1. REST in peace
A handbook of software waste
Alessandro Nadalin
DNSEE
430
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2. AGENDA
> Vol. 1: REST in a nutshell > Vol. 2: To the rescue
– Tenets – HTTP cache
– Antipatterns – ESI
> WWW: a tremendous architecture – HATEOAS
– Stateless > Vol. 3: REST is not a panacea
– Layered – SOAP
– Cacheable – Limited horizon
– Fault-tolerant – Agile development
– Failure-prone
2
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3. Sorry for the ugly slide.
There will be others.
Really sorry.
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4. REST in a nutshell:
1. Client <> Server
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5. REST in a nutshell:
2. Stateless
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6. REST in a nutshell:
3. Cacheable
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7. REST in a nutshell:
4. Layered system
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8. REST in a nutshell:
5. Uniform
interface
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9. And obviously nobody had a clue
9
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10. ANTIPATTERNS
10
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11. 1
URIs
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12. "REST is about
cool URI design"
http://apple.com/users/1/licenses/4.json
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13. "REST is about
cool URI design"
http://apple.com/users/1/licenses/4.json
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14. http://apple.com/site/en_US/showUsers.jsp?uid=1&license=4
is OK too
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15. but
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16. cool URIs help you
think in term of resources
David Zuelke
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17. 2
URIs (bis)
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18. REST follows a URI schema
GET /users
POST /users
PUT /users/{id}
DELETE /users/{id}
...
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19. REST follows a URI schema
GET /users
POST /users
PUT /users/{id}
DELETE /users/{id}
...
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20. what if you change your
URL?
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21. Yeah,
client is
broken
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22. RESTful clients should
be driven by service's
hypermedia controls
Roy Fielding : http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven
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23. HATEOAS
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24. 3
POST is cool
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25. said SOAP
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26. said SOAP
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27. loosing meaningful verbs at the protocol level
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28. loosing meaningful verbs at the protocol level
nothing cacheable by default
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29. loosing meaningful verbs at the protocol level
nothing cacheable by default
what about bookmarking?
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30. Have a break
30
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31. The WWW
31
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32. the largest data-exchange network on the planet
32
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33. And meanwhile, at Facebook...
12TB of new data every day
(1 year ago)
500 million users 33
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34. via HTTP , baby!
34
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35. HTTP in a nutshell:
1. Client <> Server
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36. HTTP in a nutshell:
2. Stateless
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37. HTTP in a nutshell:
3. widespread cache spec
http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
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38. HTTP in a nutshell:
Lao Tze Song office's laptop
Company proxy
Great chinese (fire)wall
Reverse proxy
Origin server
4. Layered system
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39. HTTP in a nutshell:
5. it is the uniform interface
between clients and servers
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40. HTTP bleeds REST
40
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41. Vol.2
Implementing all this goodness
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42. 1.
caching & scalability
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43. Caching with
Expiration
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44. HTTP/1.1 200 OK
Host: www.example.com
Expires: 0
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45. HTTP/1.1 200 OK
Host: www.example.com
Expires: 0
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46. HTTP/1.1 200 OK
Host: www.example.com
Expires: Tue, 31 Jan 2011 01:00 GMT
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47. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: max-age=60, public
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48. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: max-age=60, public
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49. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: max-age=60, public
Cacheable for 60 seconds
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50. GET / HTTP/1.1
Host: www.example.com
Cache-Control: max-age=60, public
Cacheable by both local and shared caches
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51. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
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52. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
fault-tolerant
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53. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
available during downtime
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54. HTTP/1.1 200 OK
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
available during revalidation
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55. Caching with
Validation
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56. HTTP/1.1 200 OK
Host: www.example.com
Etag: 1234
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57. HTTP/1.1 200 OK
Host: www.example.com
Etag: 1234
an identifier for your response
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58. Conditional requests
GET / HTTP/1.1
Host: www.example.com
If-None-Match: 1234
the browsers asks you if it has been modified
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59. HTTP/1.1 304 Not Modified
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60. Calculating an Etag is cheaper than generating a full MVC
response
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61. but hey, you say
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62. HTTP's cache fails when dealing with really dynamic
pages, because consumers will always have to hit the
origin server, although a part of the page would be
cacheable ( header and footer, for example )
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63. Nope
Nope
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64. ESI was built for that
http://www.w3.org/TR/esi-lang
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65. Edge Side Includes
Server side includes ( not SSI! ) usually handled by
the architecture's ESI processor.
http://www.w3.org/TR/esi-lang
http://www.w3.org/TR/edge-arch
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66. <esi:include src="http://jazoon.com/talks/1" />
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67. <esi:include src="http://jazoon.com/talks/1" />
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68. <esi:include src="http://jazoon.com/talks/1" />
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69. 15 seconds cache
1 day cache
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70. <esi:include src='tweets.html' />
<esi:include src='footer.html' />
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71. and hey, Varnish is a reverse proxy implementing what
you need of the ESI specification
take 2, pay for 1
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72. So what does HTTP cache is meant to solve?
