alpha-wallet-android/util

TokenScript utilities

This (in-development) module provides command-line utilities for using TokenScript.

Currently, util has a demonstration to extract token data from a smart contract. It shows, for example, that TokenScript can be used as a supernode's data extraction layer. (A supernode is an Ethereum node that not only service clients enquire about blockchain data, but also enquires about token data.)

TokenScript can serve as a data abstraction layer, help a supernode to catch and index token data.

+--------------------+                           +--------------------+
| Blockchain data    |    +-----------------+    | Token Data         |
| · Transactions     | -> | Data Abstraction| -> | · Token IDs        |
| · Addresses        |    | (TokenScript)   |    | · Token Balances   |
| · Smart Contracts  |    +-----------------+    | · Token Attributes |
+--------------------+                           +--------------------+

Run a demonstration

To see how TokenScript extracts TokenData, first, download a tokenscript

$ curl -O http://repo.tokenscript.org/aw.app/2019/10/fifa.tsml

Then run gradle run in this module. You should see something like this:

$ gradle run

> Task :util:run
Holding Token Name: FIFA
Token Addresses: 
0xa66a3f08068174e8f005112a8b2c7a507a822335 ChainID: 1

Attributes:
-----------
Contract: 0xa66a3f08068174e8f005112a8b2c7a507a822335 ChainID: 1 Type: erc875
Geth/v1.9.9-omnibus-e320ae4c-20191206/linux-amd64/go1.13.4
Contract Name (Eth): FIFA WC2018(SHANKAI)

venue: "Luzhniki Stadium",
numero: "1",
locality: "Moscow",
match: "1",
time: { generalizedTime: "20180614180000+0300", date: new Date("2018-06-14T06:00:00+0300") },
category: "Match Club",
countryA: "RUS",
countryB: "KSA",

Which returned the token data of a token that represents a FIFA ticket. Observe that

countryA: "RUS",
countryB: "KSA",

Means that this token is for the match Russia vs Saudi Arabia.

Note that this is unlike Token Registries where all ICO projects list their tokens. The token here represents a specific ticket (it has a unique-ID which is 1) and has to be indexed for search by a supernode's database. If someone wishes to purchase a ticket of Russia vs Saudi Arabia, this ticket can then, in turn, be retrieved.

Each token attribute may be sourced from several origins.

• TokenID: a part of tokenID akin to ERC721 is used for the value of some attributes.
• The return value of a call to a smart contract (must be a view call).
• An event (Ethereum blockchain event)
• A constant
• A value from an attestation (if the supernode is in possession of such an attestation)
• A trusted 3rd party source (e.g. an HTTPS API's return value)

For example, a FIFA ticket token might have the match encoded in the TokenID. However, some tkoen attributes, like askPrice, might be defined in an attestation signed by the seller; another attribute, like expiry, might originate from the return value of the smart contract's view function getExpiry since the event organiser can define and change the date of the event, and lastSoldPrice might originate from an Ethereum blockchain event.