This document discusses Symfony2 and REST APIs. It provides an overview of REST including its history and core concepts like requests, responses, and URLs to identify resources. It also discusses best practices for building REST APIs with Symfony2, including using a wrapper class, error handling guidelines, and documentation/monitoring goals.

1. Symfony2 & REST API
Alexey Verkeenko
Grossum
alex.verkeenko@gmail.com

2. WHAT IS REST?
• REST (Representational State Transfer) is the
software architectural style of the World Wide
Web.
• REST gives a coordinated set of constraints to the
design of components in a distributed hypermedia
system that can lead to a higher-performing and
more maintainable architecture.

3. A BIT OF REST HISTORY
• This technology became popular, when it was
described in detail and presented by Roy Fielding in
his doctoral dissertation called “Architectural Styles
and the Design of Network-based Software
Architectures” in 2000.

4. REST RULES
• The general rule stands that each unit of
information is identified by URL – which means, in
turn, that URL in essence is the primary key for the
data unit.
• For example, third book on the bookshelf would
have a view of /book/3, and 35th page of that book
would be found here: /book/3/page/35.

5. FULL LIST OF REQUEST TYPES
• CONNECT
• DELETE
• GET
• HEAD
• OPTIONS
• PATCH
• POST
• PUT
• TRACE

6. RESPONSE CODES
• There are 38 response
codes and you can see
the list on the right:

7. API TRANSACTION EXAMPLE
• One transaction for this API would consist from
following (minimum):
• Request method, for example, GET
• Request path, for example, /object/list
• Request body, for example, form
• Response code, for example, 200 OK
• Response body, for example data in JSON format

8. REST EXCLUSIONS
• You cannot call a service a REST one, if:
• It has single point of entry
• All requests are processed by POST method
• Response metadata is located in the body of the
response and not in its header
• URL-addresses contain method names

9. REST ADVANTAGES
• The advantages of using REST in our projects:
• All our resources have unique identifiers (URL), which
gives us an opportunity to logically formulate our
requests and structure URLs available for requests
• Universality. You can use the same server response data
to return back to XML or JSON for software processing
or to wrap in a beautiful design for people to see.
• REST is a service that implements actual service-
oriented architecture (SOA), an architectural pattern in
computer software design in which application
components provide services to other components via a
communications protocol, typically over a network.

10. ERRORS GUIDELINES
• Basic error informing guidelines:
• Use expected format
• Do not neglect available response types
• Show coherent messages

11. USAGE PROBLEMS
• Absence of mutual agreement and standardization
• Partial support of response headers
• Different clients’ behavior for the same response
code
• Complex process of searching for errors during
development

12. REQUEST OPTIONS
• Safe request – a request that does not change the
application’s condition.
• Idempotent request – a request, the multiple
execution of which equals to the single execution
effect.

13. CORRELATION TABLE
• Table of HTTP method correlation for safe and
idempotent requests:
HTTP-method Safe Idempotent
GET Yes Yes
HEAD Yes Yes
OPTIONS Yes Yes
PUT No Yes
DELETE No Yes
POST No No

14. MONITORING GOALS
• In order to choose correct instruments and
concentrate your attention on really important
issues, begin from identifying main needs you
want to satisfy with monitoring.

15. TWO QUESTIONS TO ASK
• Ask yourself these two questions:
• What do I want to find out?
• What am I planning to do based on this information?

16. WRAPPER CLASS
• Do not call API directly from your code. Instead,
implement a wrapper class for it.
• This allows you to:
• Cache results if the response speed is not high or there
is a big data exchange
• In case you need to incorporate changes, you only have
to do it in one place
• Convenient implementation because you only deal with
one class
• Mock-object’s easy realization to change our wrapper
class during the work on testing

17. CREATION AND DOCUMENTATION
• You can find information here:
• https://restunited.com/
• https://apimatic.io/
• http://swagger.io/

18. • Upload the bundle and its dependencies with the
help of composer:
• Connect it to the application core:
IN THE BEGINNING…

19. CONFIGURATION PARAMETERS

20. POST ENTITY

21. FORM & CONTROLLER CREATION

22. FORM TYPE

23. POST CREATION

24. PUT ACTION

25. PATCH ACTION

26. DELETE ACTION

27. THANK YOU!
GOT QUESTIONS?
Alexey Verkeenko
alex.verkeenko@gmail.com
Grossum