Find if a file exists, if not, revert to original path

Question

I've written a function to take an image path, add some text to the end of it, then join it back together. I'm trying to write an if else branch to test if the file exists after I've appended the new text to the image.

For example, if I request the image path:

http://example.com/image1.jpg

It could be modified to this:

http://example.com/image1-150x100.jpg

The function is intended for WordPress, so takes the $post->ID argument, the custom field name, width and height of the intended target.

Here is the function:

function get_galleria_image ( $post_id, $customFieldName, $width, $height ) {

    $imagePath = get_post_meta($post_id, $customFieldName, true);

    $splitImage = explode('.', $imagePath);

    $count = count($splitImage);

    $firstHalf =  array_slice($splitImage, 0, $count-1);

    $secondHalf = array_slice($splitImage, $count-1);

    $secondHalf[0] = '-' . $width . 'x' . $height . '.' . $secondHalf[0];

    $firstHalfJoined = implode('.', $firstHalf);

    $completedString = $firstHalfJoined . $secondHalf[0];

    // if the filename with the joined string does not exist, return the original image
    if (file_exists($completedString)){
        return $completedString;
    } else {
        return $imagePath;
    }
}

I know this is crude, so any ideas to condense this code and make it "better" is welcomed. What I'm finding is that the function always returns the original image path. Can file_exists() take an absolute path like "http://example.com/image1.jpg', or will it only accept a root-style absolute path, like '/path/to/file/image1.jpg'?

Answer 1

file_exists wont accept url path. Try this for url path to check if the given url is an image or not

function isImage($url)
  {
     $params = array('http' => array(
                  'method' => 'HEAD'
               ));
     $ctx = stream_context_create($params);
     $fp = @fopen($url, 'rb', false, $ctx);
     if (!$fp) 
        return false;  // Problem with url

    $meta = stream_get_meta_data($fp);
    if ($meta === false)
    {
        fclose($fp);
        return false;  // Problem reading data from url
    }

    $wrapper_data = $meta["wrapper_data"];
    if(is_array($wrapper_data)){
      foreach(array_keys($wrapper_data) as $hh){
          if (substr($wrapper_data[$hh], 0, 19) == "Content-Type: image") // strlen("Content-Type: image") == 19 
          {
            fclose($fp);
            return true;
          }
      }
    }

    fclose($fp);
    return false;
  }

Answer 2

As far as I know, file_exists() only checks if a file or directory on the local file system exits. You may want to connect to another server via fsockopen() and then check the HTTP-Code to find out if the file exists.

// you will need to set $host and $file

$sock = fsockopen ( $host );
fwrite ( $sock, "HEAD ".$image." HTTP/1.1\r\n" );
fwrite ( $sock, "Host: ".$file."\r\n" );
fwrite ( $sock, "Connection: close\r\n\r\n" );

// Get the first twelve characters of the response - enough to check the response code
if ( fgets ( $sock, 12 ) == "HTTP/1.1 404" )
    //file doesn't exist
else
    //file exists

fclose ( $sock );

Answer 3

to make more compact the first part of your procedure you can do something like:

$completedString = preg_replace("/(.+)\.([^.]+)$/siU", "$1" . "-" . $width ."x" . $height . "$2", $splitImage);

then use the function posted from @ayush to check the file on the remote server

Answer 4

if(@getimagesize($imghttppath))
{
     echo '<img src="'. $imghttppath . '" />';
}
else
{
     echo '<img src="http://www.domain.com/images/default.jpg" />';
}

It's kinda an unorthodox use of getimagesize, and it has to be @ unless you turn off errors because it returns an error if the file doesn't exist. But it's about as simple as you can get. Works with External URLs, Local URLs, Local Absolute Paths, and Relative Paths to the working directory to check whether or not an image exists and is an actual image.