I am using Leapjs external library and trying to execute a simple Leapjs function : loop in lightning component.

I got content security policy error which goes like this

Refused to connect to 'ws://' because it violates the following Content Security Policy directive: "connect-src 'self'".

now in documentation it says that XHR and websockets can only be called by same domain. (mostly it is lightning.force.com but my domain is

I have also added

<meta http-equiv="Content-Security-Policy" content="connect-src 'self'"/>

in my code

any workaround ?

3 Answers 3


Tested WebSockets in Open CTI adapter url. It works perfectly fine. Change the ws:// uri as per your setup in below source code.

   <script type="text/javascript" src="http://na11.salesforce.com/support/api/28.0/interaction.js"></script>
   <script type="text/javascript">
       var callback = function (response) {
           if (response.result) {
              alert('Screen pop was set successfully.');
           else {
              alert('Screen pop failed.' + result.error);
       function screenPop() {
                //Invokes API method
                sforce.interaction.screenPop('/001x0000003DGQR', true, callback);

        <script type="text/javascript">
            var webSocket;
            var data = "";

            function openSocket()
                // Open server socket
                if (webSocket !== undefined && webSocket.readyState !== WebSocket.CLOSED) {
                    alert("WebSocket is already opened");

                webSocket = new WebSocket("ws://xxx.xxx.xxx.xxx:8080/sample/sampleendpoint");

                if (webSocket === undefined)
                    alert("Error creating socket...");

                webSocket.onopen = function()
                    alert("in onopen callback");

                webSocket.onmessage = function(event)
                    alert("in onmessage callback   " + data);

                webSocket.onclose = function()
                    alert("in onclose callback");


       <button onclick="openSocket();">Open Socket</button>

This is a known limitation with lightning currently

However I see that your script is trying to make the call to a third party URL .You will need to identify the script and try and make the callout via apex .From lightning due to security limitations no XHR will be allowed .

The other workaround will be to proxy this via the Visualforce .There is a neat article on how to do this

Blog article from developer force

Also if the webserver is just returning a JSON without any processing you may download the file and keep inside static resource .

  • I have Leap motion controller and it feeds data to websocket as json. Its is very dynamic data as per my hand movements. it cannot be static
    – Manju
    Oct 12, 2015 at 2:32
  • You may need to go via vf proxy..Looks no other alternative to me.. Oct 12, 2015 at 2:58
  • I tried using VF , i have another juggling . there is reference to local storage in in leapjs library and VF is not liking it!
    – Manju
    Oct 12, 2015 at 3:02
  • @MohithShrivastava I just tripped upon this today, but it looks like CSP Trusted Sites now supports Websockets. Notice in the official documentation that wss is now supported. Finally! Dec 30, 2019 at 18:57

I'm not sure when this went live as there's still an open idea on this topic, but WebSockets are now supported in CSP Trusted Site settings.

Add you wss:// endpoint via Setup -> CSP Trusted Site and you should be good to go.

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