Add support for sending binary data in websockets

Summary:This is a reprise of #6327, but with iOS 7.0 compatibility and less `package.json` changes.

**Test Plan:** Load WebSocketExample in UIExplorer app and start websocket test server script (both provided in #6889) and test sending binary data on both iOS and Android
Closes https://github.com/facebook/react-native/pull/6961

Differential Revision: D3202022

Pulled By: mkonicek

fb-gh-sync-id: 38843d0a9c0172971c5c70a5139ded04042b280a
fbshipit-source-id: 38843d0a9c0172971c5c70a5139ded04042b280a

Examples/UIExplorer/websocket_test_server.js

@@ -31,7 +31,7 @@ const respondWithBinary = process.argv.indexOf('--binary') !== -1;
 const server = new WebSocket.Server({port: 5555});
 server.on('connection', (ws) => {
   ws.on('message', (message) => {
-    console.log('Received message: %s', message);
+    console.log('Received message:', message);
     if (respondWithBinary) {
       message = new Buffer(message);
     }

Libraries/WebSocket/RCTWebSocketModule.m

@@ -67,6 +67,12 @@ RCT_EXPORT_METHOD(send:(NSString *)message socketID:(nonnull NSNumber *)socketID
   [_sockets[socketID] send:message];
 }
 
+RCT_EXPORT_METHOD(sendBinary:(NSString *)base64String socketID:(nonnull NSNumber *)socketID)
+{
+  NSData *message = [[NSData alloc] initWithBase64EncodedString:base64String options:0];
+  [_sockets[socketID] send:message];
+}
+
 RCT_EXPORT_METHOD(close:(nonnull NSNumber *)socketID)
 {
   [_sockets[socketID] close];

Libraries/WebSocket/WebSocket.js

@@ -21,6 +21,18 @@ const base64 = require('base64-js');
 
 import type EventSubscription from 'EventSubscription';
 
+type ArrayBufferView =
+  Int8Array |
+  Uint8Array |
+  Uint8ClampedArray |
+  Int16Array |
+  Uint16Array |
+  Int32Array |
+  Uint32Array |
+  Float32Array |
+  Float64Array |
+  DataView;
+
 const CONNECTING = 0;
 const OPEN = 1;
 const CLOSING = 2;
@@ -94,18 +106,31 @@ class WebSocket extends EventTarget(WEBSOCKET_EVENTS) {
     this._close(code, reason);
   }
 
-  send(data: any): void {
+  send(data: string | ArrayBuffer | ArrayBufferView): void {
     if (this.readyState === this.CONNECTING) {
       throw new Error('INVALID_STATE_ERR');
     }
 
     if (typeof data === 'string') {
       RCTWebSocketModule.send(data, this._socketId);
-    } else if (data instanceof ArrayBuffer) {
-      console.warn('Sending ArrayBuffers is not yet supported');
-    } else {
-      throw new Error('Not supported data type');
+      return;
     }
+
+    // Maintain iOS 7 compatibility which doesn't have JS typed arrays.
+    if (typeof ArrayBuffer !== 'undefined' &&
+        typeof Uint8Array !== 'undefined') {
+      if (ArrayBuffer.isView(data)) {
+        // $FlowFixMe: no way to assert that 'data' is indeed an ArrayBufferView now
+        data = data.buffer;
+      }
+      if (data instanceof ArrayBuffer) {
+        data = base64.fromByteArray(new Uint8Array(data));
+        RCTWebSocketModule.sendBinary(data, this._socketId);
+        return;
+      }
+    }
+
+    throw new Error('Unsupported data type');
   }
 
   _close(code?: number, reason?: string): void {

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

@@ -44,6 +44,7 @@ import java.util.concurrent.TimeUnit;
 
 import okio.Buffer;
 import okio.BufferedSource;
+import okio.ByteString;
 
 public class WebSocketModule extends ReactContextBaseJavaModule {
 
@@ -216,6 +217,22 @@ public class WebSocketModule extends ReactContextBaseJavaModule {
     }
   }
 
+  @ReactMethod
+  public void sendBinary(String base64String, 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.BINARY,
+        new Buffer().write(ByteString.decodeBase64(base64String)));
+    } catch (IOException | IllegalStateException e) {
+      notifyWebSocketFailed(id, e.getMessage());
+    }
+  }
+
   private void notifyWebSocketFailed(int id, String message) {
     WritableMap params = Arguments.createMap();
     params.putInt("id", id);