.block_id == first_block.id
+    end
+
+    test "that it does not create a block transaction when there is no block" do
+      transaction_attrs = %{@raw_transaction | "hash" => "0xab1"}
+      Fetcher.create_transaction(nil, transaction_attrs)
+
+      transaction = Transaction |> Repo.get_by(hash: "0xab1")
+      block_transaction = BlockTransaction |> Repo.get_by(transaction_id: transaction.id)
+      refute block_transaction
+    end
+
     test "that it creates a 'to address'" do
       block = insert(:block)
       transaction_attrs = %{@raw_transaction | "to" => "0xSmoothiesRGr8"}
@@ -238,14 +276,14 @@ defmodule Explorer.FetcherTest do
     end
   end
 
-  describe "extract_transaction/2" do
+  describe "extract_transaction/1" do
     test "that it extracts the transaction" do
-      assert Fetcher.extract_transaction(%{id: 100}, @raw_transaction) == @processed_transaction
+      assert Fetcher.extract_transaction(@raw_transaction) == @processed_transaction
     end
 
     test "when the transaction value is zero it returns a decimal" do
       transaction = %{@raw_transaction | "value" => "0x0"}
-      assert Fetcher.extract_transaction(%{id: 100}, transaction).value == 0
+      assert Fetcher.extract_transaction(transaction).value == 0
     end
   end
 
diff --git a/test/explorer/forms/block_form_test.exs b/test/explorer/forms/block_form_test.exs
index 0d8e5ef8c6..be7de6bb7d 100644
--- a/test/explorer/forms/block_form_test.exs
+++ b/test/explorer/forms/block_form_test.exs
@@ -5,13 +5,13 @@ defmodule Explorer.BlockFormTest do
   describe "build/1" do
     test "that it has a number" do
       block = insert(:block, number: 311)
-      insert_list(2, :transaction, block: block)
+      insert_list(2, :transaction) |> list_with_block(block)
       assert BlockForm.build(block).number == 311
     end
 
     test "that it returns a count of transactions" do
       block = insert(:block, number: 311)
-      insert_list(2, :transaction, block: block)
+      insert_list(2, :transaction) |> list_with_block(block)
       assert BlockForm.build(block).transactions_count == 2
     end
 
diff --git a/test/explorer/forms/transaction_form_test.exs b/test/explorer/forms/transaction_form_test.exs
index 2d9b9d92dd..1ffe85c439 100644
--- a/test/explorer/forms/transaction_form_test.exs
+++ b/test/explorer/forms/transaction_form_test.exs
@@ -11,31 +11,55 @@ defmodule Explorer.TransactionFormTest do
         gas_used: 99523,
         timestamp: Timex.parse!(date, "%b-%d-%Y %H:%M:%S %p %Z", :strftime),
       })
-      transaction = insert(:transaction, block: block) |> with_addresses(%{to: "0xsleepypuppy", from: "0xilovefrogs"})
+      transaction =
+        insert(:transaction)
+        |> with_block(block)
+        |> with_addresses(%{to: "0xsleepypuppy", from: "0xilovefrogs"})
+
       form = TransactionForm.build(transaction)
       {:ok, %{form: form}}
     end
 
-    test "that it has a block number", %{form: form} do
+    test "that it has a block number when it has a block", %{form: form} do
       assert form.block_number == 1
     end
 
-    test "that it returns the block's age" do
+    test "shows a blank block number when the transaction is pending" do
+      transaction = insert(:transaction) |> with_addresses
+      assert TransactionForm.build(transaction).block_number == ""
+    end
+
+    test "that it returns the block's age when has a block" do
       block = insert(:block, %{
         number: 1,
         gas_used: 99523,
         timestamp: Timex.now |> Timex.shift(hours: -2),
       })
-      transaction = insert(:transaction, block: block) |> with_addresses(%{to: "0xsiskelnebert", from: "0xleonardmaltin"})
+      transaction = insert(:transaction) |> with_block(block) |> with_addresses(%{to: "0xsiskelnebert", from: "0xleonardmaltin"})
       assert TransactionForm.build(transaction).age == "2 hours ago"
     end
 
-    test "formats the block's timestamp", %{form: form} do
+    test "that it has an empty age when it is pending" do
+      transaction = insert(:transaction) |> with_addresses
+      assert TransactionForm.build(transaction).age == ""
+    end
+
+    test "formats the timestamp when it has a block", %{form: form} do
       assert form.formatted_timestamp == "Feb-02-2010 10:48:56 AM Etc/UTC"
     end
 
+    test "formats the timestamp when the transaction is pending" do
+      transaction = insert(:transaction) |> with_addresses
+      assert TransactionForm.build(transaction).formatted_timestamp == ""
+    end
+
     test "that it returns the cumulative gas used for validating the block", %{form: form} do
-      assert form.cumulative_gas_used == 99523
+      assert form.cumulative_gas_used == "99,523"
+    end
+
+    test "shows the cumulative gas used for a pending transaction" do
+      transaction = insert(:transaction) |> with_addresses
+      assert TransactionForm.build(transaction).cumulative_gas_used == ""
     end
 
