pdfForm.php

<?php

class PdfForm
{

    /*
    * Path to raw PDF form
    * @var string
    */
    private $pdfurl;

    /*
    * Form data
    * @var array
    */
    private $data;

    /*
    * Path to filled PDF form
    * @var string
    */
    private $output;

    /*
    * Flag for flattening the file
    * @var string
    */
    private $flatten;

    /**
    * Class Conctructor
    *
    * @param string $pdfurl
    * @param string $data
    */
    public function __construct($pdfurl, $data)
    {
        $this->pdfurl = $pdfurl;
        $this->data   = $data;
    }

    /**
    * Generate a filled PDF file
    *
    */
    private function generate()
    {

        $fdf = $this->makeFdf($this->data);
        $this->output = $this->tmpfile();
        exec("pdftk {$this->pdfurl} fill_form {$fdf} output {$this->output}{$this->flatten}");

        unlink($fdf);
    }

    /**
    * Extract fields information
    *
    * @param boolean $pretty
    * @return string
    */
    public function fields($pretty = false)
    {
        $tmp = $this->tmpfile();

        exec("pdftk {$this->pdfurl} dump_data_fields > {$tmp}");
        $con = file_get_contents($tmp);

        unlink($tmp);
        return $pretty == true ? nl2br($con) : $con;
    }

    /**
    * Generate FDF file
    * @param array $data
    * @return string
    */
    public function makeFdf($data)
    {

        $fdf = '%FDF-1.2
        1 0 obj<</FDF<< /Fields[';

        foreach ($data as $key => $value) {
            $fdf .= '<</T(' . $key . ')/V(' . $value . ')>>';
        }

        $fdf .= "] >> >>
        endobj
        trailer
        <</Root 1 0 R>>
        %%EOF";

        $fdf_file = $this->tmpfile();
        file_put_contents($fdf_file, $fdf);

        return $fdf_file;
    }

    /**
    * Set the flatten flag
    *
    * @return pdfWriter
    */
    public function flatten()
    {
        $this->flatten = ' flatten';
        return $this;
    }

    /**
    * Save the file
    *
    * @param string $path
    */
    public function save($path = null)
    {
        if (is_null($path)) {
            return $this;
        }

        if (!$this->output) {
            $this->generate();
        }

        $dest = pathinfo($path, PATHINFO_DIRNAME);
        if (!file_exists($dest)) {
            mkdir($dest, 0775, true);
        }

        copy($this->output, $path);
        unlink($this->output);

        $this->output = $path;

        return $this;
    }

    /**
    * Force download the filled PDF file
    *
    */
    public function download()
    {

        if (!$this->output) {
            $this->generate();
        }

        $filepath = $this->output;
        if (file_exists($filepath)) {

            header('Content-Description: File Transfer');
            header('Content-Type: application/pdf');
            header('Content-Disposition: attachment; filename=' . uniqid(gethostname()) . '.pdf');
            header('Expires: 0');
            header('Cache-Control: must-revalidate');
            header('Pragma: public');
            header('Content-Length: ' . filesize($filepath));

            readfile($filepath);

            exit;
        }
    }

    /**
    * Create a temporary file and return the name
    *
    * @return string
    */
    private function tmpfile()
    {
        return tempnam(sys_get_temp_dir(), gethostname());
    }

}