聊天功能中未定义的索引用户名

Question

我正在我的网站中实现聊天功能。我收到此错误：

注意：未定义索引：用户名

所以在我的聊天框中显示未定义而不是用户名。

我已经包含了 chat.js 和 jquery.js 文件。

这是我的Chat.php 文件：

<?php
define ('DBPATH','localhost');
define ('DBUSER','root');
define ('DBPASS','');
define ('DBNAME','abc');

session_start();
global $dbh;
$dbh = @mysql_connect(DBPATH,DBUSER,DBPASS);
@mysql_select_db(DBNAME,$dbh);

if ($_GET['action'] == "chatheartbeat") { chatHeartbeat(); } 
if ($_GET['action'] == "sendchat") { sendChat(); } 
if ($_GET['action'] == "closechat") { closeChat(); } 
if ($_GET['action'] == "startchatsession") { startChatSession(); } 

if (!isset($_SESSION['chatHistory'])) {
    $_SESSION['chatHistory'] = array(); 
}

if (!isset($_SESSION['openChatBoxes'])) {
    $_SESSION['openChatBoxes'] = array();   
}

function chatHeartbeat() {

    $sql = "select * from chat where (chat.to = '".mysql_real_escape_string($_SESSION['username'])."' AND recd = 0) order by id ASC";
    $query = @mysql_query($sql);
    $items = '';

    $chatBoxes = array();

    while ($chat = mysql_fetch_array($query)) {

        if (!isset($_SESSION['openChatBoxes'][$chat['from']]) && isset($_SESSION['chatHistory'][$chat['from']])) {
            $items = $_SESSION['chatHistory'][$chat['from']];
        }

        $chat['message'] = sanitize($chat['message']);

        $items .= <<<EOD
                       {
            "s": "0",
            "f": "{$chat['from']}",
            "m": "{$chat['message']}"
       },
EOD;

    if (!isset($_SESSION['chatHistory'][$chat['from']])) {
        $_SESSION['chatHistory'][$chat['from']] = '';
    }

    $_SESSION['chatHistory'][$chat['from']] .= <<<EOD
                           {
            "s": "0",
            "f": "{$chat['from']}",
            "m": "{$chat['message']}"
       },
EOD;

        unset($_SESSION['tsChatBoxes'][$chat['from']]);
        $_SESSION['openChatBoxes'][$chat['from']] = $chat['sent'];
    }

    if (!empty($_SESSION['openChatBoxes'])) {
    foreach ($_SESSION['openChatBoxes'] as $chatbox => $time) {
        if (!isset($_SESSION['tsChatBoxes'][$chatbox])) {
            $now = time()-strtotime($time);
            $time = date('g:iA M dS', strtotime($time));

            $message = "Sent at $time";
            if ($now > 180) {
                $items .= <<<EOD
{
"s": "2",
"f": "$chatbox",
"m": "{$message}"
},
EOD;

    if (!isset($_SESSION['chatHistory'][$chatbox])) {
        $_SESSION['chatHistory'][$chatbox] = '';
    }

    $_SESSION['chatHistory'][$chatbox] .= <<<EOD
        {
"s": "2",
"f": "$chatbox",
"m": "{$message}"
},
EOD;
            $_SESSION['tsChatBoxes'][$chatbox] = 1;
        }
        }
    }
}

    $sql = "update chat set recd = 1 where chat.to = '".mysql_real_escape_string($_SESSION['username'])."' and recd = 0";
    $query = mysql_query($sql);

    if ($items != '') {
        $items = substr($items, 0, -1);
    }
header('Content-type: application/json');
?>
{
        "items": [
            <?php echo $items;?>
        ]
}
<?php
            exit(0);
}

function chatBoxSession($chatbox) {

    $items = '';

    if (isset($_SESSION['chatHistory'][$chatbox])) {
        $items = $_SESSION['chatHistory'][$chatbox];
    }

    return $items;
}

function startChatSession() {
    $items = '';
    if (!empty($_SESSION['openChatBoxes'])) {
        foreach ($_SESSION['openChatBoxes'] as $chatbox => $void) {
            $items .= chatBoxSession($chatbox);
        }
    }


    if ($items != '') {
        $items = substr($items, 0, -1);
    }

header('Content-type: application/json');
?>
{
        "username": "<?php echo $_SESSION['username'];?>",
        "items": [
            <?php echo $items;?>
        ]
}
<?php
    exit(0);
}

function sendChat() {
    $from = $_SESSION['username'];
    $to = $_POST['to'];
    $message = $_POST['message'];

    $_SESSION['openChatBoxes'][$_POST['to']] = date('Y-m-d H:i:s', time());

    $messagesan = sanitize($message);

    if (!isset($_SESSION['chatHistory'][$_POST['to']])) {
        $_SESSION['chatHistory'][$_POST['to']] = '';
    }

    $_SESSION['chatHistory'][$_POST['to']] .= <<<EOD
                       {
            "s": "1",
            "f": "{$to}",
            "m": "{$messagesan}"
       },
EOD;


    unset($_SESSION['tsChatBoxes'][$_POST['to']]);

    $sql = "insert into chat (chat.from,chat.to,message,sent) values ('".mysql_real_escape_string($from)."', '".mysql_real_escape_string($to)."','".mysql_real_escape_string($message)."',NOW())";
    $query = mysql_query($sql);
    echo "1";
    exit(0);
}

function closeChat() {

    unset($_SESSION['openChatBoxes'][$_POST['chatbox']]);
    exit(0);
}

function sanitize($text) {
    $text = htmlspecialchars($text, ENT_QUOTES);
    $text = str_replace("\n\r","\n",$text);
    $text = str_replace("\r\n","\n",$text);
    $text = str_replace("\n","<br>",$text);
    return $text;
}
?>

当时调用 startChatSession 方法时出现此错误。

Answer 1

在您的代码中，您从未将任何值设置为 $_SESSION['username']。 这就是 PHP 抱怨 $_SESSION 中不存在索引“用户名”的原因。