Make HTTP request implementations tree-shakable

We expose XHRRequest and FetchRequest modules.

The user is required to provide an HTTP module, even for Realtime, since
it’s used for the internet connectivity check and for making a token
request to the authUrl.

Resolves #1395.

scripts/moduleReport.js

@@ -9,6 +9,8 @@ const moduleNames = [
   'XHRPolling',
   'XHRStreaming',
   'WebSocketTransport',
+  'XHRRequest',
+  'FetchRequest',
 ];
 
 // List of all free-standing functions exported by the library along with the

src/common/lib/client/baseclient.ts

@@ -15,6 +15,7 @@ import { Rest } from './rest';
 import { IUntypedCryptoStatic } from 'common/types/ICryptoStatic';
 import { throwMissingModuleError } from '../util/utils';
 import { MsgPack } from 'common/types/msgpack';
+import { HTTPRequestImplementations } from 'platform/web/lib/http/http';
 
 type BatchResult<T> = API.Types.BatchResult<T>;
 type BatchPublishSpec = API.Types.BatchPublishSpec;
@@ -41,8 +42,12 @@ class BaseClient {
   private readonly _rest: Rest | null;
   readonly _Crypto: IUntypedCryptoStatic | null;
   readonly _MsgPack: MsgPack | null;
+  // Extra HTTP request implementations available to this client, in addition to those in web’s Http.bundledRequestImplementations
+  readonly _additionalHTTPRequestImplementations: HTTPRequestImplementations;
 
   constructor(options: ClientOptions | string, modules: ModulesMap) {
+    this._additionalHTTPRequestImplementations = modules;
+
     if (!options) {
       const msg = 'no options provided';
       Logger.logAction(Logger.LOG_ERROR, 'BaseClient()', msg);

src/common/lib/client/modulesmap.ts

@@ -3,6 +3,8 @@ import { IUntypedCryptoStatic } from '../../types/ICryptoStatic';
 import { MsgPack } from 'common/types/msgpack';
 import RealtimePresence from './realtimepresence';
 import { TransportInitialiser } from '../transport/connectionmanager';
+import XHRRequest from 'platform/web/lib/http/request/xhrrequest';
+import fetchRequest from 'platform/web/lib/http/request/fetchrequest';
 
 export interface ModulesMap {
   Rest?: typeof Rest;
@@ -12,6 +14,8 @@ export interface ModulesMap {
   WebSocketTransport?: TransportInitialiser;
   XHRPolling?: TransportInitialiser;
   XHRStreaming?: TransportInitialiser;
+  XHRRequest?: typeof XHRRequest;
+  FetchRequest?: typeof fetchRequest;
 }
 
 export const allCommonModules: ModulesMap = { Rest };

src/platform/nativescript/index.ts

@@ -19,6 +19,7 @@ import { getDefaults } from '../../common/lib/util/defaults';
 import WebStorage from './lib/util/webstorage';
 import PlatformDefaults from '../web/lib/util/defaults';
 import msgpack from '../web/lib/util/msgpack';
+import { defaultBundledRequestImplementations } from '../web/lib/http/request';
 
 const Crypto = createCryptoClass(Config, BufferUtils);
 
@@ -34,6 +35,8 @@ for (const clientClass of [DefaultRest, DefaultRealtime]) {
   clientClass._MsgPack = msgpack;
 }
 
+Http.bundledRequestImplementations = defaultBundledRequestImplementations;
+
 Logger.initLogHandlers();
 
 Platform.Defaults = getDefaults(PlatformDefaults);

src/platform/react-native/index.ts

@@ -17,6 +17,7 @@ import { getDefaults } from '../../common/lib/util/defaults';
 import WebStorage from '../web/lib/util/webstorage';
 import PlatformDefaults from '../web/lib/util/defaults';
 import msgpack from '../web/lib/util/msgpack';
+import { defaultBundledRequestImplementations } from '../web/lib/http/request';
 
 const Config = configFactory(BufferUtils);
 
@@ -34,6 +35,8 @@ for (const clientClass of [DefaultRest, DefaultRealtime]) {
   clientClass._MsgPack = msgpack;
 }
 
+Http.bundledRequestImplementations = defaultBundledRequestImplementations;
+
 Logger.initLogHandlers();
 
