使用jquery / ajax / php / oop codeigniter聊天应用程序
您好，这个问题涉及我最近发布的一个问题，我试图找到至少一些有助于解决整个问题的总体帮助。 下面的代码不是我的，我不得不修复它，只是为了让它在现在的范围内工作，但是_get_chat_messages中的算法继续执行else条件。 这没有意义，因为Mysql中有聊天消息数据。 我试图让这个源代码工作，希望它能够带领我在正确的方向上自动刷新聊天消息内容，而不会强制浏览器客户端刷新或重定向标头。
什么导致_get_chat_messages执行else条件而不考虑if条件。 如果条件似乎评估为真，这是没有意义的。
任何帮助非常感谢。 谢谢。
// JQUERY / AJAX：
$(document).ready(function() {
setInterval(function() { get_chat_messages(); } , 2500);
$("input#chat_message").keypress(function(e) {
if (e.which == 13) {
$("a#submit_message").click();
return false;
}
});
$("#submit_message").click(function() {
var chat_message_content = $("input#chat_message").val();
//this if condition seems to be ignored not sure why?
if (chat_message_content == "") { return false; }
$.post(base_url + "chat/ajax_add_chat_message", { chat_message_content : chat_message_content, chat_id : chat_id, user_id : user_id }, function(data) {
if (data.status == 'ok')
{
var current_content = $("div#chat_viewport").html();
$("div#chat_viewport").html(current_content + data.message_content);
}
else
{
// there was an error do something
}
}, "json");
$("input#chat_message").val("");
return false;
});
function get_chat_messages()
{
$.post(base_url + "chat/ajax_get_chat_messages", { chat_id : chat_id }, function(data) {
if (data.status == 'ok')
{
var current_content = $("div#chat_viewport").html();
$("div#chat_viewport").html(current_content + data.message_content);
}
else
{
// there was an error do something
}
}, "json");
}
get_chat_messages();
});
//控制器：
class Chat extends CI_Controller {
public function __construct()
{
parent:: __construct();
$this->load->model('chat_model');
}
public function index()
{
/* send in chat id and user id */
$this->view_data['chat_id'] = 1;
// check they are logged in
if (! $this->session->userdata('logged_in')) {
redirect('user/login');
}
$this->view_data['user_id'] = $this->session->userdata('user_id');
$this->session->set_userdata('last_chat_message_id_' . $this->view_data['chat_id'], 0);
$this->view_data['page_title'] = 'web based chat app :)';
$this->view_data['page_content'] = 'view_chat';
$this->load->view('view_main', $this->view_data);
}
public function ajax_add_chat_message()
{
/* Scalar Variable data that needs to be POST'ed to this function
*
* chat_id
* user_id
* chat_message_content
* *
*/
$chat_id = $this->input->post('chat_id');
$user_id = $this->input->post('user_id');
$chat_message_content = $this->input->post('chat_message', TRUE);
$this->chat_model->add_chat_message($chat_id, $user_id, $chat_message_content);
// grab and return all messages
$this->ajax_get_chat_messages($chat_id);
}
public function ajax_get_chat_messages($chat_id)
{
$chat_id = $this->input->post('chat_id');
echo $this->_get_chat_messages($chat_id);
}
private function _get_chat_messages($chat_id)
{
$last_chat_message_id = (int)$this->session->userdata('last_chat_message_id_' . $chat_id);
$chat_messages = $this->chat_model->get_chat_messages($chat_id, $last_chat_message_id);
if ($chat_messages->num_rows() > 0)
{
// store the last chat message id
$last_chat_message_id = $chat_messages->row($chat_messages->num_rows() - 1)->chat_message_id;
$this->session->set_userdata('last_chat_message_id_' . $chat_id, $last_chat_message_id);
// we have some chat let's return it
$chat_messages_html = '<ul>';
foreach ($chat_messages->result() as $chat_message)
{
