Implement WebSocket module for Android. Fixes #2837

Summary: The JavaScript code for Android is same as the iOS counterpart, I just added few new lines and used arrow functions instead of binding `this`.
Closes https://github.com/facebook/react-native/pull/2839

Reviewed By: @​svcscm, @vjeux

Differential Revision: D2498703

Pulled By: @mkonicek

fb-gh-sync-id: 3fe958dd5af0efba00df07515f8e33b5d87eb05b

ReactAndroid/src/main/java/com/facebook/react/modules/websocket/WebSocketModule.java

@@ -0,0 +1,170 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+package com.facebook.react.modules.websocket;
+
+import java.io.IOException;
+
+import com.facebook.common.logging.FLog;
+import com.facebook.react.bridge.Arguments;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.bridge.ReactContextBaseJavaModule;
+import com.facebook.react.bridge.ReactMethod;
+import com.facebook.react.bridge.WritableMap;
+import com.facebook.react.common.ReactConstants;
+import com.facebook.react.modules.core.DeviceEventManagerModule;
+
+import com.squareup.okhttp.OkHttpClient;
+import com.squareup.okhttp.Request;
+import com.squareup.okhttp.Response;
+import com.squareup.okhttp.ws.WebSocket;
+import com.squareup.okhttp.ws.WebSocketCall;
+import com.squareup.okhttp.ws.WebSocketListener;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import okio.Buffer;
+import okio.BufferedSource;
+
+public class WebSocketModule extends ReactContextBaseJavaModule {
+
+  private Map<Integer, WebSocket> mWebSocketConnections = new HashMap<>();
+  private ReactContext mReactContext;
+
+  public WebSocketModule(ReactApplicationContext context) {
+    super(context);
+    mReactContext = context;
+  }
+
+  private void sendEvent(String eventName, WritableMap params) {
+    mReactContext
+      .getJSModule(DeviceEventManagerModule.RCTDeviceEventEmitter.class)
+      .emit(eventName, params);
+  }
+
+  @Override
+  public String getName() {
+    return "WebSocketModule";
+  }
+
+  @ReactMethod
+  public void connect(final String url, final int id) {
+    OkHttpClient client = new OkHttpClient();
+
+    client.setConnectTimeout(10, TimeUnit.SECONDS);
+    client.setWriteTimeout(10, TimeUnit.SECONDS);
+    // Disable timeouts for read
+    client.setReadTimeout(0, TimeUnit.MINUTES);
+
+    Request request = new Request.Builder()
+        .tag(id)
+        .url(url)
+        .build();
+
+    WebSocketCall.create(client, request).enqueue(new WebSocketListener() {
+
+      @Override
+      public void onOpen(WebSocket webSocket, Response response) {
+        mWebSocketConnections.put(id, webSocket);
+        WritableMap params = Arguments.createMap();
+        params.putInt("id", id);
+        sendEvent("websocketOpen", params);
+      }
+
+      @Override
+      public void onClose(int code, String reason) {
+        WritableMap params = Arguments.createMap();
+        params.putInt("id", id);
+        params.putInt("code", code);
+        params.putString("reason", reason);
+        sendEvent("websocketClosed", params);
+      }
+
+      @Override
+      public void onFailure(IOException e, Response response) {
+        notifyWebSocketFailed(id, e.getMessage());
+      }
+
+      @Override
+      public void onPong(Buffer buffer) {
+      }
+
+      @Override
+      public void onMessage(BufferedSource bufferedSource, WebSocket.PayloadType payloadType) {
+        String message;
+        try {
+          message = bufferedSource.readUtf8();
+        } catch (IOException e) {
+          notifyWebSocketFailed(id, e.getMessage());
+          return;
+        }
+        try {
+          bufferedSource.close();
+        } catch (IOException e) {
+          FLog.e(
+            ReactConstants.TAG,
+            "Could not close BufferedSource for WebSocket id " + id,
+            e);
+        }
+
+        WritableMap params = Arguments.createMap();
+        params.putInt("id", id);
+        params.putString("data", message);
+        sendEvent("websocketMessage", params);
+      }
+    });
+
+    // Trigger shutdown of the dispatcher's executor so this process can exit cleanly
+    client.getDispatcher().getExecutorService().shutdown();
+  }
+
+  @ReactMethod
+  public void close(int code, String reason, int id) {
+    WebSocket client = mWebSocketConnections.get(id);
+    if (client == null) {
+      // This is a programmer error
+      throw new RuntimeException("Cannot close WebSocket. Unknown WebSocket id " + id);
+    }
+    try {
+      client.close(code, reason);
+      mWebSocketConnections.remove(id);
+    } catch (Exception e) {
+      FLog.e(
+        ReactConstants.TAG,
+        "Could not close WebSocket connection for id " + id,
+        e);
+    }
+  }
+
+  @ReactMethod
+  public void send(String message, int id) {
+    WebSocket client = mWebSocketConnections.get(id);
+    if (client == null) {
+      // This is a programmer error
+      throw new RuntimeException("Cannot send a message. Unknown WebSocket id " + id);
+    }
+    try {
+      client.sendMessage(
+        WebSocket.PayloadType.TEXT,
+        new Buffer().writeUtf8(message));
+    } catch (IOException e) {
+      notifyWebSocketFailed(id, e.getMessage());
+    }
+  }
+
+  private void notifyWebSocketFailed(int id, String message) {
+    WritableMap params = Arguments.createMap();
+    params.putInt("id", id);
+    params.putString("message", message);
+    sendEvent("websocketFailed", params);
+  }
+}

ReactAndroid/src/main/java/com/facebook/react/shell/MainReactPackage.java

@@ -21,6 +21,7 @@ import com.facebook.react.modules.fresco.FrescoModule;
 import com.facebook.react.modules.network.NetworkingModule;
 import com.facebook.react.modules.storage.AsyncStorageModule;
 import com.facebook.react.modules.toast.ToastModule;
+import com.facebook.react.modules.websocket.WebSocketModule;
 import com.facebook.react.uimanager.ViewManager;
 import com.facebook.react.views.drawer.ReactDrawerLayoutManager;
 import com.facebook.react.views.image.ReactImageManager;
@@ -47,6 +48,7 @@ public class MainReactPackage implements ReactPackage {
       new AsyncStorageModule(reactContext),
       new FrescoModule(reactContext),
       new NetworkingModule(reactContext),
+      new WebSocketModule(reactContext),
       new ToastModule(reactContext));
   }