 Platform.Defaults = getDefaults(PlatformDefaults);

src/platform/web-noencryption/index.ts

@@ -16,6 +16,7 @@ import { getDefaults } from '../../common/lib/util/defaults';
 import WebStorage from '../web/lib/util/webstorage';
 import PlatformDefaults from '../web/lib/util/defaults';
 import msgpack from '../web/lib/util/msgpack';
+import { defaultBundledRequestImplementations } from '../web/lib/http/request';
 
 Platform.Crypto = null;
 Platform.BufferUtils = BufferUtils;
@@ -28,6 +29,8 @@ for (const clientClass of [DefaultRest, DefaultRealtime]) {
   clientClass._MsgPack = msgpack;
 }
 
+Http.bundledRequestImplementations = defaultBundledRequestImplementations;
+
 Logger.initLogHandlers();
 
 Platform.Defaults = getDefaults(PlatformDefaults);

src/platform/web/index.ts

@@ -17,6 +17,7 @@ import { getDefaults } from '../../common/lib/util/defaults';
 import WebStorage from './lib/util/webstorage';
 import PlatformDefaults from './lib/util/defaults';
 import msgpack from './lib/util/msgpack';
+import { defaultBundledRequestImplementations } from './lib/http/request';
 
 const Crypto = createCryptoClass(Config, BufferUtils);
 
@@ -32,6 +33,8 @@ for (const clientClass of [DefaultRest, DefaultRealtime]) {
   clientClass._MsgPack = msgpack;
 }
 
+Http.bundledRequestImplementations = defaultBundledRequestImplementations;
+
 Logger.initLogHandlers();
 
 Platform.Defaults = getDefaults(PlatformDefaults);

src/platform/web/lib/http/http.ts

@@ -2,16 +2,17 @@ import Platform from 'common/platform';
 import * as Utils from 'common/lib/util/utils';
 import Defaults from 'common/lib/util/defaults';
 import ErrorInfo, { PartialErrorInfo } from 'common/lib/types/errorinfo';
-import { IHttpStatic, RequestCallback, RequestParams } from 'common/types/http';
+import { RequestCallback, RequestParams } from 'common/types/http';
 import HttpMethods from 'common/constants/HttpMethods';
 import BaseClient from 'common/lib/client/baseclient';
 import BaseRealtime from 'common/lib/client/baserealtime';
-import XHRRequest from './request/xhrrequest';
 import XHRStates from 'common/constants/XHRStates';
 import Logger from 'common/lib/util/logger';
 import { StandardCallback } from 'common/types/utils';
-import fetchRequest from './request/fetchrequest';
 import { isSuccessCode } from 'common/constants/HttpStatusCodes';
+import { ModulesMap } from 'common/lib/client/modulesmap';
+
+export type HTTPRequestImplementations = Pick<ModulesMap, 'XHRRequest' | 'FetchRequest'>;
 
 function shouldFallback(errorInfo: ErrorInfo) {
   const statusCode = errorInfo.statusCode as number;
@@ -39,10 +40,20 @@ function getHosts(client: BaseClient): string[] {
   return Defaults.getHosts(client.options);
 }
 
-const Http: IHttpStatic = class {
+function createMissingImplementationError() {
+  return new ErrorInfo(
+    'No HTTP request module provided. Provide at least one of the FetchRequest or XHRRequest modules.',
+    400,
+    40000
+  );
+}
+
+const Http = class {
   static methods = [HttpMethods.Get, HttpMethods.Delete, HttpMethods.Post, HttpMethods.Put, HttpMethods.Patch];
   static methodsWithoutBody = [HttpMethods.Get, HttpMethods.Delete];
   static methodsWithBody = [HttpMethods.Post, HttpMethods.Put, HttpMethods.Patch];
+  // HTTP request implementations that are available even without a BaseClient object (needed by some tests which directly instantiate `Http` without a client)
+  static bundledRequestImplementations: HTTPRequestImplementations;
   checksInProgress: Array<StandardCallback<boolean>> | null = null;
   private client: BaseClient | null;
 
