Presentation given at the International PHP conference in Mainz, October 2012, dealing with a bit of history about the HTTP protocol, SPDY and the future (HTTP/2.0).

1. Alessandro Nadalin | NAMSHI.com
http://end.of.the.road?

2. AGENDA
. History of HTTP
. Hidden features
. HTTP/2.0
. SPDY

3. HTTP/X.Y ?

4. Web development?

5. WWW
Web development?

6. Clients
WWW
Web development?

7. Clients
WWW
Web development?
Servers

8. Clients
WWW
M2M Web development?
Servers
Server

9. Clients
WWW
M2M Web development?
Servers
Automation

10. Any user can easily
interact with a
Webpage.

11. ( except my mom )

12. What about machines?

13. They need rules.

14. verbs
They need rules.

15. verbs
They need rules.
domains

16. verbs
They need rules.
workflows
domains

17. verbs
logic
They need rules.
workflows
domains

18. verbs
logic
They need rules.
constraints
workflows
domains

19. PROTOCOLS

20. HTTP/0.9

21. HTTP/0.9
(1991)

22. HTTP/1.0

23. 1996 GET
Tim Berners-Lee
POST
separate connections
HEAD Roy Fielding

24. HTTP/1.1

25. PUT
Tim Berners-Lee 1996 GET
TRACE
Domain Application Protocol
PATCH
POST Roy Fielding
separate connections DELET
OPTIONS
HEAD
E
DIFF

26. EXPIRES MAX-AGE
CACHE CHANNELS
CACHE 304 Not modified
http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
SCALABILITY

27. <feed xmlns="http://www.w3.org/2005/Atom"
xmlns:cc="http://purl.org/syndication/cache-channel">
<title>Invalidations for www.example.org</title>
<id>http://admin.example.org/events/</id>
<link rel="self"
href="http://admin.example.org/events/current"/>
<link rel="prev-archive"
href="http://admin.example.org/events/archive/1234"/>
<updated>2007-04-13T11:23:42Z</updated>
<author>
<name>Administrator</name>
<email>web-admin@example.org</email>
</author>
<cc:precision>60</cc:precision>
<cc:lifetime>2592000</cc:lifetime>
<entry>
<title>stale</title>
<id>http://admin.example.org/events/1124</id>
<updated>2007-04-13T11:23:42Z</updated>
<link href="urn:uuid:50D3565C-97A8-40E1-A5C8-CFA070166FEF"/>
<cc:stale/>
</entry>
<entry>
<title>stale</title>
<id>http://admin.example.org/events/1125</id>
<updated>2007-04-13T10:31:01Z</updated>
<link href="http://www.example.org/img/123.gif" type="image/gif"/>
<link href="http://www.example.org/img/123.png" type="image/png"/>
<cc:stale/>
</entry>

28. GET /users/1 HTTP/1.1 200 Ok
HTTP/1.1 Etag: 123abc
Host: example.com
GET /users/1 HTTP/1.1 HTTP/1.1 304 Not
Host: example.com Modified
If-None-Match: 123abc
POST /users/1 HTTP/1.1 HTTP/1.1 412
Host: example.com Precondition Failed
Etag: 123abcdefgh
...

29. GET /users/1 HTTP/1.1 HTTP/1.1 200 Ok
Host: example.com Cache-Control: max-age=60
GET /users/1 HTTP/1.1
Host: example.com

30. FOR FREE

31. and here are a few ways to do
so, using
expiration
validation
invalidation

32. Expiration

33. GET / HTTP/1.1
Host: www.example.com
Expires: 0

34. GET / HTTP/1.1
Host: www.example.com
Expires: 0

35. GET / HTTP/1.1
Host: www.example.com
Expires: Tue, 15 Nov 1994 01:00 GMT

36. GET / HTTP/1.1
Host: www.example.com
Cache-Control: max-age=60, public

37. GET / HTTP/1.1
Host: www.example.com
Cache-Control: max-age=60, public

38. GET / HTTP/1.1
Host: www.example.com
Cache-Control: max-age=60, public
Cacheable for 60 seconds

39. GET / HTTP/1.1
Host: www.example.com
Cache-Control: max-age=60, public
Cacheable by both local and shared caches

40. GET / HTTP/1.1
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600

41. GET / HTTP/1.1
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
fault-tolerant

42. GET / HTTP/1.1
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
available during downtime

43. GET / HTTP/1.1
Host: www.example.com
Cache-Control: stale-if-error=600, stale-while-revalidate=600
available during revalidation

