[PyCon SE 2016] HTTP/2 and Asynchronous APIs

HTTP/2 (H2) is coming, and along with it a whole new way of communicating over the web. Connection re-use, prioritization, multiplexing, and server push are just some of the features in H2.

In this talk we'll look at the HTTP/2 protocol, and at how we can use asynchronous request now with HTTP/1.x. We will also look at what asynchronous requests and H2 mean for your API and clients in the future.

Transcript

1. H T T P/ 2 A N D A SY N C H R O N O U S A P I S
2. D AV E Y S H A F I K • Developer • Author • Open Source Contributor • @dshafik
3. h tt p : / /d e v e l o p e r. a ka m a i .co m
4. Let’s start a conversation about mental health in tech mhprompt.org
5. H T T P/ 2 A KA : H 2
7. W H AT I S H T T P/ 2 ? CC-BY: Marco Bellucci
8. R F C 7 5 4 0 H Y P E RT E XT T R A N S F E R P R OTO CO L V E RS I O N 2
9. R F C 7 5 4 1 H PA C K - H E A D E R CO M P R E SS I O N FO R H T T P/ 2
10. C R E AT E D BY I E T F H T T P W O R K I N G G R O U P C H A I R E D BY A K A M A I ' S M A R K N OT T I N G H A M
11. CC-BY: mrbill 1991 HTTP/0.9
12. CC-BY: mrbill 1991 1996 HTTP/0.9 HTTP/1.0
13. CC-BY: mrbill 1991 1996 1999 HTTP/0.9 HTTP/1.0 HTTP/1.1
14. CC-BY: mrbill 1991 1996 1999 HTTP/0.9 HTTP/1.0 HTTP/1.1 2009 SPDY
15. –J O H N N Y A P P L E S E E D CC-BY: mrbill 1991 1996 1999 HTTP/0.9 HTTP/1.0 HTTP/1.1 2015 HTTP/2 2009 SPDY
16. B R O W S E R S U P P O RT
17. B R O W S E R S U P P O RT • Chrome + Chrome Mobile • Firefox • IE 11 on Windows 10 • MS Edge • Safari (El Capitan/iOS 9) • Opera
18. B I N A R Y I N ST E A D O F T E XT CC-BY: brett jordan
19. F U L LY M U LT I P L E X E D CC-BY: vadikunc I N S T E A D O F O R D E R E D A N D B L O C K I N G
20. C A N US E O N E CO N N E CT I O N 
 FO R PA R A L L E L R E Q U E STS CC-BY: Alosh Bennett
21. US E S H E A D E R CO M P R E SS I O N CC-BY-SA: Magnus Hagdorn R E D U C E S O V E R H E A D
22. S E R V E R P U S H I S S U P E R CO O L ( N O R E A L LY ) CC-BY-SA: Takeshi
23. S E R V E R P U S H • Allows the server to proactively push assets like stylesheets and images to the client without them needing to parse the HTML page and make subsequent requests • Done by pushing the assets into the client cache, avoiding the roundtrip necessary to pull them up once the client makes the request
