用PHP测试404的简单方法?

I'm teaching myself some basic scraping and I've found that sometimes the URL's that I feed into my code return 404, which gums up all the rest of my code.

我教自己一些基本的抓取，我发现有时候我将URL发送到我的代码返回404，这将破坏我所有的代码。

So I need a test at the top of the code to check if the URL returns 404 or not.

因此，我需要在代码的顶部进行测试，以检查URL是否返回404。

This would seem like a pretty straightfoward task, but Google's not giving me any answers. I worry I'm searching for the wrong stuff.

这看起来很简单，但是谷歌没有给我任何答案。我担心我在寻找错误的东西。

One blog recommended I use this:

有一个博客建议我这样做:

$valid = @fsockopen($url, 80, $errno, $errstr, 30);

and then test to see if $valid if empty or not.

然后测试$是否为空。

But I think the URL that's giving me problems has a redirect on it, so $valid is coming up empty for all values. Or perhaps I'm doing something else wrong.

但是我认为给我问题的URL有一个重定向，所以$valid对所有值都是空的。或者我做错了什么。

I've also looked into a "head request" but I've yet to find any actual code examples I can play with or try out.

我也研究了“head request”，但是我还没有找到任何实际的代码示例，我可以使用它们或尝试它们。

Suggestions? And what's this about curl?

建议吗?关于旋度是什么?

14 个解决方案

#1

If you are using PHP's curl bindings, you can check the error code using curl_getinfo as such:

如果您正在使用PHP的curl绑定，您可以使用curl_getinfo来检查错误代码:

$handle = curl_init($url);
curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);

/* Get the HTML or whatever is linked in $url. */
$response = curl_exec($handle);

/* Check for 404 (file not found). */
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
if($httpCode == 404) {
    /* Handle 404 here. */
}

curl_close($handle);

/* Handle $response here. */

#2

If your running php5 you can use:

如果您正在运行php5，您可以使用:

$url = 'http://www.example.com';
print_r(get_headers($url, 1));

Alternatively with php4 a user has contributed the following:

另一种方法是使用php4用户提供以下内容:

/**
This is a modified version of code from "stuart at sixletterwords dot com", at 14-Sep-2005 04:52. This version tries to emulate get_headers() function at PHP4. I think it works fairly well, and is simple. It is not the best emulation available, but it works.

Features:
- supports (and requires) full URLs.
- supports changing of default port in URL.
- stops downloading from socket as soon as end-of-headers is detected.

Limitations:
- only gets the root URL (see line with "GET / HTTP/1.1").
- don't support HTTPS (nor the default HTTPS port).
*/

if(!function_exists('get_headers'))
{
    function get_headers($url,$format=0)
    {
        $url=parse_url($url);
        $end = "\r\n\r\n";
        $fp = fsockopen($url['host'], (empty($url['port'])?80:$url['port']), $errno, $errstr, 30);
        if ($fp)
        {
            $out  = "GET / HTTP/1.1\r\n";
            $out .= "Host: ".$url['host']."\r\n";
            $out .= "Connection: Close\r\n\r\n";
            $var  = '';
            fwrite($fp, $out);
            while (!feof($fp))
            {
                $var.=fgets($fp, 1280);
                if(strpos($var,$end))
                    break;
            }
            fclose($fp);

            $var=preg_replace("/\r\n\r\n.*\$/",'',$var);
            $var=explode("\r\n",$var);
            if($format)
            {
                foreach($var as $i)
                {
                    if(preg_match('/^([a-zA-Z -]+): +(.*)$/',$i,$parts))
                        $v[$parts[1]]=$parts[2];
                }
                return $v;
            }
            else
                return $var;
        }
    }
}

Both would have a result similar to:

两者的结果都类似:

Array
(
    [0] => HTTP/1.1 200 OK
    [Date] => Sat, 29 May 2004 12:28:14 GMT
    [Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
    [ETag] => "3f80f-1b6-3e1cb03b"
    [Accept-Ranges] => bytes
    [Content-Length] => 438
    [Connection] => close
    [Content-Type] => text/html
)

Therefore you could just check to see that the header response was OK eg:

因此你可以检查一下头的反应是否正常例如:

