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SNS Index Canister

The index canister fetches transactions from the ledger canister and indexes them by Account. It allows to query the transactions of an Account in descending order from the ledger chain, and the list of Account that belongs to a Principal. An index canister is always deployed as part of the SNS canisters.

This canister is useful for applications that want to show the transactions of a specific account.

Regularly (at each heartbeat), the index canister will query the transactions from the ledger canister and then build the index of known transaction per account.

Initialisation​

This sections explains how to deploy an index canister in isolation. You can also deploy a full SNS, which will be deployed with an SNS index canister.

The index canister initialisation requires the principal of the ICRC-1 ledger canister to index:

type InitArgs = record {
ledger_id : principal;
};

Example with dfx:

dfx deploy icrc1-index --argument "(record {
      ledger_id = principal \"rrkah-fqaaa-aaaaa-aaaaq-cai\"
    }
)"

Usage​

The provided methods are:

get_account_transactions : (GetAccountTransactionsArgs) -> (GetTransactionsResult);

Return the transactions for a given account. Transactions are returned in descending id order. Optionally, the user can specify a starting transaction id allowing to only query for transactions before this id. If no start is specified, the last transaction is used.

ledger_id : () -> (principal) query;

Return the principal of the ledger canister being indexed.

list_subaccounts : (ListSubaccountsArgs) -> (vec SubAccount) query;

List all indexed subaccounts for a principal.

Candid reference file​

Please check the Candid file of the index canister for the interface details.