blocks|key|1317321|text|if+(false+===+file_get_contents("http://example.com/path/to/image"))+{
++++$image+=+$default_image;
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1317322|应该可以工作;)|unstyled|1317323|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

<pre><code>if (false === file_get_contents("http://example.com/path/to/image")) {
 $image = $default_image;
}
</code></pre>

Should work ;)

blocks|key|1317395|text|您可以通过CURLOPT_NOBODY指示curl使用HTTP+HEAD方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317396|大体上|1317397|$ch+=+curl_init("http://www.example.com/favicon.ico");

curl_setopt($ch,+CURLOPT_NOBODY,+true);
curl_exec($ch);
$retcode+=+curl_getinfo($ch,+CURLINFO_HTTP_CODE);
//+$retcode+>=+400+->+not+found,+$retcode+=+200,+found.
curl_close($ch);|code-block|syntax|javascript|1317398|无论如何，您只节省了HTTP传输的成本，而不是TCP连接的建立和关闭。由于图标很小，你可能看不到太多的改进。|1317399|如果结果被证明太慢，在本地缓存结果似乎是一个好主意。HEAD检查文件的时间，并在headers中返回。你可以像浏览器一样获取图标的CURLINFO_FILETIME。在你的缓存中，你可以存储URL，=>时间戳。然后，您可以比较时间戳并重新加载图标。|1317400|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

You can instruct curl to use the HTTP HEAD method via CURLOPT_NOBODY. 

More or less

<pre><code>$ch = curl_init("http://www.example.com/favicon.ico");

curl_setopt($ch, CURLOPT_NOBODY, true);
curl_exec($ch);
$retcode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
// $retcode &gt;= 400 -&gt; not found, $retcode = 200, found.
curl_close($ch);
</code></pre>

Anyway, you only save the cost of the HTTP transfer, not the TCP connection establishment and closing. And being favicons small, you might not see much improvement.

Caching the result locally seems a good idea if it turns out to be too slow.
HEAD checks the time of the file, and returns it in the headers. You can do like browsers and get the CURLINFO_FILETIME of the icon. 
In your cache you can store the URL => [ favicon, timestamp ]. You can then compare the timestamp and reload the favicon.

blocks|key|1317454|text|不知道当文件不是远程存在的时候，这个是不是更快，is_file()，但是你可以试一下。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1317455|$favIcon+=+'default+FavIcon';
if(is_file($remotePath))+{
+++$favIcon+=+file_get_contents($remotePath);
}|code-block|syntax|javascript|1317456|entityMap|0|LINK|mutability|MUTABLE|url|http://se2.php.net/is_file^0|O|9|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Don't know if this one is any faster when the file does not exist remotely, <a href="http://se2.php.net/is_file" rel="nofollow noreferrer">is_file()</a>, but you could give it a shot.

<pre><code>$favIcon = 'default FavIcon';
if(is_file($remotePath)) {
 $favIcon = file_get_contents($remotePath);
}
</code></pre>

blocks|key|1317527|text|您应该发出HEAD请求，而不是获取请求，因为您根本不需要URI内容。正如Pies上面所说的，你应该检查状态代码(在200-299范围内，你可以选择遵循3xx重定向)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317528|答案问题包含许多可能会有帮助的代码示例：PHP+/+Curl:+HEAD+Request+takes+a+long+time+on+some+sites|offset|length|1317529|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/770179/php-curl-head-request-takes-a-long-time-on-some-sites^0|0|K|1K|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

You should issue HEAD requests, not GET one, because you don't need the URI contents at all. As Pies said above, you should check for status code (in 200-299 ranges, and you may optionally follow 3xx redirects).

