AJAX调用返回状态200，但没有内容 [英] AJAX call returns status 200 but no content

问题描述

我有一个简单的AJAX调用，从文件中检索的文本，它推到一个表，并显示。在Mac上运行的Apache 2.2.26 / PHP 5.3和运行Apache 2.2.1.6/PHP 5.3 Ubuntu的箱测试时，调用工作没有问题。运行Apache 2.2.4 / PHP 5.1在RedHat它不工作。当然，RedHat的箱子是唯一的地方，我需要它来工作。

I have a simple AJAX call that retrieves text from a file, pushes it into a table, and displays it. The call works without issue when testing on a Mac running Apache 2.2.26/PHP 5.3 and on an Ubuntu box running Apache 2.2.1.6/PHP 5.3. It does not work on RedHat running Apache 2.2.4/PHP 5.1. Naturally, the RedHat box is the only place where I need it to be working.

调用返回200 OK，但没有内容。即使没有在文件中找到的（或者它无法访问），表头是呼应因此，如果权限是一个问题，我仍然希望看到的东西。但可以肯定，我验证该文件是所有用户可读。

The call returns 200 OK but no content. Even if nothing is found in the file (or it's inaccessible), the table header is echoed so if permissions were a problem I would still expect to see something. But to be sure, I verified the file is readable by all users.

code经过编辑和简化。

Code has been redacted and simplified.

我的ajax功能：

function ajax(page,targetElement,ajaxFunction,getValues)
{
    xmlhttp=new XMLHttpRequest();
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState===4 && xmlhttp.status===200)
        {
            document.getElementById(targetElement).innerHTML=xmlhttp.responseText;
        }
    };

    xmlhttp.open('GET','/appdir/dir/filedir/'+page+'_funcs.php?function='+ajaxFunction+'&'+getValues+'&'+new Date().getTime(),false);
    xmlhttp.setRequestHeader('cache-control','no-cache');
    xmlhttp.send();
}

我把它称为是这样的：

I call it like this:

ajax('pagename','destelement','load_info');

和返回结果：

// Custom file handler
function warn_error($errno, $errstr) {
    // Common function for warning-prone functions
    throw new Exception($errstr, $errno);
}

function get_file_contents() {
// File operation failure would return a warning
// So handle specially to suppress the default message
    set_error_handler('warn_error');
    try
    {
        $fh =   fopen(dirname(dirname(__FILE__))."/datafile.txt","r");
    }
    catch (Exception $e)
    {
        // Craft a nice-looking error message and get out of here
        $info    =  "<tr><td class=\"center\" colspan=\"9\"><b>Fatal Error: </b>Could not load customer data.</td></tr>";
        restore_error_handler();
        return $info;
    }
    restore_error_handler();

    // Got the file so get and return its contents
    while (!feof($fh))
    {
        $line               =   fgets($fh);
        // Be sure to avoid empty lines in our array
        if (!empty($line))
        {
            $info[] =   explode(",",$line);
        }
    }

    fclose($fh);

    return $info;
}

function load_info() {

    // Start the table
    $content    .=  "<table>
            <th>Head1</th>
            <th>Head2</th>
            <th>Head3</th>
            <th>Head4</th>";

    // Get the data 
    // Returns all contents in an array if successful,
    // Returns an error string if it fails
    $info   =   get_file_contents();

    if (!is_array($info))
    {
        // String was returned because of an error
        echo $content.$info;
        exit();
    }

    // Got valid data array, so loop through it to build the table
    foreach ($info as $detail)
    {
        list($field1,$field2,$field3,$field4)   =   $detail;

        $content    .=  "<tr>
                <td>$field1</td>
                <td>$field2</td>
                <td>$field3</td>
                <td>$field4</td>
                </tr>";
    }

    $content    .=  "</table>";
    echo $content;
}

如果它的工作原理，响应头表示连接的保活;在那里失败，则连接被关闭。我不知道这是否重要。

Where it works, the response header indicates the connection as keep-alive; where it fails, the connection is closed. I don't know if that matters.

我过来，让并网的一些线索，但找遍了没有内容的问题不约而同地指向同源策略的问题。就我而言，所有的内容都是一样的服务器上。

I've looked all over SO and the net for some clues but "no content" issues invariably point to same-origin policy problems. In my case, all content is on the same server.

我在一个损失，因为做什么/在哪里寻找下一个。

I'm at a loss as to what to do/where to look next.

推荐答案

这竟然是一个PHP版本的问题。在load_info功能，我使用filter_input（INPUT_GET，值），但这是不具备的PHP 5.1。我把从我最初的code后，因为我不认为这是问题的一部分。经验教训。

This turned out to be a PHP version issue. In the load_info function I was using filter_input(INPUT_GET,"value"), but that was not available in PHP 5.1. I pulled that from my initial code post because I didn't think it was part of the problem. Lesson learned.

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