Add async txsub endpoint in Horizon (#989)

* Add async txsub endpoint

* Update src/horizon/server.ts

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Update src/horizon/server.ts

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Update test/unit/server_async_transaction.test.js

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Update test/unit/server_async_transaction.test.js

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Update test/unit/server_async_transaction.test.js

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Directly compare with response object

* Add docstring

* Update test/unit/server_async_transaction.test.js

Co-authored-by: George <Shaptic@users.noreply.github.com>

* Add endpoint back after main merge

---------

Co-authored-by: George <Shaptic@users.noreply.github.com>

src/horizon/horizon_api.ts

@@ -20,6 +20,12 @@ export namespace HorizonApi {
     paging_token: string;
   }
 
+  export interface SubmitAsyncTransactionResponse {
+    hash: string;
+    tx_status: string;
+    error_result_xdr: string;
+  }
+
   export interface FeeBumpTransactionResponse {
     hash: string;
     signatures: string[];

src/horizon/server.ts

@@ -507,6 +507,59 @@ export class Server {
       });
   }
 
+  /**
+   * Submits an asynchronous transaction to the network. Unlike the synchronous version, which blocks
+   * and waits for the transaction to be ingested in Horizon, this endpoint relays the response from
+   * core directly back to the user.
+   *
+   * By default, this function calls {@link Server#checkMemoRequired}, you can
+   * skip this check by setting the option `skipMemoRequiredCheck` to `true`.
+   *
+   * @see [Submit
+   * Async Transaction](https://developers.stellar.org/docs/data/horizon/api-reference/resources/submit-async-transaction)
+   * @param {Transaction|FeeBumpTransaction} transaction - The transaction to submit.
+   * @param {object} [opts] Options object
+   * @param {boolean} [opts.skipMemoRequiredCheck] - Allow skipping memo
+   * required check, default: `false`. See
+   * [SEP0029](https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0029.md).
+   * @returns {Promise} Promise that resolves or rejects with response from
+   * horizon.
+   */
+  public async submitAsyncTransaction(
+      transaction: Transaction | FeeBumpTransaction,
+      opts: Server.SubmitTransactionOptions = { skipMemoRequiredCheck: false }
+  ): Promise<HorizonApi.SubmitAsyncTransactionResponse> {
+    // only check for memo required if skipMemoRequiredCheck is false and the transaction doesn't include a memo.
+    if (!opts.skipMemoRequiredCheck) {
+      await this.checkMemoRequired(transaction);
+    }
+
+    const tx = encodeURIComponent(
+        transaction
+            .toEnvelope()
+            .toXDR()
+            .toString("base64"),
+    );
+
+    return AxiosClient.post(
+        URI(this.serverURL as any)
+            .segment("transactions_async")
+            .toString(),
+        `tx=${tx}`,
+    ).then((response) => response.data
+    ).catch((response) => {
+      if (response instanceof Error) {
+        return Promise.reject(response);
+      }
+      return Promise.reject(
+          new BadResponseError(
+              `Transaction submission failed. Server responded: ${response.status} ${response.statusText}`,
+              response.data,
+          ),
+      );
+    });
+  }
+
   /**
    * @returns {AccountCallBuilder} New {@link AccountCallBuilder} object configured by a current Horizon server configuration.
    */

