How to download csv file from Google app engine? - google-app-engine

Question

I can't download file from google app engine. This is working in Compute engine.
$sql="SELECT * FROM $table ";
$query = $db->runQuery($sql);
if($query->num_rows > 0) {
$delimiter = ",";
$filename = $table . date('Y-m-d') . ".csv";
// create a file pointer
$f = fopen('php://memory', 'w');
// set column headers
$fields = array('id', 'srno', 'empid', 'empname');
fputcsv($f, $fields, $delimiter);
// output each row of the data, format line as csv and write to file pointer
while($row = $query->fetch_assoc()) {
// $status = ($row['status'] == '1') ? 'Active' : 'Inactive';
$lineData = array(
$row['id'], $row['srno'], $row['empid'], $row['empname'], ]
);
fputcsv($f, $lineData, $delimiter);
}
// move back to beginning of file
fseek($f, 0);
// set headers to download file rather than display it
header('Content-Type: text/csv');
header('Content-Disposition: attachment; filename="' . $filename . '";');
//output all remaining data on a file pointer
fpassthru($f);
}
exit;

Answer 1

What are the logs, error message? How did you deploy this app? Can you show the app.yaml? Is the App in the same project as the Cloud SQL instance? Standard or Flexible environment? PHP 5 or 7?
Most common issues while connecting App Engine to Cloud SQL:
App Engine service account must have the Cloud SQL Admin role
Project in which the Cloud SQL instance resides must have both the Cloud SQL and the SQL Admin API activated
The connection between the app and the MySQL instance is done via proxy, that you configure in your php code and yaml file.
Here is an example of connection to a MySQL instance from PHP72, you can also use this code for local testing. For this you will need to install and run the Cloud SQL Proxy Client.
app.yaml
runtime: php72
handlers:
- url: .*
script: auto
env_variables:
MYSQL_USER: [MYSQL_USER]
MYSQL_PASSWORD: [MYSQL_PASSWORD]
MYSQL_DSN: 'mysql:dbname=[MYSQL_DB_NAME];unix_socket=/cloudsql/[MYSQL_INSTANCE_CONNECTION_NAME]'
beta_settings:
cloud_sql_instances: [MYSQL_INSTANCE_CONNECTION_NAME]
index.php
<?php
$user = getenv('MYSQL_USER');
$password = getenv('MYSQL_PASSWORD');
$dsn = getenv("MYSQL_DSN") ?: "mysql:host=127.0.0.1;port=3306;dbname=[MYSQL_DB_NAME]";
$db = new PDO($dsn, $user, $password);
try {
$db = new PDO($dsn, $user, $password);
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "Connected successfully";
}
catch(PDOException $e)
{
echo "Connection failed: " . $e->getMessage();
}
$statement = $db->prepare("SELECT * from [MYSQL_TABLE_NAME]");
$statement->execute();
$all = $statement->fetchAll();
foreach ($all as $data) {
echo $data["id"];
}
?>