Add "experimentalForceLongPolling" option.

Author: Michael Lehenbauer

packages/firebase/index.d.ts

@@ -5853,6 +5853,19 @@ declare namespace firebase.firestore {
      * CACHE_SIZE_UNLIMITED to disable garbage collection.
      */
     cacheSizeBytes?: number;
+
+    /**
+     * Forces the SDK’s underlying network transport (WebChannel) to use
+     * long-polling. Each response from the backend will be closed immediately
+     * after the backend sends data (by default responses are kept open in
+     * case the backend has more data to send). This avoids incompatibility
+     * issues with certain proxies, antivirus software, etc. that incorrectly
+     * buffer traffic indefinitely. Use of this option will cause some
+     * performance degradation though.
+     *
+     * This setting may be removed in a future release.
+     */
+    experimentalForceLongPolling?: boolean;
   }
 
   /**
@@ -7209,14 +7222,14 @@ declare namespace firebase.firestore {
     /**
      * Returns a special value that can be used with `set()` or `update()` that tells
      * the server to increment the field's current value by the given value.
-     * 
+     *
      * If either the operand or the current field value uses floating point precision,
      * all arithmetic follows IEEE 754 semantics. If both values are integers,
      * values outside of JavaScript's safe number range (`Number.MIN_SAFE_INTEGER` to
      * `Number.MAX_SAFE_INTEGER`) are also subject to precision loss. Furthermore,
      * once processed by the Firestore backend, all integer operations are capped
      * between -2^63 and 2^63-1.
-     * 
+     *
      * If the current field value is not of type `number`, or if the field does not
      * yet exist, the transformation sets the field to the given value.
      *

packages/firestore-types/index.d.ts

@@ -76,6 +76,19 @@ export interface Settings {
    * CACHE_SIZE_UNLIMITED to disable garbage collection.
    */
   cacheSizeBytes?: number;
+
+  /**
+   * Forces the SDK’s underlying network transport (WebChannel) to use
+   * long-polling. Each response from the backend will be closed immediately
+   * after the backend sends data (by default responses are kept open in case
+   * the backend has more data to send). This avoids incompatibility issues
+   * with certain proxies, antivirus software, etc. that incorrectly buffer
+   * traffic indefinitely. Use of this option will cause some performance
+   * degradation though.
+   *
+   * This setting may be removed in a future release.
+   */
+  experimentalForceLongPolling?: boolean;
 }
 
 /**

packages/firestore/CHANGELOG.md

@@ -1,4 +1,6 @@
 # Unreleased
+- [feature] Added an `experimentalForceLongPolling` setting that may be helpful
+  to diagnose and avoid connection issues with proxies in certain cases.
 
 # 1.1.1
 - [changed] Increased a connection timeout that could lead to large writes

packages/firestore/src/api/database.ts

@@ -109,6 +109,7 @@ import {
 const DEFAULT_HOST = 'firestore.googleapis.com';
 const DEFAULT_SSL = true;
 const DEFAULT_TIMESTAMPS_IN_SNAPSHOTS = true;
+const DEFAULT_FORCE_LONG_POLLING = false;
 
 /**
  * Constant used to indicate the LRU garbage collection should be disabled.
@@ -151,6 +152,8 @@ class FirestoreSettings {
 
   readonly cacheSizeBytes: number;
 
+  readonly forceLongPolling: boolean;
+
   // Can be a google-auth-library or gapi client.
   // tslint:disable-next-line:no-any
   credentials?: any;
@@ -177,7 +180,8 @@ class FirestoreSettings {
       'ssl',
       'credentials',
       'timestampsInSnapshots',
-      'cacheSizeBytes'
+      'cacheSizeBytes',
+      'experimentalForceLongPolling'
     ]);
 
     validateNamedOptionalType(
@@ -253,6 +257,17 @@ class FirestoreSettings {
         this.cacheSizeBytes = settings.cacheSizeBytes;
       }
     }
+
+    validateNamedOptionalType(
+      'settings',
+      'boolean',
+      'experimentalForceLongPolling',
+      settings.experimentalForceLongPolling
+    );
+    this.forceLongPolling =
+      settings.experimentalForceLongPolling === undefined
+        ? DEFAULT_FORCE_LONG_POLLING
+        : settings.experimentalForceLongPolling;
   }
 
