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
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
|
<!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">
<title>Nine Nines: cowboy_req(3)</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=7" 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="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>cowboy_req(3)</span></h1>
<h2 id="_name">Name</h2>
<p>cowboy_req - HTTP request and response</p>
<h2 id="_description">Description</h2>
<p>The module <code>cowboy_req</code> provides functions to access, manipulate and respond to requests.</p>
<p>There are four types of functions in this module. They can be differentiated by their name and their return type:</p>
<table rules="all" width="100%" frame="border"
cellspacing="0" cellpadding="4">
<thead><tr><th>Type</th>
<th>Name pattern</th>
<th>Return type</th>
</tr></thead><tbody><tr><td>access</td>
<td>no verb, parse_*, match_*</td>
<td><code>Value</code></td>
</tr>
<tr><td>question</td>
<td>has_*</td>
<td><code>boolean()</code></td>
</tr>
<tr><td>modification</td>
<td>set_*</td>
<td><code>Req</code></td>
</tr>
<tr><td>action</td>
<td>any other verb</td>
<td><code>ok | {Result, Value, Req}</code></td>
</tr>
</tbody></table>
<p>Any <code>Req</code> returned must be used in place of the one passed as argument. Functions that perform an action in particular write state in the Req object to make sure you are using the function correctly. For example, it's only possible to send one response, and to read the body once.</p>
<h2 id="_exports">Exports</h2>
<p>Connection:</p>
<ul><li><a href="../cowboy_req.peer">cowboy_req:peer(3)</a> - Peer address and port
</li>
<li><a href="../cowboy_req.sock">cowboy_req:sock(3)</a> - Socket address and port
</li>
<li><a href="../cowboy_req.cert">cowboy_req:cert(3)</a> - Client TLS certificate
</li>
</ul>
<p>Raw request:</p>
<ul><li><a href="../cowboy_req.method">cowboy_req:method(3)</a> - HTTP method
</li>
<li><a href="../cowboy_req.version">cowboy_req:version(3)</a> - HTTP version
</li>
<li><a href="../cowboy_req.scheme">cowboy_req:scheme(3)</a> - URI scheme
</li>
<li><a href="../cowboy_req.host">cowboy_req:host(3)</a> - URI host name
</li>
<li><a href="../cowboy_req.port">cowboy_req:port(3)</a> - URI port number
</li>
<li><a href="../cowboy_req.path">cowboy_req:path(3)</a> - URI path
</li>
<li><a href="../cowboy_req.qs">cowboy_req:qs(3)</a> - URI query string
</li>
<li><a href="../cowboy_req.uri">cowboy_req:uri(3)</a> - Reconstructed URI
</li>
<li><a href="../cowboy_req.header">cowboy_req:header(3)</a> - HTTP header
</li>
<li><a href="../cowboy_req.headers">cowboy_req:headers(3)</a> - HTTP headers
</li>
</ul>
<p>Processed request:</p>
<ul><li><a href="../cowboy_req.parse_qs">cowboy_req:parse_qs(3)</a> - Parse the query string
</li>
<li><a href="../cowboy_req.match_qs">cowboy_req:match_qs(3)</a> - Match the query string against constraints
</li>
<li><a href="../cowboy_req.parse_header">cowboy_req:parse_header(3)</a> - Parse the given HTTP header
</li>
<li><a href="../cowboy_req.filter_cookies">cowboy_req:filter_cookies(3)</a> - Filter cookie headers
</li>
<li><a href="../cowboy_req.parse_cookies">cowboy_req:parse_cookies(3)</a> - Parse cookie headers
</li>
<li><a href="../cowboy_req.match_cookies">cowboy_req:match_cookies(3)</a> - Match cookies against constraints
</li>
<li><a href="../cowboy_req.binding">cowboy_req:binding(3)</a> - Access a value bound from the route
</li>
<li><a href="../cowboy_req.bindings">cowboy_req:bindings(3)</a> - Access all values bound from the route
</li>
<li><a href="../cowboy_req.host_info">cowboy_req:host_info(3)</a> - Access the route's heading host segments
</li>
<li><a href="../cowboy_req.path_info">cowboy_req:path_info(3)</a> - Access the route's trailing path segments
</li>
</ul>
<p>Request body:</p>
<ul><li><a href="../cowboy_req.has_body">cowboy_req:has_body(3)</a> - Is there a request body?
