PHP Slim - using anonymous functions with a simple rest api - php

Question

I have created a simple rest api which handles some POST data. I would like to add some functions to sanitize the data before sending a response.
I am new to Slim and PHP so unsure if this is possible / i am solving the problem using the "correct" approach.
Here is my attempt so far (which does not work!) The middleware is called, but the process function always returns NULL
<?php
use \Psr\Http\Message\ServerRequestInterface as Request;
use \Psr\Http\Message\ResponseInterface as Response;
require __DIR__ . '/../vendor/autoload.php';
$app = new \Slim\App();
// add function to $app
$app->process = function ($request, $response, $next) use($app) {
return 'process';
};
$process = $app->process;
// middleware
$mw = function ($request, $response, $next) {
$response = $next($request, $response);
// should return string from above function
$variable = $process
$data = array('name' => $name, 'process' => $variable);
$newResp = $response->withJson($data);
return $newResp;
};
$app->post('/api/name', function (Request $request, Response $response, array $args) {
$parsed= $request->getParsedBody();
$response = $response->withStatus(200);
})->add($mw);
$app->run();

Answer 1

There were several issues:
Added function to $app which results in a BadMethodCallException
$appalready has a method called process
Missed ; after $variable = $process
This code gives your desired result:
use \Psr\Http\Message\ServerRequestInterface as Request;
use \Psr\Http\Message\ResponseInterface as Response;
require __DIR__ . '/../vendor/autoload.php';
// turn error logging on!
$app = new \Slim\App(['settings' => ['displayErrorDetails' => true]]);
// your function
$sanitize = function(){
return 'process';
};
// middleware + pass function
$mw = function ($request, $response, $next) use($sanitize) {
$response = $next($request, $response);
$variable = $sanitize(); // execute function
$data = array('name' => $name, 'process' => $variable);
$newResp = $response->withJson($data);
return $newResp;
};
$app->get('/api/name', function (Request $request, Response $response, array $args) {
$parsed= $request->getParsedBody();
$response = $response->withStatus(200);
})->add($mw);
$app->run();
When you don't need to use the functions in other middleware, you could simply define the functions in your middleware, like this:
// middleware
$mw = function ($request, $response, $next) use($sanitize) {
$response = $next($request, $response);
// your function
function sanitize(){
return 'process';
}
$data = array('name' => $name, 'process' => sanitize());
$newResp = $response->withJson($data);
return $newResp;
};