1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
|
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta name="description" content="">
<meta name="author" content="Loïc Hoguin based on a design from (Soft10) Pol Cámara">
<meta name="generator" content="Hugo 0.17" />
<title>Nine Nines: Listeners</title>
<link href='https://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'>
<link href="/css/99s.css?r=1" rel="stylesheet">
<link rel="shortcut icon" href="/img/ico/favicon.ico">
<link rel="apple-touch-icon-precomposed" sizes="114x114" href="/img/ico/apple-touch-icon-114.png">
<link rel="apple-touch-icon-precomposed" sizes="72x72" href="/img/ico/apple-touch-icon-72.png">
<link rel="apple-touch-icon-precomposed" href="/img/ico/apple-touch-icon-57.png">
</head>
<body class="">
<header id="page-head">
<div id="topbar" class="container">
<div class="row">
<div class="span2">
<h1 id="logo"><a href="/" title="99s">99s</a></h1>
</div>
<div class="span10">
<div id="side-header">
<nav>
<ul>
<li><a title="Hear my thoughts" href="/articles">Articles</a></li>
<li><a title="Watch my talks" href="/talks">Talks</a></li>
<li class="active"><a title="Read the docs" href="/docs">Documentation</a></li>
<li><a title="Request my services" href="/services">Consulting & Training</a></li>
</ul>
</nav>
<ul id="social">
<li>
<a href="https://github.com/ninenines" title="Check my Github repositories"><img src="/img/ico_github.png" data-hover="/img/ico_github_alt.png" alt="Github"></a>
</li>
<li>
<a title="Keep in touch!" href="http://twitter.com/lhoguin"><img src="/img/ico_microblog.png" data-hover="/img/ico_microblog_alt.png"></a>
</li>
<li>
<a title="Contact me" href="mailto:[email protected]"><img src="/img/ico_mail.png" data-hover="/img/ico_mail_alt.png"></a>
</li>
</ul>
</div>
</div>
</div>
</div>
</header>
<div id="contents" class="two_col">
<div class="container">
<div class="row">
<div id="docs" class="span9 maincol">
<h1 class="lined-header"><span>Listeners</span></h1>
<div class="paragraph"><p>A listener is a set of processes that listens on a port for
new connections. Incoming connections get handled by Cowboy.
Depending on the connection handshake, one or another protocol
may be used.</p></div>
<div class="paragraph"><p>This chapter is specific to Cowboy. Please refer to the
<a href="http://ninenines.eu/docs/en/ranch/1.3/guide/listeners/">Ranch User Guide</a>
for more information about listeners.</p></div>
<div class="paragraph"><p>Cowboy provides two types of listeners: one listening for
clear TCP connections, and one listening for secure TLS
connections. Both of them support the HTTP/1.1 and HTTP/2
protocols.</p></div>
<div class="sect1">
<h2 id="_clear_tcp_listener">Clear TCP listener</h2>
<div class="sectionbody">
<div class="paragraph"><p>The clear TCP listener will accept connections on the
given port. A typical HTTP server would listen on port 80.
Port 80 requires special permissions on most platforms
however so a common alternative is port 8080.</p></div>
<div class="paragraph"><p>The following snippet starts listening for connections
on port 8080:</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #000000">start</span></span>(<span style="color: #009900">_Type</span>, <span style="color: #009900">_Args</span>) <span style="color: #990000">-></span>
<span style="color: #009900">Dispatch</span> <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_router:compile</span></span>([
{<span style="color: #FF6600">'_'</span>, [{<span style="color: #FF0000">"/"</span>, <span style="color: #FF6600">hello_handler</span>, []}]}
]),
{<span style="color: #FF6600">ok</span>, <span style="color: #990000">_</span>} <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy:start_clear</span></span>(<span style="color: #FF6600">my_http_listener</span>,
[{<span style="color: #FF6600">port</span>, <span style="color: #993399">8080</span>}],
#{<span style="color: #0000FF">env</span> <span style="color: #990000">=></span> #{<span style="color: #0000FF">dispatch</span> <span style="color: #990000">=></span> <span style="color: #009900">Dispatch</span>}}
),
<span style="font-weight: bold"><span style="color: #000000">hello_erlang_sup:start_link</span></span>()<span style="color: #990000">.</span></tt></pre></div></div>
<div class="paragraph"><p>The <a href="../getting_started">Getting Started</a> chapter uses a
clear TCP listener.</p></div>
<div class="paragraph"><p>Clients connecting to Cowboy on the clear listener port are
expected to use either HTTP/1.1 or HTTP/2.</p></div>
<div class="paragraph"><p>Cowboy supports both methods of initiating a clear
HTTP/2 connection: through the Upgrade mechanism
(<a href="https://tools.ietf.org/html/rfc7540#section-3.2">RFC 7540 3.2</a>)
or by sending the preface directly
(<a href="https://tools.ietf.org/html/rfc7540#section-3.4">RFC 7540 3.4</a>).</p></div>
<div class="paragraph"><p>Compatibility with HTTP/1.0 is provided by Cowboy’s HTTP/1.1
implementation.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_secure_tls_listener">Secure TLS listener</h2>
<div class="sectionbody">
<div class="paragraph"><p>The secure TLS listener will accept connections on the
given port. A typical HTTPS server would listen on port 443.