24. W H AT D O E S H T T P/ 2 M E A N F O R M Y A P P L I C AT I O N ?
25. T R A N S PA R E N T CC-BY-SA: Patty H A N D L E D B Y N G I N X / A PA C H E
26. S O W H AT ’ S T H E P O I N T ?
27. H T T P/ 1 . X S U C K S CC-BY: Flóra Soós
28. H T T P/ 1 . X S U C K S • Minify + Concat JavaScript and CSS • Inlining small JavaScript and CSS • Using image sprites • Using data: URIs • Domain sharding
29. T H E S E T H I N G S A R E A L L " C L E V E R " H AC K S CC-BY: Matt Biddulph
30. R E M E M B E R T H I S ? CC-BY: Alosh Bennett C A N US E O N E CO N N E CT I O N 
 FO R PA R A L L E L R E Q U E STS
31. U P LO A D I N G M U LT I P L E I M A G E S CC-BY: John Trainor
32. S E R I A L U P LO A D S Ȑ
33. S E R I A L U P LO A D S Ȑ
34. S E R I A L U P LO A D S Ȑ
35. S E R I A L U P LO A D S Ȑ 
36. S E R I A L U P LO A D S Ȑ 
37. S E R I A L U P LO A D S Ȑ  
38. S E R I A L U P LO A D S Ȑ   
39. CO N CU R R E N T Ȑ 
40. CO N CU R R E N T Ȑ 
41. CO N CU R R E N T Ȑ 
42. CO N CU R R E N T Ȑ 
43. CO N CU R R E N T Ȑ 
44. A P I S
45. F E TC H I N G A B LO G P O ST + CO M M E N TS CC-BY: John Trainor
46. Ȑ
47. Ȑ
48. Ȑ GET /post/1
49. Ȑ GET /post/1 200 OK application/json
50. { "type": "post", "id": "1", "title": "JSON API paints my bikeshed!", "tags": ["json", "api", "relationships"], "author": "http://example.com/posts/1/author", "comments": "http://example.com/posts/1/comments" }
51. Ȑ
52. Ȑ
53. Ȑ GET /posts/1/comments
54. Ȑ GET /posts/1/comments 200 OK application/json
55. [ "http://example.org/post/1/comment/1", "http://example.org/post/1/comment/2", "http://example.org/post/1/comment/3", "http://example.org/post/1/comment/4" ]
56. Ȑ
57. Ȑ
58. Ȑ GET /post/example/comments/1
59. Ȑ GET /post/example/comments/ 200 OK application/json 1
60. 2 Ȑ GET /post/example/comments/ 200 OK application/json 1
61. 2 3 Ȑ GET /post/example/comments/ 200 OK application/json 1
62. 2 3 4 Ȑ GET /post/example/comments/ 200 OK application/json 1
63. { "type": "comment", "id": "1", "title": "FIRST!", "author": "http://example.com/post/1/comment/1/author" }
64. 6 requests (possibly connections)
65. 14 requests (possibly connections)
66. M U LT I P L E X E D Ȑ
67. M U LT I P L E X E D Ȑ GET /post/example/comments/3
68. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1
69. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1 GET /post/example/comments/2
70. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1 GET /post/example/comments/2 200 OK application/json
71. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1 GET /post/example/comments/2 200 OK application/json 200 OK application/json
72. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1 GET /post/example/comments/2 200 OK application/json 200 OK application/json 200 OK application/json
73. CO D E
74. num_requests = 378;
76. H T T P/ 1 . 1 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
77. H T T P/ 1 . 1 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
78. import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close() H T T P/ 1 . 1 : SY N C H R O N O US
79. import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close() H T T P/ 1 . 1 : SY N C H R O N O US
80. H T T P/ 1 . 1 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
81. 2 0 
 s e co n d s CC-BY: Hernán Piñera
82. H T T P/ 2 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
83. H T T P/ 2 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
84. H T T P/ 2 : SY N C H R O N O US import pycurl from StringIO import StringIO for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) c.perform() c.close()
85. 3 4 
 s e co n d s CC-BY-NC: Scott Beckner
86. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 1) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 1 . 1 : CO N CU R R E N T
87. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 1) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 1 . 1 : CO N CU R R E N T
88. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 1) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 1 . 1 : CO N CU R R E N T
89. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 1) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 1 . 1 : CO N CU R R E N T
