Implement deep link functionality and enable it for android.

android/app/src/main/AndroidManifest.xml

@@ -55,9 +55,7 @@
                 <category android:name="android.intent.category.DEFAULT" />
                 <category android:name="android.intent.category.BROWSABLE" />
 
-                <data
-                    android:host="login"
-                    android:scheme="zulip" />
+                <data android:scheme="zulip" />
             </intent-filter>
         </activity>
 

docs/howto/testing.md

@@ -169,3 +169,18 @@ find something in its docs, it's worth
 [flow-typed]: https://github.com/flowtype/flow-typed
 [flow-issues]: https://github.com/facebook/flow/issues?q=is%3Aissue
 [flow-cheat-sheet]: https://www.saltycrane.com/flow-type-cheat-sheet/latest/
+
+## Manual Testing
+
+### Deep Link
+
+Testing deep link url is much more productive when one uses cli instead of going to the browser and typing the link.  
+
+#### Android
+
+To send a deeplink event to android (debug build) use the following:
+```bash
+adb shell am start -W -a android.intent.action.VIEW -d "zulip://test.realm.com/?email=test@example.com#narrow/valid-narrow" com.zulipmobile.debug
+```
+
+Make sure to change the domain name, email parameter and narrow as required.

src/boot/AppEventHandlers.js

@@ -16,6 +16,7 @@ import {
   notificationOnAppActive,
 } from '../notification';
 import { ShareReceivedListener, handleInitialShare } from '../sharing';
+import { UrlListener, handleInitialUrl } from '../deeplink';
 import { appOnline, appOrientation } from '../actions';
 import PresenceHeartbeat from '../presence/PresenceHeartbeat';
 
@@ -117,6 +118,7 @@ class AppEventHandlers extends PureComponent<Props> {
 
   notificationListener = new NotificationListener(this.props.dispatch);
   shareListener = new ShareReceivedListener(this.props.dispatch);
+  urlListener = new UrlListener(this.props.dispatch);
 
   handleMemoryWarning = () => {
     // Release memory here
@@ -126,13 +128,15 @@ class AppEventHandlers extends PureComponent<Props> {
     const { dispatch } = this.props;
     handleInitialNotification(dispatch);
     handleInitialShare(dispatch);
+    handleInitialUrl(dispatch);
 
     this.netInfoDisconnectCallback = NetInfo.addEventListener(this.handleConnectivityChange);
     AppState.addEventListener('change', this.handleAppStateChange);
     AppState.addEventListener('memoryWarning', this.handleMemoryWarning);
     ScreenOrientation.addOrientationChangeListener(this.handleOrientationChange);
     this.notificationListener.start();
     this.shareListener.start();
+    this.urlListener.start();
   }
 
   componentWillUnmount() {
@@ -145,6 +149,7 @@ class AppEventHandlers extends PureComponent<Props> {
     ScreenOrientation.removeOrientationChangeListeners();
     this.notificationListener.stop();
     this.shareListener.stop();
+    this.urlListener.stop();
   }
 
   render() {

src/deeplink/index.js

@@ -0,0 +1,59 @@
+/* @flow strict-local */
+import { Linking } from 'react-native';
+import * as webAuth from '../start/webAuth';
+import type { Dispatch, LinkingEvent } from '../types';
+import { navigateViaDeepLink } from './urlActions';
+
+const handleUrl = (url: URL, dispatch: Dispatch) => {
+  switch (url.hostname) {
+    case 'login':
+      webAuth.endWebAuth({ url: url.toString() }, dispatch);
+      break;
+    default:
+      dispatch(navigateViaDeepLink(url));
+  }
+};
+
+export const handleInitialUrl = async (dispatch: Dispatch) => {
+  const initialUrl: ?string = await Linking.getInitialURL();
+  if (initialUrl != null) {
+    handleUrl(new URL(initialUrl), dispatch);
+  }
+};
+
+export class UrlListener {
+  dispatch: Dispatch;
+  unsubs: Array<() => void> = [];
+
+  constructor(dispatch: Dispatch) {
+    this.dispatch = dispatch;
+  }
+
+  /** Private. */
+  handleUrlEvent(event: LinkingEvent) {
+    handleUrl(new URL(event.url), this.dispatch);
+  }
+
+  /** Private. */
+  listen(handler: (event: LinkingEvent) => void | Promise<void>) {
+    Linking.addEventListener('url', handler);
+    this.unsubs.push(() => Linking.removeEventListener('url', handler));
+  }
+
+  /** Private. */
+  unlistenAll() {
+    while (this.unsubs.length > 0) {
+      this.unsubs.pop()();
+    }
+  }
+
+  /** Start listening.  Don't call twice without intervening `stop`. */
+  start() {
+    this.listen((event: LinkingEvent) => this.handleUrlEvent(event));
+  }
+
+  /** Stop listening. */
+  stop() {
+    this.unlistenAll();
+  }
+}