$headers = get_headers($url, 1);
if ($headers[0] == 'HTTP/1.1 200 OK') {
//valid 
}

if ($headers[0] == 'HTTP/1.1 301 Moved Permanently') {
//moved or redirect page
}

W3C Codes and Definitions

W3C规范和定义

#3

With strager's code, you can also check the CURLINFO_HTTP_CODE for other codes. Some websites do not report a 404, rather they simply redirect to a custom 404 page and return 302 (redirect) or something similar. I used this to check if an actual file (eg. robots.txt) existed on the server or not. Clearly this kind of file would not cause a redirect if it existed, but if it didn't it would redirect to a 404 page, which as I said before may not have a 404 code.

使用strager的代码，您还可以检查CURLINFO_HTTP_CODE以获取其他代码。有些网站不报告404页面，而是简单地重定向到自定义404页面并返回302(重定向)或类似的东西。我用这个来检查一个实际的文件。在服务器上存在或不存在。显然，如果存在这种文件，它不会导致重定向，但如果不存在，它会重定向到404页面，正如我之前所说，404页面可能没有404代码。

function is_404($url) {
    $handle = curl_init($url);
    curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);

    /* Get the HTML or whatever is linked in $url. */
    $response = curl_exec($handle);

    /* Check for 404 (file not found). */
    $httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
    curl_close($handle);

    /* If the document has loaded successfully without any redirection or error */
    if ($httpCode >= 200 && $httpCode < 300) {
        return false;
    } else {
        return true;
    }
}

#4

As strager suggests, look into using cURL. You may also be interested in setting CURLOPT_NOBODY with curl_setopt to skip downloading the whole page (you just want the headers).

正如strager所建议的，考虑使用旋度。您可能还想用CURLOPT_NOBODY设置curl_setopt来跳过下载整个页面(您只需要标题)。

#5

If you are looking for an easiest solution and the one you can try in one go on php5 do

如果你正在寻找一个最简单的解决方案，你可以尝试一下php5

file_get_contents('www.yoursite.com');
//and check by echoing
echo $http_response_header[0];

#6

I found this answer here:

我在这里找到了答案:

if(($twitter_XML_raw=file_get_contents($timeline))==false){
    // Retrieve HTTP status code
    list($version,$status_code,$msg) = explode(' ',$http_response_header[0], 3);

    // Check the HTTP Status code
    switch($status_code) {
        case 200:
                $error_status="200: Success";
                break;
        case 401:
                $error_status="401: Login failure.  Try logging out and back in.  Password are ONLY used when posting.";
                break;
        case 400:
                $error_status="400: Invalid request.  You may have exceeded your rate limit.";
                break;
        case 404:
                $error_status="404: Not found.  This shouldn't happen.  Please let me know what happened using the feedback link above.";
                break;
        case 500:
                $error_status="500: Twitter servers replied with an error. Hopefully they'll be OK soon!";
                break;
        case 502:
                $error_status="502: Twitter servers may be down or being upgraded. Hopefully they'll be OK soon!";
                break;
        case 503:
                $error_status="503: Twitter service unavailable. Hopefully they'll be OK soon!";
                break;
        default:
                $error_status="Undocumented error: " . $status_code;
                break;
    }

Essentially, you use the "file get contents" method to retrieve the URL, which automatically populates the http response header variable with the status code.

本质上，您可以使用“file get contents”方法来检索URL，该URL将自动使用状态代码填充http响应头变量。

#7

addendum;tested those 3 methods considering performance.

附录;测试了这三种方法的性能。

The result, at least in my testing environment:

结果，至少在我的测试环境中:

Curl wins

旋度赢得

This test is done under the consideration that only the headers (noBody) is needed. Test yourself:

这个测试是在只需要报头(没有人)的情况下进行的。测试自己:

$url = "http://de.wikipedia.org/wiki/Pinocchio";

$start_time = microtime(TRUE);
$headers = get_headers($url);
echo $headers[0]."<br>";
$end_time = microtime(TRUE);
echo $end_time - $start_time."<br>";


$start_time = microtime(TRUE);
$response = file_get_contents($url);
echo $http_response_header[0]."<br>";
$end_time = microtime(TRUE);
echo $end_time - $start_time."<br>";

