Hi,
I have a PHP script which creates an image using GD and I'm trying to read its contents with PHP. When the file physically exists on the server, I can fopen it and use fread to read it. Is there a way to get the same results with a PHP page?
Thanks
My first thought would be to remove the "header-content: image/png" line from the PHP file I'm opening, but fread doesnt accept a URL...
I don't understand what you're trying to do... if you create an image with the GD library, the image resource is held in a variable.
Can you show us some code so we can see what you're trying to do?
I'm using the fpdf library to insert an image into a pdf file. Below is the code, if $file = images/penguin.png, it works, but if I link to a GD file, $file=code.php?a=a&b=b, there is a problem with fopen.
function _parsepng($file)
{
//Extract info from a PNG file
$f=fopen($file,'rb');
if(!$f)
$this->Error('Can\'t open image file: '.$file);
//Check signature
if(fread($f,8)!=chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10))
$this->Error('Not a PNG file: '.$file);
//Read header chunk
fread($f,4);
if(fread($f,4)!='IHDR')
$this->Error('Incorrect PNG file: '.$file);
$w=$this->_freadint($f);
$h=$this->_freadint($f);
$bpc=ord(fread($f,1));
if($bpc>8)
$this->Error('16-bit depth not supported: '.$file);
$ct=ord(fread($f,1));
if($ct==0)
$colspace='DeviceGray';
elseif($ct==2)
$colspace='DeviceRGB';
elseif($ct==3)
$colspace='Indexed';
else
$this->Error('Alpha channel not supported: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Unknown compression method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Unknown filter method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Interlacing not supported: '.$file);
fread($f,4);
$parms='/DecodeParms <</Predictor 15 /Colors '.($ct==2 ? 3 : 1).' /BitsPerComponent '.$bpc.' /Columns '.$w.'>>';
//Scan chunks looking for palette, transparency and image data
$pal='';
$trns='';
$data='';
do
{
$n=$this->_freadint($f);
$type=fread($f,4);
if($type=='PLTE')
{
//Read palette
$pal=fread($f,$n);
fread($f,4);
}
elseif($type=='tRNS')
{
//Read transparency info
$t=fread($f,$n);
if($ct==0)
$trns=array(ord(substr($t,1,1)));
elseif($ct==2)
$trns=array(ord(substr($t,1,1)),ord(substr($t,3,1)),ord(substr($t,5,1)));
else
{
$pos=strpos($t,chr(0));
if($pos!==false)
$trns=array($pos);
}
fread($f,4);
}
elseif($type=='IDAT')
{
//Read image data block
$data.=fread($f,$n);
fread($f,4);
}
elseif($type=='IEND')
break;
else
fread($f,$n+4);
}
while($n);
if($colspace=='Indexed' && empty($pal))
$this->Error('Missing palette in '.$file);
fclose($f);
return array('w'=>$w,'h'=>$h,'cs'=>$colspace,'bpc'=>$bpc,'f'=>'FlateDecode','parms'=>$parms,'pal'=>$pal,'trns'=>$trns,'data'=>$data);
}
Try using a full HTTP path (e.g. http://yoursite.com/path/to/code.php )... otherwise, it'll think it's a relative path and open it via the local file system (and obviously it can't find "code.php?a=a&b=b").
I still get an error with that:
Warning: fopen() [function.fopen]: URL file-access is disabled in the server configuration in /home/mysite.com/pdf/fpdf.php on line 1524
Warning: fopen(http://www.site.com/page.php?PDF=true) [function.fopen]: failed to open stream: no suitable wrapper could be found in /home/mysite.com/pdf/fpdf.php on line 1524
FPDF error: Can't open image file: http://www.site.com/page.php?PDF=true
Okay, I see what's up here, my webhost disabled fopen on URLs. So they require that I use cURL. Problem is, with the script they give me, I still cannot do fread...
<?php
$image_url = "http://example.com/image.jpg";
$ch = curl_init();
$timeout = 0;
curl_setopt ($ch, CURLOPT_URL, $image_url);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
// Getting binary data
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
$image = curl_exec($ch);
curl_close($ch);
// output to browser
header("Content-type: image/jpeg");
print $image;
?>
So I replaced the fopen($file) and made it equal to $image, but fread doesn't like that input.