src/deeplink/urlActions.js

@@ -0,0 +1,50 @@
+/* @flow strict-local */
+import type { Dispatch, GetState, Narrow } from '../types';
+
+import * as NavigationService from '../nav/NavigationService';
+import { getNarrowFromLink } from '../utils/linkProcessors';
+import { getStreamsById } from '../subscriptions/subscriptionSelectors';
+import { getOwnUserId } from '../users/userSelectors';
+import { navigateToChat, navigateToRealmInputScreen } from '../nav/navActions';
+import { getAccountStatuses } from '../account/accountsSelectors';
+import { accountSwitch } from '../account/accountActions';
+
+/** Navigate to the given narrow. */
+const doNarrow = (narrow: Narrow) => (dispatch: Dispatch, getState: GetState) => {
+  NavigationService.dispatch(navigateToChat(narrow));
+};
+
+/**
+ * Navigates to a screen (of any logged in account) based on the deep link url.
+ *
+ * @param url deep link url of the form
+ * `zulip://example.com/?email=example@example.com#narrow/valid-narrow`
+ *
+ */
+export const navigateViaDeepLink = (url: URL) => async (dispatch: Dispatch, getState: GetState) => {
+  const state = getState();
+  const account = getAccountStatuses(state);
+  const index = account.findIndex(
+    x => x.realm.hostname === url.hostname && x.email === url.searchParams.get('email'),
+  );
+  if (index === -1) {
+    NavigationService.dispatch(navigateToRealmInputScreen());
+    return;
+  }
+  if (index > 0) {
+    dispatch(accountSwitch(index));
+    // TODO navigate to the screen pointed by deep link in new account.
+    return;
+  }
+
+  const streamsById = getStreamsById(getState());
+  const ownUserId = getOwnUserId(state);
+
+  // For the current use case of the "realm" variable set below, it doesn't
+  // matter if it is hosted on `http` or `https` hence choosing one arbitrarily.
+  const realm = new URL(`http://${url.hostname}/`);
+  const narrow = getNarrowFromLink(url.toString(), realm, streamsById, ownUserId);
+  if (narrow) {
+    dispatch(doNarrow(narrow));
+  }
+};

src/message/messagesActions.js

@@ -2,7 +2,7 @@
 import * as NavigationService from '../nav/NavigationService';
 import type { Narrow, Dispatch, GetState } from '../types';
 import { getAuth } from '../selectors';
-import { getMessageIdFromLink, getNarrowFromLink } from '../utils/internalLinks';
+import { getMessageIdFromLink, getNarrowFromLink } from '../utils/linkProcessors';
 import { openLinkWithUserPreference } from '../utils/openLink';
 import { navigateToChat } from '../nav/navActions';
 import { FIRST_UNREAD_ANCHOR } from '../anchor';

src/start/AuthScreen.js

@@ -1,7 +1,7 @@
 /* @flow strict-local */
 
 import React, { PureComponent } from 'react';
-import { Linking, Platform } from 'react-native';
+import { Platform } from 'react-native';
 import type { AppleAuthenticationCredential } from 'expo-apple-authentication';
 import * as AppleAuthentication from 'expo-apple-authentication';
 
@@ -30,7 +30,7 @@ import { Centerer, Screen, ZulipButton } from '../common';
 import RealmInfo from './RealmInfo';
 import { encodeParamsForUrl } from '../utils/url';
 import * as webAuth from './webAuth';
-import { loginSuccess, navigateToDevAuth, navigateToPasswordAuth } from '../actions';
+import { navigateToDevAuth, navigateToPasswordAuth } from '../actions';
 import IosCompliantAppleAuthButton from './IosCompliantAppleAuthButton';
 import { openLinkEmbedded } from '../utils/openLink';
 
