Check Whether Image Exists on Remote Url

Check if image exists on remote URL with or without http/https

Instead of checking the accessibility and the image size in 2 steps, you could combine it in one:

Validator::extend('valid_img_url', function ($attribute, $value, $parameters, $validator) {
     $ch = curl_init($value);
     curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
     curl_setopt($ch, CURLOPT_HEADER, TRUE);
     curl_setopt($ch, CURLOPT_NOBODY, TRUE);

     $data = curl_exec($ch);
     $size = curl_getinfo($ch, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
     $mime = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
     curl_close($ch);
     return $httpCode >= 200 && $httpCode <= 400 && $size > 0 && substr($mime, 0, 5) == 'image');
}

To use the power of getimageSize you could add this piece of code:

Validator::extend('valid_img_url', function ($attribute, $value, $parameters, $validator) {
    $handle = curl_init($value);
    curl_setopt($handle,  CURLOPT_RETURNTRANSFER, TRUE);

    $response = curl_exec($handle);
    $httpCode = curl_getinfo($handle, CURLINFO_HTTP_CODE);
    if($httpCode >= 200 && $httpCode <= 400) {
        if (!preg_match("~^(?:f|ht)tps?://~i", $value)) {
            $value = "http://" . $value;
        }
       return getimagesize($value) !== false;   
    }
});

It will add the missing http if there is no one. But remember if the url is only accessible via https without any redirect it can throw an error.

How to check if Image exists on server using URL

Use fopen function

if (@fopen($resultUF['destination'], "r")) {
    echo "File Exist";
} else {
    echo "File Not exist";
}

Check if Image Exists on Remote Site ASP.NET VB

Assuming that your database column Name contains only the short filename (i.e. no directory path information or folder names) then you can do this:

String nameFromDatabase = (String)dsDriver.Tables("Driver").Rows[0]["Name"] + ".png";

String appRootRelativeHttpResourcePath = "~/Images/DriversNew/" + nameFromDatabase;

String localFileSystemPath = Server.MapPath( appRootRelativeHttpResourcePath  );

if( File.Exists( localFileSystemPath ) ) {

    imgDriver.ImageUrl = appRootRelativeHttpResourcePath; // you can specify app-root-relative URLs ("~/...") here
}
else {

    imgDriver.ImageUrl = "~/Images/DriversNew/Blank.png";
}

Check if image exists on server using JavaScript?

You could use something like:

function imageExists(image_url){

    var http = new XMLHttpRequest();

    http.open('HEAD', image_url, false);
    http.send();

    return http.status != 404;

}

Obviously you could use jQuery/similar to perform your HTTP request.

$.get(image_url)
    .done(function() { 
        // Do something now you know the image exists.

    }).fail(function() { 
        // Image doesn't exist - do something else.

    })

Fast way to check if image on remote URL exists in python

Your requests are blocking and synchronous which is why it is taking a bit of time. In simple terms, it means that the second request doesn't start, until the first one finishes.

Think of it like one conveyer belt with a bunch of boxes and you have one worker to process each box.

The worker can only process one box at a time; and he has to wait for the processing to be done before he can start processing another box (in other words, he cannot take a box from the belt, drop it somewhere to be processed, come back and pick another one).

To reduce the time it takes to processes boxes, you can:

1. Reduce the time it takes to process each box.
2. Make it so that multiple boxes can be processed at the same time (in other words, the worker doesn't have to wait).
3. Increase the number of belts and workers and then divide the boxes between belts.

We really can't do #1 because this delay is from the network (you could reduce the timeout period, but this is not recommended).

Instead what we want to do is #2 - since the processing of one box is independent, we don't need to wait for one box to finish to start processing the next.

So we want to do the following:

1. Quickly send multiple requests to a server for URLs at the same time.
2. Wait for each of them to finish (independent of each other).
3. Collect the results.

There are multiples ways to do this which are listed in the documentation for requests; here is an example using grequests:

import grequests

# Create a map between url and the item
url_to_item = {item.item_low_url: item for item in items}

# Create a request queue, but don't send them
rq = (grequests.head(url) for url in url_to_item.keys())

# Send requests simultaneously, and collect the results,
# and filter those that are valid

# Each item returned in the Response object, which has a request
# property that is the original request to which this is a response;
# we use that to filter out the item objects

results = [url_to_item[i.request.url]
           for i in filter(lambda x: x.status_code == 200,
                           grequests.map(rq)))]

Check if URL exist, and if it's an image

You can never be 100% sure but i would at least check for:

1. Content Headers rather than extension (works even if the image is being served dynamically with the extension of ".php" or anything else)
2. Check the content length header to make sure it's greater than zero and the server is not sending me a soft 404

3. Finally check if the final image is a redirect. (incase of 404 page or a default image file)

   $content_type = curl_getinfo($ch, CURLINFO_CONTENT_TYPE);
   $content_length = curl_getinfo($ch, CURLINFO_CONTENT_LENGTH_DOWNLOAD);
   $content_redirect = curl_getinfo($ch, CURLINFO_REDIRECT_COUNT );
   
   $imageTypes = array('image/png','image/jpeg','image/gif');
   
   if(in_array($content_type,$imageTypes) && $content_redirect == 0 && $content_length >0){
   // is a vald image
   }
   

to stop curl from downloading the whole image file set CURLOPT_NOBODY to true.

curl_setopt($ch, CURLOPT_NOBODY, true);

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

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.

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