     test "that it returns a 'to address'", %{form: form} do
@@ -49,13 +73,29 @@ defmodule Explorer.TransactionFormTest do
     test "that it returns confirmations", %{form: form} do
       assert form.confirmations == 23
     end
+
+    test "shows confirmations when the transaction is pending" do
+      transaction = insert(:transaction) |> with_addresses
+      assert TransactionForm.build(transaction).confirmations == 0
+    end
+  end
+
+  describe "cumulative_gas_used/1" do
+    test "when there is a block" do
+      block = insert(:block, %{gas_used: 1_000})
+      assert TransactionForm.cumulative_gas_used(block) == "1,000"
+    end
+
+    test "when there is not a block" do
+      assert TransactionForm.cumulative_gas_used(nil) == ""
+    end
   end
 
   describe "confirmations/1" do
     test "when there is only one block" do
       block = insert(:block, %{number: 1})
-      transaction = insert(:transaction, %{block: block})
-      assert TransactionForm.confirmations(transaction) == 0
+      insert(:transaction) |> with_block(block) |> with_addresses
+      assert TransactionForm.confirmations(block) == 0
     end
   end
 end
diff --git a/test/explorer/importers/transaction_importer_test.exs b/test/explorer/importers/transaction_importer_test.exs
new file mode 100644
index 0000000000..5e82ad90bf
--- /dev/null
+++ b/test/explorer/importers/transaction_importer_test.exs
@@ -0,0 +1,235 @@
+defmodule Explorer.TransactionImporterTest do
+  use Explorer.DataCase
+
+  alias Explorer.Address
+  alias Explorer.BlockTransaction
+  alias Explorer.FromAddress
+  alias Explorer.ToAddress
+  alias Explorer.Transaction
+  alias Explorer.TransactionImporter
+
+  @raw_transaction %{
+    "creates" => nil,
+    "hash" => "pepino",
+    "value" => "0xde0b6b3a7640000",
+    "from" => "0x34d0ef2c",
+    "gas" => "0x21000",
+    "gasPrice" => "0x10000",
+    "input" => "0x5c8eff12",
+    "nonce" => "0x31337",
+    "publicKey" => "0xb39af9c",
+    "r" => "0x9",
+    "s" => "0x10",
+    "to" => "0x7a33b7d",
+    "standardV" => "0x11",
+    "transactionIndex" => "0x12",
+    "v" => "0x13",
+  }
+
+  @processed_transaction %{
+    hash: "pepino",
+    value: 1000000000000000000,
+    gas: 135168,
+    gas_price: 65536,
+    input: "0x5c8eff12",
+    nonce: 201527,
+    public_key: "0xb39af9c",
+    r: "0x9",
+    s: "0x10",
+    standard_v: "0x11",
+    transaction_index: "0x12",
+    v: "0x13",
+  }
+
+  describe "import/1" do
+    test "imports and saves a transaction to the database" do
+      use_cassette "transaction_importer_import_saves_the_transaction" do
+        TransactionImporter.import("0xdc3a0dfd0bbffd5eabbe40fb13afbe35ac5f5c030bff148f3e50afe32974b291")
+        transaction = Transaction |> order_by(desc: :inserted_at) |> Repo.one
+
+        assert transaction.hash == "0xdc3a0dfd0bbffd5eabbe40fb13afbe35ac5f5c030bff148f3e50afe32974b291"
+      end
+    end
+
+    test "when it has previously been saved it updates the transaction" do
+      use_cassette "transaction_importer_updates_the_association" do
+        insert(:transaction, hash: "0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23", gas: 5)
+        TransactionImporter.import("0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23")
+        transaction = Transaction |> order_by(desc: :inserted_at) |> Repo.one
+
+        assert transaction.gas == Decimal.new(231855)
+      end
+    end
+
+    test "when it has a block hash that's saved in the database it saves the association" do
+      use_cassette "transaction_importer_saves_the_association" do
+        block = insert(:block, hash: "0xfce13392435a8e7dab44c07d482212efb9dc39a9bea1915a9ead308b55a617f9")
+        TransactionImporter.import("0x64d851139325479c3bb7ccc6e6ab4cde5bc927dce6810190fe5d770a4c1ac333")
+        transaction = Transaction |> Repo.get_by(hash: "0x64d851139325479c3bb7ccc6e6ab4cde5bc927dce6810190fe5d770a4c1ac333")
+        block_transaction = BlockTransaction |> Repo.get_by(transaction_id: transaction.id)
+
+        assert block_transaction.block_id == block.id
+      end
+    end
+
+    test "when there is no block it does not save a block transaction" do
+      use_cassette "transaction_importer_txn_without_block" do
+        TransactionImporter.import("0xc6aa189827c14880f012a65292f7add7b5310094f8773a3d85b66303039b9dcf")
+        transaction = Transaction |> Repo.get_by(hash: "0xc6aa189827c14880f012a65292f7add7b5310094f8773a3d85b66303039b9dcf")
+        block_transaction = BlockTransaction |> Repo.get_by(transaction_id: transaction.id)
+
+        refute block_transaction
+      end
+    end
+
+    test "it creates a from address" do
+      use_cassette "transaction_importer_creates_a_from_address" do
+        TransactionImporter.import("0xc445f5410912458c480d992dd93355ae3dad64d9f65db25a3cf43a9c609a2e0d")
+
+        transaction = Transaction |> Repo.get_by(hash: "0xc445f5410912458c480d992dd93355ae3dad64d9f65db25a3cf43a9c609a2e0d")
+        address = Address |> Repo.get_by(hash: "0xa5b4b372112ab8dbbb48c8d0edd89227e24ec785")
+        from_address = FromAddress |> Repo.get_by(transaction_id: transaction.id, address_id: address.id)
+
+        assert from_address
+      end
+    end
+
+    test "it creates a to address" do
+      use_cassette "transaction_importer_creates_a_to_address" do
+        TransactionImporter.import("0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c")
+
+        transaction = Transaction |> Repo.get_by(hash: "0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c")
+        address = Address |> Repo.get_by(hash: "0x24e5b8528fe83257d5fe3497ef616026713347f8")
