Use ConcurrentHashMap for handling concurrent Android websockets, and…

Summary:
… prevent unknown websocket IDs from crashing on Android (show warning on development builds instead)

This PR addresses #3346; an unknown websocket ID should produce a warning during development, but not cause crashes in production RN apps. This PR was created by satya164's request, and was inspired by tanthanh289's suggestion on #3346's thread.

On Android, create a websocket using a service like Pusher (`pusher-js` npm package) or manually, and then induce removal of its websocket ID. Result should be a red warning screen during development, and no crash in the app's release variant.

 [ANDROID] [BUGFIX] [WebSocket] - Prevent unknown websocket IDs from crashing on Android
Closes #17884

Differential Revision: D6954038

Pulled By: hramos

fbshipit-source-id: b346d80d7568996b8819c0de54552abb534cbfae

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

@@ -27,6 +27,7 @@
 import java.io.IOException;
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -48,8 +49,8 @@ public interface ContentHandler {
     void onMessage(ByteString byteString, WritableMap params);
   }
 
-  private final Map<Integer, WebSocket> mWebSocketConnections = new HashMap<>();
-  private final Map<Integer, ContentHandler> mContentHandlers = new HashMap<>();
+  private final Map<Integer, WebSocket> mWebSocketConnections = new ConcurrentHashMap<>();
+  private final Map<Integer, ContentHandler> mContentHandlers = new ConcurrentHashMap<>();
 
   private ReactContext mReactContext;
   private ForwardingCookieHandler mCookieHandler;
@@ -224,8 +225,19 @@ public void close(int code, String reason, int id) {
   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);
+      // This is a programmer error -- display development warning
+      WritableMap params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putString("message", "client is null");
+      sendEvent("websocketFailed", params);
+      params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putInt("code", 0);
+      params.putString("reason", "client is null");
+      sendEvent("websocketClosed", params);
+      mWebSocketConnections.remove(id);
+      mContentHandlers.remove(id);
+      return;
     }
     try {
       client.send(message);
@@ -238,8 +250,19 @@ public void send(String message, int id) {
   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);
+      // This is a programmer error -- display development warning
+      WritableMap params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putString("message", "client is null");
+      sendEvent("websocketFailed", params);
+      params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putInt("code", 0);
+      params.putString("reason", "client is null");
+      sendEvent("websocketClosed", params);
+      mWebSocketConnections.remove(id);
+      mContentHandlers.remove(id);
+      return;
     }
     try {
       client.send(ByteString.decodeBase64(base64String));
@@ -251,8 +274,19 @@ public void sendBinary(String base64String, int id) {
   public void sendBinary(ByteString byteString, 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);
+      // This is a programmer error -- display development warning
+      WritableMap params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putString("message", "client is null");
+      sendEvent("websocketFailed", params);
+      params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putInt("code", 0);
+      params.putString("reason", "client is null");
+      sendEvent("websocketClosed", params);
+      mWebSocketConnections.remove(id);
+      mContentHandlers.remove(id);
+      return;
     }
     try {
       client.send(byteString);
@@ -265,8 +299,19 @@ public void sendBinary(ByteString byteString, int id) {
   public void ping(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);
+      // This is a programmer error -- display development warning
+      WritableMap params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putString("message", "client is null");
+      sendEvent("websocketFailed", params);
+      params = Arguments.createMap();
+      params.putInt("id", id);
+      params.putInt("code", 0);
+      params.putString("reason", "client is null");
+      sendEvent("websocketClosed", params);
+      mWebSocketConnections.remove(id);
+      mContentHandlers.remove(id);
+      return;
     }
     try {
       client.send(ByteString.EMPTY);