Zend PHP - 将Google Chart保存为PDF

Question

I am developing a site using Zend PHP framework. On a page I have a chart created with Google Chart API - https://developers.google.com/chart/. I would like to add a button to allow the user to download the chart as a PDF file (essentially convert the chart to an image and embed it in a PDF).

I have been able to convert the google chart to an image using a javascript function that generates the image data string - http://www.battlehorse.net/attach/topics/charts/google_charts_to_image.html

function getImgData(chartId) {
    var chartContainer = document.getElementById(chartId);
    var chartArea = chartContainer.getElementsByTagName('iframe')[0].
    contentDocument.getElementById('chartArea');
    var svg = chartArea.innerHTML;
    var doc = chartContainer.ownerDocument;
    var canvas = doc.createElement('canvas');
    canvas.setAttribute('width', chartArea.offsetWidth);
    canvas.setAttribute('height', chartArea.offsetHeight);   
    canvas.setAttribute(
        'style',
        'position: absolute; ' +
        'top: ' + (-chartArea.offsetHeight * 2) + 'px;' +
        'left: ' + (-chartArea.offsetWidth * 2) + 'px;');
    doc.body.appendChild(canvas);
    canvg(canvas, svg);
    var imgData = canvas.toDataURL("image/png");
    canvas.parentNode.removeChild(canvas);
    return imgData;
}

I have also downloaded a free PHP class to handle generating the PDF - http://www.fpdf.org/

I have been able to use an ajax function to pass the image data string to a zend controller. I can then save the image locally and use it to build a PDF file and save that locally too.

//store the image locally
    $data = substr($image,strpos($image,",")+1); //removing the "data:image/png;base64," part
    file_put_contents ('downloads/'.$title.'.png', base64_decode($data));

    // create PDF document
    $pdf = new FPDF();
    $pdf->AliasNbPages();
    $pdf->AddPage();
    $pdf->Image('downloads/'.$title.'.png',10,6,30);

    //destroy the local copy of the image
    fclose('downloads/'.$title.'.png');
    unlink('downloads/'.$title.'.png');

    //save the PDF document
    $pdf->Output('downloads/'.$title.'.pdf');

I am now stuck because I cannot find a way to present the PDF file for downloading. I need to use an Ajax request to generate the PDF as the image data string is too long for a standard URL. So I think I need to redirect the user to the download link for the file after it has been generated (and then delete it again afterwards).

Does anyone know how I can serve the file for download, if I enter the file path into my browser I get a path not found error (e.g. "MyApp/public/downloads/myChart.pdf"). I have read in a few places how to set the header and body of the response in the controller but nothing has worked so far.

Answer 1

Whe you are generating the download link. Why don't you replace yourpath/public with domain.com? Assuming that ur PDF is generated In the directory public/downloads/blahblah

Possibly the next step would be lik

$path = 'downloads/'.$title.'.pdf';

Header("Location: http://domain.com.$path");

Now when the user calls this script file , using Ajax, the PDF will be generated and the location will be transferred to pdf's path!