Slim Framework - How to query db in normal function - php

Question

I'm very new to PHP and Slim Framework which helps creating APIs.
Everything is ok If i query db inside $app->post or get. But I want to separate it to normal function. It will help when I need to use it later in other APIs.
I tried to call this
$app->get('/search/[{phone}]', function($request, $response, $args) use ($app){
$token = $response->getHeader('token');
// $phone = $args['phone'];
if (isTokenValid($token)){
return $this->response->withJson("valid");
}
return $this->response->withJson("invalid");
});
My isTokenValid() function
function isTokenValid($token){
$sql = 'SELECT id FROM users WHERE token = :token';
$s = $app->db->prepare($sql); //<< this line 25
$s->bindParam(':token', $token);
if ($s->execute()){
if($sth->rowCount() > 0){
return true;
}
}
return false;
}
But I get 500 Internal Server Error
Type: Error
Message: Call to a member function prepare() on null
File: /Applications/MAMP/htdocs/aigoido/src/functions.php
Line: 25
How to call it outside $app? Thanks.

Answer 1

You want to create a dependency injection container for your database connection and pass that object in as the function parameter rather than app object. This makes the db connection reusable throughout your app.
https://www.slimframework.com/docs/concepts/di.html
Also, you can return $response rather than $this->response.
$c = $app->getContainer();
$c['db'] = function() {
return new DB($host,$user,$pass,$name);
};
$app->post('/search/[{phone}]', function($request, $response, $args) use ($c) {
$token = $response->getHeader('token');
// $phone = $args['phone'];
if (isTokenValid($c->db,$token)){
return $response->withJson("valid");
}
return $response->withJson("invalid");
});
function isTokenValid($db, $token){
$sql = 'SELECT id FROM users WHERE token = :token';
$s = $db->prepare($sql);
$s->bindParam(':token', $token);
if ($s->execute()){
if($sth->rowCount() > 0){
return true;
}
}
return false;
}

Answer 2

Pass $app to your function as parameter. The function has it own context so $app is not available without that.
function isTokenValid($token, $app){
$sql = 'SELECT id FROM users WHERE token = :token';
$s = $app->db->prepare($sql); //<< this line 25
$s->bindParam(':token', $token);
if ($s->execute()){
if($sth->rowCount() > 0){
return true;
}
}
return false;
}