</li>
<li><a href="../cowboy_req.body_length">cowboy_req:body_length(3)</a> - Body length
</li>
<li><a href="../cowboy_req.read_body">cowboy_req:read_body(3)</a> - Read the request body
</li>
<li><a href="../cowboy_req.read_urlencoded_body">cowboy_req:read_urlencoded_body(3)</a> - Read and parse a urlencoded request body
</li>
<li><a href="../cowboy_req.read_and_match_urlencoded_body">cowboy_req:read_and_match_urlencoded_body(3)</a> - Read, parse and match a urlencoded request body against constraints
</li>
<li><a href="../cowboy_req.read_part">cowboy_req:read_part(3)</a> - Read the next multipart headers
</li>
<li><a href="../cowboy_req.read_part_body">cowboy_req:read_part_body(3)</a> - Read the current part's body
</li>
</ul>
<p>Response:</p>
<ul><li><a href="../cowboy_req.set_resp_cookie">cowboy_req:set_resp_cookie(3)</a> - Set a cookie
</li>
<li><a href="../cowboy_req.set_resp_header">cowboy_req:set_resp_header(3)</a> - Set a response header
</li>
<li><a href="../cowboy_req.set_resp_headers">cowboy_req:set_resp_headers(3)</a> - Set several response headers
</li>
<li><a href="../cowboy_req.has_resp_header">cowboy_req:has_resp_header(3)</a> - Is the given response header set?
</li>
<li><a href="../cowboy_req.resp_header">cowboy_req:resp_header(3)</a> - Response header
</li>
<li><a href="../cowboy_req.resp_headers">cowboy_req:resp_headers(3)</a> - Response headers
</li>
<li><a href="../cowboy_req.delete_resp_header">cowboy_req:delete_resp_header(3)</a> - Delete a response header
</li>
<li><a href="../cowboy_req.set_resp_body">cowboy_req:set_resp_body(3)</a> - Set the response body
</li>
<li><a href="../cowboy_req.has_resp_body">cowboy_req:has_resp_body(3)</a> - Is there a response body?
</li>
<li><a href="../cowboy_req.inform">cowboy_req:inform(3)</a> - Send an informational response
</li>
<li><a href="../cowboy_req.reply">cowboy_req:reply(3)</a> - Send the response
</li>
<li><a href="../cowboy_req.stream_reply">cowboy_req:stream_reply(3)</a> - Send the response headers
</li>
<li><a href="../cowboy_req.stream_body">cowboy_req:stream_body(3)</a> - Stream the response body
</li>
<li><a href="../cowboy_req.stream_events">cowboy_req:stream_events(3)</a> - Stream events
</li>
<li><a href="../cowboy_req.stream_trailers">cowboy_req:stream_trailers(3)</a> - Send the response trailers
</li>
<li><a href="../cowboy_req.push">cowboy_req:push(3)</a> - Push a resource to the client
</li>
</ul>
<p>Stream handlers:</p>
<ul><li><a href="../cowboy_req.cast">cowboy_req:cast(3)</a> - Cast a stream handler event
</li>
</ul>
<h2 id="_types">Types</h2>
<h3 id="_push_opts">push_opts()</h3>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">push_opts</font></b>() <font color="#990000">::</font> #{
<font color="#0000FF">method</font> <font color="#990000">=></font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% case sensitive</font></i>
<font color="#0000FF">scheme</font> <font color="#990000">=></font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% lowercase; case insensitive</font></i>
<font color="#0000FF">host</font> <font color="#990000">=></font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% lowercase; case insensitive</font></i>
<font color="#0000FF">port</font> <font color="#990000">=></font> <b><font color="#000000">inet:port_number</font></b>(),
<font color="#0000FF">qs</font> <font color="#990000">=></font> <b><font color="#000080">binary</font></b>() <i><font color="#9A1900">%% case sensitive</font></i>
}</tt></pre>
</div></div>
<p>Push options.</p>
<p>By default, Cowboy will use the GET method, an empty query string, and take the scheme, host and port directly from the current request's URI.</p>
