# Contributor Guidelines I encourage everyone to contribute to the Slim Framework project. You can find the latest code on GitHub at [https://github.com/slimphp/Slim](https://github.com/slimphp/Slim). ## Issue Tracker You can find outstanding issues on the [GitHub Issue Tracker](https://github.com/slimphp/Slim/issues). If you intend to work on a specific issue, leave a comment on the appropriate thread to inform other project contributors. ## Pull Requests * Each pull request should contain only one new feature or improvement. * Pull requests should be submitted to the `master` branch ## Code Style All pull requests must use the [PSR-2](http://www.php-fig.org/psr/psr-2/) code style. * Code MUST use the [PSR-1](http://www.php-fig.org/psr/psr-1/) code style. * Code MUST use 4 spaces for indenting, not tabs. * There MUST NOT be a hard limit on line length; the soft limit MUST be 120 characters; lines SHOULD be 80 characters or less. * There MUST be one blank line after the namespace declaration, and there MUST be one blank line after the block of use declarations. * Opening braces for classes MUST go on the next line, and closing braces MUST go on the next line after the body. * Opening braces for methods MUST go on the next line, and closing braces MUST go on the next line after the body. * Visibility MUST be declared on all properties and methods; abstract and final MUST be declared before the visibility; static MUST be declared after the visibility. * Control structure keywords MUST have one space after them; method and function calls MUST NOT. * Opening braces for control structures MUST go on the same line, and closing braces MUST go on the next line after the body. * Opening parentheses for control structures MUST NOT have a space after them, and closing parentheses for control structures MUST NOT have a space before.

# Branching Strategy The Slim Framework uses a simple branching strategy. There is one `master` branch, and the`master` branch `HEAD` reference points to the latest unstable code. Each stable release is denoted with a numeric tag (e.g., `3.0.0`).

# Flash Messages Coming soon.

# CSRF Protection Slim 3 uses the optional standalone [slimphp/Slim-Csrf](https://github.com/slimphp/Slim-Csrf) PHP component to protect your application from CSRF (cross-site request forgery). This component generates a unique token per request that validates subsequent POST requests from client-side HTML forms. ## Installation Execute this bash command from your project’s root directory: ~~~ composer require slim/csrf ~~~ ## Usage The `slimphp/Slim-Csrf` component contains an application middleware. Add it to your application like this: ~~~ // Add middleware to the application $app = new \Slim\App; $app->add(new \Slim\Csrf\Guard); // Create your application routes... // Run application $app->run(); ~~~ ## Fetch the CSRF token name and value The latest CSRF token’s name and value are available as attributes on the PSR7 request object. The CSRF token name and value are unique for each request. You can fetch the current CSRF token name and value like this. ~~~ $app->get('/foo', function ($req, $res, $args) { // Fetch CSRF token name and value $name = $req->getAttribute('csrf_name'); $value = $req->getAttribute('csrf_value'); // TODO: Render template with HTML form and CSRF token hidden field }); ~~~ You should pass the CSRF token name and value to the template so they may be submitted with HTML form POST requests. They are often stored as a hidden field with HTML forms.

# HTTP Caching Slim 3 uses the optional standalone [slimphp/Slim-HttpCache](https://github.com/slimphp/Slim-HttpCache) PHP component for HTTP caching. You can use this component to create and return responses that contain `Cache`,`Expires`, `ETag`, and `Last-Modified` headers that control when and how long application output is retained by client-side caches. ## Installation Execute this bash command from your project’s root directory: ~~~ composer require slim/http-cache ~~~ ## Usage The `slimphp/Slim-HttpCache` component contains a service provider and an application middleware. You should add both to your application like this: ~~~ // Register service provider with the container $container = new \Slim\Container; $container['cache'] = function () { new \Slim\HttpCache\CacheProvider(); }; // Add middleware to the application $app = new \Slim\App($container); $app->add(new \Slim\HttpCache\Cache('public', 86400)); // Create your application routes... // Run application $app->run(); ~~~ ## ETag Use the service provider’s `withEtag()` method to create a Response object with the desired`ETag` header. This method accepts a PSR7 response object, and it returns a cloned PSR7 response with the new HTTP header. ~~~ $app->get('/foo', function ($req, $res, $args) { $resWithEtag = $this->cache->withEtag($res, 'abc'); return $resWithEtag; }); ~~~ ## Expires Use the service provider’s `withExpires()` method to create a Response object with the desired `Expires` header. This method accepts a PSR7 response object, and it returns a cloned PSR7 response with the new HTTP header. ~~~ $app->get('/bar',function ($req, $res, $args) { $resWithExpires = $this->cache->withExpires($res, time() + 3600); return $resWithExpires; }); ~~~ ## Last-Modified Use the service provider’s `withLastModified()` method to create a Response object with the desired `Last-Modified` header. This method accepts a PSR7 response object, and it returns a cloned PSR7 response with the new HTTP header. ~~~ //Example route with LastModified $app->get('/foobar',function ($req, $res, $args) { $resWithLastMod = $this->cache->withLastModified($res, time() - 3600); return $resWithLastMod; }); ~~~

