Session keys with meta-transactions

Meta-transactions (outside execution) allows external contracts to execute transactions from outside an account contract, thereby opening up new use-cases such as sponsored transactions, deploying an account on behalf of a user, transaction scheduling (limit orders) etc.

Get outside execution call

To retrieve the data needed to perform an execute_from_outside:

• sessionRequest , accountSessionSignature and the account address are needed

• import ArgentSessionService and SessionDappService from @argent/x-sessions .

  • The first is required to instantiate SessionDappService

  • SessionDappService expose the method getOutsideExecutionCall

const transferCallData = erc20Contract.populate("transfer", {
  recipient: address,
  amount: parseInputAmountToUint256(amount),
});

const beService = new ArgentSessionService(
  dappKey.publicKey,
  accountSessionSignature,
  ARGENT_SESSION_SERVICE_BASE_URL // Do not share publicly
);

const sessionDappService = new SessionDappService(beService, await provider.getChainId(), dappKey);

const { contractAddress, entrypoint, calldata } = await sessionDappService.getOutsideExecutionCall(
  sessionRequest,
  stark.formatSignature(accountSessionSignature),
  false, // keep false, will be a feat for caching
  [transferCallData],
  address,
  chainId,
  shortString.encodeShortString("ANY_CALLER"), // Optional: default value ANY_CALLER
  execute_after, // Optional: timestamp in seconds - this is the lower value in the range. Default value: 5 mins before Date.now()
  execute_before, // Optional: timestamp in seconds - this is the upper value in the range. Default value: 20 mins after Date.now()
  nonce: BigNumberish, // Optional: nonce, default value is a random nonce
);

The result can be executed by another account or at backend level

Get outside execution TypedData

To retrieve the TypedData for an outside execution along with the compiled signature (session + guardian).

• sessionRequest , accountSessionSignature and the account address are needed

• import ArgentSessionService and SessionDappService from @argent/x-sessions .

  • The first is required to instantiate SessionDappService

  • SessionDappService expose the method getOutsideExecutionTypedData

    • it takes the same parameters as getOutsideExecutionCall

const transferCallData = erc20Contract.populate("transfer", {
  recipient: address,
  amount: parseInputAmountToUint256(amount),
});

const beService = new ArgentSessionService(
  dappKey.publicKey,
  accountSessionSignature,
  ARGENT_SESSION_SERVICE_BASE_URL
);

const { signature, outsideExecutionTypedData } = await sessionDappService.getOutsideExecutionTypedData(
  sessionRequest,
  stark.formatSignature(accountSessionSignature),
  false,
  [transferCallData],
  address
);

Session backend service

If needed, @argent/x-sessions provides the sessionBackenService to directly call the argent backend for signing a session or signing a session for en execution from outside

sign session

public async signTxAndSession(
  calls: Call[],
  transactionsDetail: InvocationsSignerDetails,
  sessionTypedData: TypedData,
  sessionSignature: bigint[],
  cacheAuthorisation: boolean,
): Promise<{
	publicKey: string
	r: bigint
	s: bigint
}

sign session for an execution from outside (EFO)

public async signSessionEFO(
  sessionTokenToSign: MySession,
  accountAddress: string,
  currentTypedData: TypedData,
  sessionSignature: bigint[],
  cacheAuthorisation: boolean,
  chainId: StarknetChainId,
): Promise<{
	publicKey: string
	r: bigint
	s: bigint
}