<h3 id="_read_body_opts">read_body_opts()</h3>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">read_body_opts</font></b>() <font color="#990000">::</font> #{
<b><font color="#000080">length</font></b> <font color="#990000">=></font> <b><font color="#000000">non_neg_integer</font></b>(),
<font color="#0000FF">period</font> <font color="#990000">=></font> <b><font color="#000000">non_neg_integer</font></b>(),
<font color="#0000FF">timeout</font> <font color="#990000">=></font> <b><font color="#000000">timeout</font></b>()
}</tt></pre>
</div></div>
<p>Body reading options.</p>
<p>The defaults are function-specific.</p>
<h3 id="_req">req()</h3>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">req</font></b>() <font color="#990000">::</font> #{
<font color="#FF6600">method</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% case sensitive</font></i>
<font color="#FF6600">version</font> <font color="#990000">:=</font> <b><font color="#000000">cowboy:http_version</font></b>() | <b><font color="#000080">atom</font></b>(),
<font color="#FF6600">scheme</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% lowercase; case insensitive</font></i>
<font color="#FF6600">host</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% lowercase; case insensitive</font></i>
<font color="#FF6600">port</font> <font color="#990000">:=</font> <b><font color="#000000">inet:port_number</font></b>(),
<font color="#FF6600">path</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% case sensitive</font></i>
<font color="#FF6600">qs</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>(), <i><font color="#9A1900">%% case sensitive</font></i>
<font color="#FF6600">headers</font> <font color="#990000">:=</font> <b><font color="#000000">cowboy:http_headers</font></b>(),
<font color="#FF6600">peer</font> <font color="#990000">:=</font> {<b><font color="#000000">inet:ip_address</font></b>(), <b><font color="#000000">inet:port_number</font></b>()},
<font color="#FF6600">sock</font> <font color="#990000">:=</font> {<b><font color="#000000">inet:ip_address</font></b>(), <b><font color="#000000">inet:port_number</font></b>()},
<font color="#FF6600">cert</font> <font color="#990000">:=</font> <b><font color="#000080">binary</font></b>() | <font color="#000080">undefined</font>
}</tt></pre>
</div></div>
<p>The Req object.</p>
<p>Contains information about the request and response. While some fields are publicly documented, others aren't and shouldn't be used.</p>
<p>You may add custom fields if required. Make sure to namespace them by prepending an underscore and the name of your application:</p>
<div class="listingblock"><div class="title">Setting a custom field</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><font color="#009900">Req</font>#{<font color="#FF6600">'_myapp_auth_method'</font> <font color="#990000">=></font> <font color="#FF6600">pubkey</font>}<font color="#990000">.</font></tt></pre>
</div></div>
<h3 id="_resp_body">resp_body()</h3>
<div class="listingblock"><div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><b><font color="#000000">resp_body</font></b>() <font color="#990000">::</font> <b><font color="#000000">iodata</font></b>()
| {<font color="#FF6600">sendfile</font>, <font color="#009900">Offset</font>, <font color="#009900">Length</font>, <font color="#009900">Filename</font>}
<font color="#009900">Offset</font> <font color="#990000">::</font> <b><font color="#000000">non_neg_integer</font></b>()
<font color="#009900">Length</font> <font color="#990000">::</font> <b><font color="#000000">non_neg_integer</font></b>()
