[WebSocket][Android] Support WebSocket sub-protocols on Android fixes #5810

Author: zxcpoiu

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

@@ -64,7 +64,6 @@ public String getName() {
 
   @ReactMethod
   public void connect(final String url, @Nullable final ReadableArray protocols, @Nullable final ReadableMap options, final int id) {
-    // ignoring protocols, since OKHttp overrides them.
     OkHttpClient client = new OkHttpClient();
 
     client.setConnectTimeout(10, TimeUnit.SECONDS);
@@ -86,6 +85,21 @@ public void connect(final String url, @Nullable final ReadableArray protocols, @
       }
     }
 
+    if (protocols != null && protocols.size() > 0) {
+      StringBuilder protocolsValue = new StringBuilder("");
+      for (int i = 0; i < protocols.size(); i++) {
+        String v = protocols.getString(i).trim();
+        if (!v.isEmpty() && !v.contains(",")) {
+          protocolsValue.append(v);
+          protocolsValue.append(",");
+        }
+      }
+      if (protocolsValue.length() > 0) {
+        protocolsValue.replace(protocolsValue.length() - 1, protocolsValue.length(), "");
+        builder.addHeader("Sec-WebSocket-Protocol", protocolsValue.toString());
+      }
+    }
+
     WebSocketCall.create(client, builder.build()).enqueue(new WebSocketListener() {
 
       @Override