+        to_address = ToAddress |> Repo.get_by(transaction_id: transaction.id, address_id: address.id)
+
+        assert(to_address)
+      end
+    end
+
+    test "it creates a to address using creates when to is nil" do
+      use_cassette "transaction_importer_creates_a_to_address_from_creates" do
+        TransactionImporter.import("0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c")
+
+        transaction = Transaction |> Repo.get_by(hash: "0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c")
+        address = Address |> Repo.get_by(hash: "0x24e5b8528fe83257d5fe3497ef616026713347f8")
+        to_address = ToAddress |> Repo.get_by(transaction_id: transaction.id, address_id: address.id)
+
+        assert(to_address)
+      end
+    end
+  end
+
+  describe "download_transaction/1" do
+    test "downloads a transaction" do
+      use_cassette "transaction_importer_download_transaction" do
+        raw_transaction = TransactionImporter.download_transaction("0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23")
+        assert(raw_transaction["from"] == "0xbe96ef1d056c97323e210fd0dd818aa027e57143")
+      end
+    end
+
+    test "when it has an invalid hash" do
+      use_cassette "transaction_importer_download_transaction_with_a_bad_hash" do
+        assert_raise MatchError, fn ->
+          TransactionImporter.download_transaction("0xdecafisbadzzzz")
+        end
+      end
+    end
+  end
+
+  describe "extract_attrs/1" do
+    test "returns a changeset-friendly list of transaction attributes" do
+      transaction_attrs = TransactionImporter.extract_attrs(@raw_transaction)
+      assert transaction_attrs == @processed_transaction
+    end
+  end
+
+  describe "create_block_transaction/2" do
+    test "inserts a block transaction" do
+      block = insert(:block)
+      transaction = insert(:transaction)
+      TransactionImporter.create_block_transaction(transaction, block.hash)
+      block_transaction =
+        BlockTransaction
+        |> Repo.get_by(transaction_id: transaction.id, block_id: block.id)
+
+      assert block_transaction
+    end
+
+    test "updates an already existing block transaction" do
+      block = insert(:block)
+      transaction = insert(:transaction)
+      the_seventies = Timex.parse!("1970-01-01T00:00:18-00:00", "{ISO:Extended}")
+      block_transaction = insert(:block_transaction, %{block_id: block.id, transaction_id: transaction.id, inserted_at: the_seventies, updated_at: the_seventies})
+      update_block = insert(:block)
+      TransactionImporter.create_block_transaction(transaction, update_block.hash)
+      updated_block_transaction =
+        BlockTransaction
+        |> Repo.get_by(transaction_id: transaction.id)
+
+      refute block_transaction.block_id == updated_block_transaction.block_id
+      refute block_transaction.updated_at == updated_block_transaction.updated_at
+    end
+  end
+
+  describe "create_from_address/2" do
+    test "that it creates a new address when one does not exist" do
+      transaction = insert(:transaction)
+      TransactionImporter.create_from_address(transaction, "0xbb8")
+      last_address = Address |> order_by(desc: :inserted_at) |> Repo.one
+
+      assert last_address.hash == "0xbb8"
+    end
+
+    test "that it joins transaction and from address" do
+      transaction = insert(:transaction)
+      TransactionImporter.create_from_address(transaction, "0xFreshPrince")
+      address = Address |> order_by(desc: :inserted_at) |> Repo.one
+      from_address = FromAddress |> order_by(desc: :inserted_at) |> Repo.one
+
+      assert from_address.transaction_id == transaction.id
+      assert from_address.address_id == address.id
+    end
+
+    test "when the address already exists it does not insert a new address" do
+      transaction = insert(:transaction)
+      insert(:address, hash: "0xbb8")
+      TransactionImporter.create_from_address(transaction, "0xbb8")
+
+      assert Address |> Repo.all |> length == 1
+    end
+  end
+
+  describe "create_to_address/2" do
+    test "that it creates a new address when one does not exist" do
+      transaction = insert(:transaction)
+      TransactionImporter.create_to_address(transaction, "0xFreshPrince")
+      last_address = Address |> order_by(desc: :inserted_at) |> Repo.one
+
+      assert last_address.hash == "0xfreshprince"
+    end
+
+    test "that it joins transaction and address" do
+      transaction = insert(:transaction)
+      TransactionImporter.create_to_address(transaction, "0xFreshPrince")
+      address = Address |> order_by(desc: :inserted_at) |> Repo.one
+      to_address = ToAddress |> order_by(desc: :inserted_at) |> Repo.one
+
+      assert to_address.transaction_id == transaction.id
+      assert to_address.address_id == address.id
+    end
+
+    test "when the address already exists it does not insert a new address" do
+      transaction = insert(:transaction)
+      insert(:address, hash: "bigmouthbillybass")
+      TransactionImporter.create_to_address(transaction, "bigmouthbillybass")
+
+      assert Address |> Repo.all |> length == 1
+    end
+  end
+
+  describe "decode_integer_field/1" do
+    test "returns the integer value of a hex value" do
+      assert(TransactionImporter.decode_integer_field("0x7f2fb") == 520955)
+    end
+  end
+end
diff --git a/test/explorer/transaction_test.exs b/test/explorer/transaction_test.exs
index 76028c4d0c..1249f4be07 100644
--- a/test/explorer/transaction_test.exs
+++ b/test/explorer/transaction_test.exs
@@ -5,17 +5,10 @@ defmodule Explorer.TransactionTest do
 