# Templates Slim does not have a view layer like traditional MVC frameworks. Instead, Slim’s “view” *is the HTTP response*. Each Slim application route is responsible for preparing and returning an appropriate PSR 7 response object. > Slim’s “view” is the HTTP response. ## The slim/twig-view component That being said, Slim does provide the optional [slim/twig-view](https://github.com/slimphp/Twig-View) PHP component to help you render [Twig](http://twig.sensiolabs.org/) templates to a PSR 7 Response object. This component is available on Packagist, and it’s easy to install with Composer like this: ~~~ composer require slim/twig-view ~~~ Figure 1: Install slim/twig-view component. Next, you need to register the component as a service on the Slim app’s container like this: ~~~ <?php // Create container $container = new \Slim\Container; // Register component on container $container['view'] = function ($c) { $view = new \Slim\Views\Twig('path/to/templates', [ 'cache' => 'path/to/cache' ]); $view->addExtension(new \Slim\Views\TwigExtension( $c['router'], $c['request']->getUri() )); return $view; }; ~~~ Figure 2: Register slim/twig-view component with container. Note : “cache” could be set to false to disable it, see also ‘auto_reload’ option, usefull in development environnement. For more information, see [Twig environment options](http://twig.sensiolabs.org/api/master/Twig_Environment.html#method___construct) Now you can use the `slim/twig-view` component service inside an app route to render a template and write it to a PSR 7 Response object like this: ~~~ // Create app $app = new \Slim\App($container); // Render Twig template in route $app->get('/hello/{name}', function ($request, $response, $args) { return $this->view->render($response, 'profile.html', [ 'name' => $args['name'] ]); })->setName('profile'); // Run app $app->run(); ~~~ Figure 3: Render template with slim/twig-view container service. In this example, `$this->view` invoked inside the route callback is a reference to the`\Slim\Views\Twig` instance returned by the `view` container service. The `\Slim\Views\Twig`instance’s `render()` method accepts a PSR 7 Response object as its first argument, the Twig template path as its second argument, and an array of template variables as its final argument. The `render()` method returns a new PSR 7 Response object whose body is the rendered Twig template. ### The path_for() method The `slim/twig-view` component exposes a custom `path_for()` function to your Twig templates. You can use this function to generate complete URLs to any named route in your Slim application. The `path_for()` function accepts two arguments: 1. A route name 2. A hash of route placeholder names and replacement values The second argument’s keys should correspond to the selected route’s pattern placeholders. This is an example Twig template that draws a link URL for the “profile” named route shown in the example Slim application above. ~~~ {% extends "layout.html" %} {% block body %} <h1>User List</h1> <ul> <li><a href="{{ path_for('profile', { 'name': 'josh' }) }}">Josh</a></li> </ul> {% endblock %} ~~~ ## Other template systems You are not limited to the `slim/twig-view` component. You can use any PHP template system assuming you ultimately write the rendered template output to the PSR 7 Response object’s body.

# 405 Not Allowed Handler If your Slim Framework application has a route that matches the current HTTP request URI but NOT the HTTP request method, the application invokes its Not Allowed handler and returns a `HTTP/1.1 405 Not Allowed` response to the HTTP client. ## Default Not Allowed handler Each Slim Framework application has a default Not Allowed handler. This handler sets the Response status to `405`, it sets the content type to `text/html`, it adds a `Allowed:` HTTP header with a comma-delimited list of allowed HTTP methods, and it writes a simple explanation to the Response body. ## Custom Not Allowed handler A Slim Framework application’s Not Allowed handler is a Pimple service. You can substitute your own Not Allowed handler by defining a custom Pimple factory method with the application container. ~~~ // Create Slim $app = new \Slim\App(); // get the app's di-container $c = $app->getContainer(); $c['notAllowedHandler'] = function ($c) { return function ($request, $response, $methods) use ($c) { return $c['response'] ->withStatus(405) ->withHeader('Allow', implode(', ', $methods)) ->withHeader('Content-type', 'text/html') ->write('Method must be one of: ' . implode(', ', $methods)); }; ~~~ > N.B Check out [Not Found](http://www.slimframework.com/docs/handlers/not-found.html) docs for pre-slim creation method using a new instance of`\Slim\Container` In this example, we define a new `notAllowedHandler` factory that returns a callable. The returned callable accepts three arguments: 1. A `\Psr\Http\Message\ServerRequestInterface` instance 2. A `\Psr\Http\Message\ResponseInterface` instance 3. A numeric array of allowed HTTP method names The callable MUST return an appropriate `\Psr\Http\Message\ResponseInterface` instance.

# 404 Not Found Handler If your Slim Framework application does not have a route that matches the current HTTP request URI, the application invokes its Not Found handler and returns a `HTTP/1.1 404 Not Found` response to the HTTP client. ## Default Not Found handler Each Slim Framework application has a default Not Found handler. This handler sets the Response status to `404`, it sets the content type to `text/html`, and it writes a simple explanation to the Response body. ## Custom Not Found handler A Slim Framework application’s Not Found handler is a Pimple service. You can substitute your own Not Found handler by defining a custom Pimple factory method with the application container. ~~~ $c = new \Slim\Container(); //Create Your container //Override the default Not Found Handler $c['notFoundHandler'] = function ($c) { return function ($request, $response) use ($c) { return $c['response'] ->withStatus(404) ->withHeader('Content-Type', 'text/html') ->write('Page not found'); }; }; //Create Slim $app = new \Slim\App($c); //... Your code ~~~ In this example, we define a new `notFoundHandler` factory that returns a callable. The returned callable accepts two arguments: 1. A `\Psr\Http\Message\ServerRequestInterface` instance 2. A `\Psr\Http\Message\ResponseInterface` instance The callable MUST return an appropriate `\Psr\Http\Message\ResponseInterface` instance.

# 500 System Error Handler Things go wrong. You can’t predict errors, but you can anticipate them. Each Slim Framework application has an error handler that receives all uncaught PHP exceptions. This error handler also receives the current HTTP request and response objects, too. The error handler must prepare and return an appropriate Response object to be returned to the HTTP client. ## Default error handler The default error handler is very basic. It sets the Response status code to `500`, it sets the Response content type to `text/html`, and appends a generic error message into the Response body. This is *probably* not appropriate for production applications. You are strongly encouraged to implement your own Slim application error handler. The default error handler can also include detailed error diagnostic information. To enable this you need to set the `displayErrorDetails` setting to true: ~~~ $configuration = [ 'settings' => [ 'displayErrorDetails' => true, ], ]; $c = new \Slim\Container($configuration); $app = new \Slim\App($c); ~~~ ## Custom error handler A Slim Framework application’s error handler is a Pimple service. You can substitute your own error handler by defining a custom Pimple factory method with the application container. There are two ways to inject handlers: ### Pre App ~~~ $c = new \Slim\Container(); $c['errorHandler'] = function ($c) { return function ($request, $response, $exception) use ($c) { return $c['response']->withStatus(500) ->withHeader('Content-Type', 'text/html') ->write('Something went wrong!'); }; }; $app = new \Slim\App($c); ~~~ ### Post App ~~~ $app = new \Slim\App(); $c = $app->getContainer(); $c['errorHandler'] = function ($c) { return function ($request, $response, $exception) use ($c) { return $c['response']->withStatus(500) ->withHeader('Content-Type', 'text/html') ->write('Something went wrong!'); }; }; ~~~ In this example, we define a new `errorHandler` factory that returns a callable. The returned callable accepts three arguments: 1. A `\Psr\Http\Message\ServerRequestInterface` instance 2. A `\Psr\Http\Message\ResponseInterface` instance 3. A `\Exception` instance The callable MUST return a new `\Psr\Http\Message\ResponseInterface` instance as is appropriate for the given exception. ### Disabling To completely disable Slim’s error handling, simply remove the error handler from the container: ~~~ unset($app->getContainer()['errorHandler']); ~~~ You are now responsible for handling any exceptions that occur in your application as they will not be handled by Slim.

