From fb6e11e217e34722b38c29d0e9d349f7ff587c0b Mon Sep 17 00:00:00 2001
From: Cutsin <cutsin@gmail.com>
Date: Thu, 16 Feb 2023 20:06:02 +0800
Subject: [PATCH] Fix an error occurred when decoding base64 encoded json

---
 CHANGELOG.md                                   |  1 +
 .../token/instance_metadata_retriever.ex       |  4 ++--
 .../token/instance_metadata_retriever_test.exs | 18 ++++++++++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cd9da06c3d..8a3fef2c90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@
 ### Fixes
 
 - [#6912](https://github.com/blockscout/blockscout/pull/6912) - Docker compose fix exposed ports
+- [#6833](https://github.com/blockscout/blockscout/pull/6833) - Fix an error occurred when decoding base64 encoded json
 - [#6891](https://github.com/blockscout/blockscout/pull/6891) - Fix read contract for geth
 - [#6889](https://github.com/blockscout/blockscout/pull/6889) - Fix Internal Server Error on tx input decoding
 - [#6893](https://github.com/blockscout/blockscout/pull/6893) - Fix token type definition for multiple interface tokens
diff --git a/apps/explorer/lib/explorer/token/instance_metadata_retriever.ex b/apps/explorer/lib/explorer/token/instance_metadata_retriever.ex
index c90174c50f..ab2eb026e0 100644
--- a/apps/explorer/lib/explorer/token/instance_metadata_retriever.ex
+++ b/apps/explorer/lib/explorer/token/instance_metadata_retriever.ex
@@ -169,7 +169,7 @@ defmodule Explorer.Token.InstanceMetadataRetriever do
   end
 
   def fetch_json(%{@token_uri => {:ok, ["data:application/json;base64," <> base64_encoded_json]}}, hex_token_id) do
-    case Base.url_decode64(base64_encoded_json) do
+    case Base.decode64(base64_encoded_json) do
       {:ok, base64_decoded} ->
         fetch_json(%{@token_uri => {:ok, [base64_decoded]}}, hex_token_id)
 
@@ -190,7 +190,7 @@ defmodule Explorer.Token.InstanceMetadataRetriever do
   end
 
   def fetch_json(%{@uri => {:ok, ["data:application/json;base64," <> base64_encoded_json]}}, hex_token_id) do
-    case Base.url_decode64(base64_encoded_json) do
+    case Base.decode64(base64_encoded_json) do
       {:ok, base64_decoded} ->
         fetch_json(%{@uri => {:ok, [base64_decoded]}}, hex_token_id)
 
diff --git a/apps/explorer/test/explorer/token/instance_metadata_retriever_test.exs b/apps/explorer/test/explorer/token/instance_metadata_retriever_test.exs
index 9ab3971f08..9734c9570e 100644
--- a/apps/explorer/test/explorer/token/instance_metadata_retriever_test.exs
+++ b/apps/explorer/test/explorer/token/instance_metadata_retriever_test.exs
@@ -307,5 +307,23 @@ defmodule Explorer.Token.InstanceMetadataRetrieverTest do
                   }
                 }}
     end
+
+    test "decodes base64 encoded json file (with unicode string) in tokenURI" do
+      data = %{
+        "c87b56dd" =>
+          {:ok,
+           [
+             "data:application/json;base64,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"
+           ]}
+      }
+
+      assert InstanceMetadataRetriever.fetch_json(data) ==
+               {:ok,
+                %{
+                  metadata: %{
+                    "description" => "Punk Domains digital identity ï. Visit https://punk.domains/"
+                  }
+                }}
+    end
   end
 end