   describe "changeset/2" do
     test "with valid attributes" do
-      block = insert(:block)
-      changeset = Transaction.changeset(%Transaction{}, %{hash: "0x0", block_id: block.id, value: 1, gas: 21000, gas_price: 10000, input: "0x5c8eff12", nonce: "31337", public_key: "0xb39af9c", r: "0x9", s: "0x10", standard_v: "0x11", transaction_index: "0x12", v: "0x13"})
+      changeset = Transaction.changeset(%Transaction{}, %{hash: "0x0", value: 1, gas: 21000, gas_price: 10000, input: "0x5c8eff12", nonce: "31337", public_key: "0xb39af9c", r: "0x9", s: "0x10", standard_v: "0x11", transaction_index: "0x12", v: "0x13"})
       assert changeset.valid?
     end
 
-    test "with a block that does not exist in the database" do
-      {:error, changeset} = Transaction.changeset(%Transaction{}, %{hash: "0x0", block_id: 0, value: 1, gas: 21000, gas_price: 10000, input: "0x5c8eff12", nonce: "31337", public_key: "0xb39af9c", r: "0x9", s: "0x10", standard_v: "0x11", transaction_index: "0x12", v: "0x13"}) |> Repo.insert
-      refute changeset.valid?
-      assert [block_id: {"does not exist", []}] = changeset.errors
-    end
-
     test "with invalid attributes" do
       changeset = Transaction.changeset(%Transaction{}, %{racecar: "yellow ham"})
       refute changeset.valid?
diff --git a/test/explorer_web/controllers/chain_controller_test.exs b/test/explorer_web/controllers/chain_controller_test.exs
index 449b66684f..5679f26103 100644
--- a/test/explorer_web/controllers/chain_controller_test.exs
+++ b/test/explorer_web/controllers/chain_controller_test.exs
@@ -1,15 +1,6 @@
 defmodule ExplorerWeb.ChainControllerTest do
   use ExplorerWeb.ConnCase
 
-  def build_transaction(block \\ nil) do
-    block = block || insert(:block)
-    transaction = insert(:transaction, block: block)
-    to_address = insert(:address)
-    from_address = insert(:address)
-    insert(:to_address, transaction: transaction, address: to_address)
-    insert(:from_address, transaction: transaction, address: from_address)
-  end
-
   describe "GET index/2 without a locale" do
     test "redirects to the en locale", %{conn: conn} do
       conn = get conn, "/"
@@ -39,25 +30,12 @@ defmodule ExplorerWeb.ChainControllerTest do
 
     test "returns a transaction", %{conn: conn} do
       block = insert(:block, number: 33)
-      insert(:transaction, hash: "0xDECAFBAD", block: block) |> with_addresses(%{to: "0xsleepypuppy", from: "0xilovefrogs"})
+      insert(:transaction, hash: "0xDECAFBAD") |> with_block(block) |> with_addresses(%{to: "0xsleepypuppy", from: "0xilovefrogs"})
 
       conn = get conn, "/en"
 
       assert(List.first(conn.assigns.transactions).hash == "0xDECAFBAD")
-      assert(List.first(conn.assigns.transactions).block.number == 33)
-    end
-
-    test "returns only the five most recent transactions", %{conn: conn} do
-      block_mined_today = insert(:block, number: 2)
-      insert(:transaction, hash: "0xStuff", block: block_mined_today) |> with_addresses
-
-      block_mined_last_week = insert(:block, number: 1)
-      for _ <- 0..4, do: insert(:transaction, %{block: block_mined_last_week}) |> with_addresses
-
-      conn = get conn, "/en"
-
-      assert Enum.count(conn.assigns.transactions) == 5
-      assert List.first(conn.assigns.transactions).hash == "0xStuff"
+      assert(List.first(conn.assigns.transactions).block_number == 33)
     end
   end
 end
diff --git a/test/explorer_web/controllers/transaction_controller_test.exs b/test/explorer_web/controllers/transaction_controller_test.exs
index 5796fd5dca..2c75cbb9b4 100644
--- a/test/explorer_web/controllers/transaction_controller_test.exs
+++ b/test/explorer_web/controllers/transaction_controller_test.exs
@@ -1,19 +1,28 @@
 defmodule ExplorerWeb.TransactionControllerTest do
   use ExplorerWeb.ConnCase
 
+  describe "GET index/2" do
+    test "returns all transactions", %{conn: conn} do
+      transaction_ids = insert_list(4, :transaction) |> list_with_block |> Enum.map(fn (transaction) -> transaction.id end)
+      conn = get(conn, "/en/transactions")
+      assert conn.assigns.transactions |> Enum.map(fn (transaction) -> transaction.id end) == transaction_ids
+    end
+  end
+
   describe "GET show/3" do
-    test "returns a transaction", %{conn: conn} do
-      transaction = insert(:transaction, hash: "0x8") |> with_addresses
+    test "when there is an associated block, it returns a transaction with block data", %{conn: conn} do
+      block = insert(:block, %{number: 777})
+      transaction = insert(:transaction, hash: "0x8") |> with_block(block) |> with_addresses
       conn = get(conn, "/en/transactions/0x8")
       assert conn.assigns.transaction.id == transaction.id
+      assert conn.assigns.transaction.block_number == block.number
     end
-  end
 