# Router [TOC=2,3] The Slim Framework’s router is built on top of the [nikic/fastroute](https://github.com/nikic/FastRoute) component, and it is remarkably fast and stable. ## How to create routes You can define application routes using proxy methods on the `\Slim\App` instance. The Slim Framework provides methods for the most popular HTTP methods. ### GET Route You can add a route that handles only `GET` HTTP requests with the Slim application’s `get()`method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->get('/books/{id}', function ($request, $response, $args) { // Show book identified by $args['id'] }); ~~~ ### POST Route You can add a route that handles only `POST` HTTP requests with the Slim application’s`post()` method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->post('/books', function ($request, $response, $args) { // Create new book }); ~~~ ### PUT Route You can add a route that handles only `PUT` HTTP requests with the Slim application’s `put()`method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->put('/books/{id}', function ($request, $response, $args) { // Update book identified by $args['id'] }); ~~~ ### DELETE Route You can add a route that handles only `DELETE` HTTP requests with the Slim application’s`delete()` method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->delete('/books/{id}', function ($request, $response, $args) { // Delete book identified by $args['id'] }); ~~~ ### OPTIONS Route You can add a route that handles only `OPTIONS` HTTP requests with the Slim application’s`options()` method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->options('/books/{id}', function ($request, $response, $args) { // Return response headers }); ~~~ ### PATCH Route You can add a route that handles only `PATCH` HTTP requests with the Slim application’s`patch()` method. It accepts two arguments: 1. The route pattern (with optional named placeholders) 2. The route callback ~~~ $app = new \Slim\App(); $app->patch('/books/{id}', function ($request, $response, $args) { // Apply changes to book identified by $args['id'] }); ~~~ ### Custom Route You can add a route that handles multiple HTTP request methods with the Slim application’s`map()` method. It accepts three arguments: 1. Array of HTTP methods 2. The route pattern (with optional named placeholders) 3. The route callback ~~~ $app = new \Slim\App(); $app->map(['GET', 'POST'], '/books', function ($request, $response, $args) { // Create new book or list all books }); ~~~ ## Route callbacks Each routing method described above accepts a callback routine as its final argument. This argument can be any PHP callable, and by default it accepts three arguments. Request The first argument is a `Psr\Http\Message\ServerRequestInterface` object that represents the current HTTP request. Response The second argument is a `Psr\Http\Message\ResponseInterface` object that represents the current HTTP response. Arguments The third argument is an associative array that contains values for the current route’s named placeholders. ### Writing content to the response There are two ways you can write content to the HTTP response. First, you can simply `echo()`content from the route callback. This content will be appended to the current HTTP response object. Second, you can return a `Psr\Http\Message\ResponseInterface` object. ### Closure binding If you use a `Closure` instance as the route callback, the closure’s state is bound to the`\Slim\App` instance. This means you can access the `\Slim\App` object from inside the route callback with `$this`. Because the `\Slim\App` itself composes the DI container, you can quickly access any services registered with the DI container from inside the Closure callback like this: ~~~ $app = new \Slim\App(); $app->get('/hello/{name}', function ($request, $response, $args) { // Use app HTTP cookie service $this->cookies->set('name', [ 'name' => $args['name'], 'expires' => '7 days' ]); }); ~~~ ## Route strategies The route callback signature is determined by a route strategy. By default, Slim expects route callbacks to accept the request, response, and an array of route placeholder arguments. This is called the RequestResponse strategy. However, you can change the expected route callback signature by simply using a different strategy. As an example, Slim provides an alternative strategy called RequestResponseArgs that accepts request and response, plus each route placeholder as a separate argument. Here is an example of using this alternative strategy; simply replace the `foundHandler` dependency provided by the default`\Slim\Container`: ~~~ $c = new \Slim\Container(); $c['foundHandler'] = function() { return new \Slim\Handlers\Strategies\RequestResponseArgs(); }; $app = new \Slim\App($c); $app->get('/hello/{name}', function ($request, $response, $name) { return $response->write($name); }); ~~~ You can provide your own route strategy by implementing the`\Slim\Interfaces\InvocationStrategyInterface`. ## Route placeholders Each routing method described above accepts a URL pattern that is matched against the current HTTP request URI. Route patterns may use named placeholders to dynamically match HTTP request URI segments. ### Format A route pattern placeholder starts with a `{`, followed by the placeholder name, ending with a`}`. This is an example placeholder named `name`: ~~~ $app = new \Slim\App(); $app->get('/hello/{name}', function ($request, $response, $args) { echo "Hello, " . $args['name']; }); ~~~ ### Regular expression matching By default the placeholders are written inside `{}` and can accept any values. However, placeholders can also require the HTTP request URI to match a particular regular expression. If the current HTTP request URI does not match a placeholder regular expression, the route is not invoked. This is an example placeholder named `id` that requires a digit. ~~~ $app = new \Slim\App(); $app->get('/users/{id:[0-9]+}', function ($request, $response, $args) { // Find user identified by $args['id'] }); ~~~ ## Route names Application route’s can be assigned a name. This is useful if you want to programmatically generate a URL to a specific route with the router’s `pathFor()` method. Each routing method described above returns a `\Slim\Route` object, and this object exposes a `setName()`method. ~~~ $app = new \Slim\App(); $app->get('/hello/{name}', function ($request, $response, $args) { echo "Hello, " . $args['name']; })->setName('hello'); ~~~ You can generate a URL for this named route with the application router’s `pathFor()` method. ~~~ echo $app->router->pathFor('hello', [ 'name' => 'Josh' ]); // Outputs "/hello/Josh" ~~~ The router’s `pathFor()` method accepts two arguments: 1. The route name 2. Associative array of route pattern placeholders and replacement values ## Route groups To help organize routes into logical groups, the `\Slim\App` also provides a `group()` method. Each group’s route pattern is prepended to the routes or groups contained within it, and any placeholder arguments in the group pattern are ultimately made available to the nested routes: ~~~ $app = new \Slim\App(); $app->group('/users/{id:[0-9]+}', function () { $this->map(['GET', 'DELETE', 'PATCH', 'PUT'], '', function ($request, $response, $args) { // Find, delete, patch or replace user identified by $args['id'] })->setName('user'); $this->get('/reset-password', function ($request, $response, $args) { // Route for /users/{id:[0-9]+}/reset-password // Reset the password for user identified by $args['id'] })->setName('user-password-reset'); }); ~~~ Note inside the group closure, `$this` is used instead of `$app`. Slim binds the closure to the application instance for you, just like it is the case with route callbacks. ## Route middleware You can also attach middleware to any route or route group. [Learn more](http://www.slimframework.com/docs/concepts/middleware.html).

