Kim Dalsgaard. Co-owner of, and Software Designer at Trifork Athene Co-founder of Aarhus Ruby Brigade

Transcription

1 Kim Dalsgaard Co-owner of, and Software Designer at Trifork Athene Co-founder of Aarhus Ruby Brigade

2 REST in Ruby How Ruby can support a RESTful architecture

3 What is REST?

4 REST is first described in Roy Fielding s PhD dissertation

5 Architectural Styles and the Design of Network-based Software Architectures

6 REST is one of these architectural styles

7 What is an architectural style?

8 An architectural style is about constraints

9 What is the constraints for REST?

10 Key constraints Identifiable resources Uniform interface Stateless communication Resource representations Hypermedia

11 Identifiable resources A resource represents a real or virtual entity Identified by URIs Each URI adds value to the Net as a whole

12 Uniform interface GET POST PUT DELETE and some more

13 Stateless communication A server does not need to maintain state for each client Massive advantages in terms of scalability Enforces loose coupling (no shared session knowledge)

14 Resource representations Resources are always accessed through a representation Resources should be represented using well-known (standardized) content types HTTP provides content types and content negotiation

15 Hypermedia Possible state transitions are made explicit through links Links are always provided by the server, not created by the client (low coupling again)

16 REST Servers

17 How can the Ruby web frameworks help us with the REST constraints?

18 Identifiable resources - mapping of URLs to controllers and parameters

19 Uniform interface - mapping of HTTP verbs to actions

20 Stateless communication - switching off the session store

21 Resource representations - executing code according to content type

22 Hypermedia - creating URLs from objects

23 REST and Rails

24 The resource and resources methods for routing

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29 The respond_to method for executing code according to content type

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31 The magic _url methods for creating URL s from objects

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33 The session method for turning off sessions

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35 REST and Merb

36 The resource and resources methods for routing

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40 The provides and display methods for rendering objects

41 The provides method for registering mimetypes to render

42 The display method for rendering objects

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44 The url methods for creating URLs from objects

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46 The :session_store configuration key for turning off sessions

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48 REST Clients

49 How can the Ruby HTTP client libraries help us with the REST constraints?

50 Identifiable resources - holding resource identity

51 Uniform interface - mapping of HTTP verbs to method calls

52 Stateless communication - a server responsibility

53 Resource representations - setting the Accept header

54 Hypermedia - fetching and following URLs

55 REST and Net::HTTP

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57 Too low level!

58 REST and rest-open-uri

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60 URI objects holding resource identity HTTP verbs mapped to key/value pair in options Hash Low level access the Accept header No fetching and following URLs

61 REST and RestClient

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63 Resource objects holding resource identity HTTP verbs mapped to methods Easy to set the Accept header No fetching and following URLs Buggy post method!

64 REST and ActiveResource

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66 Base objects holding resource identity HTTP verbs mapped to alternative methods Fetching and following URLs Possible to change the serialization format

67 Links are not provided by the server, but created by the client! Too much additional protocol

68 Questions?