-  describe "GET index/2" do
-    test "returns all blocks", %{conn: conn} do
-      transaction_ids = insert_list(4, :transaction) |> Enum.map(fn (transaction) -> transaction.id end)
-      conn = get(conn, "/en/transactions")
-      assert conn.assigns.transactions |> Enum.reverse |> Enum.map(fn (transaction) -> transaction.id end) == transaction_ids
+    test "returns a transaction without associated block data", %{conn: conn} do
+      transaction = insert(:transaction, hash: "0x8") |> with_addresses
+      conn = get(conn, "/en/transactions/0x8")
+      assert conn.assigns.transaction.id == transaction.id
+      assert conn.assigns.transaction.block_number == ""
     end
   end
 end
diff --git a/test/explorer_web/features/contributor_browsing_test.exs b/test/explorer_web/features/contributor_browsing_test.exs
index b3106ef7d2..b14284db9b 100644
--- a/test/explorer_web/features/contributor_browsing_test.exs
+++ b/test/explorer_web/features/contributor_browsing_test.exs
@@ -27,7 +27,7 @@ defmodule ExplorerWeb.UserListTest do
       gas_used: 1010101,
       gas_limit: 5030101
     })
-    for _ <- 0..2, do: insert(:transaction, %{block: fifth_block}) |> with_addresses
+    for _ <- 0..2, do: insert(:transaction) |> with_block(fifth_block) |> with_addresses
 
     session
     |> visit("/en")
@@ -56,7 +56,7 @@ defmodule ExplorerWeb.UserListTest do
       timestamp: Timex.now |> Timex.shift(hours: -2),
       gas_used: 123987,
     })
-    for _ <- 0..3, do: insert(:transaction, %{block: block}) |> with_addresses
+    for _ <- 0..3, do: insert(:transaction) |> with_block(block) |> with_addresses
 
     insert(:transaction, %{
       hash: "0xSk8",
@@ -65,8 +65,8 @@ defmodule ExplorerWeb.UserListTest do
       gas_price: 7890000000898912300045,
       input: "0x00012",
       nonce: 99045,
-      block: block,
     })
+    |> with_block(block)
     |> with_addresses(%{to: "0xabelincoln", from: "0xhowardtaft"})
 
     session
diff --git a/test/support/factories/block_transaction_factory.ex b/test/support/factories/block_transaction_factory.ex
new file mode 100644
index 0000000000..5d7ca72918
--- /dev/null
+++ b/test/support/factories/block_transaction_factory.ex
@@ -0,0 +1,9 @@
+defmodule Explorer.BlockTransactionFactory do
+  defmacro __using__(_opts) do
+    quote do
+      def block_transaction_factory do
+        %Explorer.BlockTransaction{}
+      end
+    end
+  end
+end
diff --git a/test/support/factories/transaction_factory.ex b/test/support/factories/transaction_factory.ex
index 5d63eedff1..c6b9b63a29 100644
--- a/test/support/factories/transaction_factory.ex
+++ b/test/support/factories/transaction_factory.ex
@@ -1,9 +1,12 @@
 defmodule Explorer.TransactionFactory do
   defmacro __using__(_opts) do
     quote do
+      alias Explorer.Address
+      alias Explorer.BlockTransaction
+      alias Explorer.Repo
+
       def transaction_factory do
         %Explorer.Transaction{
-          block: build(:block),
           hash: sequence("0x"),
           value: Enum.random(1..100_000),
           gas: Enum.random(21_000..100_000),
@@ -20,12 +23,24 @@ defmodule Explorer.TransactionFactory do
       end
 
