Is there a way to check whether a remote image is exist? PHP

Question

My site is running in LAMP, my image CDN is in nginx.

I want to do is: Check if a requested image has a copy in CDN server, if yes then loan the copy in cdn server, otherwise, load the local copy for user.

Is there a programmatically way to check whether the remote CDN image is exist?

(perhaps determine the header? as I notice that if request image isn't exist, it returns 404)

enter image description here

possible duplicate of [Check whether image exists on remote URL](http://stackoverflow.com/questions/1363925/check-whether-image-exists-on-remote-url) — Gordon, Jan 19 '12 at 12:47
What do you mean by load.. do you want to display the image using ? — Ninja, Jan 19 '12 at 12:56

score 3 · Accepted Answer · answered Jan 19 '12 at 12:34

I use this method to ping distant files:

  /**
   * Use HTTP GET to ping an url
   *
   * /!\ Warning, the return value is always true, you must use === to test the response type too.
   * 
   * @param string $url
   * @return boolean true or the error message
   */
  public static function pingDistantFile($url)
  {
    $options = array(
      CURLOPT_FOLLOWLOCATION => true,
      CURLOPT_URL => $url,
      CURLOPT_FAILONERROR => true, // HTTP code > 400 will throw curl error
    );

    $ch = curl_init();
    curl_setopt_array($ch, $options);
    $return = curl_exec($ch);

    if ($return === false)
    {
      return curl_error($ch);
    }
    else
    {
      return true;
    }
  }

You can also use the HEAD method but maybe your CDN as disabled it.

score 2 · Answer 2 · edited May 23 '17 at 10:32

2

So long as the copy is public, you could just check for a 404 with cURL. See this question detailing how to do it.

edited May 23 '17 at 10:32

Community

1
1

answered Jan 19 '12 at 12:32

Zoe Edwards

12,999
3
24
43

score 2 · Answer 3 · edited May 23 '17 at 12:34

2

You can use file_get_contents for this:

 $content = file_get_contents("path_to_your_remote_img_file");
 if ($content === FALSE)
 {
     /*Load local copy*/
 }
 else
 {
     /*Load $content*/
 }

Oh and one more thing- if you only want to display the image with an img tag, you can simply do this- using img tags onerror attribute- if the image does not exist on the server, the onerror attribute will display the local file:

<img src="path_to_your_remote_img_file" onerror='this.src="path_to_your_local_img_file"'>

You can read a similar question on this here: detect broken image using php

edited May 23 '17 at 12:34

Community

1
1

answered Jan 19 '12 at 12:57

Ninja

5,082
6
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Yes, but it depends on what he wants to do with the image. If he just wants to display it, I have updated my answer with a way to do it using simple html, without having to do any header or file exists checks – Ninja Jan 19 '12 at 13:33

score 1 · Answer 4 · answered Jan 19 '12 at 12:58

1

Another easier way – without cURL:

$headers = get_headers('http://example.com/image.jpg', 1);
if($headers[0] == 'HTTP/1.1 200 OK')
{
  //image exist
}
else
{
  //some kind of error
}

answered Jan 19 '12 at 12:58

kuboslav

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5
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HEAD method can be disabled by server admins, but in a controlled environnement it's the best method. – Damien Jan 19 '12 at 13:01
Does the header method also load the image content? – gilzero Jan 19 '12 at 13:22
@gilzero No, function fetch only headers. – kuboslav Jan 19 '12 at 13:24

score -1 · Answer 5 · answered Feb 14 '13 at 16:32

-1

<?php
if (is_array(getimagesize("http://www.imagelocation.com/image.png"))){
   // Image ok
} else {
   // Image not ok
}
?>

answered Feb 14 '13 at 16:32

GrooveNow

44
3

This would download the whole image to the webserver from the CDN, unnecessarily adding load to both servers. – WesleyE Feb 14 '13 at 16:51

Is there a way to check whether a remote image is exist? PHP

5 Answers5