# Response [TOC=2,3] Your Slim app’s routes and middleware are given a PSR 7 response object that represents the current HTTP response to be returned to the client. The response object implements the [PSR 7 ResponseInterface](http://www.php-fig.org/psr/psr-7/#3-2-1-psr-http-message-responseinterface) with which you can inspect and manipulate the HTTP response status, headers, and body. ## How to get the Response object The PSR 7 response object is injected into your Slim application routes as the second argument to the route callback like this: ~~~ <?php use Psr\Http\Message\ServerRequestInterface; use Psr\Http\Message\ResponseInterface; $app = new \Slim\App; $app->get('/foo', function (ServerRequestInterface $request, ResponseInterface $response) { // Use the PSR 7 $response object return $response; }); $app->run(); ~~~ Figure 1: Inject PSR 7 response into application route callback. The PSR 7 response object is injected into your Slim application *middleware* as the second argument of the middleware callable like this: ~~~ <?php use Psr\Http\Message\ServerRequestInterface; use Psr\Http\Message\ResponseInterface; $app = new \Slim\App; $app->add(function (ServerRequestInterface $request, ResponseInterface $response, callable $next) { // Use the PSR 7 $response object return $next($request, $response); }); // Define app routes... $app->run(); ~~~ Figure 2: Inject PSR 7 response into application middleware. ## The Response Status Every HTTP response has a numeric [status code](http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html). The status code identifies the *type* of HTTP response to be returned to the client. The PSR 7 Response object’s default status code is `200`(OK). You can get the PSR 7 Response object’s status code with the `getStatusCode()`method like this. ~~~ $status = $response->getStatusCode(); ~~~ Figure 3: Get response status code. You can copy a PSR 7 Response object and assign a new status code like this: ~~~ $newResponse = $response->withStatus(302); ~~~ Figure 4: Create response with new status code. ## The Response Headers Every HTTP response has headers. These are metadata that describe the HTTP response but are not visible in the response’s body. Slim’s PSR 7 Response object provides several methods to inspect and manipulate its headers. ### Get All Headers You can fetch all HTTP response headers as an associative array with the PSR 7 Response object’s `getHeaders()` method. The resultant associative array’s keys are the header names and its values are themselves a numeric array of string values for their respective header name. ~~~ $headers = $response->getHeaders(); foreach ($headers as $name => $values) { echo $name . ": " . implode(", ", $values); } ~~~ Figure 5: Fetch and iterate all HTTP response headers as an associative array. ### Get One Header You can get a single header’s value(s) with the PSR 7 Response object’s `getHeader($name)`method. This returns an array of values for the given header name. Remember, *a single HTTP header may have more than one value!* ~~~ $headerValueArray = $response->getHeader('Vary'); ~~~ Figure 6: Get values for a specific HTTP header. You may also fetch a comma-separated string with all values for a given header with the PSR 7 Response object’s `getHeaderLine($name)` method. Unlike the `getHeader($name)` method, this method returns a comma-separated string. ~~~ $headerValueString = $response->getHeaderLine('Vary'); ~~~ Figure 7: Get single header's values as comma-separated string. ### Detect Header You can test for the presence of a header with the PSR 7 Response object’s`hasHeader($name)` method. ~~~ if ($response->hasHeader('Vary')) { // Do something } ~~~ Figure 8: Detect presence of a specific HTTP header. ### Set Header You can set a header value with the PSR 7 Response object’s `withHeader($name, $value)`method. ~~~ $newResponse = $oldResponse->withHeader('Content-type', 'application/json'); ~~~ Figure 9: Set HTTP header Reminder The Response object is immutable. This method returns a *copy* of the Response object that has the new header value. This method is destructive, and it *replaces* existing header values already associated with the same header name. ### Append Header You can append a header value with the PSR 7 Response object’s `withAddedHeader($name, $value)` method. ~~~ $newResponse = $oldResponse->withAddedHeader('Allow', 'PUT'); ~~~ Figure 10: Append HTTP header Reminder Unlike the `withHeader()` method, this method *appends* the new value to the set of values that already exist for the same header name. The Response object is immutable. This method returns a *copy* of the Response object that has the appended header value. ### Remove Header You can remove a header with the Response object’s `withoutHeader($name)` method. ~~~ $newResponse = $oldResponse->withoutHeader('Allow'); ~~~ Figure 11: Remove HTTP header Reminder The Response object is immutable. This method returns a *copy* of the Response object that has the appended header value. ## The Response Body 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. ~~~ $body = $response->getBody(); ~~~ Figure 12: Get HTTP response body The resultant `\Psr\Http\Message\StreamInterface` instance provides the following methods to read from, iterate, and write to its underlying PHP `resource`. * `getSize()` * `tell()` * `eof()` * `isSeekable()` * `seek()` * `rewind()` * `isWritable()` * `write($string)` * `isReadable()` * `read($length)` * `getContents()` * `getMetadata($key = null)` Most often, you’ll need to write to the PSR 7 Response object. You can write content to the`StreamInterface` instance with its `write()` method like this: ~~~ $body = $response->getBody(); $body->write('Hello'); ~~~ Figure 13: Write content to the HTTP response body You can also *replace* the PSR 7 Response object’s body with an entirely new`StreamInterface` instance. This is particularly useful when you want to pipe content from a remote destination (e.g. the filesystem or a remote API) into the HTTP response. You can replace the PSR 7 Response object’s body with its `withBody(StreamInterface $body)`method. Its argument MUST be an instance of `\Psr\Http\Message\StreamInterface`. ~~~ $newStream = new \GuzzleHttp\Psr7\LazyOpenStream('/path/to/file', 'r'); $newResponse = $oldResponse->withBody($newStream); ~~~ Figure 13: Replace the HTTP response body Reminder The Response object is immutable. This method returns a *copy* of the Response object that contains the new body.

