检索和发布会话数据

Question

我正在创建一个聊天框，检索会话中保存的user_id，然后使用ajax帖子，但由于某种原因，保存在会话中的user_id为空，而不是保存在数据库中，我现在已经存货了。 / p>

控制器

function add_chat_messages() {
        // Grab the $chat_message_content, $user_id and $chat_id 
        $user_id = $this->session->userdata("user_id");
        $chat_message_content = $this->input->post('chat_message_content');

        $this->abt_db->add_chat_message($user_id, $chat_message_content);
    }

模型

function add_chat_message($user_id, $chat_message_content) {

    $query_str = "INSERT INTO chat_message(user_id, chat_message_content) VALUES (?,?)";
    $this->db->query($query_str, array($user_id, $chat_message_content));
}

function set_session() {
        // session->set_userdata is a CodeIgniter function that
        // stores data in a cookie in the user's browser.  Some of the values are built in
        // to CodeIgniter, others are added (like the user_id).  
        $this->session->set_userdata(array(
            'user_id' => $this->details->user_id,
            'email' => $this->details->email,
            'username' => $this->details->username,
            'isLoggedIn' => true
                )
        );

    }

查看

<script type="text/javascript">

    var user_id = "<?php echo $this->session->userdata('user_id'); ?>";
    var base_url = "<?php echo base_url(); ?>";


</script>

<!--loads the header-->
<?php $this->load->view('abt-header'); ?>
<!--this is the login page-->

<div data-role="page" id="Abt-chat" data-add-back-btn="true">
    <div data-role="header" data-position="fixed">
        <h1>Peer Chat</h1>

    </div>
    <div data-role="content">

        <div data-role="fieldcontain">
            <div id="chat_viewport"></div>

            <p>
                <label>Input Chat: </label>
                <input name="chat" id="chat" type="text" value=""/>

            </p>

            <p>
                <?php echo anchor('#', 'Send Chat', array('title' => 'Send Chat', 'id' => 'submit')); ?>
            </p>  

        </div> 
        <?php echo form_close(); ?>

    </div>

</div>

Javascript文件

$(document).bind("mobileinit", function(){
    $.mobile.ajaxEnabled = false;
}); 


$(document).ready(function(){

    $("a#submit").click(function(){

        var chat_message_content = $("input#chat").val();

        if(chat_message_content == ""){

            return false;
        }

        $.post(base_url + "index.php/abovetheblues/add_chat_messages", {
            chat_message_content : chat_message_content,
            user_id : user_id
        }, 
        function(data){

            alert(data);
        },"json");


        return false;
    });
    return false;

});