How to modify slim v3 response body before and after route execution?

Question

I'm unable to get response body in slim v3 and its always blank. My code is:

<?php

use \Psr\Http\Message\ServerRequestInterface as Request;
use \Psr\Http\Message\ResponseInterface as Response;
use \Slim\App as Slim;

require 'vendor/autoload.php';

$config['determineRouteBeforeAppMiddleware'] = true;

$app = new Slim(['settings' => $config]);

$mw = (function (Request $request, Response $response, callable $next) {
    $response = $response->withStatus(200)->write(' before ');
    $response = $next($request, $response);
    $body = $response->getBody()->getContents();
    $response = $response->withJson(array('data' => $body)); // output should be {"data":" Hello, User  seq1  seq2 "}
    return $response;
});

$mw1 = (function (Request $request, Response $response, callable $next) {
    $response = $next($request, $response);
    $response = $response->withStatus(200)->write(' seq1 ');
    return $response;
});

$mw2 = (function (Request $request, Response $response, callable $next) {
    $response = $next($request, $response);
    $response->withStatus(200)->write(' seq2 ');
    return $response;

});

$app->add($mw);

$app->get('/hello/{name}', function (Request $request, Response $response) {
    $name = $request->getAttribute('name');
    $response->getBody()->write(" Hello, $name ");
    return $response;
})->add($mw1)->add($mw2);

$app->run();

What I want to do is the following:

• I don't want to add withJson() at the end of each route just to encode my json and output to client (browser). I want the middleware to handle this for me after (any) route execution ends.
• I want to get the final body and assign it to an array like $data['data'] = $body and than json encode it and return the modified response.

P.S. Slim v2 was much easier than Slim v3

Answer 1

Try to change getContents() for __toString() at the middleware mw. Another change that should be done is on mw2: you have to return the new response created.

Look the complete code:

<?php

use \Psr\Http\Message\ServerRequestInterface as Request;
use \Psr\Http\Message\ResponseInterface as Response;
use \Slim\App as Slim;

require 'vendor/autoload.php';

$config['determineRouteBeforeAppMiddleware'] = true;

$app = new Slim(['settings' => $config]);

$mw = (function (Request $request, Response $response, callable $next): Response {
    $response = $response->withStatus(200)->write(' before ');
    $response = $next($request, $response);
    $body = $response->getBody()->__toString();
    $response = $response->withJson(array('data' => $body)); // output should be {"data":" Hello, User  seq1  seq2 "}
    return $response;
});

$mw1 = (function (Request $request, Response $response, callable $next): Response {
    $response = $next($request, $response);
    $response = $response->withStatus(200)->write(' seq1 ');
    return $response;
});

$mw2 = (function (Request $request, Response $response, callable $next): Response {
    $response = $next($request, $response);
    $response = $response->withStatus(200)->write(' seq2 ');
    return $response;
});

$app->add($mw);

$app->get('/hello/{name}', function (Request $request, Response $response): Response {
    $name = $request->getAttribute('name');
    $response->getBody()->write(" Hello, $name ");
    return $response;
})->add($mw1)->add($mw2);

$app->run();

I hope it can help you.

PS: I prefer Slim 3 :D