   isEqual(other: FirestoreSettings): boolean {
@@ -261,7 +276,8 @@ class FirestoreSettings {
       this.ssl === other.ssl &&
       this.timestampsInSnapshots === other.timestampsInSnapshots &&
       this.credentials === other.credentials &&
-      this.cacheSizeBytes === other.cacheSizeBytes
+      this.cacheSizeBytes === other.cacheSizeBytes &&
+      this.forceLongPolling === other.forceLongPolling
     );
   }
 }
@@ -412,7 +428,8 @@ export class Firestore implements firestore.FirebaseFirestore, FirebaseService {
       this._config.databaseId,
       this._config.persistenceKey,
       this._config.settings.host,
-      this._config.settings.ssl
+      this._config.settings.ssl,
+      this._config.settings.forceLongPolling
     );
 
     const preConverter = (value: unknown) => {

packages/firestore/src/core/database_info.ts

@@ -27,12 +27,15 @@ export class DatabaseInfo {
    * storage (used in conjunction with the databaseId).
    * @param host The Firestore backend host to connect to.
    * @param ssl Whether to use SSL when connecting.
+   * @param forceLongPolling Whether to use the forceLongPolling option
+   * when using WebChannel as the network transport.
    */
   constructor(
     readonly databaseId: DatabaseId,
     readonly persistenceKey: string,
     readonly host: string,
-    readonly ssl: boolean
+    readonly ssl: boolean,
+    readonly forceLongPolling: boolean
   ) {}
 }
 

packages/firestore/src/platform_browser/webchannel_connection.ts

@@ -61,11 +61,13 @@ const XHR_TIMEOUT_SECS = 15;
 export class WebChannelConnection implements Connection {
   private readonly databaseId: DatabaseId;
   private readonly baseUrl: string;
+  private readonly forceLongPolling: boolean;
 
   constructor(info: DatabaseInfo) {
     this.databaseId = info.databaseId;
     const proto = info.ssl ? 'https' : 'http';
     this.baseUrl = proto + '://' + info.host;
+    this.forceLongPolling = info.forceLongPolling;
   }
 
   /**
@@ -217,7 +219,8 @@ export class WebChannelConnection implements Connection {
         // set it very large (5-10 minutes) and rely on the browser's builtin
         // timeouts to kick in if the request isn't working.
         forwardChannelRequestTimeoutMs: 10 * 60 * 1000
-      }
+      },
+      forceLongPolling: this.forceLongPolling
     };
 
     this.modifyHeadersForRequest(request.initMessageHeaders, token);

packages/firestore/test/integration/browser/webchannel.test.ts

@@ -35,7 +35,8 @@ describeFn('WebChannel', () => {
       new DatabaseId('testproject'),
       'persistenceKey',
       'example.com',
-      false
+      /*ssl=*/ false,
+      /*forceLongPolling=*/ false
     );
     const conn = new WebChannelConnection(info);
     const makeUrl = conn.makeUrl.bind(conn);

packages/firestore/test/integration/util/internal_helpers.ts

@@ -39,7 +39,8 @@ export function getDefaultDatabaseInfo(): DatabaseInfo {
     new DatabaseId(DEFAULT_PROJECT_ID),
     'persistenceKey',
     DEFAULT_SETTINGS.host!,
-    !!DEFAULT_SETTINGS.ssl
+    !!DEFAULT_SETTINGS.ssl,
+    !!DEFAULT_SETTINGS.experimentalForceLongPolling
   );
 }
 

packages/webchannel-wrapper/externs/overrides.js

@@ -65,3 +65,6 @@ goog.net.WebChannel.Options.fastHandshake;
 
 /** @type {!Object<string, boolean|number>|undefined} */
 goog.net.WebChannel.Options.internalChannelParams;
+
+/** @type {boolean|undefined} */
+goog.net.WebChannel.Options.forceLongPolling;