sep-0007-urischeme.md

SEP-0007 - URI Scheme to facilitate delegated signing

URI Scheme to facilitate delegated signing is described in SEP-0007. This Stellar Ecosystem Proposal introduces a URI Scheme that can be used to generate a URI that will serve as a request to sign a transaction. The URI (request) will typically be signed by the user’s trusted wallet where she stores her secret key(s).

This SDK provides utility features to facilitate the implementation of SEP-0007 in a Flutter Wallet. These features are implemented in the URIScheme class and are described below.

Generate a transaction uri

String generateSignTransactionURI(String transactionEnvelopeXdrBase64,
      {String? replace,
      String? callback,
      String? publicKey,
      String? chain,
      String? message,
      String? networkPassphrase,
      String? originDomain,
      String? signature})

This function can be used to generate a URIScheme compliant URL to serve as a request to sign a transaction.

Example:

AccountResponse sourceAccount = await sdk.accounts.account(accountId);
SetOptionsOperationBuilder setOp = SetOptionsOperationBuilder();
setOp.setSourceAccount(accountId);
setOp.setHomeDomain("www.soneso.com");

Transaction transaction =
    TransactionBuilder(sourceAccount).addOperation(setOp.build()).build();

URIScheme uriScheme = URIScheme();
String url =
    uriScheme.generateSignTransactionURI(transaction.toEnvelopeXdrBase64());

print(url);

// web+stellar:tx?xdr=AAAAAgAAAADNQvJCahsRijRFXMHgyGXdar95Wya9ONBFmFGORBZkWAAAAGQABwWpAAAAKwAAAAAAAAAAAAAAAQAAAAEAAAAAzULyQmobEYo0RVzB4Mhl3Wq%2FeVsmvTjQRZhRjkQWZFgAAAAFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAAOd3d3LnNvbmVzby5jb20AAAAAAAAAAAAAAAAAAA%3D%3D

Generate a pay operation uri

String generatePayOperationURI(String destinationAccountId,
      {String? amount,
      String? assetCode,
      String? assetIssuer,
      String? memo,
      String? memoType,
      String? callback,
      String? message,
      String? networkPassphrase,
      String? originDomain,
      String? signature})

This function can be used to generate a URIScheme compliant URL to serve as a request to pay a specific address with a specific asset, regardless of the source asset used by the payer.

Example:

URIScheme uriScheme = URIScheme();
String url = uriScheme.generatePayOperationURI(accountId,
    amount: "123.21",
    assetCode: "ANA",
    assetIssuer:
        "GC4HC3AXQDNAMURMHVGMLFGLQELEQBCE4GI7IOKEAWAKBXY7SXXWBTLV");

print(url);
//web+stellar:pay?destination=GDGUF4SCNINRDCRUIVOMDYGIMXOWVP3ZLMTL2OGQIWMFDDSECZSFQMQV&amount=123.21&asset_code=ANA&asset_issuer=GC4HC3AXQDNAMURMHVGMLFGLQELEQBCE4GI7IOKEAWAKBXY7SXXWBTLV

Check if URI Scheme is valid

Future<bool> checkUIRSchemeIsValid(String url) async 

Checks if the received SEP-0007 URL is valid; signature and domain must be present and correct for the signer's keypair. Returns true if valid, otherwise throws the corresponding URISchemeError.

Example:

URIScheme uriScheme = URIScheme();
await uriScheme.checkUIRSchemeIsValid(url).then((response) {
  // success
}).catchError((error) async {
  if (error is URISchemeError &&
      error.type == URISchemeError.tomlSignatureMissing){
    // handle error      
  } 
});

Possible URISchemeErrors are:

static const int invalidSignature = 0;
static const int invalidOriginDomain = 1;
static const int missingOriginDomain = 2;
static const int missingSignature = 3;
static const int tomlNotFoundOrInvalid = 4;
static const int tomlSignatureMissing = 5;

Sign URI

String signURI(String url, KeyPair signerKeypair)

Signs the URIScheme compliant SEP-0007 url with the signer's key pair. Returns the signed url having the signature parameter attached. Be careful with this function, you should validate the url and ask the user for permission before using this function.

Example:

print(url);
// web+stellar:tx?xdr=AAAAAgAAAADNQvJCahsRijRFXMHgyGXdar95Wya9ONBFmFGORBZkWAAAAGQABwWpAAAAKwAAAAAAAAAAAAAAAQAAAAEAAAAAzULyQmobEYo0RVzB4Mhl3Wq%2FeVsmvTjQRZhRjkQWZFgAAAAFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAAOd3d3LnNvbmVzby5jb20AAAAAAAAAAAAAAAAAAA%3D%3D&origin_domain=place.domain.com

URIScheme uriScheme = URIScheme();
url = uriScheme.signURI(url, signerKeyPair);
print(url);
// web+stellar:tx?xdr=AAAAAgAAAADNQvJCahsRijRFXMHgyGXdar95Wya9ONBFmFGORBZkWAAAAGQABwWpAAAAKwAAAAAAAAAAAAAAAQAAAAEAAAAAzULyQmobEYo0RVzB4Mhl3Wq%2FeVsmvTjQRZhRjkQWZFgAAAAFAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAEAAAAOd3d3LnNvbmVzby5jb20AAAAAAAAAAAAAAAAAAA%3D%3D&origin_domain=place.domain.com&signature=bIZ53bPKkNe0OoNK8PGLTnzHS%2FBCMzXTvwv1mc4DWc0XC4%2Bp197AmUB%2FIPL1UZAega7cLYv7%2F%2FaflB7CLGqZCw%3D%3D

Sign and submit transaction

Future<SubmitUriSchemeTransactionResponse> signAndSubmitTransaction(
  String url, KeyPair signerKeyPair,
  {Network? network}) async 

Signs the given transaction and submits it to the callback url if available, otherwise it submits it to the stellar network. Be careful with this function, you should validate the url and ask the user for permission before using this function.

Example:

URIScheme uriScheme = URIScheme();
SubmitUriSchemeTransactionResponse response = await uriScheme
        .signAndSubmitTransaction(url, signerKeyPair, network: Network.TESTNET);

SubmitUriSchemeTransactionResponse has two members: submitTransactionResponse and response. submitTransactionResponse is filled if the transaction has been send to the stellar network. response is filled if the transaction has been sent to the callback.

class SubmitUriSchemeTransactionResponse {
  SubmitTransactionResponse?
      submitTransactionResponse; // if submitted to stellar

  http.Response? response; // if submitted to callback

  SubmitUriSchemeTransactionResponse(
      this.submitTransactionResponse, this.response);
}

Get parameter value

String? getParameterValue(String name, String url)

Utility function that returns the value of the given url parameter from the specified SEP-0007 url.

More examples

You can find more examples in the SEP-0007 Test Cases