       def with_addresses(transaction, %{to: to, from: from} \\ %{to: nil, from: nil}) do
-        to_address = if to, do: Explorer.Repo.get_by(Explorer.Address, %{hash: to}) || insert(:address, hash: to), else: insert(:address)
-        from_address = if from, do: Explorer.Repo.get_by(Explorer.Address, %{hash: from}) ||insert(:address, hash: from), else: insert(:address)
+        to_address = if to, do: Repo.get_by(Address, %{hash: to}) || insert(:address, hash: to), else: insert(:address)
+        from_address = if from, do: Repo.get_by(Address, %{hash: from}) ||insert(:address, hash: from), else: insert(:address)
         insert(:to_address, %{transaction_id: transaction.id, address_id: to_address.id})
         insert(:from_address, %{transaction_id: transaction.id, address_id: from_address.id})
         transaction
       end
+
+      def with_block(transaction, block \\ nil) do
+        block = block || insert(:block)
+        insert(:block_transaction, %{block_id: block.id, transaction_id: transaction.id})
+        # block_transaction_changeset = BlockTransaction.changeset(%BlockTransaction{}, %{block_id: block.id, transaction_id: transaction.id})
+        # Repo.insert(block_transaction_changeset)
+        transaction
+      end
+
+      def list_with_block(transactions, block \\ nil) do
+        Enum.map(transactions, fn(transaction) -> with_block(transaction, block) end)
+      end
     end
   end
 end
diff --git a/test/support/factory.ex b/test/support/factory.ex
index cd940603ea..cd062eeb7f 100644
--- a/test/support/factory.ex
+++ b/test/support/factory.ex
@@ -3,6 +3,7 @@ defmodule Explorer.Factory do
   use ExMachina.Ecto, repo: Explorer.Repo
   use Explorer.BlockFactory
   use Explorer.TransactionFactory
+  use Explorer.BlockTransactionFactory
   use Explorer.AddressFactory
   use Explorer.ToAddressFactory
   use Explorer.FromAddressFactory
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_from_address.json b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_from_address.json
new file mode 100644
index 0000000000..c3a0716495
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_from_address.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xc445f5410912458c480d992dd93355ae3dad64d9f65db25a3cf43a9c609a2e0d\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":2}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x30996f4f3e53a2b22766f535877b6840b08518027268b3385e46dbcd4ebe633d\",\"blockNumber\":\"0xc197a\",\"chainId\":null,\"condition\":null,\"creates\":\"0x60d5233e8a1798c7b7a8a1f9083ae31f770073d7\",\"from\":\"0xa5b4b372112ab8dbbb48c8d0edd89227e24ec785\",\"gas\":\"0x3782f\",\"gasPrice\":\"0x3b9aca00\",\"hash\":\"0xc445f5410912458c480d992dd93355ae3dad64d9f65db25a3cf43a9c609a2e0d\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0xa3cd\",\"publicKey\":\"0x3366f04816d42836375b8f28d5b0d341f8a47fb46a59a754ca924c7397d335a7b89a0f94f7c4d36f29ae6f6acdd3f2c0bdf12d9314799c407cf5b6bc4b370d4f\",\"r\":\"0xbfabcb7ca06c8b1f78cd4a2e70ae645bea6e5b512febbb93663d152541e26923\",\"raw\":\"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\",\"s\":\"0x35bb5cf4b0c14240954bc73254cd761a964f7f8ceb45a79fb2a7464fd16383a1\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x5\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":2}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:33:25 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d291677b65b9ebf5fbc09dec36364c58f1517888004; expires=Wed, 06-Feb-19 03:33:24 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b0c3ebff39607-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address.json b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address.json
new file mode 100644
index 0000000000..1c42192fcd
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":5}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x30996f4f3e53a2b22766f535877b6840b08518027268b3385e46dbcd4ebe633d\",\"blockNumber\":\"0xc197a\",\"chainId\":null,\"condition\":null,\"creates\":null,\"from\":\"0xb2867180771b196518651c174c9240d5e8bd0ecd\",\"gas\":\"0x3755b\",\"gasPrice\":\"0x3b9aca00\",\"hash\":\"0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0xa4e9\",\"publicKey\":\"0xbf0cf158b32b838553af2c4f9e3393e6fb4cb0a97a7e4025d3fe3a552e3cfa720779da708ec4a5a89c9a6ca7f16d1b49605a9b8bdb28bd2a45818418743d153c\",\"r\":\"0xb40a4357f5b6316df0bd0f054a94c09b443fc16ebed9c9c95932c460776dc7bf\",\"raw\":\"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\",\"s\":\"0x1672c0bcc52ae7348a226ab8232118f6a74197c99ec715d7186c16b0837766bf\",\"standardV\":\"0x0\",\"to\":\"0x24e5b8528fe83257d5fe3497ef616026713347f8\",\"transactionIndex\":\"0x2\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":5}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:33:26 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d9137691f355994dc6bb3a8c2e4033e621517888006; expires=Wed, 06-Feb-19 03:33:26 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b0c46aac89607-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address_from_creates.json b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address_from_creates.json
new file mode 100644
index 0000000000..11db281292