<font color="#009900">Filename</font> <font color="#990000">::</font> <b><font color="#000000">file:name_all</font></b>()</tt></pre>
</div></div>
<p>Response body.</p>
<p>It can take two forms: the actual data to be sent or a tuple indicating which file to send.</p>
<p>When sending data directly, the type is either a binary or an iolist. Iolists are an efficient way to build output. Instead of concatenating strings or binaries, you can simply build a list containing the fragments you want to send in the order they should be sent:</p>
<div class="listingblock"><div class="title">Example iolists usage</div>
<div class="content"><!-- Generator: GNU source-highlight 3.1.9
by Lorenzo Bettini
http://www.lorenzobettini.it
http://www.gnu.org/software/src-highlite -->
<pre><tt><font color="#993399">1</font><font color="#990000">></font> <font color="#009900">RespBody</font> <font color="#990000">=</font> [<font color="#FF0000">"Hello "</font>, [<font color="#990000"><<</font><font color="#FF0000">"world"</font><font color="#990000">>></font>, <font color="#FF0000">$!</font>]]<font color="#990000">.</font>
[<font color="#FF0000">"Hello "</font>,[<font color="#990000"><<</font><font color="#FF0000">"world"</font><font color="#990000">>></font>,<font color="#993399">33</font>]]
<font color="#993399">2</font><font color="#990000">></font> <b><font color="#000000">io:format</font></b>(<font color="#FF0000">"~s~n"</font>, [<font color="#009900">RespBody</font>])<font color="#990000">.</font>
<font color="#009900">Hello</font> <font color="#FF6600">world</font><font color="#990000">!</font></tt></pre>
</div></div>
<p>Note that the length must be greater than zero for any data to be sent. Cowboy will send an empty body when the length is zero.</p>
<h2 id="_see_also">See also</h2>
<p><a href="..">cowboy(7)</a></p>
</div>
<div class="span3 sidecol">
<h3>
Cowboy
2.9
Function Reference
</h3>
<ul>
<li><a href="/docs/en/cowboy/2.9/guide">User Guide</a></li>
<li><a href="/docs/en/cowboy/2.9/manual">Function Reference</a></li>
</ul>
<h4 id="docs-nav">Navigation</h4>
<h4>Version select</h4>
<ul>
<li><a href="/docs/en/cowboy/2.9/manual">2.9</a></li>
<li><a href="/docs/en/cowboy/2.8/manual">2.8</a></li>
<li><a href="/docs/en/cowboy/2.7/manual">2.7</a></li>
<li><a href="/docs/en/cowboy/2.6/manual">2.6</a></li>
<li><a href="/docs/en/cowboy/2.5/manual">2.5</a></li>
<li><a href="/docs/en/cowboy/2.4/manual">2.4</a></li>
</ul>
<h3 id="_like_my_work__donate">Like my work? Donate!</h3>
<p>Donate to Loïc Hoguin because his work on Cowboy, Ranch, Gun and Erlang.mk is fantastic:</p>
<form action="https://www.paypal.com/cgi-bin/webscr" method="post" style="display:inline">
<input type="hidden" name="cmd" value="_donations">
<input type="hidden" name="business" value="[email protected]">
<input type="hidden" name="lc" value="FR">
<input type="hidden" name="item_name" value="Loic Hoguin">
<input type="hidden" name="item_number" value="99s">
<input type="hidden" name="currency_code" value="EUR">
<input type="hidden" name="bn" value="PP-DonationsBF:btn_donate_LG.gif:NonHosted">
<input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donate_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<img alt="" border="0" src="https://www.paypalobjects.com/fr_FR/i/scr/pixel.gif" width="1" height="1">
</form><p>Recurring payment options are also available via <a href="https://github.com/sponsors/essen">GitHub Sponsors</a>. These funds are used to cover the recurring expenses like food, dedicated servers or domain names.</p>
</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 2012-2018</p>
</div>
</div>
</div>
</footer>
<script src="/js/custom.js"></script>
</body>
</html>
|
