Add SEP0010 transaction challenge builder.

package.json

@@ -131,13 +131,15 @@
   "dependencies": {
     "@types/eventsource": "^1.1.2",
     "@types/node": ">= 8",
+    "@types/randombytes": "^2.0.0",
     "@types/urijs": "^1.19.2",
     "axios": "^0.19.0",
     "bignumber.js": "^4.0.0",
     "detect-node": "^2.0.4",
     "es6-promise": "^4.2.4",
     "eventsource": "^1.0.7",
     "lodash": "^4.17.11",
+    "randombytes": "^2.1.0",
     "stellar-base": "^1.0.3",
     "toml": "^2.3.0",
     "tslib": "^1.10.0",

src/index.ts

@@ -27,6 +27,7 @@ export {
   SERVER_TIME_MAP,
   getCurrentServerTime,
 } from "./horizon_axios_client";
+export * from "./utils";
 
 // expose classes and functions from stellar-base
 export * from "stellar-base";

src/utils.ts

@@ -0,0 +1,66 @@
+import randomBytes from "randombytes";
+import {
+  Account,
+  BASE_FEE,
+  Keypair,
+  Operation,
+  TransactionBuilder,
+} from "stellar-base";
+
+/**
+ * @namespace Utils
+ */
+export namespace Utils {
+  /**
+   * Returns a valid [SEP0010](https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0010.md)
+   * challenge transaction which you can use for Stellar Web Authentication.
+   *
+   * @see [SEP0010: Stellar Web Authentication](https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0010.md)
+   * @function
+   * @memberof Utils
+   * @param {Keypair} serverKeypair Keypair for server's signing account.
+   * @param {string} clientAccountID The stellar account that the wallet wishes to authenticate with the server.
+   * @param {string} anchorName Anchor's name to be used in the manage_data key.
+   * @param {number} [timeout=300] Challenge duration (default to 5 minutes).
+   * @example
+   * import { Utils, Keypair, Network }  from 'stellar-sdk'
+   *
+   * Network.useTestNetwork();
+   *
+   * let serverKeyPair = Keypair.fromSecret("server-secret")
+   * let challenge = Utils.buildChallengeTx(serverKeyPair, "client-stellar-account-id", "SDF", 300)
+   * @returns {string} A base64 encoded string of the raw TransactionEnvelope xdr struct for the transaction.
+   */
+  export function buildChallengeTx(
+    serverKeypair: Keypair,
+    clientAccountID: string,
+    anchorName: string,
+    timeout: number = 300,
+  ): string {
+    const account = new Account(serverKeypair.publicKey(), "-1");
+    const now = Math.floor(Date.now() / 1000);
+
+    const transaction = new TransactionBuilder(account, {
+      fee: BASE_FEE,
+      timebounds: {
+        minTime: now,
+        maxTime: now + timeout,
+      },
+    })
+      .addOperation(
+        Operation.manageData({
+          name: `${anchorName} auth`,
+          value: randomBytes(64),
+          source: clientAccountID,
+        }),
+      )
+      .build();
+
+    transaction.sign(serverKeypair);
+
+    return transaction
+      .toEnvelope()
+      .toXDR("base64")
+      .toString();
+  }
+}

