Using CodeIgniter to download CSV of results - php

Question

We run queries using CodeIgniter against our MySQL database, and display those results on the page. Sometimes, we want to download those as a CSV. The guy before me set up this download button, but it does not function at all. Never has.
This is the existing code for the download:
public function download_csv_search(){
$dbresults = $this->do_search();
$results = $dbresults['results'];
$csv = "First Name, Last Name, MI, Age, Details(RA), Status, Home Phone, Gender, Notes\n";
$filename = "data_export";
//header('Content-Type: text/csv; charset=utf-8');
//header('Content-Disposition: attachment; filename=data.csv');
//$output = fopen('php://output', 'w');
//fputcsv($output, array('First Name', 'Last Name', 'Middle Name', 'DOB', 'Details(RA)', 'Status', 'Home Phone', 'Gender', 'Notes'));
foreach($results as $result) {
$birthday_timestamp = strtotime($result->VoterDOB);
$age = date('md', $birthday_timestamp) > date('md') ? date('Y') - date('Y', $birthday_timestamp) - 1 : date('Y') - date('Y', $birthday_timestamp);
$csv .= $result->VoterFN.",".$result->VoterLN.",".$result->VoterMN.",".$dob.",".$result->Street.",".$result->VoterStatusID.",".$result->phone.",N/A,\n";
// $dataArray = array('VoterFN'=>$result->VoterFN, 'VoterLN'=>$result->$VoterLN, 'VoterMN'=>$result->VoterMN,'VoterDOB'=>$result->date('m/d/Y', strtotime($result->VoterDOB)), 'Street'=>$result->Street, "VoterStatusID"=>$result->VoterStatusID,'phone'=>$result->phone);
//fputcsv($output, $dataArray);
}
//OUPUT HEADERS
header("Pragma: public");
header("Expires: 0");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Cache-Control: private",false);
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=\"$filename.csv\";" );
header("Content-Transfer-Encoding: binary");
//OUTPUT CSV CONTENT
echo($csv);
exit();
}
I'm guessing I need to use the download helper + the force_download function, but I can't seem to get it. Any ideas?

Answer 1

I think you have so many headers, but more important, if the file is a CSV, why sending it as a binary file? Why aren't you using text/csv? I only use the following code, I suppose that Cache-Control is to avoid downloading the same file without hit the server. Anyway, only with:
header('Content-type: text/csv');
header("Content-Disposition: attachment; filename=\"$filename.csv\";" );
should work. After a bit of research in SO, depending on what browser you use you may have problems with your Cache headers:
Creating and downloading CSV with PHP, so research a bit that in order to avoid future issues.