Slim is a PHP micro framework that helps you quickly write simple yet powerful REST API

1. Slim
SLIM IS A PHP MICRO FRAMEWORK THAT HELPS YOU QUICKLY WRITE SIMPLE YET POWERFUL REST API
PRAMOD KUMAR RAGHAV

2. REST Vs SOAP
REST (Representational State Transfer)

3. REST Vs SOAP
REST (Representational State Transfer)
SOAP (Simple Object Access Protocol)

4. REST Vs SOAP
REST (Representational State Transfer)
SOAP (Simple Object Access Protocol)
RESTs is good when you are exposing a public API over the internet to handle CRUD
operations on data. REST is focused on accessing named resources through a single consistent
interface.
SOAP brings it’s own protocol and focuses on exposing pieces of application logic (not data)
as services.

5. REST Vs SOAP Cont…
REST permits many different data formats like (JSON, XML, CSV,RSS …)
SOAP only permits XML data formats.
REST allows better support for browser clients due to it’s support for JSON.
REST reads can be cached, SOAP based reads cannot be cached.
SOAP support ACID Transactions over a service while REST isn’t ACID compliant.

6. REST Vs SOAP Cont…
REST is limited by HTTP itself which can’t provide two-phase commit across distributed
transactional resources, but SOAP can.

7. OVERVIEW
Slim is a dispatcher that receives an HTTP request, invokes an appropriate
callback routine, and returns an HTTP response. That’s it.

8. Installation
System Requirements
o Web server with URL rewriting
o PHP 5.5 or newer
How to Install Slim
Install Slim with Composer and execute the below command under your project
root directory.
composer require slim/slim "^3.0"
This command downloads the Slim Framework and its third-party dependencies
into your project’s vendor/ directory.

9. Application
The Application, (or SlimApp) is the entry point to your Slim application and
is used to register the route that link to your callbacks or controllers.
The Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.

10. Application Configuration
The Application accepts just one argument. This can be either
a Container instance or an array to configure the default container that is
created automatically.
The Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.

11. Request & Response
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 Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.
 The PSR 7 request object is injected into your Slim application routes as the first argument
to the route callback.
 The PSR 7 response object is injected into your Slim application routes as the second
argument to the route callback.

12. Request & Response
The Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.

13. 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.
The Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.

14. The Request Headers ….
Get All Headers: You can fetch all HTTP request headers as an associative array.
The Application, (or SlimApp) is the entry point to your Slim application and is used to register the route that link to your callbacks or controllers.

15. The Request Headers ….
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!

16. The Request Body
Following methods have request body
POST, PUT, PATCH
Slim can parse JSON, XML, and URL-encoded data out of the box.
 JSON requests are converted into associative arrays with json_decode($input, true).
 XML requests are converted into a SimpleXMLElement with
simplexml_load_string($input).
 URL-encoded requests are converted into a PHP array with parse_str($input).

17. The Request Body
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.
 JSON requests are converted into associative arrays with json_decode($input, true).
 XML requests are converted into a SimpleXMLElement with
simplexml_load_string($input).
 URL-encoded requests are converted into a PHP array with parse_str($input).

18. Response Status
Every HTTP response has a numeric status code. The status code identifies the type of
HTTP response to be returned to the client.
You can copy a PSR 7 Response object and assign a new status code like this:

19. Response Headers
Every HTTP response has headers. These are metadata that describe the HTTP response
but are not visible in the response’s body.

20. Response Status
Set Header: You can set a header value with the PSR 7 Response object’s withHeader($name,
$value) method.
Append Header: You can append a header value with the PSR 7 Response object’s
withAddedHeader($name, $value) method.
Remove Header: You can remove a header with the Response object’s withoutHeader($name) method.

21. Returning JSON
Slim’s Response object has a custom method withJson($data, $status, $encodingOptions) to
help simplify the process of returning JSON data.
JSON data can be returned with a default 200 HTTP status code. But we can also return JSON data with
a custom HTTP status code.