如何通过 PHP 检查 URL 是否存在？
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原文地址: http://stackoverflow.com/questions/2280394/
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How can I check if a URL exists via PHP?
提问by X10nD
How do I check if a URL exists (not 404) in PHP?
如何检查 PHP 中是否存在 URL（不是 404）？
回答by karim79
Here:
这里：
$file = 'http://www.domain.com/somefile.jpg';
$file_headers = @get_headers($file);
if(!$file_headers || $file_headers[0] == 'HTTP/1.1 404 Not Found') {
$exists = false;
}
else {
$exists = true;
}
From hereand right belowthe above post, there's a curlsolution:
function url_exists($url) {
if (!$fp = curl_init($url)) return false;
return true;
}
回答by MoonLite
When figuring out if an url exists from php there are a few things to pay attention to:
在确定 php 中是否存在 url 时，需要注意以下几点：
- Is the url itself valid (a string, not empty, good syntax), this is quick to check server side.
- Waiting for a response might take time and block code execution.
- Not all headers returned by get_headers() are well formed.
- Use curl (if you can).
- Prevent fetching the entire body/content, but only request the headers.
- Consider redirecting urls:
- Do you want the first code returned?
- Or follow all redirects and return the last code?
- You might end up with a 200, but it could redirect using meta tags or javascript. Figuring out what happens after is tough.
- url 本身是否有效（字符串，非空，语法良好），这可以快速检查服务器端。
- 等待响应可能需要时间并阻止代码执行。
- 并非 get_headers() 返回的所有标头都是格式良好的。
- 使用 curl（如果可以）。
- 防止获取整个正文/内容，而只请求标题。
- 考虑重定向网址：
- 你想返回第一个代码吗？
- 还是按照所有重定向并返回最后一个代码？
- 您最终可能会得到 200，但它可以使用元标记或 javascript 进行重定向。弄清楚之后会发生什么是很困难的。
Keep in mind that whatever method you use, it takes time to wait for a response.
All code might (and probably will) halt untill you either know the result or the requests have timed out.
请记住，无论您使用什么方法，等待响应都需要时间。
所有代码都可能（并且可能会）停止，直到您知道结果或请求超时。
For example: the code below could take a LONG time to display the page if the urls are invalid or unreachable:
例如：如果网址无效或无法访问，下面的代码可能需要很长时间才能显示页面：
<?php
$urls = getUrls(); // some function getting say 10 or more external links
foreach($urls as $k=>$url){
// this could potentially take 0-30 seconds each
// (more or less depending on connection, target site, timeout settings...)
if( ! isValidUrl($url) ){
unset($urls[$k]);
}
}
echo "yay all done! now show my site";
foreach($urls as $url){
echo "<a href=\"{$url}\">{$url}</a><br/>";
}
The functions below could be helpfull, you probably want to modify them to suit your needs:
以下功能可能会有所帮助，您可能希望修改它们以满足您的需求：
function isValidUrl($url){
// first do some quick sanity checks:
if(!$url || !is_string($url)){
return false;
}
// quick check url is roughly a valid http request: ( http://blah/... )
if( ! preg_match('/^http(s)?:\/\/[a-z0-9-]+(\.[a-z0-9-]+)*(:[0-9]+)?(\/.*)?$/i', $url) ){
return false;
}
// the next bit could be slow:
if(getHttpResponseCode_using_curl($url) != 200){
// if(getHttpResponseCode_using_getheaders($url) != 200){ // use this one if you cant use curl
return false;
}
// all good!
return true;
}
function getHttpResponseCode_using_curl($url, $followredirects = true){
// returns int responsecode, or false (if url does not exist or connection timeout occurs)
// NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
// if $followredirects == false: return the FIRST known httpcode (ignore redirects)
// if $followredirects == true : return the LAST known httpcode (when redirected)
if(! $url || ! is_string($url)){
return false;
}
$ch = @curl_init($url);
if($ch === false){
return false;
}
@curl_setopt($ch, CURLOPT_HEADER ,true); // we want headers
@curl_setopt($ch, CURLOPT_NOBODY ,true); // dont need body
@curl_setopt($ch, CURLOPT_RETURNTRANSFER ,true); // catch output (do NOT print!)
