jaggedsoft / account-scanner

A simple example of a multi-call contract for token scanning.

Account Scanner

Note: Experimental work-in-progress

This is a simple example of how to create a multi-call contract to aggregate data into fewer JSON-RPC calls.

This example currently uses:

• two getLogs to fetch all tokens from addr and to addr
• one call to our multicall contract, getInfos for metadata and state

From this, it returns:

• Every ERC-20 token transfer history event sent to or received from addr
• Every ERC-721 token transfer history event sent to or received from addr
• The ERC-20 balance for addr of each token
• The list of owned ERC-721 tokens for addr
• The number of decimals for ERC-20 token
• The name and symbol for each ERC-20 and ERC-721 token
• The block number this is all consistent to (which can be passed in to future calls; @TODO)

Notes

Since there are external calls to unknown token contracts, additional sanitization is performed on each call and the gas limit is restricted to prevent malicious tokens from crashing us.

To do

• Slice up requests and responses in the event the history or list of tokens is too long
• Allow a fromBlock to reduce the cost and effort of backends to maintain an already updated list
• The token URIs returned seem to follow various formats, so some effort is required to normalize the actual dereferenced URL to use for token images
• Wrap this up in a nicer library to make it easy for everyone to use

License

MIT License