Port 443 requires special permissions on most platforms
however so a common alternative is port 8443.</p></div>
<div class="paragraph"><p>The function provided by Cowboy will ensure that the TLS
options given are following the HTTP/2 RFC with regards
to security. For example some TLS extensions or ciphers
may be disabled. This also applies to HTTP/1.1 connections
on this listener. If this is not desirable, Ranch can be
used directly to setup a custom listener.</p></div>
<div class="listingblock">
<div class="content"><!-- Generator: GNU source-highlight 3.1.8
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><span style="font-weight: bold"><span style="color: #000000">start</span></span>(<span style="color: #009900">_Type</span>, <span style="color: #009900">_Args</span>) <span style="color: #990000">-></span>
<span style="color: #009900">Dispatch</span> <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_router:compile</span></span>([
{<span style="color: #FF6600">'_'</span>, [{<span style="color: #FF0000">"/"</span>, <span style="color: #FF6600">hello_handler</span>, []}]}
]),
{<span style="color: #FF6600">ok</span>, <span style="color: #990000">_</span>} <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy:start_tls</span></span>(<span style="color: #FF6600">my_http_listener</span>,
[
{<span style="color: #FF6600">port</span>, <span style="color: #993399">8443</span>},
{<span style="color: #FF6600">certfile</span>, <span style="color: #FF0000">"/path/to/certfile"</span>},
{<span style="color: #FF6600">keyfile</span>, <span style="color: #FF0000">"/path/to/keyfile"</span>}
],
#{<span style="color: #0000FF">env</span> <span style="color: #990000">=></span> #{<span style="color: #0000FF">dispatch</span> <span style="color: #990000">=></span> <span style="color: #009900">Dispatch</span>}}
),
<span style="font-weight: bold"><span style="color: #000000">hello_erlang_sup:start_link</span></span>()<span style="color: #990000">.</span></tt></pre></div></div>
<div class="paragraph"><p>Clients connecting to Cowboy on the secure listener are
expected to use the ALPN TLS extension to indicate what
protocols they understand. Cowboy always prefers HTTP/2
over HTTP/1.1 when both are supported. When neither are
supported by the client, or when the ALPN extension was
missing, Cowboy expects HTTP/1.1 to be used.</p></div>
<div class="paragraph"><p>Cowboy also advertises HTTP/2 support through the older
NPN TLS extension for compatibility. Note however that
this support will likely not be enabled by default when
Cowboy 2.0 gets released.</p></div>
<div class="paragraph"><p>Compatibility with HTTP/1.0 is provided by Cowboy’s HTTP/1.1
implementation.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_protocol_configuration">Protocol configuration</h2>
<div class="sectionbody">
<div class="paragraph"><p>The HTTP/1.1 and HTTP/2 protocols share the same semantics;
only their framing differs. The first is a text protocol and
the second a binary protocol.</p></div>
<div class="paragraph"><p>Cowboy doesn’t separate the configuration for HTTP/1.1 and
HTTP/2. Everything goes into the same map. Many options are
shared.</p></div>
</div>
</div>
<nav style="margin:1em 0">
<a style="float:left" href="https://ninenines.eu/docs/en/cowboy/2.0/guide/flow_diagram/">
Flow diagram
</a>
<a style="float:right" href="https://ninenines.eu/docs/en/cowboy/2.0/guide/routing/">
Routing
</a>
</nav>
</div>
<div class="span3 sidecol">
<h3>
Cowboy
2.0
User Guide
</h3>
<ul>
<li><a href="/docs/en/cowboy/2.0/guide">User Guide</a></li>
<li><a href="/docs/en/cowboy/2.0/manual">Function Reference</a></li>
</ul>
<h4 id="docs-nav">Navigation</h4>
<h4>Version select</h4>
<ul>
<li><a href="/docs/en/cowboy/2.0/guide">2.0</a></li>
<li><a href="/docs/en/cowboy/1.0/guide">1.0</a></li>
</ul>
</div>
</div>
</div>
</div>
<footer>
<div class="container">
<div class="row">
<div class="span6">
<p id="scroll-top"><a href="#">↑ Scroll to top</a></p>
<nav>
<ul>
<li><a href="mailto:[email protected]" title="Contact us">Contact us</a></li><li><a href="https://github.com/ninenines/ninenines.github.io" title="Github repository">Contribute to this site</a></li>
</ul>
</nav>
</div>
<div class="span6 credits">
<p><img src="/img/footer_logo.png"></p>
<p>Copyright © Loïc Hoguin 2012-2016</p>
</div>
</div>
</div>
</footer>
<script src="/js/custom.js"></script>
</body>
</html>
|