@@ -51,7 +62,20 @@ const Http: IHttpStatic = class {
     const connectivityCheckUrl = client?.options.connectivityCheckUrl || Defaults.connectivityCheckUrl;
     const connectivityCheckParams = client?.options.connectivityCheckParams ?? null;
     const connectivityUrlIsDefault = !client?.options.connectivityCheckUrl;
-    if (Platform.Config.xhrSupported) {
+
+    const requestImplementations = {
+      ...Http.bundledRequestImplementations,
+      ...client?._additionalHTTPRequestImplementations,
+    };
+    const xhrRequestImplementation = requestImplementations.XHRRequest;
+    const fetchRequestImplementation = requestImplementations.FetchRequest;
+    const hasImplementation = !!(xhrRequestImplementation || fetchRequestImplementation);
+
+    if (!hasImplementation) {
+      throw createMissingImplementationError();
+    }
+
+    if (Platform.Config.xhrSupported && xhrRequestImplementation) {
       this.supportsAuthHeaders = true;
       this.Request = function (
         method: HttpMethods,
@@ -61,7 +85,7 @@ const Http: IHttpStatic = class {
         body: unknown,
         callback: RequestCallback
       ) {
-        const req = XHRRequest.createRequest(
+        const req = xhrRequestImplementation.createRequest(
           uri,
           headers,
           params,
@@ -104,10 +128,10 @@ const Http: IHttpStatic = class {
           );
         };
       }
-    } else if (Platform.Config.fetchSupported) {
+    } else if (Platform.Config.fetchSupported && fetchRequestImplementation) {
       this.supportsAuthHeaders = true;
       this.Request = (method, uri, headers, params, body, callback) => {
-        fetchRequest(method, client ?? null, uri, headers, params, body, callback);
+        fetchRequestImplementation(method, client ?? null, uri, headers, params, body, callback);
       };
       this.checkConnectivity = function (callback: (err: ErrorInfo | null, connectivity: boolean) => void) {
         Logger.logAction(Logger.LOG_MICRO, '(Fetch)Http.checkConnectivity()', 'Sending; ' + connectivityCheckUrl);
@@ -119,7 +143,10 @@ const Http: IHttpStatic = class {
       };
     } else {
       this.Request = (method, uri, headers, params, body, callback) => {
-        callback(new PartialErrorInfo('no supported HTTP transports available', null, 400), null);
+        const error = hasImplementation
+          ? new PartialErrorInfo('no supported HTTP transports available', null, 400)
+          : createMissingImplementationError();
+        callback(error, null);
       };
     }
   }

src/platform/web/lib/http/request/index.ts

@@ -0,0 +1,10 @@
+import { HTTPRequestImplementations } from '../http';
+import XHRRequest from './xhrrequest';
+import fetchRequest from './fetchrequest';
+
+export const defaultBundledRequestImplementations: HTTPRequestImplementations = {
+  XHRRequest: XHRRequest,
+  FetchRequest: fetchRequest,
+};
+
+export const modulesBundledRequestImplementations: HTTPRequestImplementations = {};

src/platform/web/modules.ts

@@ -15,13 +15,16 @@ import Logger from '../../common/lib/util/logger';
 import { getDefaults } from '../../common/lib/util/defaults';
 import WebStorage from './lib/util/webstorage';
 import PlatformDefaults from './lib/util/defaults';
+import { modulesBundledRequestImplementations } from './lib/http/request';
 
 Platform.BufferUtils = BufferUtils;
 Platform.Http = Http;
 Platform.Config = Config;
 Platform.Transports = ModulesTransports;
 Platform.WebStorage = WebStorage;
 
+Http.bundledRequestImplementations = modulesBundledRequestImplementations;
+
 Logger.initLogHandlers();
 
 Platform.Defaults = getDefaults(PlatformDefaults);
@@ -45,5 +48,6 @@ export * from './modules/presencemessage';
 export * from './modules/msgpack';
 export * from './modules/realtimepresence';
 export * from './modules/transports';
+export * from './modules/http';
 export { Rest } from '../../common/lib/client/rest';
 export { BaseRest, BaseRealtime, ErrorInfo };

src/platform/web/modules/http.ts

@@ -0,0 +1,2 @@
+export { default as XHRRequest } from '../lib/http/request/xhrrequest';
+export { default as FetchRequest } from '../lib/http/request/fetchrequest';