From 1f0a615e1121522890680ba55d9e4778cbc57020 Mon Sep 17 00:00:00 2001
From: Pierre HUBERT <pierre.git@communiquons.org>
Date: Sat, 19 Jan 2019 13:10:28 +0100
Subject: [PATCH] Can exchange messages between clients

---
 client/SignalExchangerClient.js | 66 +++++++++++++++++++++++++++++++++
 client/test-client.js           |  8 +++-
 sockets.js                      | 62 +++++++++++++++++++++++++++++--
 3 files changed, 132 insertions(+), 4 deletions(-)

diff --git a/client/SignalExchangerClient.js b/client/SignalExchangerClient.js
index 0e8a7dc..dacc182 100644
--- a/client/SignalExchangerClient.js
+++ b/client/SignalExchangerClient.js
@@ -79,6 +79,21 @@ class SignalExchangerClient {
                 setTimeout(this.onConnected, 10);
         });
 
+        this.socket.addEventListener("message", message => {
+
+            let data;
+            try {
+                data = JSON.parse(message.data);
+            } catch(e){
+                console.error("Could not parse message from server!");
+                return;
+            }
+
+            console.log("New message from socket", data);
+
+            this.serverMessage(data);
+        });
+
         this.socket.addEventListener("error", () => {
             if(this.onError != null)
                 setTimeout(this.onError, 0);
@@ -103,12 +118,63 @@ class SignalExchangerClient {
 
     }
 
+    /**
+     * Send a signal to the server
+     * 
+     * @param target_id The ID of the target for the signal
+     * @param content Signal to send to the target
+     */
+    sendSignal(target_id, content){
+        
+        //Send directly the message to the server
+        this.sendData({
+            signal: content,
+            target_id: target_id
+        });
+
+        //Save the current signal being sent to be able to send
+        //it again in case of failure
+        this.pending_signal = content;
+        this.pending_signal_target = target_id;
+    }
+
     /**
      * Send data to the server
      * 
      * @param {Object} data The data to send to the server
      */
     sendData(data){
+        console.log("Sending data to server", data);
         this.socket.send(JSON.stringify(data));
     }
+
+    /**
+     * This method is called when the server has sent a new message to this client
+     * 
+     * @param {Object} message The message sent by the server, as a JSON object
+     */
+    serverMessage(message){
+
+        //Check if it is a callback for a pending message
+        if(message.signal_sent){
+            if(message.number_of_targets < 1 && this.pending_signal && this.pending_signal_target){
+
+                //We have to send the message again
+                setTimeout(() => {
+                    this.sendSignal(this.pending_signal, this.pending_signal_target);
+                }, 1000);
+
+            }
+
+            else {
+
+                //Else we can remove from this class information about the signal being sent
+                this.pending_signal = undefined;
+                this.pending_signal_target = undefined;
+
+            }
+        } 
+
+
+    }
 }
\ No newline at end of file
diff --git a/client/test-client.js b/client/test-client.js
index 29eab7b..0f0d3e9 100644
--- a/client/test-client.js
+++ b/client/test-client.js
@@ -7,7 +7,8 @@
 const Config = {
     port: 8081,
     server_name: "localhost",
-    clientID: location.href.toString().includes("#1") ? "client-1" : "client-2"
+    clientID: location.href.toString().includes("#1") ? "client-1" : "client-2",
+    otherPeerID: location.href.toString().includes("#1") ? "client-2" : "client-1"
 };
 
 let client = new SignalExchangerClient(
@@ -18,6 +19,11 @@ let client = new SignalExchangerClient(
 
 client.onConnected = function(){
     console.log("Connected to signal exchanger server.");
+
+    client.sendSignal(
+        Config.otherPeerID,
+        "A signal content from " + Config.clientID + " to " + Config.otherPeerID, 
+    );
 }
 
 client.onError = function() {
diff --git a/sockets.js b/sockets.js
index d801807..51b3d20 100644
--- a/sockets.js
+++ b/sockets.js
@@ -49,6 +49,34 @@ function RemoveSocketFromList(socket){
 
 }
 
+/**
+ *  
+ * @param {String} content The content of the signal
+ * @param {String} source_id The ID of the source of the message
+ * @param {String} target_id The ID of the target client
+ * @return {Number} The number of sockets to which the message was sent
+ */
+function SendSignalToClient(content, source_id, target_id){
+
+    let count = 0;
+
+    SocketsList.forEach(info => {
+
+        if(info.id == target_id){
+            SendMessageToSocket(info.socket, {
+                signal: content,
+                source_id: source_id
+            });
+
+            count++;
+        }
+
+    });
+
+    return count;
+
+}
+
 /**
  * Add a socket to the list of active sockets
  * 
@@ -71,6 +99,14 @@ exports.addSocket = function(socket){
      */
     socket.on("message",  message => {
 
+        //Make sure the message is not too heavy
+        if(message.length > 10000){
+            SendMessageToSocket(socket, {
+                error: "Your request is too heavy for this server!"
+            })
+            return;
+        }
+
         //Decode message
         let data;
         try {
@@ -110,10 +146,30 @@ exports.addSocket = function(socket){
             });
         }
 
+        //Check if the client wants to send a signal to another client
+        else if(data.signal && data.target_id) {
+
+            if(typeof data.signal !== "string" || typeof data.target_id !== "string"){
+                SendMessageToSocket(socket, {
+                    error: "Unsecure request!"
+                });
+                return;
+            }
+
+            //Send the signal to the target client
+            let number_target = SendSignalToClient(data.signal, client_id, data.target_id);
+
+            SendMessageToSocket(socket, {
+                signal_sent: true,
+                number_of_targets: number_target
+            });
+        }
+
+        //Message not understood
         else {
-
-
-
+            SendMessageToSocket(socket, {
+                error: "Could not understand your request!"
+            });
         }
     });