The answers question contain a lot of code examples which may be helpful: <a href="https://stackoverflow.com/questions/770179/php-curl-head-request-takes-a-long-time-on-some-sites">PHP / Curl: HEAD Request takes a long time on some sites</a>

blocks|key|1317597|text|正如派所说，你可以使用cURL。你可以让cURL只给你头部，而不是主体，这可能会让它更快。坏的域总是需要一段时间，因为您将等待请求超时；您可能可以使用cURL更改超时长度。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317598|下面是一个例子：|1317599|function+remoteFileExists($url)+{
++++$curl+=+curl_init($url);

++++//don't+fetch+the+actual+page,+you+only+want+to+check+the+connection+is+ok
++++curl_setopt($curl,+CURLOPT_NOBODY,+true);

++++//do+request
++++$result+=+curl_exec($curl);

++++$ret+=+false;

++++//if+request+did+not+fail
++++if+($result+!==+false)+{
++++++++//if+request+was+ok,+check+response+code
++++++++$statusCode+=+curl_getinfo($curl,+CURLINFO_HTTP_CODE);++

++++++++if+($statusCode+==+200)+{
++++++++++++$ret+=+true;+++
++++++++}
++++}

++++curl_close($curl);

++++return+$ret;
}

$exists+=+remoteFileExists('http://stackoverflow.com/favicon.ico');
if+($exists)+{
++++echo+'file+exists';
}+else+{
++++echo+'file+does+not+exist';+++
}|code-block|syntax|javascript|1317600|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

As Pies say you can use cURL. You can get cURL to only give you the headers, and not the body, which might make it faster. A bad domain could always take a while because you will be waiting for the request to time-out; you could probably change the timeout length using cURL.

Here is example:


<pre><code>function remoteFileExists($url) {
 $curl = curl_init($url);

 //don't fetch the actual page, you only want to check the connection is ok
 curl_setopt($curl, CURLOPT_NOBODY, true);

 //do request
 $result = curl_exec($curl);

 $ret = false;

 //if request did not fail
 if ($result !== false) {
 //if request was ok, check response code
 $statusCode = curl_getinfo($curl, CURLINFO_HTTP_CODE); 

 if ($statusCode == 200) {
 $ret = true; 
 }
 }

 curl_close($curl);

 return $ret;
}

$exists = remoteFileExists('http://stackoverflow.com/favicon.ico');
if ($exists) {
 echo 'file exists';
} else {
 echo 'file does not exist'; 
}
</code></pre>

blocks|key|1317693|text|一个激进的解决方案是在默认图标上方的div中将图标显示为背景图像。这样，所有开销都会放在客户端上，同时仍然不会显示损坏的图像(在所有浏览器AFAIK中，丢失的背景图像都会被忽略)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317694|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

A radical solution would be to display the favicons as background images in a div above your default icon. That way, all overhead would be placed on the client while still not displaying broken images (missing background images are ignored in all browsers AFAIK).

blocks|key|1317786|text|还有一种更复杂的替代方案。您可以使用JQuery技巧检查所有客户端。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317787|$('a[href%5E="http://"]').filter(function(){
+++++return+this.hostname+&&+this.hostname+!==+location.hostname;
}).each(function()+{
++++var+link+=+jQuery(this);
++++var+faviconURL+=
++++++link.attr('href').replace(/%5E(http:\/\/[%5E\/]%2B).*$/,+'$1')%2B'/favicon.ico';
++++var+faviconIMG+=+jQuery('<img+src="favicon.png"+alt=""+/>')['appendTo'](link);
++++var+extImg+=+new+Image();
++++extImg.src+=+faviconURL;
++++if+(extImg.complete)
++++++faviconIMG.attr('src',+faviconURL);
++++else
++++++extImg.onload+=+function()+{+faviconIMG.attr('src',+faviconURL);+};
});|code-block|syntax|javascript|1317788|来自http://snipplr.com/view/18782/add-a-favicon-near-external-links-with-jquery/+(原始博客目前已关闭)|offset|length|1317789|entityMap|0|LINK|mutability|MUTABLE|url|http://snipplr.com/view/18782/add-a-favicon-near-external-links-with-jquery/^0|0|0|2|24|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

There's an even more sophisticated alternative. You can do the checking all client-side using a JQuery trick. 

