Persistent websocket connection from Android to Packager

Reviewed By: astreet

Differential Revision: D3447685

fbshipit-source-id: 0e4e3fb02b84b9b15c2c798c0e4c89ff6fd1665c

ReactAndroid/src/main/java/com/facebook/react/bridge/JSPackagerWebSocketClient.java

@@ -0,0 +1,164 @@
+/**
+ * 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.bridge;
+
+import javax.annotation.Nullable;
+
+import java.io.IOException;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.concurrent.TimeUnit;
+
+import com.facebook.common.logging.FLog;
+
+import com.fasterxml.jackson.core.JsonFactory;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.JsonToken;
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+import okhttp3.ResponseBody;
+import okhttp3.ws.WebSocket;
+import okhttp3.ws.WebSocketCall;
+import okhttp3.ws.WebSocketListener;
+import okio.Buffer;
+
+/**
+ * A wrapper around WebSocketClient that recognizes packager's message format.
+ */
+public class JSPackagerWebSocketClient implements WebSocketListener {
+
+  private static final String TAG = "JSPackagerWebSocketClient";
+  private final String mUrl;
+
+  public interface JSPackagerCallback {
+    void onMessage(String target, String action);
+  }
+
+  private @Nullable WebSocket mWebSocket;
+  private @Nullable JSPackagerCallback mCallback;
+
+  public JSPackagerWebSocketClient(String url, JSPackagerCallback callback) {
+    super();
+    mUrl = url;
+    mCallback = callback;
+  }
+
+  public void connect() {
+    OkHttpClient  httpClient = new OkHttpClient.Builder()
+        .connectTimeout(10, TimeUnit.SECONDS)
+        .writeTimeout(10, TimeUnit.SECONDS)
+        .readTimeout(0, TimeUnit.MINUTES) // Disable timeouts for read
+        .build();
+
+    Request request = new Request.Builder().url(mUrl).build();
+    WebSocketCall call = WebSocketCall.create(httpClient, request);
+    call.enqueue(this);
+  }
+
+  private void reconnect() {
+    new Timer().schedule(new TimerTask() {
+      @Override
+      public void run() {
+        connect();
+      }
+    }, 2000);
+  }
+
+  public void closeQuietly() {
+    if (mWebSocket != null) {
+      try {
+        mWebSocket.close(1000, "End of session");
+      } catch (IOException e) {
+        // swallow, no need to handle it here
+      }
+      mWebSocket = null;
+    }
+  }
+
+  private void triggerMessageCallback(String target, String action) {
+    if (mCallback != null) {
+      mCallback.onMessage(target, action);
+    }
+  }
+
+  @Override
+  public void onMessage(ResponseBody response) throws IOException {
+    if (response.contentType() != WebSocket.TEXT) {
+      FLog.w(TAG, "Websocket received unexpected message with payload of type " + response.contentType());
+      return;
+    }
+
+    String message = null;
+    try {
+      message = response.source().readUtf8();
+    } finally {
+      response.close();
+    }
+
+    try {
+      JsonParser parser = new JsonFactory().createParser(message);
+
+      Integer version = null;
+      String target = null;
+      String action = null;
+
+      while (parser.nextToken() != JsonToken.END_OBJECT) {
+        String field = parser.getCurrentName();
+        if ("version".equals(field)) {
+          parser.nextToken();
+          version = parser.getIntValue();
+        } else if ("target".equals(field)) {
+          parser.nextToken();
+          target = parser.getText();
+        } else if ("action".equals(field)) {
+          parser.nextToken();
+          action = parser.getText();
+        }
+      }
+      if (version != 1) {
+        return;
+      }
+      if (target == null || action == null) {
+        return;
+      }
+
+      triggerMessageCallback(target, action);
+    } catch (IOException e) {
+      abort("Parsing response message from websocket failed", e);
+    }
+  }
+
+  @Override
+  public void onFailure(IOException e, Response response) {
+    abort("Websocket exception", e);
+    reconnect();
+  }
+
+  @Override
+  public void onOpen(WebSocket webSocket, Response response) {
+    mWebSocket = webSocket;
+  }
+
+  @Override
+  public void onClose(int code, String reason) {
+    mWebSocket = null;
+    reconnect();
+  }
+
+  @Override
+  public void onPong(Buffer payload) {
+    // ignore
+  }
+
+  private void abort(String message, Throwable cause) {
+    FLog.e(TAG, "Error occurred, shutting down websocket connection: " + message, cause);
+    closeQuietly();
+  }
+}