That's because $image will contain the binary image date, not a path (which your _parsepng() function is looking for).
The simplest solution I can think of would be to make a new stream type that allows you to fopen/fread a variable as if it were a normal file stream. To do this, you'd use the [man]stream_wrapper_register/man function:
class VariableStream {
// This class is provided on the manual page linked above.
// Copy it into your script here.
}
// Do the cURL stuff here, loading the data into $image as you have above.
stream_wrapper_register("var", "VariableStream")
// Run your function like this:
$data = _parsepng('var://image');Haven't tried this myself; no promises that it'll work.
I tried it, but it seems that the fread still doesn't like the input.... is there a way to test out what fread shows, by perhaps echoing the function?
This is what I have so far (I pasted the variablestream stuff all the way at the bottom of the page):
function _parsepngphp($file)
{
//Extract info from a PNG file
$image_url = $file;
$ch = curl_init();
$timeout = 0;
curl_setopt ($ch, CURLOPT_URL, $image_url);
curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, $timeout);
// Getting binary data
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_BINARYTRANSFER, 1);
$image = curl_exec($ch);
curl_close($ch);
$f = $image;
stream_wrapper_register("var", "VariableStream")
or die("Failed to register protocol");
$f = fopen("var://image", "rb");
if(!$f)
$this->Error('Can\'t open image file: '.$file);
//Check signature
if(fread($f,8)!=chr(137).'PNG'.chr(13).chr(10).chr(26).chr(10)) {
$contents = fread($f,8);
$this->Error('Not a PNG file: '. $image);
}
//Read header chunk
fread($f,4);
if(fread($f,4)!='IHDR')
$this->Error('Incorrect PNG file: '.$file);
$w=$this->_freadint($f);
$h=$this->_freadint($f);
$bpc=ord(fread($f,1));
if($bpc>8)
$this->Error('16-bit depth not supported: '.$file);
$ct=ord(fread($f,1));
if($ct==0)
$colspace='DeviceGray';
elseif($ct==2)
$colspace='DeviceRGB';
elseif($ct==3)
$colspace='Indexed';
else
$this->Error('Alpha channel not supported: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Unknown compression method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Unknown filter method: '.$file);
if(ord(fread($f,1))!=0)
$this->Error('Interlacing not supported: '.$file);
fread($f,4);
$parms='/DecodeParms <</Predictor 15 /Colors '.($ct==2 ? 3 : 1).' /BitsPerComponent '.$bpc.' /Columns '.$w.'>>';
//Scan chunks looking for palette, transparency and image data
$pal='';
$trns='';
$data='';
do
{
$n=$this->_freadint($f);
$type=fread($f,4);
if($type=='PLTE')
{
//Read palette
$pal=fread($f,$n);
fread($f,4);
}
elseif($type=='tRNS')
{
//Read transparency info
$t=fread($f,$n);
if($ct==0)
$trns=array(ord(substr($t,1,1)));
elseif($ct==2)
$trns=array(ord(substr($t,1,1)),ord(substr($t,3,1)),ord(substr($t,5,1)));
else
{
$pos=strpos($t,chr(0));
if($pos!==false)
$trns=array($pos);
}
fread($f,4);
}
elseif($type=='IDAT')
{
//Read image data block
$data.=fread($f,$n);
fread($f,4);
}
elseif($type=='IEND')
break;
else
fread($f,$n+4);
}
while($n);
if($colspace=='Indexed' && empty($pal))
$this->Error('Missing palette in '.$file);
fclose($f);
return array('w'=>$w,'h'=>$h,'cs'=>$colspace,'bpc'=>$bpc,'f'=>'FlateDecode','parms'=>$parms,'pal'=>$pal,'trns'=>$trns,'data'=>$data);
}
I don't have the complete class you're using (e.g. I'm missing what the _freadint() function does), but one problem is that the VariableStream class can only read variables that are in the global scope. To fix this, change this:
$image = curl_exec($ch);
curl_close($ch);
$f = $image; to this:
global $image;
$image = curl_exec($ch);
curl_close($ch);If that doesn't work, you'll have to show me the rest of this class.
Posiblemente puede que necesiten comentar la linea open_basedir en el php.ini y reiniciar el servicio web