<pre><code>$('a[href^="http://"]').filter(function(){
 return this.hostname &amp;&amp; this.hostname !== location.hostname;
}).each(function() {
 var link = jQuery(this);
 var faviconURL =
 link.attr('href').replace(/^(http:\/\/[^\/]+).*$/, '$1')+'/favicon.ico';
 var faviconIMG = jQuery('&lt;img src="favicon.png" alt="" /&gt;')['appendTo'](link);
 var extImg = new Image();
 extImg.src = faviconURL;
 if (extImg.complete)
 faviconIMG.attr('src', faviconURL);
 else
 extImg.onload = function() { faviconIMG.attr('src', faviconURL); };
});
</code></pre>

From <a href="http://snipplr.com/view/18782/add-a-favicon-near-external-links-with-jquery/" rel="nofollow noreferrer">http://snipplr.com/view/18782/add-a-favicon-near-external-links-with-jquery/</a> (the original blog is presently down)

blocks|key|1533072|text|CoolGoose的解决方案很好，但对于大文件来说速度更快(因为它只尝试读取1个字节)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1533073|if+(false+===+file_get_contents("http://example.com/path/to/image",0,null,0,1))+{
++++$image+=+$default_image;
}|code-block|syntax|javascript|1533074|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

CoolGoose's solution is good but this is faster for large files (as it only tries to read 1 byte):

<pre><code>if (false === file_get_contents("http://example.com/path/to/image",0,null,0,1)) {
 $image = $default_image;
}
</code></pre>

blocks|key|1317921|text|这不是对你最初问题的回答，而是做你想做的事情的一种更好的方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1317922|而不是直接尝试获取站点的favicon+(这是王室痛苦，因为它可以是/favicon.png，/favicon.ico，/favicon.gif，甚至/path/+to+/favicon.png)，使用谷歌：|1317923|<img+src="http://www.google.com/s2/favicons?domain=[domain]">|code-block|syntax|javascript|1317924|好了。|1317925|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This is not an answer to your original question, but a better way of doing what you're trying to do:

Instead of actually trying to get the site's favicon directly (which is a royal pain given it could be /favicon.png, /favicon.ico, /favicon.gif, or even /path/to/favicon.png), use google:

<pre><code>&lt;img src="http://www.google.com/s2/favicons?domain=[domain]"&gt;
</code></pre>

Done.

blocks|key|1317930|text|function+remote_file_exists($url){
+++return(bool)preg_match('~HTTP/1\.\d\s%2B200\s%2BOK~',+@current(get_headers($url)));
}++
$ff+=+"http://www.emeditor.com/pub/emed32_11.0.5.exe";
++++if(remote_file_exists($ff)){
++++++++echo+"file+exist!";
++++}
++++else{
++++++++echo+"file+not+exist!!!";
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1317931|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>function remote_file_exists($url){
 return(bool)preg_match('~HTTP/1\.\d\s+200\s+OK~', @current(get_headers($url)));
} 
$ff = "http://www.emeditor.com/pub/emed32_11.0.5.exe";
 if(remote_file_exists($ff)){
 echo "file exist!";
 }
 else{
 echo "file not exist!!!";
 }
</code></pre>

blocks|key|1533241|text|如果您正在处理图像，请使用getimagesize。与file_exists不同，此内建函数支持远程文件。它将返回一个包含图像信息(宽度、高度、type..etc)的数组。您所要做的就是检查数组中的第一个元素(宽度)。使用print_r输出数组的内容|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1533242|$imageArray+=+getimagesize("http://www.example.com/image.jpg");
if($imageArray[0])
{
++++echo+"it's+an+image+and+here+is+the+image's+info ";
++++print_r($imageArray);
}
else
{
++++echo+"invalid+image";
}|code-block|syntax|javascript|1533243|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you are dealing with images, use getimagesize. Unlike file_exists, this built-in function supports remote files. It will return an array that contains the image information (width, height, type..etc). All you have to do is to check the first element in the array (the width). use print_r to output the content of the array