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_creates_a_to_address_from_creates.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":5}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x30996f4f3e53a2b22766f535877b6840b08518027268b3385e46dbcd4ebe633d\",\"blockNumber\":\"0xc197a\",\"chainId\":null,\"condition\":null,\"creates\":\"0x24e5b8528fe83257d5fe3497ef616026713347f8\",\"from\":\"0xb2867180771b196518651c174c9240d5e8bd0ecd\",\"gas\":\"0x3755b\",\"gasPrice\":\"0x3b9aca00\",\"hash\":\"0xdc533d4227734a7cacd75a069e8dc57ac571b865ed97bae5ea4cb74b54145f4c\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0xa4e9\",\"publicKey\":\"0xbf0cf158b32b838553af2c4f9e3393e6fb4cb0a97a7e4025d3fe3a552e3cfa720779da708ec4a5a89c9a6ca7f16d1b49605a9b8bdb28bd2a45818418743d153c\",\"r\":\"0xb40a4357f5b6316df0bd0f054a94c09b443fc16ebed9c9c95932c460776dc7bf\",\"raw\":\"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\",\"s\":\"0x1672c0bcc52ae7348a226ab8232118f6a74197c99ec715d7186c16b0837766bf\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x2\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":5}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:33:26 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d9137691f355994dc6bb3a8c2e4033e621517888006; expires=Wed, 06-Feb-19 03:33:26 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b0c46aac89607-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction.json b/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction.json
new file mode 100644
index 0000000000..ad7bea2f74
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":0}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x8663df28453934be1e0fc59995d8b5295e83e4db689ade8b0244525f8f7c118a\",\"blockNumber\":\"0xc10ab\",\"chainId\":null,\"condition\":null,\"creates\":\"0xac4ff5b5c29338d0046e40f22dbec4d9ef32ed11\",\"from\":\"0xbe96ef1d056c97323e210fd0dd818aa027e57143\",\"gas\":\"0x389af\",\"gasPrice\":\"0x77359400\",\"hash\":\"0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0x9601\",\"publicKey\":\"0x565e1e48534a6764a50baead6ec60f573d3294cab28b766c928fd6eb8b9c89268bf3452b57bbe8d0c699ac8ed9227344ee72e42f41577fb51777d66520ccdc9c\",\"r\":\"0x81c2771372d8e71d4569bbb0a830f5bb6cdba285178f68e0917e65a682a1cd46\",\"raw\":\"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\",\"s\":\"0xa1718c45816d32ddbe5efcbe2e41cffe537bc703d80b9632b75ee5a9d445dcd\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x11\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":0}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:37:56 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d5ef068dc553a6d30310731eac55ffcf11517888276; expires=Wed, 06-Feb-19 03:37:56 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b12de6e6992b8-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction_with_a_bad_hash.json b/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction_with_a_bad_hash.json
new file mode 100644
index 0000000000..22a21f15bd
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_download_transaction_with_a_bad_hash.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xdecafisbadzzzz\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":0}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"error\":{\"code\":-32602,\"message\":\"Invalid params: invalid length 14, expected a 0x-prefixed, padded, hex-encoded hash with length 64.\"},\"id\":0}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:36:54 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d53dce2a5d0bec9953b3957e3b0384b2d1517888214; expires=Wed, 06-Feb-19 03:36:54 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b115c59f89342-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_import_saves_the_transaction.json b/test/support/fixture/vcr_cassettes/transaction_importer_import_saves_the_transaction.json
new file mode 100644
index 0000000000..d57e8ebb95
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_import_saves_the_transaction.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xdc3a0dfd0bbffd5eabbe40fb13afbe35ac5f5c030bff148f3e50afe32974b291\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":5}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x8663df28453934be1e0fc59995d8b5295e83e4db689ade8b0244525f8f7c118a\",\"blockNumber\":\"0xc10ab\",\"chainId\":null,\"condition\":null,\"creates\":\"0x353fe3ffbf77edef7f9c352c47965a38c07e837c\",\"from\":\"0x8a35723e64a47764b9acfec5e647b39a4e5d635c\",\"gas\":\"0x381ae\",\"gasPrice\":\"0x77359400\",\"hash\":\"0xdc3a0dfd0bbffd5eabbe40fb13afbe35ac5f5c030bff148f3e50afe32974b291\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0x9b62\",\"publicKey\":\"0xbd2c35eb20bfab52e22b8b9fbcfc3f5f8a927f7d6b800960026921929eeb0976a304639c785ce1a509900922d6ef8fd1222b7b48cdcb38c97b49c0f37c59c0f7\",\"r\":\"0x380bb4c084a241ffbf69ad1f52cd8689aeb986db451bf85d715b4d9afdd89b0d\",\"raw\":\"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\",\"s\":\"0x1b1b1cca94b24cabba08bcc5d4fb99f2fdcb4f1f76d80091c061771040af3432\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x0\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":5}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:41:44 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=db1f077d751ae0ba2508cbbe43d8047de1517888504; expires=Wed, 06-Feb-19 03:41:44 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b1871fa3d6d42-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_saves_the_association.json b/test/support/fixture/vcr_cassettes/transaction_importer_saves_the_association.json
new file mode 100644
index 0000000000..d8dddce89a
