How to download the xls file using codeigniter - php

Question

Here i have one button, if i click the button means i want to download the one demo.xls file,using php i did, but now i want to do codeigniter, i tried but i am not able to do? please see my below code
<button class="btn btn-warning" id="download-btn">
<i class="fa fa-download" aria-hidden="true"></i> Download Demo File
</button>
<script type="text/javascript">
$(document).ready(function(){
$("#download-btn").click(function(e){
e.preventDefault();
$.ajax({
type:'POST',
url :"Staff/downloadDemoFile",
cache: false,
contentType: false,
processData: false,
success: function(data) {
console.log(data);
},
error:function(exception){
alert('Exeption:'+exception);
}
});
});
});
</script>
My controller
public function downloadDemoFile()
{
if($this->session->logged_in != TRUE){
$this->load->view('login');
}
else{
$download= $this->Add_staff_model->downloadFile();
}
}
My model
public function downloadFile()
{
$sFileName = 'demo.xls';
header("Cache-Control: public");
header("Content-Description: File Transfer");
header("Content-Disposition: attachment; filename=$sFileName");
header("Content-Type: application/zip");
header("Content-Transfer-Encoding: binary");
// read the file from disk
readfile(UPLOAD_PATH_XLS.$sFileName);
}

Answer 1

Downloading a file from disk is pretty straightfoward using CodeIgniter Download Helper. Read the manual here.
public function downloadFile()
{
// load the helper somewhere, i.e in the constructor.
$this->load->helper('download');
// Use it when necessary
$sFileName = 'demo.xls'; // filename to be download. With path if necessary: /path/to/demo-xls
force_download($sFileName, NULL);
}
As a final consideration, in such a situation I wouldn't put the downloadFile() method in the model but in the controller itself.