# Request [TOC=2,3] Your Slim app’s routes and middleware are given a PSR 7 request object that represents the current HTTP request received by your web server. The request object implements the [PSR 7 ServerRequestInterface](http://www.php-fig.org/psr/psr-7/#3-2-1-psr-http-message-serverrequestinterface) with which you can inspect and manipulate the HTTP request method, headers, and body. ## How to get the Request object The PSR 7 request object is injected into your Slim application routes as the first argument to the route callback like this: ~~~ <?php use Psr\Http\Message\ServerRequestInterface; use Psr\Http\Message\ResponseInterface; $app = new \Slim\App; $app->get('/foo', function (ServerRequestInterface $request, ResponseInterface $response) { // Use the PSR 7 $request object return $response; }); $app->run(); ~~~ Figure 1: Inject PSR 7 request into application route callback. The PSR 7 request object is injected into your Slim application *middleware* as the first argument of the middleware callable like this: ~~~ <?php use Psr\Http\Message\ServerRequestInterface; use Psr\Http\Message\ResponseInterface; $app = new \Slim\App; $app->add(function (ServerRequestInterface $request, ResponseInterface $response, callable $next) { // Use the PSR 7 $request object return $next($request, $response); }); // Define app routes... $app->run(); ~~~ Figure 2: Inject PSR 7 request into application middleware. ## The Request Method Every HTTP request has a method that is typically one of: * GET * POST * PUT * DELETE * HEAD * PATCH * OPTIONS You can inspect the HTTP request’s method with the Request object method appropriately named `getMethod()`. ~~~ $method = $request->getMethod(); ~~~ Because this is a common task, Slim’s built-in PSR 7 implementation also provides these proprietary methods that return `true` or `false`. * `$request->isGet()` * `$request->isPost()` * `$request->isPut()` * `$request->isDelete()` * `$request->isHead()` * `$request->isPatch()` * `$request->isOptions()` It is possible to fake or *override* the HTTP request method. This is useful if, for example, you need to mimic a `PUT` request using a traditional web browser that only supports `GET` or `POST`requests. There are two ways to override the HTTP request method. You can include a `_METHOD`parameter in a `POST` request’s body. The HTTP request must use the `application/x-www-form-urlencoded` content type. ~~~ POST /path HTTP/1.1 Host: example.com Content-type: application/x-www-form-urlencoded Content-length: 22 data=value&_METHOD=PUT ~~~ Figure 3: Override HTTP method with _METHOD parameter. You can also override the HTTP request method with a custom `X-Http-Method-Override`HTTP request header. This works with any HTTP request content type. ~~~ POST /path HTTP/1.1 Host: example.com Content-type: application/json Content-length: 16 X-Http-Method-Override: PUT {"data":"value"} ~~~ Figure 4: Override HTTP method with X-Http-Method-Override header. You can fetch the *original* (non-overridden) HTTP method with the PSR 7 Request object’s method named `getOriginalMethod()`. ## The Request URI Every HTTP request has a URI that identifies the requested application resource. The HTTP request URI has several parts: * Scheme (e.g. `http` or `https`) * Host (e.g. `example.com`) * Port (e.g. `80` or `443`) * Path (e.g. `/users/1`) * Query string (e.g. `sort=created&dir=asc`) You can fetch the PSR 7 Request object’s URI with its `getUri()` method: ~~~ $uri = $request->getUri(); ~~~ The PSR 7 Request object’s URI is itself an object that provides the following methods to inspect the HTTP request’s URL parts: * `getScheme()` * `getHost()` * `getPort()` * `getPath()` * `getBasePath()` * `getQuery()` (returns string) * `getQueryParams()` (returns associative array) Base Path If your Slim application's front-controller lives in a physical subdirectory beneath your document root directory, you can fetch the HTTP request's physical base path (relative to the document root) with the Uri object's `getBasePath()` method. This will be an empty string if the Slim application is installed in the document root's top-most directory. ## The Request Headers Every HTTP request has headers. These are metadata that describe the HTTP request but are not visible in the request’s body. Slim’s PSR 7 Request object provides several methods to inspect its headers. ### Get All Headers You can fetch all HTTP request headers as an associative array with the PSR 7 Request object’s `getHeaders()` method. The resultant associative array’s keys are the header names and its values are themselves a numeric array of string values for their respective header name. ~~~ $headers = $request->getHeaders(); foreach ($headers as $name => $values) { echo $name . ": " . implode(", ", $values); } ~~~ Figure 5: Fetch and iterate all HTTP request headers as an associative array. ### Get One Header You can get a single header’s value(s) with the PSR 7 Request object’s `getHeader($name)`method. This returns an array of values for the given header name. Remember, *a single HTTP header may have more than one value!* ~~~ $headerValueArray = $request->getHeader('Accept'); ~~~ Figure 6: Get values for a specific HTTP header. You may also fetch a comma-separated string with all values for a given header with the PSR 7 Request object’s `getHeaderLine($name)` method. Unlike the `getHeader($name)` method, this method returns a comma-separated string. ~~~ $headerValueString = $request->getHeaderLine('Accept'); ~~~ Figure 7: Get single header's values as comma-separated string. ### Detect Header You can test for the presence of a header with the PSR 7 Request object’s `hasHeader($name)`method. ~~~ if ($request->hasHeader('Accept')) { // Do something } ~~~ Figure 8: Detect presence of a specific HTTP request header. ## The Request Body Every HTTP request has a body. If you are building a Slim application that consumes JSON or XML data, you can use the PSR 7 Request object’s `getParsedBody()` method to parse the HTTP request body into a native PHP format. Slim can parse JSON, XML, and URL-encoded data out of the box. ~~~ $parsedBody = $request->getParsedBody(); ~~~ Figure 9: Parse HTTP request body into native PHP format * JSON requests are converted into a PHP object with `json_decode($input)`. * XML requests are converted into a `SimpleXMLElement` with`simplexml_load_string($input)`. * URL-encoded requests are converted into a PHP array with `parse_str($input)`. Technically speaking, Slim’s PSR 7 Request object represents the HTTP request body as an instance of `\Psr\Http\Message\StreamInterface`. You can get the HTTP request body`StreamInterface` instance with the PSR 7 Request object’s `getBody()` method. The`getBody()` method is preferable if the incoming HTTP request size is unknown or too large for available memory. ~~~ $body = $request->getBody(); ~~~ Figure 10: Get HTTP request body The resultant `\Psr\Http\Message\StreamInterface` instance provides the following methods to read and iterate its underlying PHP `resource`. * `getSize()` * `tell()` * `eof()` * `isSeekable()` * `seek()` * `rewind()` * `isWritable()` * `write($string)` * `isReadable()` * `read($length)` * `getContents()` * `getMetadata($key = null)` ## Request Helpers Slim’s PSR 7 Request implementation provides these additional proprietary methods to help you further inspect the HTTP request. ### Detect XHR requests You can detect XHR requests with the Request object’s `isXhr()` method. This method detects the presence of the `X-Requested-With` HTTP request header and ensures its value is`XMLHttpRequest`. ~~~ POST /path HTTP/1.1 Host: example.com Content-type: application/x-www-form-urlencoded Content-length: 7 X-Requested-With: XMLHttpRequest foo=bar ~~~ Figure 11: Example XHR request. ~~~ if ($request->isXhr()) { // Do something } ~~~ ### Content Type You can fetch the HTTP request content type with the Request object’s `getContentType()`method. This returns the `Content-Type` header’s full value as provided by the HTTP client. ~~~ $contentType = $request->getContentType(); ~~~ ### Media Type You may not want the complete `Content-Type` header. What if, instead, you only want the media type? You can fetch the HTTP request media type with the Request object’s`getMediaType()` method. ~~~ $mediaType = $request->getMediaType(); ~~~ You can fetch the appended media type parameters as an associative array with the Request object’s `getMediaTypeParams()` method. ~~~ $mediaParams = $request->getMediaTypeParams(); ~~~ ### Character Set One of the most common media type parameters is the HTTP request character set. The Request object provides a dedicated method to retrieve this media type parameter. ~~~ $charset = $request->getContentCharset(); ~~~ ### Content Length You can fetch the HTTP request content length with the Request object’s `getContentLength()`method. ~~~ $length = $request->getContentLength(); ~~~ ### IP Address You can fetch the HTTP request’s source IP address with the Request object’s `getIp()`method. This method respects the `X-Forwarded-For` header, if present. ~~~ $ip = $request->getIp(); ~~~