90. H T T P/ 1 . 1 : CO N CU R R E N T ( CO N T. ) while True: ret, num_handles = m.perform() if ret != pycurl.E_CALL_MULTI_PERFORM: break while num_handles: ret = m.select(1.0) if ret == -1: continue while True: ret, num_handles = m.perform() if ret != pycurl.E_CALL_MULTI_PERFORM: break
91. 6 
 s e co n d s
92. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 2) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 2 : M U LT I P L E X E D
93. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 2) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 2 : M U LT I P L E X E D
94. import pycurl from StringIO import StringIO m = pycurl.CurlMulti() m.setopt(m.M_PIPELINING, 2) m.handles = [] for i in range(0, num_requests): url = 'https://http2.akamai.com/demo/tile-%d.png' % i buffer = StringIO() c = pycurl.Curl() c.setopt(c.URL, url) c.setopt(c.HTTP_VERSION, c.CURL_HTTP_VERSION_2_0) c.setopt(c.WRITEDATA, buffer) m.handles.append(c) m.add_handle(c) H T T P/ 2 : M U LT I P L E X E D
95. H T T P/ 2 : M U LT I P L E X E D ( CO N T. ) while True: ret, num_handles = m.perform() if ret != pycurl.E_CALL_MULTI_PERFORM: break while num_handles: ret = m.select(1.0) if ret == -1: continue while True: ret, num_handles = m.perform() if ret != pycurl.E_CALL_MULTI_PERFORM: break
96. 4 
 s e co n d s CC-BY: motoracereports
97. H T T P/ 2 N E G OT I AT I O N CC-BY-ND: dhendrix73
98. P R OTO CO L I D E N T I F I E RS • h2 — HTTP/2 over TLS, negotiated via ALPN (Application-Layer Protocol Negotiation) • h2c — HTTP/2 over TCP (plain text), uses an HTTP/1.1 request with a 101 Switching Protocols status response if supported
99. – W I K I P E D I A /A P P L I C AT I O N - L AY E R _ P R OTO CO L _ N E G OT I AT I O N Application-Layer Protocol Negotiation (ALPN) is a Transport Layer Security (TLS) extension for application layer protocol negotiation. ALPN allows the application layer to negotiate which protocol should be performed over a secure connection in a manner which avoids additional round trips and which is independent of the application layer protocols. It is used by HTTP/2. […] On July 11, 2014, ALPN was published as RFC 7301
100. H 2 C U P G R A D E N E G OT I AT I O N > GET / HTTP/1.1 > Host: server.example.com > Connection: Upgrade, HTTP2-Settings > Upgrade: h2c > HTTP2-Settings: <base64url SETTINGS payload> < HTTP/1.1 101 Switching Protocols < Connection: Upgrade < Upgrade: h2c < < [ HTTP/2 connection ...
101. H 2 C U P G R A D E N E G OT I AT I O N ( CO N T. ) • May be an OPTIONS request if concurrency of multiple requests is important • May be any request type (e.g. PUT/POST/GET/HEAD/DELETE) but any body must be sent in it's entirety before HTTP/2 can start • A server must ignore an "h2" token in an Upgrade header field. Presence of a token with "h2" implies HTTP/2 over TLS, which is instead negotiated via TLS-ALPN • It must include a settings payload with the initial request
102. A L L B R O W S E RS R E Q U I R E T LS FO R H T T P/ 2 CC-BY: Jason Baker
103. D I R E CT CO N N E CT W I T H H T T P/ 2
104. P R I O R K N O W L E D G E • It is possible to set up a connection with HTTP/1.1 or ALPN negotiation when prior knowledge of HTTP/2 is known • Performance enhancement • Client/Server must send the HTTP/2 connection prefix • Not supported in curl yet
105. S E R V E R P US H CC-BY: Steven Depolo
106. M U LT I P L E X E D Ȑ GET /post/example/comments/3 GET /post/example/comments/1 GET /post/example/comments/2 200 OK application/json 200 OK application/json 200 OK application/json
107. ST I L L M A K I N G S U B - R E Q U E STS
108. { "type": "post", "id": "1", "title": "JSON API paints my bikeshed!", "tags": ["json", "api", "relationships"], "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" }, "comments": [ { "type": "comment", "id": "1", "content": "FIRST!", "author": { "type": "author", "id": 2, "name": "Jill Random", "gravatar": "706b16b2fb732ab6079a10fea61d078b" } }, { "type": "comment", "id": "2", "content": "second", "author": { "type": "author", "id": 3, "name": "John Person", "gravatar": "8e2279479945ca4778eb3cb8d88cda58" } }, { "type": "comment", "id": "3", "content": "third", "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" } }, { "type": "comment", "id": "4", "content": "fourth", "author": { "type": "author", "id": 2, "name": "Jill Random", "gravatar": "706b16b2fb732ab6079a10fea61d078b" } } ] }