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73. Less work
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74. http://www.flickr.com/photos/snakphotography/5004775320/sizes/o/in/photostream/
because the hard work is delegated to the browser/proxy
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75. evolve
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76. because cache is abstracted from the application
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77. loose coupling
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78. because caching is bound to the protocol, HTTP, not
to your implementation ( Sf, RoR, Django )
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79. 2.
adaptability & durability
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80. Hypermedia
another long-time friend
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81. Links
outrageously semplifying
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82. <link rel="payment" href="/checkout" type="text/html" ... />
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83. <link rel="payment" href="/checkout" type="text/html" ... />
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84. <link rel="payment" href="/checkout" type="text/html" ... />
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85. <link rel="payment" href="/checkout" type="text/html" ... />
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86. POST /users
Host:
www.example.com
HTTP/1.1 201 Created
Host: www.example.com
Etag: 1234
X-Powered-By: php/5.3
Location: /users/1
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87. POST /users
Host:
www.example.com
HTTP/1.1 201 Created
Host: www.example.com
Etag: 1234
X-Powered-By: php/5.3
Location: /users/1
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88. POST /users
Host:
www.example.com
HTTP/1.1 201 Created
Host: www.example.com
Etag: 1234
X-Powered-By: php/5.3
Location: /new-users-db/1
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89. POST /users
Host:
www.example.com
HTTP/1.1 201 Created
Host: www.example.com
Etag: 1234
X-Powered-By: php/5.3
Location: /new-users-db/1
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90. consumers of your API are able to follow
the changes of your design
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91. everything seems
cool
But why REST?
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92. Pros
Performances
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93. Pros
Scalability
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94. SPEAKER‘S COMPANY
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95. Pros
Durability
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96. "REST is software design on the scale of decades: every detail is intended to
promote software longevity and independent evolution. Many of the constraints
are directly opposed to short-term efficiency. Unfortunately, people are fairly
good at short-term design, and usually awful at long-term design. "
Roy Fielding
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97. Put a bit of
REST
everywhere
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98. Rules of
good design
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99. Use natives
=
Eliminate waste
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100. The wheel!
HTTP - 1991~1997
REST - 2000
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101. Vol.3
REST is not a panacea
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102. SOAP
No need to re-invent the wheel: if you need to do SOAP integration, SOAP
is the way.
If you have a completely functional SOAP service, no - apparent - need to
rewrite it RESTful from scratch.
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103. AGILE
The last responsible moment conflicts with REST.
But quality enhance agility: REST is quality.
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104. LIMITED
HORIZON
My blog won't ever be RESTful.
But incremental design, bare it in mind.
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105. Alessandro Nadalin odino.org
DNSEE @_odino_
Rome github.com/odino
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106. Credits
http://www.flickr.com/photos/larachris/16564077/sizes/o/in/photostream/
http://www.flickr.com/photos/ashatenbroeke/4367373081/sizes/z/in/photostream/
http://www.flickr.com/photos/yourdon/3140270189/sizes/l/in/photostream/
http://www.flickr.com/photos/jox1989/4964706072/sizes/l/in/photostream/
http://www.flickr.com/photos/brainfg/168506259/sizes/o/in/photostream/
http://www.flickr.com/photos/norte_it/3897091546/sizes/o/in/photostream/
http://www.zdnet.com/blog/service-oriented/soap-versus-rest-a-matter-of-style/3568
http://www.flickr.com/photos/turtlemom_nancy/2046347762/sizes/l/in/photostream/
http://www.flickr.com/photos/juanpg/3333385784/sizes/z/in/photostream/
http://www.flickr.com/photos/congvo/301678287/sizes/l/in/photostream/
http://www.flickr.com/photos/ihasb33r/2573196546/sizes/z/in/photostream/
http://www.flickr.com/photos/martin_heigan/4544138976/sizes/o/in/photostream/
http://www.flickr.com/photos/cknara/4195099999/sizes/o/in/photostream/
http://www.flickr.com/photos/1080p/3076529265/sizes/l/in/photostream/
http://www.flickr.com/photos/adamrice/280300202/sizes/l/in/photostream/
http://www.flickr.com/photos/tomer_a/541411897/sizes/o/in/photostream/
http://www.flickr.com/photos/subpra/4514008262/sizes/l/in/photostream/
http://www.flickr.com/photos/lippincott/2539720043/sizes/l/in/photostream/
http://www.flickr.com/photos/rawryder/5086090931/sizes/l/in/photostream/
http://www.flickr.com/photos/robboudon/5312731161/sizes/l/in/photostream/
http://www.flickr.com/photos/bc-burnslibrary/4158243488/sizes/o/in/photostream/
http://www.flickr.com/photos/13606325@N08/2416993706/sizes/o/in/photostream/
http://www.flickr.com/photos/neothezion/5135841069/sizes/l/in/photostream/
http://www.flickr.com/photos/planetschwa/2494067809/
http://www.flickr.com/photos/thomasthomas/258931782/
http://www.flickr.com/photos/rustyboxcars/2629631562/sizes/l/in/photostream/
http://www.flickr.com/photos/ell-r-brown/4138727474/sizes/l/in/photostream/
http://www.flickr.com/photos/noah123/5082076630/sizes/z/in/photostream/
http://www.flickr.com/photos/jungle_boy/220181177/sizes/l/in/photostream/
http://www.flickr.com/photos/prettydaisies/872539081/sizes/l/in/photostream/
http://www.flickr.com/photos/kaptainkobold/76256150/sizes/o/in/photostream/
http://www.flickr.com/photos/uomoincravatta/1438372865/sizes/z/in/photostream/
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