<pre><code>$imageArray = getimagesize("http://www.example.com/image.jpg");
if($imageArray[0])
{
 echo "it's an image and here is the image's info&lt;br&gt;";
 print_r($imageArray);
}
else
{
 echo "invalid image";
}
</code></pre>

blocks|key|1533259|text|您可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1533260|$url=getimagesize(“http://www.flickr.com/photos/27505599@N07/2564389539/”);

if(!is_array($url))
{
+++$default_image+=”…/directoryFolder/junal.jpg”;
}|code-block|syntax|javascript|1533261|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can use :

<pre><code>$url=getimagesize(“http://www.flickr.com/photos/27505599@N07/2564389539/”);

if(!is_array($url))
{
 $default_image =”…/directoryFolder/junal.jpg”;
}
</code></pre>

blocks|key|1318102|text|这里使用get_headers()的所有答案都是GET请求。只做HEAD请求要快得多/便宜得多。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318103|为了确保get_headers()执行HEAD请求而不是GET请求，您应该添加以下内容：|1318104|stream_context_set_default(
++++array(
++++++++'http'+=>+array(
++++++++++++'method'+=>+'HEAD'
++++++++)
++++)
);|code-block|syntax|javascript|1318105|因此，要检查文件是否存在，您的代码应如下所示：|1318106|stream_context_set_default(
++++array(
++++++++'http'+=>+array(
++++++++++++'method'+=>+'HEAD'
++++++++)
++++)
);
$headers+=+get_headers('http://website.com/dir/file.jpg',+1);
$file_found+=+stristr($headers[0],+'200');|1318107|显然，$file_found将返回false或true。|1318108|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

all the answers here that use get_headers() are doing a GET request. 
It's much faster/cheaper to just do a HEAD request.

To make sure that get_headers() does a HEAD request instead of a GET you should add this:

<pre><code>stream_context_set_default(
 array(
 'http' =&gt; array(
 'method' =&gt; 'HEAD'
 )
 )
);
</code></pre>

so to check if a file exists, your code would look something like this:

<pre><code>stream_context_set_default(
 array(
 'http' =&gt; array(
 'method' =&gt; 'HEAD'
 )
 )
);
$headers = get_headers('http://website.com/dir/file.jpg', 1);
$file_found = stristr($headers[0], '200');
</code></pre>

$file_found will return either false or true, obviously.

blocks|key|1318138|text|投票最多的答案的完整功能：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318139|function+remote_file_exists($url)
{
++++$ch+=+curl_init($url);
++++curl_setopt($ch,+CURLOPT_NOBODY,+1);
++++curl_setopt($ch,+CURLOPT_FOLLOWLOCATION,+1);+#+handles+301/2+redirects
++++curl_exec($ch);
++++$httpCode+=+curl_getinfo($ch,+CURLINFO_HTTP_CODE);
++++curl_close($ch);
++++if(+$httpCode+==+200+){return+true;}
}|code-block|syntax|javascript|1318140|1318141|你可以这样使用它：|1318142|if(remote_file_exists($url))
{
++++//file+exists,+do+something
}|1318143|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|O|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|P|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Q|8|@]|9|@]|A|$]]|$1|J|3|K|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|L|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|M|$]]

A complete function of the most voted answer:
<pre><code>function remote_file_exists($url)
{
 $ch = curl_init($url);
 curl_setopt($ch, CURLOPT_NOBODY, 1);
 curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1); # handles 301/2 redirects
 curl_exec($ch);
 $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
 curl_close($ch);
 if( $httpCode == 200 ){return true;}
}
</code></pre>
<hr />
You can use it like this:
<pre><code>if(remote_file_exists($url))
{
 //file exists, do something
}
</code></pre>

blocks|key|1318184|text|您可以使用以下内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318185|$file+=+'http://mysite.co.za/images/favicon.ico';
$file_exists+=+(@fopen($file,+"r"))+?+true+:+false;|code-block|syntax|javascript|1318186|在尝试检查URL上是否存在图像时，适用于我|1318187|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You could use the following:

<pre><code>$file = 'http://mysite.co.za/images/favicon.ico';
$file_exists = (@fopen($file, "r")) ? true : false;
</code></pre>

Worked for me when trying to check if an image exists on the URL

blocks|key|1318260|text|这可以让我检查PHP中是否存在远程文件：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318261|$url+=+'https://cdn.sstatic.net/Sites/stackoverflow/img/favicon.ico';
++++$header_response+=+get_headers($url,+1);

++++if+(+strpos(+$header_response[0],+"404"+)+!==+false+)+{
++++++++echo+'File+does+NOT+exist';
++++++++}+else+{
++++++++echo+'File+exists';
++++++++}|code-block|syntax|javascript|1318262|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This works for me to check if a remote file exist in PHP:

<pre><code>$url = 'https://cdn.sstatic.net/Sites/stackoverflow/img/favicon.ico';
 $header_response = get_headers($url, 1);

 if ( strpos( $header_response[0], "404" ) !== false ) {
 echo 'File does NOT exist';
 } else {
 echo 'File exists';
 }
</code></pre>

blocks|key|1318280|text|您可以使用文件系统:+use+Symfony\Component\Filesystem\Filesystem；使用Symfony\Component\Filesystem\Exception\IOExceptionInterface；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1318281|并检查$fileSystem+=+new+Filesystem()；if+($fileSystem->exists('path_to_file')==true)+{...|1318282|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

You can use the filesystem:
use Symfony\Component\Filesystem\Filesystem;
use Symfony\Component\Filesystem\Exception\IOExceptionInterface;

and check
 $fileSystem = new Filesystem();
 if ($fileSystem->exists('path_to_file')==true) {...

blocks|key|1318329|text|如果您使用Symfony框架，还有一种使用HttpClientInterface的更简单的方法|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1318330|private+function+remoteFileExists(string+$url,+HttpClientInterface+$client):+bool+{
++++$response+=+$client->request(
++++++++'GET',
++++++++$url+//e.g.+http://example.com/file.txt
++++);

++++return+$response->getStatusCode()+==+200;
}|code-block|syntax|javascript|1318331|如果您需要更具体的方法，那么HttpClient的文档也非常好，也许值得一看：https://symfony.com/doc/current/http_client.html|1318332|entityMap|0|LINK|mutability|MUTABLE|url|https://symfony.com/doc/current/http_client.html^0|L|J|0|0|13|1C|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|M|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

If you're using the Symfony framework, there is also a much simpler way using the <code>HttpClientInterface</code>:
<pre><code>private function remoteFileExists(string $url, HttpClientInterface $client): bool {
 $response = $client-&gt;request(
 'GET',
 $url //e.g. http://example.com/file.txt
 );

 return $response-&gt;getStatusCode() == 200;
}
</code></pre>
The docs for the HttpClient are also very good and maybe worth looking into if you need a more specific approach: <a href="https://symfony.com/doc/current/http_client.html" rel="nofollow noreferrer">https://symfony.com/doc/current/http_client.html</a>

blocks|key|1533582|text|如果你正在使用Laravel框架或guzzle包，还有一种使用guzzle客户端的更简单的方法，当链接被重定向时，它也是有效的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1533583|$client+=+new+\GuzzleHttp\Client(['allow_redirects'+=>+['track_redirects'+=>+true]]);
try+{
++++$response+=+$client->request('GET',+'your/url');
++++if+($response->getStatusCode()+!=+200)+{
++++++++//+not+exists
++++}
}+catch+(\GuzzleHttp\Exception\GuzzleException+$e)+{
++++//+not+exists
}|code-block|syntax|javascript|1533584|文档中有更多信息：https://docs.guzzlephp.org/en/latest/faq.html#how-can-i-track-redirected-requests|offset|length|1533585|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.guzzlephp.org/en/latest/faq.html#how-can-i-track-redirected-requests^0|0|0|9|29|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

