为什么我的PHP查询在页面加载时执行两次？

我对PHP很新,我似乎遇到了一个insert语句的问题,当我打开这个页面来查看文档时,它会执行两次.该文档显示没有错误.在数据库中,第二次插入是1秒后.它仅在Google Chrome中发生,仅在此页面上发生. IE没有问题,我没有firefox检查.

view_document.php

require_once($_SERVER['DOCUMENT_ROOT'] . '/../includes/core.php');
require_once($_SERVER['DOCUMENT_ROOT'] . '/../includes/connect.php');
$webusername = $_SESSION['webname'];
if (isset($_GET['document']))
{
$ainumber = (int) $_GET['document'];
if (!ctype_digit($_GET['document']) || !preg_match('~^[0-9]+$~', $_GET['document']) || !is_numeric($_GET['document']))
{
$_SESSION = array();
session_destroy();
header('Location: login.php');
}
else
{
$stmt = $connect->prepare("SELECT s_filename, s_reference FROM dmsmain WHERE s_ainumber = ?") or die(mysqli_error());
$stmt->bind_param('s', $ainumber);
$stmt->execute();
$stmt->bind_result($filename, $reference);
$stmt->fetch();
$stmt->close();
$file = $_SERVER['DOCUMENT_ROOT'] . '/../dms/files/' . $filename . '.pdf';
if (file_exists($file))
{
header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename=' . basename($file));
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($file));
header('Accept-Ranges: bytes');
readfile($file);
$stmt = $connect->prepare("INSERT INTO dmslog (s_reference, s_userid, s_lastactivity, s_actiontype) VALUES (?, ?, ?, ?)") or die(mysqli_error());
date_default_timezone_set('Africa/Johannesburg');
$date = date('Y-m-d H:i:s');
$actiOntype= 'DL';
$stmt->bind_param('ssss', $reference, $webusername, $date, $actiontype);
$stmt->execute();
$stmt->close();
}
else
{
$missing = "File not found";
}
exit(0); // Correct Place?
}
}
?>











Denso SA Document Management System

" ?>

Document Search

Add Document

我假设我的HTTP访问记录

[15/Nov/2012:10:14:32 +0200] "POST /dms/search.php HTTP/1.1" 200 5783 "http://www.denso.co.za/dms/search.php" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11"
[15/Nov/2012:10:14:33 +0200] "GET /favicon.ico HTTP/1.1" 404 - "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11"
[15/Nov/2012:10:14:34 +0200] "GET /dms/view_document.php?document=8 HTTP/1.1" 200 2965 "http://www.denso.co.za/dms/search.php" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11"
[15/Nov/2012:10:14:35 +0200] "GET /favicon.ico HTTP/1.1" 404 - "-" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11"


我检查了我的链接,我没有看到他们的问题.

记录表明有一个favicon.ico请求所以我创建了一个空白的favicon并将其放在我的public_html文件夹中,并将其链接到页面中,如此

不幸的是,由于声明仍然执行两次,因此无效.
我不确定它是否是一个favicon问题,因为我的上传页面使用插入查询并执行一次.

如果有人能告诉我我哪里出错了或指出我正确的方向,我将非常感激

解决方法:

这段代码：

if (file_exists($file))
{
header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename=' . basename($file));
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($file));
header('Accept-Ranges: bytes');
readfile($file);
//...
}


绝对应该在它的末尾有exit()调用,如下所示：

if (file_exists($file))
{
header('Content-Type: application/pdf');
header('Content-Disposition: inline; filename=' . basename($file));
header('Content-Transfer-Encoding: binary');
header('Content-Length: ' . filesize($file));
header('Accept-Ranges: bytes');
readfile($file);
//...
exit(0);
}


否则你首先发送文件,然后输出HTML,导致各种奇怪的行为.不知道是不是原因,但试试吧.

(另外,作为一个原则,如果找不到文件,你需要用代码404提供服务……)