# Dependency Container Slim uses a dependency container to prepare, manage, and inject application dependencies. Slim supports containers that implement the [Container-Interop](https://github.com/container-interop/container-interop) interface. You can use Slim’s built-in container (based on [Pimple](http://pimple.sensiolabs.org/)) or third-party containers like [Acclimate](https://github.com/jeremeamia/acclimate-container) or [PHP-DI](http://php-di.org/). ## How to use the container You don’t *have* to provide a dependency container. If you do, however, you must inject the container instance into the Slim application’s constructor. ~~~ $container = new \Slim\Container; $app = new \Slim\App($container); ~~~ You can fetch services from your container explicitly or implicitly. You can fetch an explicit reference to the container instance from inside a Slim application route like this: ~~~ /** * Example GET route * * @param \Psr\Http\Message\ServerRequestInterface $req PSR7 request * @param \Psr\Http\Message\ResponseInterface $res PSR7 response * @param array $args Route parameters * * @return \Psr\Http\Message\ResponseInterface */ $app->get('/foo', function ($req, $res, $args) { $container = $this->getContainer(); $myService = $container->get('myService'); return $res; }); ~~~ You can implicitly fetch services from the container like this: ~~~ /** * Example GET route * * @param \Psr\Http\Message\ServerRequestInterface $req PSR7 request * @param \Psr\Http\Message\ResponseInterface $res PSR7 response * @param array $args Route parameters * * @return \Psr\Http\Message\ResponseInterface */ $app->get('/foo', function ($req, $res, $args) { $myService = $this->myService; return $res; }); ~~~ Slim uses `__get()` and `__isset()` magic methods that defer to the application’s container for all properties that do not already exist on the application instance. ## Required services Your container MUST implement these required services. If you use Slim’s built-in container, these are provided for you. If you choose a third-party container, you must define these required services on your own. ### settings Associative array of application settings, including keys `httpVersion`, `outputBuffering`,`responseChunkSize` and `determineRouteBeforeAppMiddleware`. ### environment Instance of `\Slim\Interfaces\Http\EnvironmentInterface`. ### request Instance of `\Psr\Http\Message\ServerRequestInterface`. ### response Instance of `\Psr\Http\Message\ResponseInterface`. ### router Instance of `\Slim\Interfaces\RouterInterface`. ### foundHandler Instance of `\Slim\Interfaces\InvocationStrategyInterface`. ### errorHandler Callable invoked if application error. The callable MUST return an instance of`\Psr\Http\Message\ResponseInterface` and accept three arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` 3. `\Exception` ### notFoundHandler Callable invoked if the current HTTP request URI does not match an application route. The callable MUST return an instance of `\Psr\Http\Message\ResponseInterface` and accept two arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` ### notAllowedHandler Callable invoked if an application route matches the current HTTP request path but not its method. The callable MUST return an instance of `\Psr\Http\Message\ResponseInterface`and accept three arguments: 1. `\Psr\Http\Message\ServerRequestInterface` 2. `\Psr\Http\Message\ResponseInterface` 3. Array of allowed HTTP methods

