Get account transactions using Substrate API

Question

I think Substrate API is really messy and difficult to understand. How could I get all the transactions for an account? And getting account by address is also counterintuitive: you need to make a query with some module and function but I didn't find any list of available functions and modules. So I would appreciate if you could suggest me clear and full documentation.

P.S. I'm using Python for development, so therefor I use py-substrate-interface and code for getting account by address looks like:

result = substrate.query(
    module='System',
    storage_function='Account',
    params=['F4xQKRUagnSGjFqafyhajLs94e7Vvzvr8ebwYJceKpr8R7T']
)

Answer 1

Substrate indeed covers quite many use-cases, not just transferring coins from one account to another, and some of that complexity will leak through any API, even if there are specialized ones in the making for a few typical use-cases.

The part of the system you care about in your question is the Balances pallet that has a pretty comprehensive Rust documentation. This pallet does not maintain a list of extrinsics that changed the balance of the account, but some nodes in the network index Transfer events while executing blocks and store these events in a database. You can also build such a node on your own, this answer to another question might help you in the right direction.

Answer 2

No blockchain is designed to be able to easily get all transactions for an account, as this is a waste of storage for a normal syncing chain.

Substrate provide the ability to run an Archive node, which stores all state for all blocks since the genesis, but querying for all transactions for a user would require searching all blocks, which can be slow for sure.

The correct solution for such a query is to use a blockchain indexer as described here: Is there a good indexer for substrate chains (like the graph)?

Or a block explorer like:

• https://polkascan.io/
• https://www.subscan.io/