为什么PHP投掷会抛出"Cannot Redeclare"(无法重新声明)?本地包含函数出错? [英] Why is PHP throwing throwing a "Cannot Redeclare" error at a local, included function?

问题描述

这是我的问题:我有一个包含本地功能的文件(VRC_Header.php).在这里:

Here's my problem: I have one file that contains a local function (VRC_Header.php). Here it is:

function sec_session_start() {
    $session_name = 'sec_session_id'; //set a custom session name
    $secure = false; //set to true if using https
    $httponly = true; //This stops javascript being able to access the session id

    ini_set('session.use_only_cookies', 1); // Forces sessions to only use cookies
    $cookieParams = session_get_cookie_params(); //Gets currtent cookies params
    session_set_cookie_params($cookieParams["lifetime"], $cookieParams["domain"], $secure, $httponly); 
    session_name($session_name); //Sets the session name to the one set above
    session_start(); //Start the php session
    session_regenerate_id(); //regernates the session, delete the old one
}   

这很简单.我在每个公共页面上都包含此文件.例如，

It's simple enough. I include this file in every public page. For instance,

include_once('VRC_Header.php');
include_once('../Classes/VRC_MasterOO.php');
include_once('../Classes/VRC_Secure_Login.php');

//Start a secure session
sec_session_start();

我的问题发生在我的登录页面与 php 处理页面之间.通过发布 jQuery 函数进行提交.第二页包含与上面相同的代码:

My problem is occurring between my login page to a php processing page. The submission occurs via a post jQuery function. This second page contains code identical to the above:

include_once('VRC_Header.php');
include_once('../Classes/VRC_MasterOO.php');
include_once('../Classes/VRC_Secure_Login.php');

//Start a secure session
sec_session_start();

不幸的是，我的jQuery函数对此进行了回复:

Unfortunately, my jQuery function replies with this:

致命错误:无法在E:\ Additional Programs \ xampp \ htdocs_Vista_Ridge_System中重新声明sec_session_start()(先前在E:\ Additional Programs \ xampp \ htdocs \ Vista_Ridge_Territory_System \ PHP \ Scripts \ VRC_Header.php:14中声明)第24行的PHP \ Scripts \ VRC_Header.php

Fatal error: Cannot redeclare sec_session_start() (previously declared in E:\Additional Programs\xampp\htdocs\Vista_Ridge_Territory_System\PHP\Scripts\VRC_Header.php:14) in E:\Additional Programs\xampp\htdocs\Vista_Ridge_Territory_System\PHP\Scripts\VRC_Header.php on line 24

请注意，我的jQuery函数会给出答复-这意味着我认为问题出在第二个文件中.因此，无法重新声明".为什么会这样呢?本地函数以前没有这个问题.

Note that my jQuery function presents the reply - meaning that I believe the problem resides in the second file. Hence, the "cannot redeclare." Why is this happening? I've not had this issue before with local functions.

任何输入表示赞赏.

注意:我已经删除了两个文件中的include函数.如果这样做， PHP 会引发另一个错误:" sec_session_start()"未定义."

Note: I have removed the include function in both files. If I do, PHP throws another error: "sec_session_start()" is not defined."

中间jQuery函数:

The intermediate jQuery function:

$(document).ready(function () {
$('.login-form').submit(function (e) {
    e.preventDefault();
    $('#reply').remove();
    var formData = $(this).serialize();
    $("input").prop("disabled", true);
    request = $.post('VRC_LoginProcess.php', formData, loginMessage);
    request.fail(function() { 
        $('.header').append("<span id=\"reply\">Login Failed. Please try again in a few minutes.</ span>"); });

    function loginMessage(data) {
        $('.header').append("<span id=\"reply\">" + data + "</ span>");
        $("input").prop("disabled", false);
    }
});
});

推荐答案

关键是以下错误消息:

致命错误:无法在E:\ Additional Programs \ xampp \ htdocs_Vista_Ridge_System中重新声明sec_session_start()(先前在E:\ Additional Programs \ xampp \ htdocs \ Vista_Ridge_Territory_System \ PHP \ Scripts \ VRC_Header.php:14中声明)第24行的PHP \ Scripts \ VRC_Header.php

Fatal error: Cannot redeclare sec_session_start() (previously declared in E:\Additional Programs\xampp\htdocs\Vista_Ridge_Territory_System\PHP\Scripts\VRC_Header.php:14) in E:\Additional Programs\xampp\htdocs\Vista_Ridge_Territory_System\PHP\Scripts\VRC_Header.php on line 24

发生此错误的唯一方法是，如果您两次包含 VRC_Header.php .这与jQuery无关，与会话或重新生成会话ID无关.两个不同的行号只是指向函数的开始/结束.

The only way for this error to occur is if you have included VRC_Header.php twice. This has nothing to do with jQuery, and nothing to do with sessions or regenerating session ids. The two different line numbers are just pointing to the start/end of the function.

尝试在函数上方放置一个 echo()命令，您应该看到回声发生了两次.更好的是，将以下代码放在函数上方，它将显示一条更有用的错误消息，包括回溯，可以帮助您第二次查看如何包含文件:

Try putting an echo() command above the function, and you should see the echo happening twice. Even better, put the following code above your function, and it'll display a more useful error message, including a backtrace that will help you see how the file is being included a second time:

if (function_exists('sec_session_start')) {
    debug_print_backtrace();
    die('Trying to define sec_session_start() a second time');
}

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