@@ -175,30 +175,8 @@ type Props = $ReadOnly<{|
   realm: URL,
 |}>;
 
-let otp = '';
-
-/**
- * An event emitted by `Linking`.
- *
- * Determined by reading the implementation source code, and documentation:
- *   https://reactnative.dev/docs/linking
- *
- * TODO move this to a libdef, and/or get an explicit type into upstream.
- */
-type LinkingEvent = {
-  url: string,
-  ...
-};
-
 class AuthScreen extends PureComponent<Props> {
   componentDidMount = () => {
-    Linking.addEventListener('url', this.endWebAuth);
-    Linking.getInitialURL().then((initialUrl: ?string) => {
-      if (initialUrl !== null && initialUrl !== undefined) {
-        this.endWebAuth({ url: initialUrl });
-      }
-    });
-
     const { serverSettings } = this.props.route.params;
     const authList = activeAuthentications(
       serverSettings.authentication_methods,
@@ -209,31 +187,6 @@ class AuthScreen extends PureComponent<Props> {
     }
   };
 
-  componentWillUnmount = () => {
-    Linking.removeEventListener('url', this.endWebAuth);
-  };
-
-  /**
-   * Hand control to the browser for an external auth method.
-   *
-   * @param url The `login_url` string, a relative URL, from an
-   * `external_authentication_method` object from `/server_settings`.
-   */
-  beginWebAuth = async (url: string) => {
-    otp = await webAuth.generateOtp();
-    webAuth.openBrowser(new URL(url, this.props.realm).toString(), otp);
-  };
-
-  endWebAuth = (event: LinkingEvent) => {
-    webAuth.closeBrowser();
-
-    const { dispatch, realm } = this.props;
-    const auth = webAuth.authFromCallbackUrl(event.url, otp, realm);
-    if (auth) {
-      dispatch(loginSuccess(auth.realm, auth.email, auth.apiKey));
-    }
-  };
-
   handleDevAuth = () => {
     NavigationService.dispatch(navigateToDevAuth({ realm: this.props.realm }));
   };
@@ -262,7 +215,7 @@ class AuthScreen extends PureComponent<Props> {
       throw new Error('`state` mismatch');
     }
 
-    otp = await webAuth.generateOtp();
+    const otp = await webAuth.generateOtp();
 
     const params = encodeParamsForUrl({
       mobile_flow_otp: otp,
@@ -307,7 +260,7 @@ class AuthScreen extends PureComponent<Props> {
     } else if (method.name === 'apple' && (await this.canUseNativeAppleFlow())) {
       this.handleNativeAppleAuth();
     } else {
-      this.beginWebAuth(action.url);
+      webAuth.beginWebAuth(action.url, this.props.realm);
     }
   };
 

src/start/__tests__/webAuth-test.js

@@ -7,7 +7,7 @@ describe('authFromCallbackUrl', () => {
 
   test('success', () => {
     const url = `zulip://login?realm=${eg.realm.toString()}&email=a@b&otp_encrypted_api_key=2636fdeb`;
-    expect(authFromCallbackUrl(url, otp, eg.realm)).toEqual({
+    expect(authFromCallbackUrl(url, eg.realm, otp)).toEqual({
       realm: eg.realm,
       email: 'a@b',
       apiKey: '5af4',
@@ -17,13 +17,13 @@ describe('authFromCallbackUrl', () => {
   test('wrong realm', () => {
     const url =
       'zulip://login?realm=https://other.example.org&email=a@b&otp_encrypted_api_key=2636fdeb';
-    expect(authFromCallbackUrl(url, otp, eg.realm)).toEqual(null);
+    expect(authFromCallbackUrl(url, eg.realm, otp)).toEqual(null);
   });
 
   test('not login', () => {
     // Hypothetical link that isn't a login... but somehow with all the same
     // query params, for extra confusion for good measure.
     const url = `zulip://message?realm=${eg.realm.toString()}&email=a@b&otp_encrypted_api_key=2636fdeb`;
-    expect(authFromCallbackUrl(url, otp, eg.realm)).toEqual(null);
+    expect(authFromCallbackUrl(url, eg.realm, otp)).toEqual(null);
   });
 });