feat: Implement polling support. (#524)

Author: kinyoklion

packages/sdk/react-native/example/src/welcome.tsx

@@ -16,6 +16,7 @@ export default function Welcome() {
       .catch((e: any) => console.error(`error identifying ${userKey}: ${e}`));
   };
 
+
   const setConnectionMode = (m: ConnectionMode) => {
     ldc.setConnectionMode(m);
   };
@@ -56,7 +57,13 @@ export default function Welcome() {
         style={styles.buttonContainer}
         onPress={() => setConnectionMode('streaming')}
       >
-        <Text style={styles.buttonText}>Set online</Text>
+        <Text style={styles.buttonText}>Set streaming</Text>
+      </TouchableOpacity>
+      <TouchableOpacity
+        style={styles.buttonContainer}
+        onPress={() => setConnectionMode('polling')}
+      >
+        <Text style={styles.buttonText}>Set polling</Text>
       </TouchableOpacity>
     </View>
   );

packages/sdk/react-native/src/RNStateDetector.ts

@@ -2,6 +2,9 @@ import { AppState, AppStateStatus } from 'react-native';
 
 import { ApplicationState, NetworkState, StateDetector } from './platform/ConnectionManager';
 
+/**
+ * @internal
+ */
 function translateAppState(state: AppStateStatus): ApplicationState {
   switch (state) {
     case 'active':
@@ -14,6 +17,9 @@ function translateAppState(state: AppStateStatus): ApplicationState {
   }
 }
 
+/**
+ * @internal
+ */
 export default class RNStateDetector implements StateDetector {
   private applicationStateListener?: (state: ApplicationState) => void;
   private networkStateListener?: (state: NetworkState) => void;

packages/sdk/react-native/src/ReactNativeLDClient.ts

@@ -98,8 +98,16 @@ export default class ReactNativeLDClient extends LDClientImpl {
     super.setConnectionMode(mode);
   }
 
+  private encodeContext(context: LDContext) {
+    return base64UrlEncode(JSON.stringify(context), this.platform.encoding!);
+  }
+
   override createStreamUriPath(context: LDContext) {
-    return `/meval/${base64UrlEncode(JSON.stringify(context), this.platform.encoding!)}`;
+    return `/meval/${this.encodeContext(context)}`;
+  }
+
+  override createPollUriPath(context: LDContext): string {
+    return `/msdk/evalx/contexts/${this.encodeContext(context)}`;
   }
 
   override async setConnectionMode(mode: ConnectionMode): Promise<void> {

packages/sdk/react-native/src/platform/ConnectionManager.ts

@@ -1,5 +1,8 @@
 import { ConnectionMode, LDLogger } from '@launchdarkly/js-client-sdk-common';
 
+/**
+ * @internal
+ */
 export enum ApplicationState {
   /// The application is in the foreground.
   Foreground = 'foreground',
@@ -11,6 +14,9 @@ export enum ApplicationState {
   Background = 'background',
 }
 
+/**
+ * @internal
+ */
 export enum NetworkState {
   /// There is no network available for the SDK to use.
   Unavailable = 'unavailable',
@@ -20,19 +26,28 @@ export enum NetworkState {
   Available = 'available',
 }
 
+/**
+ * @internal
+ */
 export interface ConnectionDestination {
   setNetworkAvailability(available: boolean): void;
   setEventSendingEnabled(enabled: boolean, flush: boolean): void;
   setConnectionMode(mode: ConnectionMode): Promise<void>;
 }
 
+/**
+ * @internal
+ */
 export interface StateDetector {
   setApplicationStateListener(fn: (state: ApplicationState) => void): void;
   setNetworkStateListener(fn: (state: NetworkState) => void): void;
 
   stopListening(): void;
 }
 
+/**
+ * @internal
+ */
 export interface ConnectionManagerConfig {
   /// The initial connection mode the SDK should use.
   readonly initialConnectionMode: ConnectionMode;
@@ -51,6 +66,9 @@ export interface ConnectionManagerConfig {
   readonly automaticBackgroundHandling: boolean;
 }
 
+/**
+ * @internal
+ */
 export class ConnectionManager {
   private applicationState: ApplicationState = ApplicationState.Foreground;
   private networkState: NetworkState = NetworkState.Available;

packages/shared/sdk-client/src/LDClientImpl.storage.test.ts

@@ -37,7 +37,7 @@ const onChangePromise = () =>
   });
 
 // Common setup code for all tests
-// 1. Sets up streamer
+// 1. Sets up streaming
 // 2. Sets up the change listener
 // 3. Runs identify
 // 4. Get all flags
@@ -58,7 +58,7 @@ const identifyGetAllFlags = async (
   }
   jest.runAllTimers();
 
-  // if streamer errors, don't wait for 'change' because it will not be sent.
+  // if streaming errors, don't wait for 'change' because it will not be sent.
   if (waitForChange && !shouldError) {
     await changePromise;
   }
@@ -91,8 +91,8 @@ describe('sdk-client storage', () => {
     jest.resetAllMocks();
   });
 
-  test('initialize from storage succeeds without streamer', async () => {
-    // make sure streamer errors
+  test('initialize from storage succeeds without streaming', async () => {
+    // make sure streaming errors
     const allFlags = await identifyGetAllFlags(true, defaultPutResponse);
 
     expect(basicPlatform.storage.get).toHaveBeenCalledWith('org:Testy Pizza');
@@ -185,7 +185,7 @@ describe('sdk-client storage', () => {
     expect(emitter.emit).not.toHaveBeenCalled();
   });
 
-  test('no storage, cold start from streamer', async () => {
+  test('no storage, cold start from streaming', async () => {
     // fake previously cached flags even though there's no storage for this context
     // @ts-ignore
     ldc.flags = defaultPutResponse;
@@ -201,7 +201,7 @@ describe('sdk-client storage', () => {
       JSON.stringify(defaultPutResponse),
     );
     expect(ldc.logger.debug).toHaveBeenCalledWith(
-      'OnIdentifyResolve no changes to emit from: streamer PUT.',
+      'OnIdentifyResolve no changes to emit from: stream PUT.',
     );
 
     // this is defaultPutResponse

packages/shared/sdk-client/src/LDClientImpl.timeout.test.ts

@@ -34,7 +34,7 @@ describe('sdk-client identify timeout', () => {
   beforeEach(() => {
     defaultPutResponse = clone<Flags>(mockResponseJson);
 
-    // simulate streamer error after a long timeout
+    // simulate streaming error after a long timeout
     setupMockStreamingProcessor(true, defaultPutResponse, undefined, undefined, 30);
 
     ldc = new LDClientImpl(testSdkKey, AutoEnvAttributes.Enabled, basicPlatform, {
@@ -50,14 +50,14 @@ describe('sdk-client identify timeout', () => {
     jest.resetAllMocks();
   });
 
-  // streamer is setup to error in beforeEach to cause a timeout
+  // streaming is setup to error in beforeEach to cause a timeout
   test('rejects with default timeout of 5s', async () => {
     jest.advanceTimersByTimeAsync(ldc.identifyTimeout * 1000).then();
     await expect(ldc.identify(carContext)).rejects.toThrow(/identify timed out/);
     expect(logger.error).toHaveBeenCalledWith(expect.stringMatching(/identify timed out/));
   });
 
-  // streamer is setup to error in beforeEach to cause a timeout
+  // streaming is setup to error in beforeEach to cause a timeout
   test('rejects with custom timeout', async () => {
     const timeout = 15;
     jest.advanceTimersByTimeAsync(timeout * 1000).then();