If you're using the Laravel framework or guzzle package, there is also a much simpler way using the guzzle client, it also works when links are redirected:
<pre class="lang-php prettyprint-override"><code>$client = new \GuzzleHttp\Client(['allow_redirects' =&gt; ['track_redirects' =&gt; true]]);
try {
 $response = $client-&gt;request('GET', 'your/url');
 if ($response-&gt;getStatusCode() != 200) {
 // not exists
 }
} catch (\GuzzleHttp\Exception\GuzzleException $e) {
 // not exists
}
</code></pre>
More in Document : <a href="https://docs.guzzlephp.org/en/latest/faq.html#how-can-i-track-redirected-requests" rel="nofollow noreferrer">https://docs.guzzlephp.org/en/latest/faq.html#how-can-i-track-redirected-requests</a>

blocks|key|1533629|text|请检查此URL。我相信它会对你有帮助的。他们提供了两种方法来克服这个问题，并给出了一些解释。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1533630|试试这个吧。|1533631|//+Remote+file+url
$remoteFile+=+'https://www.example.com/files/project.zip';

//+Initialize+cURL
$ch+=+curl_init($remoteFile);
curl_setopt($ch,+CURLOPT_NOBODY,+true);
curl_exec($ch);
$responseCode+=+curl_getinfo($ch,+CURLINFO_HTTP_CODE);
curl_close($ch);

//+Check+the+response+code
if($responseCode+==+200){
++++echo+'File+exists';
}else{
++++echo+'File+not+found';
}|code-block|syntax|javascript|1533632|或访问URL|1533633|https://www.codexworld.com/how-to/check-if-remote-file-exists-url-php/#:~:text=The%2520file_exists()%2520function%2520in,a%2520remote%2520server%2520using%2520PHP。|offset|length|1533634|entityMap|0|LINK|mutability|MUTABLE|url|https://www.codexworld.com/how-to/check-if-remote-file-exists-url-php/#:~:text=The%2520file_exists()%2520function%2520in,a%2520remote%2520server%2520using%2520PHP)^0|0|0|0|0|0|44|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|10|8|@]|9|@$M|11|N|12|1|13]]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Please check this URL. I believe it will help you. They provide two ways to overcome this with a bit of explanation.
Try this one.
<pre><code>// Remote file url
$remoteFile = 'https://www.example.com/files/project.zip';

// Initialize cURL
$ch = curl_init($remoteFile);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_exec($ch);
$responseCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

// Check the response code
if($responseCode == 200){
 echo 'File exists';
}else{
 echo 'File not found';
}
</code></pre>
or visit the URL
<a href="https://www.codexworld.com/how-to/check-if-remote-file-exists-url-php/#:%7E:text=The%20file_exists()%20function%20in,a%20remote%20server%20using%20PHP" rel="nofollow noreferrer">https://www.codexworld.com/how-to/check-if-remote-file-exists-url-php/#:~:text=The%20file_exists()%20function%20in,a%20remote%20server%20using%20PHP</a>.

The best I could find, an <code>if</code> <code>fclose</code> <code>fopen</code> type thing, makes the page load really slowly. 

Basically what I'm trying to do is the following: I have a list of websites, and I want to display their favicons next to them. However, if a site doesn't have one, I'd like to replace it with another image rather than display a broken image.

How can one check to see if a remote file exists using PHP?

文件系统

jQuery

我所能找到的最好的if fclose fopen类型的东西，使页面加载非常慢。基本上，我想要做的是:我有一个网站列表，我想在它们旁边显示它们的图标。但是，如果一个站点没有，我想用另一个图像替换它，而不是显示一个损坏的图像。

问如何使用PHP检查远程文件是否存在？
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