我正在使用HTML，PHP，MySQL和CSS创建即时消息平台。我的函数fetch_conversation_messages（在private_message.inc.php上）。这是private_message.inc.php：
<?php
// Fetches a summary of the conversations.
function fetch_conversation_summary(){
$sql = "SELECT
`conversations`.`conversation_id`,
`conversations`.`conversation_subject`,
MAX(`conversations_messages`.`message_date`) AS `conversation_last_reply`,
MAX(`conversations_messages`.`message_date`) > `conversations_members`.`conversation_last_view` AS `conversation_unread`
FROM `conversations`
LEFT JOIN `conversations_messages` ON `conversations`.`conversation_id` = `conversations_messages`.`conversation_id`
INNER JOIN `conversations_members` ON `conversations`.`conversation_id` = `conversations_messages`.`conversation_id`
WHERE `conversations_members`.`user_id` = {$_SESSION['user_id']}
AND `conversations_members`.`conversation_deleted` = 0
GROUP BY `conversations`.`conversation_id`
ORDER BY `conversation_last_reply` DESC";
$result = mysql_query($sql);
$conversations = array();
while (($row = mysql_fetch_assoc($result)) !== false){
$conversations[] = array(
'id' => $row['conversation_id'],
'subject' => $row['conversation_subject'],
'last_reply' => $row['conversation_last_reply'],
'unread_messages' => ($row['conversation_unread'] == 1),
);
}
return $conversations;
}
// Fetches all of the messages in the given converstion.
function fetch_conversation_messages($conversation_id){
$conversation_id = (int)$conversation_id;
$sql = "SELECT
`conversations_messages`.`message_date`,
`conversations_messages`.`message_date` > `conversations_members`.`conversation_last_view` AS `message_unread`,
`conversations_message`.`message_text`,
`users`.`user_name`
FROM `conversations_messages`
INNER JOIN `users` ON `conversations_messages`.`user_id` = `users`.`user_id`
INNER JOIN `conversations_members` ON `conversations_messages`.`conversation_id` = `conversations_members`.`conversation_id`
WHERE `conversations_messages`.`conversation_id` = {$conversation_id}
AND `conversations_members`.`user_id` = {$_SESSION['user_id']}
ORDER BY `conversations_messages`.`message_date` DESC";
$result = mysql_query($sql);
$messages = array();
while ($row = mysql_fetch_assoc($result)){
$messages[] = array(
'date' => $row['message_date'],
'unread' => $row['message_unread'],
'text' => $row['message_text'],
'user_name' => $row['user_name'],
);
echo mysql_num_rows($result);
var_dump($row);
}
return print_r($messages);}
// Sets the last view time to the current time for the given conversation.
function update_conversation_last_view($conversation_id){
$conversation_id = (int)$conversation_id;
$time = time() + 18000;
$sql ="UPDATE `conversations_members`
SET `conversation_last_view` = {$time}
WHERE `conversation_id` = {$conversation_id}
AND `user_id` = {$_SESSION['user_id']}";
mysql_query($sql);
}
// Creates a new conversation, making the given users a member.
function create_conversation($user_ids, $subject, $body){
$subject = mysql_real_escape_string(htmlentities($subject));
$body = mysql_real_escape_string(htmlentities($body));
mysql_query("INSERT INTO `conversations` (`conversation_subject`) VALUES ('{$subject}')");
$conversation_id = mysql_insert_id();
$sql = "INSERT INTO `conversations_messages` (`conversation_id`, `user_id`, `message_date`, `message_text`)
VALUES ({$conversation_id}, {$_SESSION['user_id']}, UNIX_TIMESTAMP(), '{$body}')";
mysql_query($sql);
$values = array("({$conversation_id}, {$_SESSION['user_id']}, UNIX_TIMESTAMP(), 0)");
foreach ($user_ids as $user_id){
$user_id = (int)$user_id;
$values = array("({$conversation_id}, {$_SESSION['user_id']}, UNIX_TIMESTAMP(), 0)"); }
$sql = "INSERT INTO `conversations_members` (`conversation_id`, `user_id`, `conversation_last_view`, `conversation_deleted`)
VALUES " . implode(", ", $values);
mysql_query($sql);
}
// Checks to see if the given user is a member of the given conversation.
function validate_conversation_id($conversation_id){
$conversation_id = (int)$conversation_id;
$sql = "SELECT COUNT(1)
FROM `conversations_members`
WHERE `conversation_id` = {$conversation_id}
AND `user_id` = {$_SESSION['user_id']}
AND `conversation_deleted` = 0";
$result = mysql_query($sql);
return(mysql_result($result, 0) == 1);
}
// Adds a message to the given conversation.
function add_conversation_message($conversation_id, $text){
$conversation_id = (int)$conversation_id;
$text = mysql_real_escape_string(htmlentities($text));
$sql = "INSERT INTO `conversations_messages` (`conversation_id`, `user_id`, `message_date`, `message_text`)
VALUES ({$conversation_id}, {$_SESSION['user_id']}, UNIX_TIMESTAMP(), '{$text}')";
mysql_query($sql);
mysql_query("UPDATE `conversations_members` SET `conversation_deleted` = 0 where `conversation_id = {$conversation_id}");
}
// Deletes (or marks as deleted) a given conversation.
