# How do I create a middleware for database connection

**URL:** <https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852>\
**Category:** Questions\
**Created:** [October 2, 2017, 3:11am UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852 "2017-10-02T03:11:25Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![emmachukwu](https://avatars.discourse-cdn.com/v4/letter/e/c4cdca/32.png) [@emmachukwu](https://discourse.slimframework.com/u/emmachukwu)\
**Post date:** [October 2, 2017, 3:11am UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/1 "2017-10-02T03:11:26Z")

</div>

Hello Guys,  
I am new to the Slim framework.  
I am trying to create a middleware for database connection that will be used for every route in my app.

My goal is: for every API call, the middleware creates a database connection, calls the NEXT function (passing the connection as a parameter) when the Next function finishes executing, the middleware closes the connection.

My challenge is how to pass the connection to the Next function. I am trying to include it as part of the request object but can’t seem to figure out the proper way to do that.  
This my coode snippet:

$connection = function ($request, $response, $next) {  
$request-\>getBody()-\>db = db\_connect(); //db\_connect() returns a database connection  
$response = $next($request, $response);  
$request-\>connection = null;

```
return $response;

```

};

$app-\>add($connection);

$app-\>group(’/api’, function () use ($app) {

```
	$app->post('/login', 'login');
	$app->post('/logout', 'logout');

```

});

function login($request, $response) {  
$param = json\_decode($request-\>getBody());  
$db = $param-\>db;  
$email = $param-\>email;  
$password = $param-\>password;  
…  
}

This is the error message I get:

Undefined property: stdClass::$db in …

Please I need help the right approach to take.

---

<div class="post-metadata">

**Author:** ![tstadler](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tstadler](https://discourse.slimframework.com/u/tstadler)\
**Post date:** [October 2, 2017, 12:03pm UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/2 "2017-10-02T12:03:42Z")

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Why do’t you use the DI-container for creating/storing the connection?

If you still want to do it in middleware, you can use request attributes, e.g.

$request = $request-\>withAttribute(‘db’, db\_connect());

---

<div class="post-metadata">

**Author:** ![emmachukwu](https://avatars.discourse-cdn.com/v4/letter/e/c4cdca/32.png) [@emmachukwu](https://discourse.slimframework.com/u/emmachukwu)\
**Post date:** [October 2, 2017, 12:46pm UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/3 "2017-10-02T12:46:10Z")

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Thanks tstadler. Shortly after I posted the problem, I tried the  
request-\>withAttribute method and it worked.

I’m totally new to using php frameworks and Slim is the first I’m working  
with. I’m yet to study and understand containers but I like doing things  
the best way possible.

Pls if you think using DI-container is better, can you help me with a code  
that will achieve that.  
Thanks.

---

<div class="post-metadata">

**Author:** ![tstadler](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tstadler](https://discourse.slimframework.com/u/tstadler)\
**Post date:** [October 2, 2017, 7:07pm UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/4 "2017-10-02T19:07:45Z")

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Pleas have a look at [https://www.slimframework.com/docs/concepts/di.html](https://www.slimframework.com/docs/concepts/di.html) for the DI-Conecpt of slim.

Basically you need to do something like

$container = $app-\>getContainer();  
$container[‘db’] = function() {  
return db\_connect();  
};

to tell the DI container about the DB-connection.

---

<div class="post-metadata">

**Author:** ![emmachukwu](https://avatars.discourse-cdn.com/v4/letter/e/c4cdca/32.png) [@emmachukwu](https://discourse.slimframework.com/u/emmachukwu)\
**Post date:** [October 3, 2017, 1:31pm UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/5 "2017-10-03T13:31:50Z")

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Thanks, Tstadler. I really appreciate.

After creating $container[‘db’] as the db connection, please how do I access it from inside another function?  
And what are the advantages of this container method over using middleware?

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<div class="post-metadata">

**Author:** ![tstadler](https://avatars.discourse-cdn.com/v4/letter/t/aca169/32.png) [@tstadler](https://discourse.slimframework.com/u/tstadler)\
**Post date:** [October 3, 2017, 6:17pm UTC](https://discourse.slimframework.com/t/how-do-i-create-a-middleware-for-database-connection/1852/6 "2017-10-03T18:17:08Z")

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You need to inject it your function/class as a dependency, e.g.

$container = $app-\>getContainer();  
$container[‘db’] = function() {  
return db\_connect();  
};

class MyController {  
private $db;

```
public function __construct($db) {
    $this->db = $db;
}

public function index($request, $response, $args) {
    return $response;
}

```

}

$container[‘myController’] = function($c) {  
return new MyController($c-\>get(‘db’));  
};

$app-\>get(’/’, ‘MyController:index’);

Also please see [https://akrabat.com/di-factories-for-slim-controllers/](https://akrabat.com/di-factories-for-slim-controllers/) for a example. The main advantages of the DI approach are discussed in the comments.