if($followredirects){
@curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,true);
@curl_setopt($ch, CURLOPT_MAXREDIRS ,10); // fairly random number, but could prevent unwanted endless redirects with followlocation=true
}else{
@curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,false);
}
// @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT ,5); // fairly random number (seconds)... but could prevent waiting forever to get a result
// @curl_setopt($ch, CURLOPT_TIMEOUT ,6); // fairly random number (seconds)... but could prevent waiting forever to get a result
// @curl_setopt($ch, CURLOPT_USERAGENT ,"Mozilla/5.0 (Windows NT 6.0) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1"); // pretend we're a regular browser
@curl_exec($ch);
if(@curl_errno($ch)){ // should be 0
@curl_close($ch);
return false;
}
$code = @curl_getinfo($ch, CURLINFO_HTTP_CODE); // note: php.net documentation shows this returns a string, but really it returns an int
@curl_close($ch);
return $code;
}
function getHttpResponseCode_using_getheaders($url, $followredirects = true){
// returns string responsecode, or false if no responsecode found in headers (or url does not exist)
// NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
// if $followredirects == false: return the FIRST known httpcode (ignore redirects)
// if $followredirects == true : return the LAST known httpcode (when redirected)
if(! $url || ! is_string($url)){
return false;
}
$headers = @get_headers($url);
if($headers && is_array($headers)){
if($followredirects){
// we want the the last errorcode, reverse array so we start at the end:
$headers = array_reverse($headers);
}
foreach($headers as $hline){
// search for things like "HTTP/1.1 200 OK" , "HTTP/1.0 200 OK" , "HTTP/1.1 301 PERMANENTLY MOVED" , "HTTP/1.1 400 Not Found" , etc.
// note that the exact syntax/version/output differs, so there is some string magic involved here
if(preg_match('/^HTTP\/\S+\s+([1-9][0-9][0-9])\s+.*/', $hline, $matches) ){// "HTTP/*** ### ***"
$code = $matches[1];
return $code;
}
}
// no HTTP/xxx found in headers:
return false;
}
// no headers :
return false;
}
回答by lunarnet76
$headers = @get_headers($this->_value);
if(strpos($headers[0],'200')===false)return false;
so anytime you contact a website and get something else than 200 ok it will work
所以只要你联系一个网站并得到 200 以外的其他东西，它就会起作用
回答by Minhaz
you cannot use curl in certain servers u can use this code
您不能在某些服务器中使用 curl 您可以使用此代码
<?php
$url = 'http://www.example.com';
$array = get_headers($url);
$string = $array[0];
if(strpos($string,"200"))
{
echo 'url exists';
}
else
{
echo 'url does not exist';
}
?>
回答by Randy Skretka
$url = 'http://google.com';
$not_url = 'stp://google.com';
if (@file_get_contents($url)): echo "Found '$url'!";
else: echo "Can't find '$url'.";
endif;
if (@file_get_contents($not_url)): echo "Found '$not_url!";
else: echo "Can't find '$not_url'.";
endif;
// Found 'http://google.com'!Can't find 'stp://google.com'.
回答by leela
function URLIsValid($URL)
{
$exists = true;
$file_headers = @get_headers($URL);
$InvalidHeaders = array('404', '403', '500');
foreach($InvalidHeaders as $HeaderVal)
{
if(strstr($file_headers[0], $HeaderVal))
{
$exists = false;
break;
}
}
return $exists;
}
回答by Ehsan
I use this function:
我使用这个功能：
/**
* @param $url
* @param array $options
* @return string
* @throws Exception
*/
function checkURL($url, array $options = array()) {
if (empty($url)) {
throw new Exception('URL is empty');
}
// list of HTTP status codes
$httpStatusCodes = array(
100 => 'Continue',
101 => 'Switching Protocols',
102 => 'Processing',
200 => 'OK',
201 => 'Created',
202 => 'Accepted',
203 => 'Non-Authoritative Information',
204 => 'No Content',
205 => 'Reset Content',
206 => 'Partial Content',
207 => 'Multi-Status',
208 => 'Already Reported',
226 => 'IM Used',
300 => 'Multiple Choices',
301 => 'Moved Permanently',
302 => 'Found',
303 => 'See Other',
304 => 'Not Modified',
305 => 'Use Proxy',
306 => 'Switch Proxy',
307 => 'Temporary Redirect',
