PHP imagecreatefromstring（）：gd-jpeg，libjpeg：可恢复的错误

Question

I'm trying to load an image from an external site over which I have no control.

Most of the time it works fine (hundreds of images tested so far).

It's now giving me this error for one particular image:

imagecreatefromstring(): gd-jpeg, libjpeg: recoverable error: Corrupt JPEG data: premature end of data segment

from this line:

$im = @imagecreatefromstring( $imageString );

The advice I'd read so far suggests adding:

ini_set("gd.jpeg_ignore_warning", true);

but that's had no effect and I'm still getting the error. I'm doing the ini_set just before the call. Is that relevant?

I'm really stuck on how to ignore this error and carry on.

Answer 1

The problem was due to my error handling. I'd set up an error handler so my call to

$im = @imagecreatefromstring( $imageString );

wasn't suppressing errors.

By modifying my error handler with:

   if (error_reporting() === 0)
   {
        // This copes with @ being used to suppress errors
        // continue script execution, skipping standard PHP error handler
        return false;
   }

I can now correctly suppress selected errors.

I found the info here: http://anvilstudios.co.za/blog/php/how-to-ignore-errors-in-a-custom-php-error-handler/

Answer 2

这可以解决：

ini_set ('gd.jpeg_ignore_warning', 1);

Answer 3

If you are just showing the image, then I suggest simply reading the contents and display the image as follows:

$img = "http://path/to/image";
$contents = file_get_contents($img);
header("Content-Type: image/jpeg");
print($contents);

If you are wanting to copy the image to your server, you have a few options, two of which are the copy() function or the method used above and then fwrite() :

Option 1 - The copy() function, available from PHP 4

$file1 = "http://path/to/file";
$dest = "/path/to/yourserver/lcoation";
$docopy = copy($file1, $dest);

Option 2 - Using file_get_contents() and fwrite()

$img = "http://path/to/image";
$contents = file_get_contents($img);
$newfile = "path/to/file.ext";
$fhandler = fopen($newfile, 'w+'); //create if not exists, truncate to 0 length
$write = fwrite($fhandler, $contents); //write image data
$close = fclose($fhandler); //close stream
chmod(0755, $newfile); //make publically readable if you want

I hope you find some use in the above

Answer 4

Considering that you want to make a thumbnail and save it, you could implement a handy resize function like the following:

<?php
function resize($sourcefile, $endfile, $thumbwidth, $thumbheight, $quality){

    $ext1 = explode(".",trim($sourcefile));
    $ext = strtolower(trim(array_slice($sext1,-1)));

    switch($ext):
        case 'jpg' or 'jpeg':
            $img = imagecreatefromjpeg($sourcefile);
        break;
        case 'gif':
            $img = imagecreatefromgif($sourcefile);
        break;
        case 'png':
            $img = imagecreatefrompng($sourcefile);
        break;
    endswitch;

    $width = imagesx( $img );
    $height = imagesy( $img );

    if ($width > $height) {
        $newwidth = $thumbwidth;
        $divisor = $width / $thumbwidth;
        $newheight = floor( $height / $divisor);
    }
    else {
        $newheight = $thumbheight;
        $divisor = $height / $thumbheight;
        $newwidth = floor( $width / $divisor );
    }

    // Create a new temporary image.
    $tmpimg = imagecreatetruecolor( $newwidth, $newheight );

    // Copy and resize old image into new image.
    imagecopyresampled( $tmpimg, $img, 0, 0, 0, 0, $newwidth, $newheight, $width, $height );

    // Save thumbnail into a file.

    switch($ext):
        case 'jpg' or 'jpeg':
            $makeimg = imagejpeg($tmpimg, $endfile, $quality);
        break;
        case 'gif':
            $makeimg = imagegif($tmpimg, $endfile, $quality);
        break;
        case 'png':
            $makeimg = imagepng($tmpimg, $endfile, $quality);
        break;
    endswitch;

    // release the memory
    imagedestroy($tmpimg);
    imagedestroy($img);

        if($makeimg){
        chmod($endfile,0755);
        return true;
        }else{
        return false;
        }
    }
?>

Then, after you've copied the file to your server using one of my methods in my answer above this, you could simply apply the function as follows:

$doresize = resize($sourcefile, $endfile, $thumbwidth, $thumbheight, $quality);
echo ($doresize == true ? "IT WORKED" : "IT FAILED");

This function serves me pretty well. I apply it to 1000's of images a day and it works like a charm.