44. Validation

45. GET / HTTP/1.1
Host: www.example.
com
Etag: 1234

46. GET / HTTP/1.1
Host: www.example.
com
Etag: 1234
an identifier for your response

47. Conditional requests
GET / HTTP/1.1
Host: www.example.
com
If-None-Match: 1234
the browsers asks you if it has been modified

48. Relax

49. Calculating an Etag is cheaper than generating a full MVC
response

50. HTTP/1.1 304 Not Modified

51. GET / HTTP/1.1
Host: www.example.com
Last-Modified: Tue, 15 Jan 2011 12:00:00 GMT

52. GET / HTTP/1.1
Host: www.example.com
Last-Modified: Tue, 15 Jan 2011 12:00:00 GMT
tell the client about the latest change

53. Conditional requests
GET / HTTP/1.1
Host: www.example.com
If-Modified-Since: Tue, 15 Jan 2011 12:00:00 GMT
the client asks you if it has been modified since the last time

54. Relax

55. Calculating a date is cheaper than retrieving an entire object

56. HTTP/1.1 304 Not Modified

57. Invalidation

58. The web is not meant for invalidating data.
Server should not be able to keep clients' state, otherwise
they wont scale well.
That's why long-polling and endless connections haven't
had big success dealing with caching.

59. but hey, you say

60. 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 )

61. Nope
Nope

62. ESI was built for that
http://www.w3.org/TR/esi-lang

63. HInclude was built for that
http://mnot.github.com/hinclude/

64. So what does HTTP cache is meant to solve?

65. Less work

66. http://www.flickr.com/photos/snakphotography/5004775320/sizes/o/in/photostream/
because the hard work is delegated to the browser/proxy

67. evolve

68. because cache is abstracted from the application

69. loose coupling

70. because caching is bound to the protocol, HTTP,
not to your implementation ( Sf, RoR, Django )

71. it all started

72. 21

73. years

74. ago

75. Damn.

76. HTTP/2.0

77. Nothing to see here.

78. SPDY

80. http://dev.chromium.org/spdy/spdy-whitepaper

81. You're already using it

85. HTTP on steroids

86. Requests prioritization

87. Client Server

88. Client Server

89. Client Server

90. Client Server

91. Compression

92. Extended compression

93. Multiplexing

94. Client Server
R/R model

95. Client Server
R/R model

96. Client Server
R/R model

97. Client Server
Pipelining

98. Client Server
Pipelining

99. Client Server
Multiplexing

100. Client Server
Multiplexing

101. Client Server
Multiplexing

102. Server push

103. Result?

105. SPDY

106. HTTP
SPDY

107. Not-so-side effect?

108. 13 years later...

109. HTTP/2.0

111. Based on?

112. SPDY
http://lists.w3.org/Archives/Public/ietf-http-wg/2012OctDec/0004.html
http://www.slideshare.net/mnot/what-http20-will-do-for-you

113. Which is based on?

114. HTTP/1.1

115. SPDY doesnt change the protocol,
it just changes the way messages are
exchanged over the wire

116. Semantics are the same.

117. Workflows are the same.

118. Verbs are the same.

119. The interface is the same.

120. And HTTP/1.1 is based on?

121. HTTP/1.0

122. 15

123. damn

124. years

125. Ago

126. PERIOD.

127. An architecture that lasts 20 years is possible.

128. ( REST )

129. You?

130. Alex Nadalin

131. Alex Nadalin
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132. Alex Nadalin
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133. Alex Nadalin
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134. Alex Nadalin
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135. Alex Nadalin
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136. Alex Nadalin
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137. We're hiring!

138. In Dubai.

139. In Dubai.
alex.nadalin@namshi.com

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141. In Dubai.
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