308 => 'Permanent Redirect',
400 => 'Bad Request',
401 => 'Unauthorized',
402 => 'Payment Required',
403 => 'Forbidden',
404 => 'Not Found',
405 => 'Method Not Allowed',
406 => 'Not Acceptable',
407 => 'Proxy Authentication Required',
408 => 'Request Timeout',
409 => 'Conflict',
410 => 'Gone',
411 => 'Length Required',
412 => 'Precondition Failed',
413 => 'Payload Too Large',
414 => 'Request-URI Too Long',
415 => 'Unsupported Media Type',
416 => 'Requested Range Not Satisfiable',
417 => 'Expectation Failed',
418 => 'I\'m a teapot',
422 => 'Unprocessable Entity',
423 => 'Locked',
424 => 'Failed Dependency',
425 => 'Unordered Collection',
426 => 'Upgrade Required',
428 => 'Precondition Required',
429 => 'Too Many Requests',
431 => 'Request Header Fields Too Large',
449 => 'Retry With',
450 => 'Blocked by Windows Parental Controls',
500 => 'Internal Server Error',
501 => 'Not Implemented',
502 => 'Bad Gateway',
503 => 'Service Unavailable',
504 => 'Gateway Timeout',
505 => 'HTTP Version Not Supported',
506 => 'Variant Also Negotiates',
507 => 'Insufficient Storage',
508 => 'Loop Detected',
509 => 'Bandwidth Limit Exceeded',
510 => 'Not Extended',
511 => 'Network Authentication Required',
599 => 'Network Connect Timeout Error'
);
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
if (isset($options['timeout'])) {
$timeout = (int) $options['timeout'];
curl_setopt($ch, CURLOPT_TIMEOUT, $timeout);
}
curl_exec($ch);
$returnedStatusCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);
if (array_key_exists($returnedStatusCode, $httpStatusCodes)) {
return "URL: '{$url}' - Error code: {$returnedStatusCode} - Definition: {$httpStatusCodes[$returnedStatusCode]}";
} else {
return "'{$url}' does not exist";
}
}
回答by Jonathan Parent Lévesque
karim79's get_headers() solution didn't worked for me as I gotten crazy results with Pinterest.
karim79 的 get_headers() 解决方案对我不起作用，因为我在 Pinterest 上得到了疯狂的结果。
get_headers(): SSL operation failed with code 1. OpenSSL Error messages: error:14090086:SSL routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
get_headers(): Failed to enable crypto
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
get_headers(https://www.pinterest.com/jonathan_parl/): failed to open stream: operation failed
Array
(
[url] => https://www.pinterest.com/jonathan_parl/
[exists] =>
)
Anyway, this developer demonstrates that cURL is way faster than get_headers():
无论如何，该开发人员证明 cURL 比 get_headers() 快得多：
http://php.net/manual/fr/function.get-headers.php#104723
http://php.net/manual/fr/function.get-headers.php#104723
Since many people asked for karim79 to fix is cURL solution, here's the solution I built today.
由于许多人要求 karim79 修复的是 cURL 解决方案，因此这是我今天构建的解决方案。
/**
* Send an HTTP request to a the $url and check the header posted back.
*
* @param $url String url to which we must send the request.
* @param $failCodeList Int array list of code for which the page is considered invalid.
*
* @return Boolean
*/
public static function isUrlExists($url, array $failCodeList = array(404)){
$exists = false;
if(!StringManager::stringStartWith($url, "http") and !StringManager::stringStartWith($url, "ftp")){
$url = "https://" . $url;
}
if (preg_match(RegularExpression::URL, $url)){
$handle = curl_init($url);
curl_setopt($handle, CURLOPT_RETURNTRANSFER, true);
curl_setopt($handle, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($handle, CURLOPT_HEADER, true);
curl_setopt($handle, CURLOPT_NOBODY, true);
curl_setopt($handle, CURLOPT_USERAGENT, true);
$headers = curl_exec($handle);
curl_close($handle);
if (empty($failCodeList) or !is_array($failCodeList)){
$failCodeList = array(404);
}
if (!empty($headers)){
$exists = true;
$headers = explode(PHP_EOL, $headers);
foreach($failCodeList as $code){
if (is_numeric($code) and strpos($headers[0], strval($code)) !== false){
$exists = false;
break;
}
}
}
}
return $exists;
}
Let me explains the curl options:
让我解释一下 curl 选项：
CURLOPT_RETURNTRANSFER: return a string instead of displaying the calling page on the screen.