# Middleware You can run code *before* and *after* your Slim application to manipulate the Request and Response objects as you see fit. This is called *middleware*. Why would you want to do this? Perhaps you want to protect your app from cross-site request forgery. Maybe you want to authenticate requests before your app runs. Middleware is perfect for these scenarios. ## What is middleware? Technically speaking, a middleware is a *callable* that accepts three arguments: 1. `\Psr\Http\Message\ServerRequestInterface` - The PSR7 request object 2. `\Psr\Http\Message\ResponseInterface` - The PSR7 response object 3. `callable` - The next middleware callable It can do whatever is appropriate with these objects. The only hard requirement is that a middleware MUST return an instance of `\Psr\Http\Message\ResponseInterface`. Each middleware SHOULD invoke the next middleware and pass it Request and Response objects as arguments. ## How does middleware work? Different frameworks use middleware differently. Slim adds middleware as concentric layers surrounding your core application. Each new middleware layer surrounds any existing middleware layers. The concentric structure expands outwardly as additional middleware layers are added. When you run the Slim application, the Request and Response objects traverse the middleware structure from the outside in. They first enter the outer-most middleware, then the next outer-most middleware, (and so on), until they ultimately arrive at the Slim application itself. After the Slim application dispatches the appropriate route, the resultant Response object exits the Slim application and traverses the middleware structure from the inside out. Ultimately, a final Response object exits the outer-most middleware, is serialized into a raw HTTP response, and is returned to the HTTP client. Here’s a diagram that illustrates the middleware process flow:  ## How do I write middleware? Middleware is a callable that accepts three arguments: a Request object, a Response object, and the next middleware. Each middleware MUST return an instance of`\Psr\Http\Message\ResponseInterface`. ### Closure middleware example. This example middleware is a Closure. ~~~ <?php /** * Example middleware closure * * @param \Psr\Http\Message\ServerRequestInterface $request PSR7 request * @param \Psr\Http\Message\ResponseInterface $response PSR7 response * @param callable $next Next middleware * * @return \Psr\Http\Message\ResponseInterface */ function ($request, $response, $next) { $response->getBody()->write('BEFORE'); $response = $next($request, $response); $response->getBody()->write('AFTER'); return $response; }; ~~~ ### Invokable class middleware example This example middleware is an invokable class that implements the magic `__invoke()`method. ~~~ <?php class ExampleMiddleware { /** * Example middleware invokable class * * @param \Psr\Http\Message\ServerRequestInterface $request PSR7 request * @param \Psr\Http\Message\ResponseInterface $response PSR7 response * @param callable $next Next middleware * * @return \Psr\Http\Message\ResponseInterface */ public function __invoke($request, $response, $next) { $response->getBody()->write('BEFORE'); $response = $next($request, $response); $response->getBody()->write('AFTER'); return $response; } } ~~~ To use this class as a middleware, you can use `->add( new ExampleMiddleware() );`function chain after the `$app`, `Route`, or `group()`, which in the code below, any one of these, could represent $subject. ~~~ $subject->add( new ExampleMiddleware() ); ~~~ ## How do I add middleware? You may add middleware to a Slim application, to an individual Slim application route or to a route group. All scenarios accept the same middleware and implement the same middleware interface. ### Application middleware Application middleware is invoked for every *incoming* HTTP request. Add application middleware with the Slim application instance’s `add()` method. This example adds the Closure middleware example above: ~~~ <?php $app = new \Slim\App(); $app->add(function ($request, $response, $next) { $response->getBody()->write('BEFORE'); $response = $next($request, $response); $response->getBody()->write('AFTER'); return $response; }); $app->get('/', function ($req, $res, $args) { echo ' Hello '; }); $app->run(); ~~~ This would output this HTTP response body: ~~~ BEFORE Hello AFTER ~~~ ### Route middleware Route middleware is invoked *only if* its route matches the current HTTP request method and URI. Route middleware is specified immediately after you invoke any of the Slim application’s routing methods (e.g., `get()` or `post()`). Each routing method returns an instance of`\Slim\Route`, and this class provides the same middleware interface as the Slim application instance. Add middleware to a Route with the Route instance’s `add()` method. This example adds the Closure middleware example above: ~~~ <?php $app = new \Slim\App(); $mw = function ($request, $response, $next) { $response->getBody()->write('BEFORE'); $response = $next($request, $response); $response->getBody()->write('AFTER'); return $response; }; $app->get('/', function ($req, $res, $args) { echo ' Hello '; })->add($mw); $app->run(); ~~~ This would output this HTTP response body: ~~~ BEFORE Hello AFTER ~~~ ### Group Middleware In addition to the overall application, and standard routes being able to accept middleware, the`group()` multi-route definition functionality, also allows individual routes internally. Route group middleware is invoked *only if* its route matches one of the defined HTTP request methods and URIs from the group. To add middleware within the callback, and entire-group middleware to be set by chaining `add()` after the `group()` method. Sample Application, making use of callback middleware on a group of url-handlers ~~~ <?php require_once __DIR__.'/vendor/autoload.php'; $app = new \Slim\App(); $app->get('/', function ($request, $response) { return $response->getBody()->write('Hello World'); }); $app->group('/utils', function () use ($app) { $app->get('/date', function ($request, $response) { return $response->getBody()->write(date('Y-m-d H:i:s')); }); $app->get('/time', function ($request, $response) { return $response->getBody()->write(time()); }); })->add(function ($request, $response, $next) { $response->getBody()->write('It is now '); $response = $next($request, $response); $response->getBody()->write('. Enjoy!'); return $response; }); ~~~ When calling the `/utils/date` method, this would output a string similar to the below ~~~ It is now 2015-07-06 03:11:01\. Enjoy! ~~~ visiting `/utils/time` would output a string similar to the below ~~~ It is now 1436148762\. Enjoy! ~~~ but visiting `/` *(domain-root)*, would be expected to generate the following output as no middleware has been assigned ~~~ Hello World ~~~