$li_class = ($this->session->userdata('user_id') == $chat_message->user_id) ? 'class="by_current_user"' : '';
$chat_messages_html .= '<li ' . $li_class . '>' . '<span class="chat_message_header">' . $chat_message->chat_message_timestamp . ' by ' . $chat_message->name . '</span><p class="message_content">' . $chat_message->chat_message_content . '</p></li>';
}
$chat_messages_html .= '</ul>';
$result = array('status' => 'ok', 'content' => $chat_messages_html);
//header('Content-Type: application/json',true);
return json_encode($result);
exit();
}
else
{
// we have no chat yet
$result = array('status' => 'no chat', 'content' => '');
//header('Content-Type: application/json',true);
return json_encode($result);
exit();
}
}
}
//模型：
class chat_model extends CI_Model {
public function __construct()
{
parent::__construct();
}
public function add_chat_message($chat_id, $user_id, $chat_message_content)
{
$query_str = "INSERT INTO chat_messages (chat_id, user_id, chat_message_content) VALUES (?, ?, ?)";
$this->db->query($query_str, array($chat_id, $user_id, $chat_message_content));
}
public function get_chat_messages($chat_id, $last_chat_message_id = 0)
{
$query_str = "SELECT
cm.chat_message_id,
cm.user_id,
cm.chat_message_content,
DATE_FORMAT(cm.create_date, '%D of %M %Y at %H:%i:%s') AS chat_message_timestamp,
u.name
FROM chat_messages cm
JOIN users u ON cm.user_id = u.user_id
WHERE cm.chat_id = ?
and cm.chat_message_id > ?
ORDER BY cm.chat_message_id ASC";
$result = $this->db->query($query_str, array($chat_id, $last_chat_message_id));
return $result;
}
}
//查看文件浏览器VIEW_CHAT.PHP
<html>
<head>
<script type="text/javascript" src="/js/jquery-1.4.2.min.js"></script>
<script type="text/javascript" src="<?php echo base_url() . 'public/';?>chat.js">
</script>
<script type="text/javascript">
var base_url = "<?php echo base_url();?>";
var chat_id = "<?php echo $chat_id; ?>";
var user_id = "<?php echo $user_id; ?>";
</script>
</head>
<body>
<style type="text/css">
div#chat_viewport {
font-family:Verdana, Arial, sans-serif;
padding:5px;
border-top:2px dashed #585858;
min-height:300px;
color:black;
max-height:650px;
overflow:auto;
margin-bottom:10px;
width:750px;
}
div#chat_viewport ul {
list-style-type:none;
padding-left:10px;
}
div#chat_viewport ul li {
margin-top:10px;
width:85%;
}
span.chat_message_header {
font-size:0.7em;
font-family:"MS Trebuchet", Arial, sans-serif;
color:#547980;
}
p.message_content {
margin-top:0px;
margin-bottom:5px;
padding-left:10px;
margin-right:0px;
}
input#chat_message {
margin-top:5px;
border:1px solid #585858;
width:70%;
font-size:1.2em;
margin-right:10px;
}
input#submit_message {
font-size:2em;
padding:5px 10px;
vertical-align:top;
margin-top:5px;
}
div#chat_input { margin-bottom:10px; }
div#chat_viewport ul li.by_current_user span.chat_message_header {
color:#e9561b;
}
</style>
<h1>Let's do some chatting :D</h1>
<div id="chat_viewport">
</div>
<div id="chat_input">
<?php echo form_open('chat/ajax_add_chat_message'); ?>
<input id="chat_message" name="chat_message" type="text" value="" tabindex="1" />
<?php echo form_submit('submit_message','submit_message'); ?>
<?php echo anchor('#', 'Say it', array('title' => 'Send this chat message', 'id' => 'submit_message'));?>
<div class="clearer"></div>
<?php echo form_close(); ?>
</div>
</body>
</html>
我不确定，但我有一种感觉，即从服务器收到的json格式不正确。 看到这个：jQuery不会从AJAX查询中解析我的JSON
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