如何将ajax结果保存为pdf文件？

Question

Trying to download a file which is dynamically generated by the the data posted. I have the results coming back. I'm just not sure how I can save the results into a proper file locally once the information (stream) is returned from the server.

Here is the ajax call:

function download_pdf(){
      alert("made it" + result_array); 
      $.ajax({
                type: "POST",
                url: "report_generation/downlaod_pdf.php",
                data: { result_array: result_array },

                success: function(results){
                    alert(results);
                },
                error: 
                    function(xmlHttpRequest, status, error){
                        alert(xmlHttpRequest + "| ajax failure: could not download haq report | " + status + " | error:" + error);
                        var xmlHttpRequestStr = "";
                        for(var x in xmlHttpRequest)
                            xmlHttpRequestStr = xmlHttpRequestStr + xmlHttpRequest[x];
                        alert(xmlHttpRequestStr);
                }
           });
}

This function is called from a hyperlink like so, and the success method is returning...

<a class="haq_button" href="javascript:download_pdf()"><span>Download Report As PDF</span></a>

UPDATE: Here is a snippet of code from the file generation in download_pdf

// set the headers, prevent caching
            header("Pragma: public");
            header("Expires: -1");
            header("Cache-Control: public, must-revalidate, post-check=0, pre-check=0");
            header("Content-Disposition: attachment; filename=\"$file_name\"");

            // set appropriate headers for attachment or streamed file
            if ($is_attachment) {
                    header("Content-Disposition: attachment; filename=\"$output_file_name\"");
            }
            else {
                    header('Content-Disposition: inline;');
                    header('Content-Transfer-Encoding: binary');
            }

            // set the mime type based on extension, add yours if needed.
            $ctype_default = "application/octet-stream";
            $content_types = array(
                    "exe" => "application/octet-stream",
                    "pdf" => "application/pdf",
                    "zip" => "application/zip",
                    "mp3" => "audio/mpeg",
                    "mpg" => "video/mpeg",
                    "avi" => "video/x-msvideo",
            );
            $ctype = isset($content_types[$file_ext]) ? $content_types[$file_ext] : $ctype_default;
            header("Content-Type: " . $ctype);

            //check if http_range is sent by browser (or download manager)
            if(isset($_SERVER['HTTP_RANGE']))
            {
                list($size_unit, $range_orig) = explode('=', $_SERVER['HTTP_RANGE'], 2);
                if ($size_unit == 'bytes')
                {
                    //multiple ranges could be specified at the same time, but for simplicity only serve the first range
                    //http://tools.ietf.org/id/draft-ietf-http-range-retrieval-00.txt
                    list($range, $extra_ranges) = explode(',', $range_orig, 2);
                }
                else
                {
                    $range = '';
                    header('HTTP/1.1 416 Requested Range Not Satisfiable');
                    exit;
                }
}
    else
    {
        $range = '';
}

        //figure out download piece from range (if set)
        list($seek_start, $seek_end) = explode('-', $range, 2);

    //set start and end based on range (if set), else set defaults
    //also check for invalid ranges.
    $seek_end   = (empty($seek_end)) ? ($file_size - 1) : min(abs(intval($seek_end)),($file_size - 1));
    $seek_start = (empty($seek_start) || $seek_end < abs(intval($seek_start))) ? 0 : max(abs(intval($seek_start)),0);

    //Only send partial content header if downloading a piece of the file (IE workaround)
    if ($seek_start > 0 || $seek_end < ($file_size - 1))
    {
        header('HTTP/1.1 206 Partial Content');
        header('Content-Range: bytes '.$seek_start.'-'.$seek_end.'/'.$file_size);
        header('Content-Length: '.($seek_end - $seek_start + 1));
    }
    else
      header("Content-Length: $file_size");

    header('Accept-Ranges: bytes');

    set_time_limit(0);
    fseek($file, $seek_start);

    while(!feof($file)) 
    {
        print(@fread($file, 1024*8));
        ob_flush();
        flush();
        if (connection_status()!=0) 
        {
            @fclose($file);
            exit;
        }           
    }

    // file save was a success
    @fclose($file);
    exit;

Answer 1

This is not possible using javascript/ajax. You have to use regural download link, or in your case form. If you want to have some error handling using javascript if pdf generation fails and still keep the same page open, you can submit into a hidden iframe.