Get number of pages from a PDF, using GhostScript.

ping.gs.php

<?php

/**
 * Return the number of pages of a PDF.
 * 
 * Imagick::pingImage() takes too much when dealing with big files.
 *
 * Command to execute:
 * 
 *     gs -q -dNODISPLAY -c "(%s) (r) file runpdfbegin pdfpagecount = quit"
 *
 * where %s is the filename.
 *
 */

try {

    $r = '';
    $f = array_key_exists(1, $argv) ? trim($argv[1]) : NULL;
    
    if( is_null($f) || ! file_exists($f))
      throw new Exception('File not found or not defined', 1);

    exec(sprintf('gs -q -dNODISPLAY -c "(%s) (r) file runpdfbegin pdfpagecount = quit"', $f), $res, $ret);

    if(0 <> $ret)
        $r = 'Error ' . $ret;

    else
        $r = (int) $res[0];

} catch (Exception $e) {

    $r  = sprintf('Error (%u) %s at line %u', $e->getCode(), $e->getMessage(), $e->getLine());
    $r .= PHP_EOL;
    $r .= 'Usage: ' . basename(__FILE__) . ' file.pdf';

} finally {

    print $r . PHP_EOL;

}