Discriminator in username

ts/test-node/util/Username_test.ts

@@ -0,0 +1,82 @@
+// Copyright 2021 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { assert } from 'chai';
+
+import * as Username from '../../util/Username';
+
+describe('Username', () => {
+  describe('getUsernameFromSearch', () => {
+    const { getUsernameFromSearch } = Username;
+
+    it('matches invalid username searches', () => {
+      assert.strictEqual(getUsernameFromSearch('use'), 'use');
+      assert.strictEqual(
+        getUsernameFromSearch('username9012345678901234567'),
+        'username9012345678901234567'
+      );
+    });
+
+    it('matches valid username searches', () => {
+      assert.strictEqual(getUsernameFromSearch('username_34'), 'username_34');
+      assert.strictEqual(getUsernameFromSearch('u5ername'), 'u5ername');
+      assert.strictEqual(getUsernameFromSearch('username.12'), 'username.12');
+      assert.strictEqual(getUsernameFromSearch('user'), 'user');
+      assert.strictEqual(
+        getUsernameFromSearch('username901234567890123456'),
+        'username901234567890123456'
+      );
+    });
+
+    it('matches valid and invalid usernames with @ prefix', () => {
+      assert.strictEqual(getUsernameFromSearch('@username!'), 'username!');
+      assert.strictEqual(getUsernameFromSearch('@1username'), '1username');
+      assert.strictEqual(getUsernameFromSearch('@username_34'), 'username_34');
+      assert.strictEqual(getUsernameFromSearch('@username.34'), 'username.34');
+      assert.strictEqual(getUsernameFromSearch('@u5ername'), 'u5ername');
+    });
+
+    it('matches valid and invalid usernames with @ suffix', () => {
+      assert.strictEqual(getUsernameFromSearch('username!@'), 'username!');
+      assert.strictEqual(getUsernameFromSearch('1username@'), '1username');
+      assert.strictEqual(getUsernameFromSearch('username_34@'), 'username_34');
+      assert.strictEqual(getUsernameFromSearch('username.34@'), 'username.34');
+      assert.strictEqual(getUsernameFromSearch('u5ername@'), 'u5ername');
+    });
+
+    it('does not match something that looks like a phone number', () => {
+      assert.isUndefined(getUsernameFromSearch('+'));
+      assert.isUndefined(getUsernameFromSearch('2223'));
+      assert.isUndefined(getUsernameFromSearch('+3'));
+      assert.isUndefined(getUsernameFromSearch('+234234234233'));
+    });
+  });
+
+  describe('isValidUsername', () => {
+    const { isValidUsername } = Username;
+
+    it('does not match invalid username searches', () => {
+      assert.isFalse(isValidUsername('username!'));
+      assert.isFalse(isValidUsername('1username'));
+      assert.isFalse(isValidUsername('u'));
+      assert.isFalse(isValidUsername('username9012345678901234567890123'));
+      assert.isFalse(isValidUsername('username.abc'));
+    });
+
+    it('matches valid usernames', () => {
+      assert.isTrue(isValidUsername('username_34'));
+      assert.isTrue(isValidUsername('u5ername'));
+      assert.isTrue(isValidUsername('_username'));
+      assert.isTrue(isValidUsername('use'));
+      assert.isTrue(isValidUsername('username901234567890123456789012'));
+      assert.isTrue(isValidUsername('username.0123'));
+    });
+
+    it('does not match valid and invalid usernames with @ prefix or suffix', () => {
+      assert.isFalse(isValidUsername('@username_34'));
+      assert.isFalse(isValidUsername('@1username'));
+      assert.isFalse(isValidUsername('username_34@'));
+      assert.isFalse(isValidUsername('1username@'));
+    });
+  });
+});

ts/test-node/util/sgnlHref_test.ts

@@ -12,7 +12,9 @@ import {
   parseSgnlHref,
   parseCaptchaHref,
   parseE164FromSignalDotMeHash,
+  parseUsernameFromSignalDotMeHash,
   parseSignalHttpsLink,
+  generateUsernameLink,
   rewriteSignalHrefsIfNecessary,
 } from '../../util/sgnlHref';
 
@@ -373,6 +375,48 @@ describe('sgnlHref', () => {
     });
   });
 
+  describe('parseUsernameFromSignalDotMeHash', () => {
+    it('returns undefined for invalid inputs', () => {
+      ['', ' u/+18885551234', 'z/18885551234'].forEach(hash => {
+        assert.isUndefined(parseUsernameFromSignalDotMeHash(hash));
+      });
+    });
+
+    it('returns the username for valid inputs', () => {
+      assert.strictEqual(
+        parseUsernameFromSignalDotMeHash('u/signal.03'),
+        'signal.03'
+      );
+      assert.strictEqual(
+        parseUsernameFromSignalDotMeHash('u/signal%2F03'),
+        'signal/03'
+      );
+    });
+  });
+
+  describe('generateUsernameLink', () => {
+    it('generates regular link', () => {
+      assert.strictEqual(
+        generateUsernameLink('signal.03'),
+        'https://signal.me/#u/signal.03'
+      );
+    });
+
+    it('generates encoded link', () => {
+      assert.strictEqual(
+        generateUsernameLink('signal/03'),
+        'https://signal.me/#u/signal%2F03'
+      );
+    });
+
+    it('generates short link', () => {
+      assert.strictEqual(
+        generateUsernameLink('signal/03', { short: true }),
+        'signal.me/#u/signal%2F03'
+      );
+    });
+  });
+
   describe('parseSignalHttpsLink', () => {
     it('returns a null command for invalid URLs', () => {
       ['', 'https', 'https://example/?foo=bar'].forEach(href => {