Include support to enumerate verified contracts

[acuarica]

It would be a good addition to add the possibility to enumerate verified contracts, both sorted and paginated. Currently the closest endpoint to do that is /files/contracts/{chain}. However this endpoint fetches all contracts, which is of no use without filtering, sorting and pagination.

After talking to @svienot, in order to support this feature we would need to add some sort of database that can be queried against.

Some verification specific information to include would be verification date/time and language. On-chain data would include TX creation.

As a reference, a couple of explorers support this feature, e.g.,

• Ethereum https://etherscan.io/contractsVerified
• Avalanche https://avascan.info/blockchain/all/verified-contracts
• Avalanche https://snowtrace.io/contractsverified

[Nana-EC]

@acuarica to update with dependency status

[acuarica]

Currently the verified contracts are stored in the filesystem. This does not allow us for easy enumeration and querying of verified smart contracts.

The Sourcify team is working to replace the filesystem storage with a DB of verified contracts. Once the DB implementation is releases and stable, we can include it in our distribution and make queries against verified contracts.