109. { "type": "post", "id": "1", "title": "JSON API paints my bikeshed!", "tags": ["json", "api", "relationships"], "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" }, "comments": [ { "type": "comment", "id": "1",
110. { "type": "post", "id": "1", "title": "JSON API paints my bikeshed!", "tags": ["json", "api", "relationships"], "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" }, "comments": [ { "type": "comment", "id": "1",
111. "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" }, "comments": [ { "type": "comment", "id": "1", "content": "FIRST!", "author": { "type": "author", "id": 2, "name": "Jill Random", "gravatar": "706b16b2fb732ab6079a10fea61d078b" } }, { "type": "comment", "id": "2",
112. } }, { "type": "comment", "id": "3", "content": "third", "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" } }, { "type": "comment", "id": "4",
113. } }, { "type": "comment", "id": "3", "content": "third", "author": { "type": "author", "id": 1, "name": "Davey Shafik", "twitter": "@dshafik", "gravatar": "fee39f0c0ffb29d9ac21607ed188be6b" } }, { "type": "comment", "id": "4",
114. } }, { "type": "comment", "id": "4", "content": "fourth", "author": { "type": "author", "id": 2, "name": "Jill Random", "gravatar": "706b16b2fb732ab6079a10fea61d078b" } } ] }
115. Ȑ
116. Ȑ
117. Ȑ GET /post/1
118. Ȑ GET /post/1 200 OK application/json
119. GET /post/1/comments Ȑ GET /post/1 200 OK application/json
120. GET /post/1/comments GET /post/1/comment/1 Ȑ GET /post/1 200 OK application/json
121. Ȑ GET /post/1/comments GET /post/1/comment/1
122. Ȑ GET /post/1/comment/2 GET /post/1/comment/3 GET /post/1/comment/4 GET /post/1/comments GET /post/1/comment/1
123. Ȑ GET /post/1/comment/2 GET /post/1/comment/3 GET /post/1/comment/4 GET /post/1/comment/1/author GET /post/1/comment/2/author GET /post/1/comment/3/author GET /post/1/comment/4/author GET /post/1/comments GET /post/1/comment/1
124. Ȑ GET /post/1/comment/2 GET /post/1/comment/3 GET /post/1/comment/4 GET /post/1/comment/1/author GET /post/1/comment/2/author GET /post/1/comment/3/author GET /post/1/comment/4/author GET /post/1/comment/1/author/avatar.png GET /post/1/comment/2/author/avatar.png GET /post/1/comment/3/author/avatar.png GET /post/1/comment/4/author/avatar.png GET /post/1/comments GET /post/1/comment/1
125. CSS /J S M I N I F I C AT I O N I S U N E C E SS A R Y CC-BY: Patrick Metzdorf G Z I P CO M P R E SS I O N + M U LT I P L E X I N G + S E R V E R P US H
126. ST R E A M S CC-BY: Kylir Horton
127. ST R E A M S • Each request/response is a stream • Streams are comprised of Frames • Streams may have a weight (1-256) • Streams may have a dependency
128. ST R E A M W E I G H TS Stream A Weight: 1 Stream B Weight: 2 Stream C Weight: 3 2X Stream A 1.5X Stream B
 3X Stream A
129. ST R E A M D E P E N D E N C I E S Stream A Stream B Depends: A Stream C Depends: B Delivered after A Delivered after B
130. F R A M E S CC-BY: Bart Everson
131. F R A M E S • Messages are composed of multiple frames, e.g. headers, data, and settings • Each frame has a common header • 9 byte, length prefixed • Easy & efficient to parse • Frames can be interleaved — this is multiplexing
132. F R A M E S POST /search HTTP/1.1 Host: example.org Content-Type: application/json Content-Length: 58 {
 "keywords":"example",
 "location":"posts"
 } HEADERS
 frame Data
 frame } }
133. H E A D E RS : H PAC K CC-BY-SA: intelligente_persona
134. H E A D E RS : H PA C K • Uses a table of known values as an index • Can represent a header name and value (e.g. :status: 404), or just a header name (e.g. accept:) • Values are either statically encoded, or use a static Huffman code
135. # Name Value 1 :authority 2 :method GET 3 :method POST 4 :path / 5 :path /index.html 6 :scheme http 7 :scheme https 8 :status 200 9 :status 204 10 :status 206 11 :status 304 12 :status 400 13 :status 404 14 :status 500 15 accept-charset
136. I N S U M M A R Y
137. N O M O R E H AC K S !
138. H U G E P E R FO R M A N C E W I N S
139. 6 0 % + M A R K E T S H A R E
140. H T T P / 2 I S A W E S O M E ! CC-BY-SA: Steven Gerner
141. F E E D B A C K & Q U E S T I O N S Twitter: Email: Slides: @dshafik dshafik@akamai.com http://daveyshafik.com/slides