# PSR 7 and Value Objects Slim supports [PSR-7](https://github.com/php-fig/http-message) interfaces for its Request and Response objects. This makes Slim flexible because it can use *any* PSR-7 implementation. For example, a Slim application route does not *have* to return an instance of `\Slim\Http\Response`. It could, for example, return an instance of `\GuzzleHttp\Psr7\CachingStream` or any instance returned by the`\GuzzleHttp\Psr7\stream_for()` function. Slim provides its own PSR-7 implementation so that it works out of the box. However, you are free to replace Slim’s default PSR 7 objects with a third-party implementation. Just override the application container’s `request` and `response` services so they return an instance of`\Psr\Http\Message\ServerRequestInterface` and`\Psr\Http\Message\ResponseInterface`, respectively. ## Value objects Slim’s Request and Response objects are [*immutable value objects*](http://en.wikipedia.org/wiki/Value_object). They can be “changed” only by requesting a cloned version that has updated property values. Value objects have a nominal overhead because they must be cloned when their properties are updated. This overhead does not affect performance in any meaningful way. You can request a copy of a value object by invoking any of its PSR 7 interface methods (these methods typically have a `with` prefix). For example, a PSR 7 Response object has a`withHeader($name, $value)` method that returns a cloned value object with the new HTTP header. ~~~ <?php $app = new \Slim\App; $app->get('/foo', function ($req, $res, $args) { return $res->withHeader( 'Content-Type', 'application/json' ); }); $app->run(); ~~~ The PSR 7 interface provides these methods to transform Request and Response objects: * `withProtocolVersion($version)` * `withHeader($name, $value)` * `withAddedHeader($name, $value)` * `withoutHeader($name)` * `withBody(StreamInterface $body)` The PSR 7 interface provides these methods to transform Request objects: * `withMethod($method)` * `withUri(UriInterface $uri, $preserveHost = false)` * `withCookieParams(array $cookies)` * `withQueryParams(array $query)` * `withUploadedFiles(array $uploadedFiles)` * `withParsedBody($data)` * `withAttribute($name, $value)` * `withoutAttribute($name)` The PSR 7 interface provides these methods to transform Response objects: * `withStatus($code, $reasonPhrase = '')` Refer to the [PSR-7 documentation](http://www.php-fig.org/psr/psr-7/) for more information about these methods.

# Web Servers It is typical to use the front-controller pattern to funnel appropriate HTTP requests received by your web server to a single PHP file. The instructions below explain how to tell your web server to send HTTP requests to your PHP front-controller file. ## Apache configuration Ensure your `.htaccess` and `index.php` files are in the same public-accessible directory. The`.htaccess` file should contain this code: ~~~ RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteCond %{REQUEST_FILENAME} !-d RewriteRule ^ index.php [QSA,L] ~~~ Make sure your Apache virtual host is configured with the `AllowOverride` option so that the`.htaccess` rewrite rules can be used: ~~~ AllowOverride All ~~~ ## Nginx configuration This is an example Nginx virtual host configuration for the domain `example.com`. It listens for inbound HTTP connections on port 80\. It assumes a PHP-FPM server is running on port 9000\. You should update the `server_name`, `error_log`, `access_log`, and `root` directives with your own values. The `root` directive is the path to your application’s public document root directory; your Slim app’s `index.php` front-controller file should be in this directory. ~~~ server { listen 80; server_name example.com; index index.php; error_log /path/to/example.error.log; access_log /path/to/example.access.log; root /path/to/public; location / { try_files $uri $uri/ /index.php$is_args$args; } location ~ \.php { try_files $uri =404; fastcgi_split_path_info ^(.+\.php)(/.+)$; include fastcgi_params; fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name; fastcgi_param SCRIPT_NAME $fastcgi_script_name; fastcgi_index index.php; fastcgi_pass 127.0.0.1:9000; } } ~~~ ## HipHop Virtual Machine Your HipHop Virtual Machine configuration file should contain this code (along with other settings you may need). Be sure you change the `SourceRoot` setting to point to your Slim app’s document root directory. ~~~ Server { SourceRoot = /path/to/public/directory } ServerVariables { SCRIPT_NAME = /index.php } VirtualHost { * { Pattern = .* RewriteRules { * { pattern = ^(.*)$ to = index.php/$1 qsa = true } } } } ~~~ ## IIS Ensure the `Web.config` and `index.php` files are in the same public-accessible directory. The`Web.config` file should contain this code: ~~~ <?xml version="1.0" encoding="UTF-8"?> <configuration> <system.webServer> <rewrite> <rules> <rule name="slim" patternSyntax="Wildcard"> <match url="*" /> <conditions> <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" /> <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" /> </conditions> <action type="Rewrite" url="index.php" /> </rule> </rules> </rewrite> </system.webServer> </configuration> ~~~ ## lighttpd Your lighttpd configuration file should contain this code (along with other settings you may need). This code requires lighttpd >= 1.4.24. ~~~ url.rewrite-if-not-file = ("(.*)" => "/index.php/$0") ~~~ This assumes that Slim’s `index.php` is in the root folder of your project (www root).