<rst>EN::12-Examples::005-PHP chat example</rst>
<rst>Header: PHP chat example</rst>

====== PHP chat example ======

An example of using the [[https://github.com/CppComet/comet-server|CppComet]] server to create a chat.   

  * [[https://jsfiddle.net/Levhav/o35kvmn2/17/|jsfiddle.net online demo]]
  * [[https://github.com/CppComet/php-chat-example|Github repo]]

{{ :en:comet:chat.gif |chat demo}}

====== Scheme of chat ======

Typical scheme of chat:

{{ :en:comet:scheme-of-chat.jpg |Typical scheme of chat}}

  * Connecting to the comet server by websockets
  * Send ajax message for add new massage to chat
  * Send message to CppComet
  * CppComet send messages for all subscribers in pipe
  * Add message to database (optional)
 
====== Step 1. Connecting to the comet server ======

[[https://github.com/CppComet/comet-server|CppComet]] has cloud saas alternative that can be used for testing and demo access. In the following examples I will use demonstration access from https://comet-server.com for those who could not or were too lazy to [[https://github.com/CppComet/comet-server#building-from-source|deploy the server on their VPS]]

<code>Login: 15
Password:lPXBFPqNg3f661JcegBY0N0dPXqUBdHXqj2cHf04PZgLHxT6z55e20ozojvMRvB8
Host: app.comet-server.ru</code>

To connect to the comet server from the JavaScript API, use the following command:

<code JavaScript>
cometApi.start({node:"app.comet-server.ru", dev_id:15})
</code>

* in parameter node - set hostname of your own server
* parameter dev_id - use only if you use saas service comet-server.com


====== Step 2. Send message to server ======

* Send ajax query to php back-end
* Send CometQL query for comet server

[[https://github.com/CppComet/php-chat-example/blob/master/chat.php|code of php back-end]]

Connection code to CppComet using MySQL protocol:
<code PHP>
$host = "app.comet-server.ru";
$user = "15";
$password = "lPXBFPqNg3f661JcegBY0N0dPXqUBdHXqj2cHf04PZgLHxT6z55e20ozojvMRvB8";
$comet = mysqli_connect($host, $user, $password, "CometQL_v1");
</code>


The code for sending a message to the pipe "simplechat" and event 'newMessage':
<code PHP>
$query = "INSERT INTO pipes_messages (name, event, message)VALUES('simplechat', 'newMessage', '".$msg."')"; 
mysqli_query($comet, $query);
</code>


====== Step 3. Receive message from comet server ======

Subscription code to the pipe on comet server. This callback will be called when somebody sends message into channel `simplechat`

<code JavaScript>
    cometApi.subscription("simplechat.newMessage", function(event){
        $("#web_chat").append('<b>'+HtmlEncode(event.data.name)+'</b>')
        $("#web_chat").append('<pre>'+HtmlEncode(event.data.text)+'</pre>')
        $("#web_chat").append('<br>')
    })
</code>

====== Full chat code ======

<html>
<script async src="//jsfiddle.net/Levhav/o35kvmn2/17/embed/"></script>
</html>

====== Links ======

  * [[en:comet:javascript_api|JavaScript API]]
  * [[en:comet:cometql|CometQL API]]
  * [[https://jsfiddle.net/o35kvmn2/5/|Online demo]]
  * [[https://github.com/CppComet/comet-server|CppComet]]
  * [[https://www.codeproject.com/script/Articles/ArticleVersion.aspx?waid=235463&aid=1181698|Creating a simple chat using CppComet]]