I have a weird situation:
I get data from a Postgres database, and from that data, I create a table in a website, using Grid.js. Each line has a "Download" button, that takes 2 arguments from that table entry and send them to a function. Originally, that function would make a XHR request to a php file, that gets files from another DB, creates a ZIP file, and should send it to the user, with readfile().
I now discovered that this is not possible. XHR does not allow downloads for safety reasons.
I could do something using window.location to call the PHP file, and get the download, but I am dealing with hundreds of files, so I cannot write hundreds of PHP files to get the data individually. I could, but it would be very hard to maintain and manage all those files, and it feels unprofessional.
Right now, I can:
- Send the data from JS to PHP, using POST;
- Using those two variables, fetch the data from another Postgres server;
- Use those files and create a ZIP file (The ZIP files cannot be stored permanently in the server, because of storage restrictions. A cronjob in the server will clean the files eventually)
I need to:
- Send the ZIP to to the user;
- Maintain the simplest code possible, in a way that I can feed 2 variables and it just works, without needing a PHP file for each table line (if that makes sense)
The current code is:
- Javascript
const getData = (schema, table) => {
const xhr = new XMLHttpRequest();
xhr.open('POST', 'php/get_data.php', true);
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
let packg = {
schema: schema,
table: table
};
const packgJSON = JSON.stringify(packg);
// Vanilla JS XHR requires this formatting to send the data
const data = new URLSearchParams({'content': packgJSON});
xhr.send(data);
};
- PHP
<?php
// File with connection info
$config = include('config.php');
// Connection info
$host = $config['host'];
$port = $config['port'];
$database = $config['database'];
$username = $config['username'];
$password = $config['password'];
// POST reception
$packg = json_decode($_POST['content']);
$schema = $packg->schema;
$table = $packg->table;
// File info and paths
$filename = $table;
$rootDir = "tempData/";
$fileDir = $filename . "/";
$filePath = $rootDir . $fileDir;
$completeFilePath = $filePath . $filename;
$shpfile = $filename . ".shp";
$zipped = $filename . ".zip";
$zipFile = $completeFilePath . ".zip";
// Function to send the file (PROBLEM - THIS DOES NOT WORK WITH XHR)
function sendZip($zipFile) {
$zipName = basename($zipFile);
header("Content-Type: application/zip");
header("Content-Disposition: attachment; filename=$zipName");
header("Content-Length: " . filesize($zipFile));
ob_flush();
flush();
readfile($zipFile);
};
// Send the zip if it's already available (NOT PROBLEMATIC)
if (file_exists($zipFile)) {
sendZip($zipFile);
};
// Get shapefile, zip it and send it, if not available (NOT PROBLEMATIC)
if (!file_exists($zipFile)) {
// Get files
exec("mkdir -p -m 777 $filePath");
exec("pgsql2shp -h $host -p $port -u $username -P $password -g geom -k -f $completeFilePath $database $schema.$table");
// ZIP the files
$zip = new ZipArchive;
if ($zip -> open($zipFile, ZipArchive::CREATE) === TRUE) {
$handlerDir = opendir($filePath);
// Iterates all files inside folder
while ($handlerFile = readdir($handlerDir)) {
// If the files are indeed files, and not directories
if (is_file($filePath . $handlerFile) && $handlerFile != "." && $handlerFile != "..") {
// Zip them
$zip -> addFile($filePath . $handlerFile, $fileDir . $handlerFile);
};
};
// Close the file
$zip -> close();
};
sendZip($zipFile);
};
?>