$start_time = microtime(TRUE);
$handle = curl_init($url);
curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($handle, CURLOPT_NOBODY, 1); // and *only* get the header 
/* Get the HTML or whatever is linked in $url. */
$response = curl_exec($handle);
/* Check for 404 (file not found). */
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
// if($httpCode == 404) {
    // /* Handle 404 here. */
// }
echo $httpCode."<br>";
curl_close($handle);
$end_time = microtime(TRUE);
echo $end_time - $start_time."<br>";

#8

As an additional hint to the great accepted answer:

作为一个额外的暗示，伟大接受的回答:

When using a variation of the proposed solution, I got errors because of php setting 'max_execution_time'. So what I did was the following:

当使用提议的解决方案的变体时，由于php设置了“max_execution_time”，所以出现了错误。我所做的是:

set_time_limit(120);
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_NOBODY, true);
$result = curl_exec($curl);
set_time_limit(ini_get('max_execution_time'));
curl_close($curl);

First I set the time limit to a higher number of seconds, in the end I set it back to the value defined in the php settings.

首先我将时间限制设置为更高的秒数，最后我将它设置为php设置中定义的值。

#9

You can use this code too, to see the status of any link:

您也可以使用此代码查看任何链接的状态:

<?php

function get_url_status($url, $timeout = 10) 
{
$ch = curl_init();
// set cURL options
$opts = array(CURLOPT_RETURNTRANSFER => true, // do not output to browser
            CURLOPT_URL => $url,            // set URL
            CURLOPT_NOBODY => true,         // do a HEAD request only
            CURLOPT_TIMEOUT => $timeout);   // set timeout
curl_setopt_array($ch, $opts);
curl_exec($ch); // do it!
$status = curl_getinfo($ch, CURLINFO_HTTP_CODE); // find HTTP status
curl_close($ch); // close handle
echo $status; //or return $status;
    //example checking
    if ($status == '302') { echo 'HEY, redirection';}
}

get_url_status('http://yourpage.comm');
?>

#10

<?php

$url= 'www.something.com';
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_HEADER, true);   
curl_setopt($ch, CURLOPT_NOBODY, true);    
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.0.3) Gecko/2008092417 Firefox/3.0.4");
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_TIMEOUT,10);
curl_setopt($ch, CURLOPT_ENCODING, "gzip");
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
$output = curl_exec($ch);
$httpcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);


echo $httpcode;
?>

#11

Here is a short solution.

这里有一个简短的解决方案。

$handle = curl_init($uri);
curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);
curl_setopt($handle,CURLOPT_HTTPHEADER,array ("Accept: application/rdf+xml"));
curl_setopt($handle, CURLOPT_NOBODY, true);
curl_exec($handle);
$httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
if($httpCode == 200||$httpCode == 303) 
{
    echo "you might get a reply";
}
curl_close($handle);

In your case, you can change application/rdf+xml to whatever you use.

在您的示例中，可以将应用程序/rdf+xml更改为您使用的任何内容。

#12

this is just and slice of code, hope works for you

这只是一小段代码，希望对你有用

            $ch = @curl_init();
            @curl_setopt($ch, CURLOPT_URL, 'http://example.com');
            @curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1");
            @curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            @curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
            @curl_setopt($ch, CURLOPT_TIMEOUT, 10);

            $response       = @curl_exec($ch);
            $errno          = @curl_errno($ch);
            $error          = @curl_error($ch);

                    $response = $response;
                    $info = @curl_getinfo($ch);
return $info['http_code'];

#13

To catch all errors : 4XX and 5XX, i use this little script :

为了捕获所有错误:4XX和5XX，我使用这个小脚本:

function URLIsValid($URL){
    $headers = @get_headers($URL);
    preg_match("/ [45][0-9]{2} /", (string)$headers[0] , $match);
    return count($match) === 0;
}

#14

This will give you true if url does not return 200 OK

如果url不返回200 OK，则返回true

function check_404($url) {
   $headers=get_headers($url, 1);
   if ($headers[0]!='HTTP/1.1 200 OK') return true; else return false;
}