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_saves_the_association.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0x64d851139325479c3bb7ccc6e6ab4cde5bc927dce6810190fe5d770a4c1ac333\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":1}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0xfce13392435a8e7dab44c07d482212efb9dc39a9bea1915a9ead308b55a617f9\",\"blockNumber\":\"0xc10d9\",\"chainId\":\"0x4d\",\"condition\":null,\"creates\":null,\"from\":\"0x82e4e61e7f5139ff0a4157a5bc687ef42294c248\",\"gas\":\"0x5208\",\"gasPrice\":\"0x3b9aca00\",\"hash\":\"0x64d851139325479c3bb7ccc6e6ab4cde5bc927dce6810190fe5d770a4c1ac333\",\"input\":\"0x\",\"nonce\":\"0x23c\",\"publicKey\":\"0x750f765a7790aa361dde0ff1d4c9dadd0e1c62fe79dee9c3d6b953abe99ce79755568215a2524d0efe0d5a48d8082e86f317434b62964b0c2e3e3446ebe08099\",\"r\":\"0xb5c079b9b6b131c1f726dc90f829a9dedf7e4d72a787ff90224c630104768afb\",\"raw\":\"0xf86f82023c843b9aca008252089496604b744e9c5a72680d33e7faf9629e19c97eaa8902a18aeae7e44a70008081bea0b5c079b9b6b131c1f726dc90f829a9dedf7e4d72a787ff90224c630104768afba0609d0d6ab60888059000f1c8b3d75c7193462c3dac83f91cf378ad5c5242ec1b\",\"s\":\"0x609d0d6ab60888059000f1c8b3d75c7193462c3dac83f91cf378ad5c5242ec1b\",\"standardV\":\"0x1\",\"to\":\"0x96604b744e9c5a72680d33e7faf9629e19c97eaa\",\"transactionIndex\":\"0x9\",\"v\":\"0xbe\",\"value\":\"0x2a18aeae7e44a7000\"},\"id\":1}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:41:43 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=df89a2810de64c37a8a65bfffe6c4a1b41517888503; expires=Wed, 06-Feb-19 03:41:43 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b18694f146d42-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_txn_without_block.json b/test/support/fixture/vcr_cassettes/transaction_importer_txn_without_block.json
new file mode 100644
index 0000000000..3b88b1f475
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_txn_without_block.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0xc6aa189827c14880f012a65292f7add7b5310094f8773a3d85b66303039b9dcf\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":0}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"null\",\"blockNumber\":\"0xc13ac\",\"chainId\":null,\"condition\":null,\"creates\":\"0xee0ea6a585b7002840cb1aab374f9ea159772196\",\"from\":\"0x23359b2330a82cca0618ffbc84cde3b760e69443\",\"gas\":\"0x3683b\",\"gasPrice\":\"0x12a05f200\",\"hash\":\"0xc6aa189827c14880f012a65292f7add7b5310094f8773a3d85b66303039b9dcf\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0x963d\",\"publicKey\":\"0x86189842eca4e1195fe49edf3c14438e3fcc1f8d9672f7cc943eee2b5f3143058dc79769a0d5b279a26169a37274eb05d5fe9e303dac3f25873a45cc13cc08a5\",\"r\":\"0x4a6668eea531cfefafc7299d83dbc975752d068b4afcff77a17de9faa6a92dd7\",\"raw\":\"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\",\"s\":\"0xcdf765f678470f08279278653caa4cbf55c42c570b996f2fb037b815111d36\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x5\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":0}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 01:25:56 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d01ad5566804036879ac82a9f9bd4bf1f1517880356; expires=Wed, 06-Feb-19 01:25:56 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8a5183b8bf9607-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
diff --git a/test/support/fixture/vcr_cassettes/transaction_importer_updates_the_association.json b/test/support/fixture/vcr_cassettes/transaction_importer_updates_the_association.json
new file mode 100644
index 0000000000..07b65010a3
--- /dev/null
+++ b/test/support/fixture/vcr_cassettes/transaction_importer_updates_the_association.json
@@ -0,0 +1,30 @@
+[
+  {
+    "request": {
+      "body": "{\"params\":[\"0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23\"],\"method\":\"eth_getTransactionByHash\",\"jsonrpc\":\"2.0\",\"id\":0}",
+      "headers": {
+        "Content-Type": "application/json"
+      },
+      "method": "post",
+      "options": [],
+      "request_body": "",
+      "url": "https://sokol.poa.network:443"
+    },
+    "response": {
+      "binary": false,
+      "body": "{\"jsonrpc\":\"2.0\",\"result\":{\"blockHash\":\"0x8663df28453934be1e0fc59995d8b5295e83e4db689ade8b0244525f8f7c118a\",\"blockNumber\":\"0xc10ab\",\"chainId\":null,\"condition\":null,\"creates\":\"0xac4ff5b5c29338d0046e40f22dbec4d9ef32ed11\",\"from\":\"0xbe96ef1d056c97323e210fd0dd818aa027e57143\",\"gas\":\"0x389af\",\"gasPrice\":\"0x77359400\",\"hash\":\"0x170baac4eca26076953370dd603c68eab340c0135b19b585010d3158a5dbbf23\",\"input\":\"0x6060604052341561000f57600080fd5b7fb94ae47ec9f4248692e2ecf9740b67ab493f3dcc8452bedc7d9cd911c28d1ca5426040518082815260200191505060405180910390a1609e806100546000396000f300606060405260043610603f576000357c0100000000000000000000000000000000000000000000000000000000900463ffffffff168063557ed1ba146044575b600080fd5b3415604e57600080fd5b6054606a565b6040518082815260200191505060405180910390f35b6000429050905600a165627a7a7230582053883c0c39da080adc15a91094921659c200b3bb60aed9e49b79b0274da3f4010029\",\"nonce\":\"0x9601\",\"publicKey\":\"0x565e1e48534a6764a50baead6ec60f573d3294cab28b766c928fd6eb8b9c89268bf3452b57bbe8d0c699ac8ed9227344ee72e42f41577fb51777d66520ccdc9c\",\"r\":\"0x81c2771372d8e71d4569bbb0a830f5bb6cdba285178f68e0917e65a682a1cd46\",\"raw\":\"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\",\"s\":\"0xa1718c45816d32ddbe5efcbe2e41cffe537bc703d80b9632b75ee5a9d445dcd\",\"standardV\":\"0x0\",\"to\":null,\"transactionIndex\":\"0x11\",\"v\":\"0x1b\",\"value\":\"0x0\"},\"id\":0}\n",
+      "headers": {
+        "Date": "Tue, 06 Feb 2018 03:41:42 GMT",
+        "Content-Type": "application/json",
+        "Transfer-Encoding": "chunked",
+        "Connection": "keep-alive",
+        "Set-Cookie": "__cfduid=d9d4f6391b8873087c5766cadd87dbbf51517888502; expires=Wed, 06-Feb-19 03:41:42 GMT; path=/; domain=.poa.network; HttpOnly; Secure",
+        "Expect-CT": "max-age=604800, report-uri=\"https://report-uri.cloudflare.com/cdn-cgi/beacon/expect-ct\"",
+        "Server": "cloudflare",
+        "CF-RAY": "3e8b1862cd286d42-SJC"
+      },
+      "status_code": 200,
+      "type": "ok"
+    }
+  }
+]
\ No newline at end of file