VIP: Add support for loading interfaces via IPFS

[fubuloubu]

Simple Summary

Allow loading interfaces (either JSON ABI or EthPM v3 contract types) from IPFS

Motivation

Vyper has limited support for importing custom interfaces from external files, which is a helpful method of code de-duplication. However, this feature is hard to use, especially with code verification utilities such as Etherscan. Since IPFS is a widely-supported data sharing protocol in the Web3 ecosystem, we can leverage this fact to make development and verification much easier with external interfaces, leveraging hash-based identifiers to lock the imported code version and make compilation more dependable.

Specification

# JSON ABI e.g. `{ "abi": [ ... ] }`
import ipfs.Qm....A21d  as MyInterface  # must rename from CID

# EthPM Package Manifest (v3)
from ipfs.Qm....b34C import ContractType # can rename `ContractType as MyInterface`

Errors

• CID is not valid
• file specified by the CID cannot be found, or it fails to load after 30 seconds
• file loaded by the CID is not in one of the accepted formats (JSON ABI or EthPM v3 Package Manifest)
• JSON ABI is used, and the import is not renamed from the CID
• EthPM v3 Manifest is used, and ContractType is not one of the available contract types (containing a valid ABI)

Backwards Compatibility

This feature is backwards compatible

Dependencies

No dependencies

References

https://web3py.readthedocs.io/en/stable/ethpm.html

Copyright

Copyright and related rights waived via CC0

[fubuloubu]

Idea: instead of introducing the full IPFS client, have it just reference the cache folder from IPFS

[fubuloubu]

Using https://github.com/ApeWorX/ethpm-types might be way nicer!