test/unit/server_async_transaction.test.js

@@ -0,0 +1,106 @@
+const { Horizon } = StellarSdk;
+
+describe("server.js async transaction submission tests", function () {
+    let keypair = StellarSdk.Keypair.random();
+    let account = new StellarSdk.Account(keypair.publicKey(), "56199647068161");
+
+    beforeEach(function () {
+        this.server = new Horizon.Server("https://horizon-live.stellar.org:1337");
+        this.axiosMock = sinon.mock(Horizon.AxiosClient);
+        let transaction = new StellarSdk.TransactionBuilder(account, {
+            fee: StellarSdk.BASE_FEE,
+            networkPassphrase: StellarSdk.Networks.TESTNET,
+        })
+            .addOperation(
+                StellarSdk.Operation.payment({
+                    destination:
+                        "GASOCNHNNLYFNMDJYQ3XFMI7BYHIOCFW3GJEOWRPEGK2TDPGTG2E5EDW",
+                    asset: StellarSdk.Asset.native(),
+                    amount: "100.50",
+                }),
+            )
+            .setTimeout(StellarSdk.TimeoutInfinite)
+            .build();
+        transaction.sign(keypair);
+
+        this.transaction = transaction;
+        this.blob = encodeURIComponent(
+            transaction.toEnvelope().toXDR().toString("base64"),
+        );
+    });
+
+    afterEach(function () {
+        this.axiosMock.verify();
+        this.axiosMock.restore();
+    });
+
+    it("sends an async transaction", function (done) {
+        this.axiosMock
+            .expects("post")
+            .withArgs(
+                "https://horizon-live.stellar.org:1337/transactions_async",
+                `tx=${this.blob}`,
+            )
+            .returns(Promise.resolve({ data: {} }));
+
+        this.server
+            .submitAsyncTransaction(this.transaction, { skipMemoRequiredCheck: true })
+            .then(() => done())
+            .catch((err) => done(err));
+    });
+    it("sends an async transaction and gets a PENDING response", function (done) {
+        const response = {
+            tx_status: "PENDING",
+            hash: "db2c69a07be57eb5baefbfbb72b95c7c20d2c4d6f2a0e84e7c27dd0359055a2f",
+        };
+
+        this.axiosMock
+            .expects("post")
+            .withArgs(
+                "https://horizon-live.stellar.org:1337/transactions_async",
+                `tx=${this.blob}`,
+            )
+            .returns(Promise.resolve({ data: response }));
+
+        this.server
+            .submitAsyncTransaction(this.transaction, { skipMemoRequiredCheck: true })
+            .then(function (res) {
+                expect(res).to.equal(response)
+                done();
+            })
+            .catch(function (err) {
+                done(err);
+            });
+    });
+    it("sends an async transaction and gets a Problem response", function (done) {
+        const response = {
+            type:   "transaction_submission_exception",
+            title:  "Transaction Submission Exception",
+            status: 500,
+            detail: "Received exception from stellar-core." +
+                "The `extras.error` field on this response contains further " +
+                "details.  Descriptions of each code can be found at: " +
+                "https://developers.stellar.org/api/errors/http-status-codes/horizon-specific/transaction-submission-async/transaction_submission_exception",
+            extras: {
+                envelope_xdr: "AAAAAIUAEW3jQt3+fbT6nCASA1/8RWdp9fJ2woxqPHZPQUH/AAAAZAEH/OgAAAAgAAAAAQAAAAAAAAAAAAAAAFyIDD0AAAAAAAAAAQAAAAAAAAADAAAAAAAAAAFCQVQAAAAAAEZK09vHmzOmEMoVWYtbbZcKv3ZOoo06ckzbhyDIFKfhAAAAAAExLQAAAAABAAAAAgAAAAAAAAAAAAAAAAAAAAFPQUH/AAAAQHk3Igj+JXqggsJBFl4mrzgACqxWpx87psxu5UHnSskbwRjHZz89NycCZmJL4gN5WN7twm+wK371K9XcRNDiBwQ=",
+                error: "There was an exception when submitting this transaction."
+            }
+        };
+
+        this.axiosMock
+            .expects("post")
+            .withArgs(
+                "https://horizon-live.stellar.org:1337/transactions_async",
+                `tx=${this.blob}`,
+            )
+            .returns(Promise.resolve({ data: response }));
+
+        this.server
+            .submitAsyncTransaction(this.transaction, { skipMemoRequiredCheck: true })
+            .then(function (res) {
+                expect(res).to.equal(response)
+                done();
+            })
+            .catch((err) => done(err));
+    });
+});