Failed to open stream: VariableStream::stream_open - php

Question

I'm currently implementing a function that generated an image I can use to print it on a PDF file with FPDI. During the creation of the image from the memory, I'm getting this error:
PHP Warning: getimagesize(var://imgd41d8cd98f00b204e9800998ecf8427e):
failed to open stream: "VariableStream::stream_open" call
failed in /Applications/MAMP/htdocs/fpdi/src/fpdi_extended.php on line
77
I don't get it anymore. This is my code:
<?php
require_once 'autoload.php';
use setasign\Fpdi\Fpdi;
class VariableStream {
private $varname;
private $position;
public function streams_open( $path, $mode, $options, &$opened_path ): bool {
$url = parse_url( $path );
$this->varname = $url['host'];
if ( ! isset( $GLOBALS[ $this->varname ] ) ) {
header( 'HTTP/1.1 500 Internal Server Error' );
header( 'Content-Type: application/json; charset=UTF-8' );
die( json_encode( array(
'message' => 'Global variable ' . $this->varname . ' does not exist',
'code' => 1337
) ) );
}
$this->position = 0;
return true;
}
public function stream_read( $count ) {
$ret = substr( $GLOBALS[ $this->varname ], $this->position, $count );
$this->position += strlen( $ret );
return $ret;
}
public function stream_eof(): bool {
return $this->position >= strlen( $GLOBALS[ $this->varname ] );
}
public function stream_tell() {
return $this->position;
}
public function stream_seek( $offset, $whence ): bool {
if ( $whence === SEEK_SET ) {
$this->position = $offset;
return true;
}
return false;
}
public function stream_stat(): array {
return array();
}
}
class Fpdi_Extended extends Fpdi {
public function __construct( $orientation = 'P', $unit = 'mm', $format = 'A4' ) {
parent::__construct( $orientation, $unit, $format );
// Register var stream protocol
stream_wrapper_register( 'var', 'VariableStream' );
}
public function MemImage( $data, $x = null, $y = null, $w = 0, $h = 0, $link = '' ): void {
// Display the image contained in $data
$v = 'img' . md5( $data );
$GLOBALS[ $v ] = $data;
$a = getimagesize( 'var://' . $v );
if ( ! $a ) {
header( 'HTTP/1.1 500 Internal Server Error' );
header( 'Content-Type: application/json; charset=UTF-8' );
die( json_encode( array( 'message' => 'ERROR: Invalid signature data.', 'code' => 1337 ) ) );
}
$type = substr( strstr( $a['mime'], '/' ), 1 );
$this->Image( 'var://' . $v, $x, $y, $w, $h, $type, $link );
unset( $GLOBALS[ $v ] );
}
public function GDImage( $im, $x = null, $y = null, $w = 0, $h = 0, $link = '' ): void {
// Display the GD image associated with $im
ob_start();
imagecreatefromstring( base64_decode( preg_replace( '#^data:image/\w+;base64,#i', '', $im ) ) );
$data = ob_get_clean();
$this->MemImage( $data, $x, $y, $w, $h, $link );
}
}
I'm calling the code this way:
require_once 'fpdf/fpdf.php';
require_once 'fpdi/src/fpdi_extended.php';
$pdf = new Fpdi_Extended();
$page_counter = $pdf->setSourceFile( 'template.pdf' );
$tplIdx = $pdf->importPage( 5 );
$pdf->AddPage();
$pdf->useTemplate( $tplIdx, 10, 10, 100 );
$pdf->GDImage( $signature );
imagedestroy( $signature );
$pdf->Output();
After fixing the typo issue streams_open -> stream_open, I'm hanging here:
PHP Notice: getimagesize(): Read error! in
/Applications/MAMP/htdocs/fpdi/src/fpdi_extended.php
An example value for $signature is: data:image/png;base64,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

Answer 1

Not able to install the FPDI package at the moment but I think you need to convert the image to a PNG before reading it from memory. Try editing your GDImage function like so:
public function GDImage( $im, $x = null, $y = null, $w = 0, $h = 0, $link = '' ): void {
ob_start();
$resource = imagecreatefromstring( base64_decode( preg_replace( '#^data:image/\w+;base64,#i', '', $im ) ) );
imagepng($resource);
$data = ob_get_clean();
$this->MemImage( $data, $x, $y, $w, $h, $link );
}

Answer 2

With the help of waterloomatt I've found my solution. I've changed the function below:
public function GDImage( $im, $x = null, $y = null, $w = 0, $h = 0, $link = '' ): void {
// Display the GD image associated with $im
$resource = imagecreatefromstring( base64_decode( preg_replace( '#^data:image/\w+;base64,#i', '', $im ) ) );
imagesavealpha( $resource, true );
ob_start();
imagepng( $resource );
$data = ob_get_clean();
imagedestroy( $resource );
$this->MemImage( $data, $x, $y, $w, $h, $link );
}
First, I was confused because the save base64 image on my PDF was completely black. So I've informed me about the used methods. So I came across this function here which saves some color informations in the resource:
imagesavealpha( $resource, true );
Now it's working great. Thanks to waterloomatt for the time!