test/unit/utils_test.js

@@ -0,0 +1,45 @@
+describe('Utils', function() {
+  describe('Utils.buildChallengeTx', function() {
+    it('returns challenge which follows SEP0010 spec', function() {
+      let keypair = StellarSdk.Keypair.random();
+
+      const challenge = StellarSdk.Utils.buildChallengeTx(
+        keypair,
+        "GBDIT5GUJ7R5BXO3GJHFXJ6AZ5UQK6MNOIDMPQUSMXLIHTUNR2Q5CFNF",
+        "SDF"
+      );
+
+      const transaction = new StellarSdk.Transaction(challenge);
+
+      expect(transaction.sequence).to.eql("0");
+      expect(transaction.source).to.eql(keypair.publicKey());
+      expect(transaction.operations.length).to.eql(1);
+
+      const { maxTime, minTime } = transaction.timeBounds;
+
+      expect(parseInt(maxTime) - parseInt(minTime)).to.eql(300);
+
+      const [ operation ] =  transaction.operations;
+
+      expect(operation.name).to.eql("SDF auth");
+      expect(operation.source).to.eql("GBDIT5GUJ7R5BXO3GJHFXJ6AZ5UQK6MNOIDMPQUSMXLIHTUNR2Q5CFNF");
+      expect(operation.type).to.eql("manageData");
+      expect(operation.value.length).to.eql(64);
+    });
+
+    it('uses the passed-in timeout', function() {
+      let keypair = StellarSdk.Keypair.random();
+
+      const challenge = StellarSdk.Utils.buildChallengeTx(
+        keypair,
+        "GBDIT5GUJ7R5BXO3GJHFXJ6AZ5UQK6MNOIDMPQUSMXLIHTUNR2Q5CFNF",
+        "SDF",
+        600
+      );
+
+      const transaction = new StellarSdk.Transaction(challenge);
+      const { maxTime, minTime } = transaction.timeBounds;
+      expect(parseInt(maxTime) - parseInt(minTime)).to.eql(600);
+    });
+  });
+});

yarn.lock

@@ -132,6 +132,11 @@
   resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.130.tgz#04b3a690d5f4fc34579963c99adae067b8c8eb5a"
   integrity sha512-H++wk0tbneBsRVfLkgAAd0IIpmpVr2Bj4T0HncoOsQf3/xrJexRYQK2Tqo0Ej3pFslM8GkMgdis9bu6xIb1ycw==
 
+"@types/node@*":
+  version "12.6.8"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-12.6.8.tgz#e469b4bf9d1c9832aee4907ba8a051494357c12c"
+  integrity sha512-aX+gFgA5GHcDi89KG5keey2zf0WfZk/HAQotEamsK2kbey+8yGKcson0hbK8E+v0NArlCJQCqMP161YhV6ZXLg==
+
 "@types/node@>= 8":
   version "11.13.8"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-11.13.8.tgz#e5d71173c95533be9842b2c798978f095f912aab"
@@ -142,6 +147,13 @@
   resolved "https://registry.yarnpkg.com/@types/parsimmon/-/parsimmon-1.10.0.tgz#ffb81cb023ff435a41d4710a29ab23c561dc9fdf"
   integrity sha512-bsTIJFVQv7jnvNiC42ld2pQW2KRI+pAG243L+iATvqzy3X6+NH1obz2itRKDZZ8VVhN3wjwYax/VBGCcXzgTqQ==
 
+"@types/randombytes@^2.0.0":
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/@types/randombytes/-/randombytes-2.0.0.tgz#0087ff5e60ae68023b9bc4398b406fea7ad18304"
+  integrity sha512-bz8PhAVlwN72vqefzxa14DKNT8jK/mV66CSjwdVQM/k3Th3EPKfUtdMniwZgMedQTFuywAsfjnZsg+pEnltaMA==
+  dependencies:
+    "@types/node" "*"
+
 "@types/urijs@^1.19.2":
   version "1.19.2"
   resolved "https://registry.yarnpkg.com/@types/urijs/-/urijs-1.19.2.tgz#45212f53c3f14f1d90ca823a719b164748ad413b"
@@ -6848,7 +6860,7 @@ randomatic@^3.0.0:
     kind-of "^6.0.0"
     math-random "^1.0.1"
 
-randombytes@^2.0.0, randombytes@^2.0.1, randombytes@^2.0.5:
+randombytes@^2.0.0, randombytes@^2.0.1, randombytes@^2.0.5, randombytes@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/randombytes/-/randombytes-2.1.0.tgz#df6f84372f0270dc65cdf6291349ab7a473d4f2a"
   integrity sha512-vYl3iOX+4CKUWuxGi9Ukhie6fsqXqS9FE2Zaic4tNFD2N2QQaXOMFbuKK4QmDHC0JO6B1Zp41J0LpT0oR68amQ==