slim framework withHeader json it does not work - php

Question

Hello everyone, I'm using slim framework for JSON API all responses work but on headers show text / html, the documentation mentions the function whitHeader:
$app = new \Slim\App;
$app->get('/new/', function (Request $request, Response $response){
$response->getBody()->write(json_encode(['message'=>'ok']));
$response_h = $response->withHeader('Content-Type', 'application/json; charset=utf-8');
return json_decode($response_h);
});
$app->run();
When using $response_h-> getHeaders (); show json header(work) but when running takes another header, I tracked where it replaces the header and is in slim / slim / container.php exactly in current function registerDefaultServices i replace:
Headers $ headers = new (['Content-Type' => 'text / html; charset = UTF-8']);
to
Headers $ headers = new (['Content-Type' => 'application / json; charset = utf-8']);
but it is not the best way, how change the headers?
and try using:
$ app-> response () -> header ();
$ app-> response () -> setHeader ();
In all the return is that the response function () does not exist.

Answer 1

Using official documentation for Slim Framework v2:
The HTTP response returned to the HTTP client will have a header. The HTTP header is a list of keys and values that provide metadata about the HTTP response. You can use the Slim application’s response object to set the HTTP response’s header. The response object has a public property headers that is an instance of \Slim\Helper\Set; this provides a simple, standardized interface to manipulate the HTTP response headers.
<?php
$app = new \Slim\Slim();
$app->response->headers->set('Content-Type', 'application/json');
You may also fetch headers from the response object's headers property, too:
<?php
$contentType = $app->response->headers->get('Content-Type');
If a header with the given name does not exist, null is returned. You may specify header names with upper, lower, or mixed case with dashes or underscores. Use the naming convention with which you are most comfortable.
Using official documentation for Slim Framework v3:
An HTTP response typically has a body. Slim provides a PSR 7 Response object with which you can inspect and manipulate the eventual HTTP response’s body.
Just like the PSR 7 Request object, the PSR 7 Response object implements the body as an instance of \Psr\Http\Message\StreamInterface. You can get the HTTP response body StreamInterface instance with the PSR 7 Response object’s getBody() method. The getBody() method is preferable if the outgoing HTTP response length is unknown or too large for available memory.
Your code should looks like this:
<?php
$app = new \Slim\App();
$app->get('/new/', function(Request $requst, Response $response) {
$response->getBody()->write(json_encode(['YOUR_ARRAY']));
$newResponse = $response->withHeader(
'Content-type',
'application/json; charset=utf-8'
);
return $newResponse;
});
Tested on my environment with Postman. Content-type were changed.