在 PHP 中测试 404 的 URL 的简单方法？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/408405/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Easy way to test a URL for 404 in PHP?
提问by strager
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.
我正在自学一些基本的抓取，我发现有时输入到我的代码中的 URL 返回 404，这会混淆我的所有其余代码。
So I need a test at the top of the code to check if the URL returns 404 or not.
所以我需要在代码顶部进行测试，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.
这似乎是一项非常简单的任务，但 Google 没有给我任何答案。我担心我正在寻找错误的东西。
One blog recommended I use this:
一个博客推荐我使用这个：
$valid = @fsockopen($url, 80, $errno, $errstr, 30);
and then test to see if $valid if empty or not.
然后测试以查看 $valid 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.
但我认为给我带来问题的 URL 有一个重定向，所以 $valid 对于所有值都是空的。或者也许我做错了什么。
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.
我还研究了“头部请求”，但我还没有找到任何可以玩或尝试的实际代码示例。
Suggestions? And what's this about curl?
建议？卷曲是怎么回事？
回答by strager
If you are using PHP's curlbindings, you can check the error code using curl_getinfoas such:
如果您使用的是 PHP 的curlbindings，则可以使用以下方法检查错误代码curl_getinfo：
$handle = curl_init($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. */
回答by Asciant
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:
或者使用 php4，用户贡献了以下内容：
/**
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:
两者都会产生类似于：
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，您只需检查标头响应是否正常，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
}
回答by Aram Kocharyan
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，而只是重定向到自定义 404 页面并返回 302（重定向）或类似内容。我用它来检查服务器上是否存在实际文件（例如 robots.txt）。很明显，这种文件如果存在就不会导致重定向，但如果不存在，它会重定向到 404 页面，正如我之前所说，它可能没有 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;
}
}
回答by Beau Simensen
As strager suggests, look into using cURL. You may also be interested in setting CURLOPT_NOBODY with curl_setoptto skip downloading the whole page (you just want the headers).
正如 strager 建议的那样，考虑使用 cURL。您可能也有兴趣使用curl_setopt设置 CURLOPT_NOBODY以跳过下载整个页面（您只需要标题）。
回答by Nasaralla
If you are looking for an easiest solution and the one you can try in one go on php5 do
如果您正在寻找一种最简单的解决方案，并且可以在 php5 上一次性尝试
file_get_contents('www.yoursite.com');
//and check by echoing
echo $http_response_header[0];
回答by Ross
I found this answer here:
我在这里找到了这个答案：
if(($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，您使用“文件获取内容”方法来检索 URL，该方法会使用状态代码自动填充 http 响应标头变量。
回答by Email
addendum;tested those 3 methods considering performance.
附录；考虑到性能，测试了这 3 种方法。
The result, at least in my testing environment:
结果，至少在我的测试环境中：
Curl wins
卷曲获胜
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头文件（noBody）的情况下完成的。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 - $start_time."<br>";
回答by Juergen
This will give you true if url does not return 200 OK
如果 url 不返回 200 OK，这将为您提供 true
function check_404($url) {
$headers=get_headers($url, 1);
if ($headers[0]!='HTTP/1.1 200 OK') return true; else return false;
}
回答by Melbin Mathew Antony
<?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;
?>
回答by Andreas
Here is a short solution.
这是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+xmlto whatever you use.
在您的情况下，您可以更改application/rdf+xml为您使用的任何内容。