CURLOPT_RETURNTRANSFER：返回一个字符串而不是在屏幕上显示调用页面。
CURLOPT_SSL_VERIFYPEER: cUrl won't checkout the certificate
CURLOPT_SSL_VERIFYPEER: cUrl 不会检出证书
CURLOPT_HEADER: include the header in the string
CURLOPT_HEADER: 在字符串中包含标题
CURLOPT_NOBODY: don't include the body in the string
CURLOPT_NOBODY: 不要在字符串中包含正文
CURLOPT_USERAGENT: some site needs that to function properly (by example : https://plus.google.com)
CURLOPT_USERAGENT：某些站点需要它才能正常运行（例如：https: //plus.google.com）
Additional note: In this function I'm using Diego Perini's regex for validating the URL before sending the request:
附加说明：在此函数中，我使用 Diego Perini 的正则表达式在发送请求之前验证 URL：
const URL = "%^(?:(?:https?|ftp)://)(?:\S+(?::\S*)?@|\d{1,3}(?:\.\d{1,3}){3}|(?:(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)(?:\.(?:[a-z\d\x{00a1}-\x{ffff}]+-?)*[a-z\d\x{00a1}-\x{ffff}]+)*(?:\.[a-z\x{00a1}-\x{ffff}]{2,6}))(?::\d+)?(?:[^\s]*)?$%iu"; //@copyright Diego Perini
Additional note 2: I explode the header string and user headers[0] to be sure to only validate only the return code and message (example: 200, 404, 405, etc.)
附加说明 2：我分解标头字符串和用户标头 [0] 以确保仅验证返回代码和消息（例如：200、404、405 等）
Additional note 3: Sometime validating only the code 404 is not enough (see the unit test), so there's an optional $failCodeList parameter to supply all the code list to reject.
附加说明 3：有时仅验证代码 404 是不够的（请参阅单元测试），因此有一个可选的 $failCodeList 参数来提供要拒绝的所有代码列表。
And, of course, here's the unit test (including all the popular social network) to legitimates my coding:
而且，当然，这是使我的编码合法化的单元测试（包括所有流行的社交网络）：
public function testIsUrlExists(){
//invalid
$this->assertFalse(ToolManager::isUrlExists("woot"));
$this->assertFalse(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque4545646456"));
$this->assertFalse(ToolManager::isUrlExists("https://plus.google.com/+JonathanParentL%C3%A9vesque890800"));
$this->assertFalse(ToolManager::isUrlExists("https://instagram.com/mariloubiz1232132/", array(404, 405)));
$this->assertFalse(ToolManager::isUrlExists("https://www.pinterest.com/jonathan_parl1231/"));
$this->assertFalse(ToolManager::isUrlExists("https://regex101.com/546465465456"));
$this->assertFalse(ToolManager::isUrlExists("https://twitter.com/arcadefire4566546"));
$this->assertFalse(ToolManager::isUrlExists("https://vimeo.com/**($%?%$", array(400, 405)));
$this->assertFalse(ToolManager::isUrlExists("https://www.youtube.com/user/Darkjo666456456456"));
//valid
$this->assertTrue(ToolManager::isUrlExists("www.google.ca"));
$this->assertTrue(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque"));
$this->assertTrue(ToolManager::isUrlExists("https://plus.google.com/+JonathanParentL%C3%A9vesque"));
$this->assertTrue(ToolManager::isUrlExists("https://instagram.com/mariloubiz/"));
$this->assertTrue(ToolManager::isUrlExists("https://www.facebook.com/jonathan.parentlevesque"));
$this->assertTrue(ToolManager::isUrlExists("https://www.pinterest.com/"));
$this->assertTrue(ToolManager::isUrlExists("https://regex101.com"));
$this->assertTrue(ToolManager::isUrlExists("https://twitter.com/arcadefire"));
$this->assertTrue(ToolManager::isUrlExists("https://vimeo.com/"));
$this->assertTrue(ToolManager::isUrlExists("https://www.youtube.com/user/Darkjo666"));
}
Great success to all,
所有人都取得了巨大的成功，
Jonathan Parent-Lévesque from Montreal
来自蒙特利尔的 Jonathan Parent-Lévesque
回答by Spir
function urlIsOk($url)
{
$headers = @get_headers($url);
$httpStatus = intval(substr($headers[0], 9, 3));
if ($httpStatus<400)
{
return true;
}
return false;
}
回答by Sebastian Lasse
pretty fast:
相当快：
function http_response($url){
$resURL = curl_init();
curl_setopt($resURL, CURLOPT_URL, $url);
curl_setopt($resURL, CURLOPT_BINARYTRANSFER, 1);
curl_setopt($resURL, CURLOPT_HEADERFUNCTION, 'curlHeaderCallback');
curl_setopt($resURL, CURLOPT_FAILONERROR, 1);
curl_exec ($resURL);
$intReturnCode = curl_getinfo($resURL, CURLINFO_HTTP_CODE);
curl_close ($resURL);
if ($intReturnCode != 200 && $intReturnCode != 302 && $intReturnCode != 304) { return 0; } else return 1;
}
echo 'google:';
echo http_response('http://www.google.com');
echo '/ ogogle:';
echo http_response('http://www.ogogle.com');
