Slim treats a URL pattern with a trailing slash as different to one without. That is, /user and /user/ are different and so can have different callbacks attached.
If you want to redirect all URLs that end in a / to the non-trailing / equivalent, then you can add this middleware:
use Psr\Http\Message\RequestInterface as Request;
use Psr\Http\Message\ResponseInterface as Response;
$app->add(function (Request $request, Response $response, callable $next) {
$uri = $request->getUri();
$path = $uri->getPath();
if ($path != '/' && substr($path, -1) == '/') {
// permanently redirect paths with a trailing slash
// to their non-trailing counterpart
$uri = $uri->withPath(substr($path, 0, -1));
return $response->withRedirect((string)$uri, 301);
}
return $next($request, $response);
});Alternatively, consider oscarotero/psr7-middlewares’ TrailingSlash middleware which also allows you to force a trailing slash to be appended to all URLs:
use Psr7Middlewares\Middleware\TrailingSlash;
$app->add(new TrailingSlash(true)); // true adds the trailing slash (false removes it)