Display message before creating excel in jquery and PHP - php

Question

I am creating a web app in my company. The user can click on a button and an csv is created with MySQL data.
So far so god.
In jquery, when the user clicks the button it redirect to:
document.location.href = '/SDR/SDRJSON.php?type=' + id;
On PHP the csv file is created:
I connect to the database and create a the csv file:
while($row = $stmt->fetch(PDO::FETCH_NUM))
{
array_push($csv, $row);
}
$fp = fopen('file.csv', 'w');
foreach ($csv as $row) {
fputcsv($fp, $row, ';');
}
$FileName = 'PEW_'.$CountryCode;
fclose($fp);
header('Content-Encoding: UTF-8');
header('Content-type: text/csv; charset=UTF-8');
header("Content-Disposition: attachment; filename='".$FileName."'.csv");
header("Pragma: public");
header("Expires: 0");
echo "\xEF\xBB\xBF"; // UTF-8 BOM
readfile('file.csv');
On the page where the button is, the user clicks there and the page starts waiting for the server and then the csv file starts downloading.
For small files is ok, because it is instantaneous. But for larger files it takes like 10 / 15 seconds. Is it possible to show a message while the page waits for the server?

Answer 1

I don't Think PHP can echo while the csv is being made ... What you could do is split the "Document Formation" and "Document Download" into two parts.
Let Ajax Make a query for the CSV to be made . And when that has been completed the PHP (Document Formation) will echo the Path of the File.
Then After that You can use document.location.href to Newly Created File.
I ll give the code
ajax-code
$('#sample-button').click(function(){
$.ajax({
url : '/SDR/SDRJSON.php?type=' + id,
success : function(data){
if(data.url)
{
var urlToDownload = data.url;
alert("File is ready for download");
document.location.href = "http://www.domain.com/file/path/"+data.url;
// Make sure data.url has the full path or append the data.url
// with some strings to make sure the full path is reflected
// into document.location.href ...
}
else
{
alert("Something went wrong");
}
}
});
alert("CSV is being prepared Please wait... ");
});
documentFormation.php
while($row = $stmt->fetch(PDO::FETCH_NUM))
{
array_push($csv, $row);
}
$FileName = 'PEW_'.$CountryCode;
$fp = fopen($FileName, 'w');
foreach ($csv as $row) {
fputcsv($fp, $row, ';');
}
fclose($fp);
$response = array();
$response['url'] = $FileName;
echo json_encode($response); // You can handle rest of the cases where to display errors (if you have any)
// Your DocumentFormation PHP Ends here. No need for header() or readFile.
If you dont want the file to stay on server , Edit the document href to This PHP passing 'path' as the parameter
document.location.href = "documentDownload.php?path="+data.url;
documentDownload.php
$path = $_GET['path'];
$filename = end(explode("/" , $path));
header('Content-Encoding: UTF-8');
header('Content-type: text/csv; charset=UTF-8');
//Assuming $filename is like 'xyz.csv'
header("Content-Disposition: attachment; filename='".$filename);
header("Pragma: public");
header("Expires: 0");
echo "\xEF\xBB\xBF"; // UTF-8 BOM
// Reading file contents
readfile('Relative Path to File'.$path);
// Deleting after Read
unlink('Relative Path to File'.$path); // To Delete right after reading