Download file through an ajax call php

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I have a button and onclick it will call an ajax function.

Here is my ajax function

function csv(){

    ajaxRequest = ajax();//ajax() is function that has all the XML HTTP Requests

    postdata = "data=" + document.getElementById("id").value;

    ajaxRequest.onreadystatechange = function(){
        var ajaxDisplay = document.getElementById('ajaxDiv');
        if(ajaxRequest.readyState == 4 && ajaxRequest.status==200){
            ajaxDisplay.innerHTML = ajaxRequest.responseText;           
        }
    }

    ajaxRequest.open("POST","csv.php",false);
    ajaxRequest.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    ajaxRequest.send(postdata);
}

I create the csv file based on the user input. After it's created I want it to prompt download or force download(preferably force). I am using the following script at the end of the php file to download the file. If I run this script in a separate file it works fine.

$fileName = 'file.csv';
$downloadFileName = 'newfile.csv';

if (file_exists($fileName)) {
    header('Content-Description: File Transfer');
    header('Content-Type: text/csv');
    header('Content-Disposition: attachment; filename='.$downloadFileName);
    ob_clean();
    flush();
    readfile($fileName);
    exit;
}
echo "done";

But If I run it at the end of csv.php it outputs the contents of the file.csv into the page(into the ajaxDiv) instead of downloading.

Is there a way to force download the file at the end of csv.php?

5 Answers

I have accomplished this with a hidden iframe. I use perl, not php, so will just give concept, not code solution.

Client sends Ajax request to server, causing the file content to be generated. This is saved as a temp file on the server, and the filename is returned to the client.

Client (javascript) receives filename, and sets the iframe src to some url that will deliver the file, like:

$('iframe_dl').src="/app?download=1&filename=" + the_filename

Server slurps the file, unlinks it, and sends the stream to the client, with these headers:

Content-Type:'application/force-download'
Content-Disposition:'attachment; filename=the_filename'

Works like a charm.

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