function delete_conversation($conversation_id){
$conversation_id = (int)$conversation_id;
$sql = "SELECT DISTINCT `conversation_deleted`
FROM `conversations_members`
WHERE `user_id` != {$_SESSION['user_id']}
AND `conversation_id` = {$conversation_id}";
$result = mysql_query($sql);
//if (mysql_num_rows($result) == 1 && mysql_result($result, 0) == 1){
if (mysql_num_rows($result) == 0){
mysql_query("DELETE FROM `conversations` WHERE `conversation_id` = {$conversation_id}");
mysql_query("DELETE FROM `conversations_members` WHERE `conversation_id` = {$conversation_id}");
mysql_query("DELETE FROM `conversations_messages` WHERE `conversation_id` = {$conversation_id}");
}else{
$sql = "UPDATE `conversations_members`
SET `conversation_deleted` = 1
WHERE `conversation_id` = {$conversation_id}
AND `user_id` = {$_SESSION['user_id']}";
mysql_query($sql);
}
}
?>
view_conversation.page.inc.php，包含private_message.inc.php的功能，如下所示：
<?php
$errors = array();
$valid_conversation = (isset($_GET['conversation_id']) && validate_conversation_id($_GET['conversation_id']));
if ($valid_conversation === false){
$errors[] = 'Invalid Conversation ID.';
}
if (isset($_POST['message'])){
if (empty($_POST['message'])){
$errors[] = 'You must enter a message.';
}
if (empty($errors)){
add_conversation_message($_GET['conversation_id'], $_POST['message']);
}
}
if (empty($errors) === false){
foreach ($errors as $error){
echo $error;
}
}
if ($valid_conversation){
/*if (isset($_POST['message'])){
update_conversation_last_view($_GET['conversation_id']);*/
$messages = fetch_conversation_messages($_GET['conversation_id']);
print_r($messages);
}else{
$messages = array();
update_conversation_last_view($_GET['conversation_id']);
}
?>
<p class="name">Username: <?php echo $message['user_name']; ?></p>
<p class="text">Date: <?php echo date('d/m/Y H:i:s', $message['date']); ?></p>
<p>Message: <?php echo $message['text']; ?></p>
<a href="index.php?page=inbox">Inbox</a>
<a href="index.php?page=logout">Logout</a>
<form action="" method="post">
<p><textarea name="message" rows="10" cols="110"></textarea></p>
<p><input type="submit" value="Add Message" /></p>
</form>
<?php
var_dump( $messages );
if($messages){
foreach ($messages as $message){
?>
<?php if ($message['unread']) echo 'unread'; ?>
<?php
}}
?>
我得到以下输出：
Array（）1 bool（true）警告：在第52行的/home/u406538221/public_html/public_html/gamma/core/pages/view_conversation.page.inc.php中为foreach（）提供的参数无效
我对这个论坛，数据库，PHP和MySQL都是全新的。
问题：参数无效 返回布尔值 - 为什么？我该如何解决？
请帮帮我。
提前谢谢。
答案 0 :(得分：1)
首先，您的fetch_conversation_messages函数正在返回print_r($messages)。这样做是打印$messages变量（这是Array（））的来源，然后它返回true。然后在调用fetch_conversation_messages后您正在print_r($messages)，而$messages是boolean，print_r正在打印1。然后在第52行var_dump($messages)之前的foreach，$messages变量是boolean等于true，这就是bool(true)的位置输出来自。因此，您尝试循环遍历boolean类似数组，该数组会为您提供有关为foreach()提供的无效参数的错误。因此，您需要做的只是在$messages函数中返回print_r($messages)而不是fetch_conversation_messages。
修改
这是fetch_conversation_messages应该是这样的：
function fetch_conversation_messages($conversation_id){
$conversation_id = (int)$conversation_id;
$sql = "SELECT
`conversations_messages`.`message_date`,
`conversations_messages`.`message_date` > `conversations_members`.`conversation_last_view` AS `message_unread`,
`conversations_message`.`message_text`,
`users`.`user_name`
FROM `conversations_messages`
INNER JOIN `users` ON `conversations_messages`.`user_id` = `users`.`user_id`
INNER JOIN `conversations_members` ON `conversations_messages`.`conversation_id` = `conversations_members`.`conversation_id`
WHERE `conversations_messages`.`conversation_id` = {$conversation_id}
AND `conversations_members`.`user_id` = {$_SESSION['user_id']}
ORDER BY `conversations_messages`.`message_date` DESC";
$result = mysql_query($sql);
$messages= array();
while ($row = mysql_fetch_assoc($result)){
$messages[] = array(
'date' => $row['message_date'],
'unread' => $row['message_unread'],
'text' => $row['message_text'],
'user_name' => $row['user_name'],
);
echo mysql_num_rows($result);
var_dump($row);
}
return $messages;
}