summaryrefslogtreecommitdiffstats
path: root/docs/en/cowboy/1.0/manual/cowboy_middleware/index.html
blob: 6e0f87a373d5672b50c2cfa240f20eff2416113d (plain) (blame)
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
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>Nine Nines Support: Cowboy Function Reference</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- Change them or set them up as you like -->
    <meta name="description" content="">
    <meta name="author" content="(Soft10) Pol Cámara">

    <!-- Stylesheets -->    
    <link href='http://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'>
    <link href="/css/bootstrap.min.css" rel="stylesheet">
    <link href="/css/99s.css" rel="stylesheet">
<!--    <link href="js/google-code-prettify/prettify.css" rel="stylesheet"> -->
    <link href="/css/sh99s.css"  rel="stylesheet"/>

    <!-- Enables html5 support on older browsers, other js is placed at the end of the page to speed up loading -->
    <!--[if lt IE 9]>
      <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->

    <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">
	<link rel="alternate" href="/feeds/atom.xml" type="application/atom+xml" title="Nine Nines Atom Feed">
  </head>

  <body class="big_text docs">
    <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">
              <!-- Top navigation and social icons-->
              <div id="side-header">
                <nav>
                  <ul>
					<li><a title="Erlang training" href="/training">Training</a></li>
                    <li><a title="Technical publications" href="/articles">Articles</a></li>
					<li><a title="Our talks" href="/talks">Talks</a></li>
					<li class="active"><a title="Our services" href="/support">Pricing &amp; Sponsoring</a></li>
					<li><a title="Community support" href="https://ninenines.eu/archives/extend/">Mailing Lists</a></li>
                    <li><a title="Contact us" href="mailto:[email protected]">Contact</a></li>
                  </ul>
                </nav> 
                <ul id="social">
                  <li>
                    <a href="https://github.com/ninenines" title="Check our Github repositories"><img src="/img/ico_github.png" data-hover="/img/ico_github_alt.png" alt="Github"></a>
                  </li>
                  <li class="dropdown" id="twitter-links">
                    <a href="#twitter-links" class="dropdown-toggle" data-toggle="dropdown"  title="Follow us on Twitter">
                        <img src="/img/ico_microblog.png" data-hover="/img/ico_microblog_alt.png" alt="Twitter">
                    </a>                 
                    <ul class="dropdown-menu">
                      <li><a title="Visit Loïc Hoguin's Twitter Account" href="http://twitter.com/lhoguin">@lhoguin</a></li>
                      <!-- <li class="divider"></li>
                      <li><a title="Visit our official Twitter account" href="#">@99s</a></li> -->
                    </ul>
                  </li>
                  <!-- <li>
                    <a href="/css/" title="Add us on Linkedin"><img src="/img/ico_linkedin.png" data-hover="img/ico_linkedin_alt.png" alt="Linkedin"></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_middleware</span></h1>

<p>The <code>cowboy_middleware</code> behaviour defines the interface used by Cowboy middleware modules.</p>

<p>Middlewares process the request sequentially in the order they are configured.</p>

<h2 id="types">Types</h2>

<h3 id="env">env() = [{atom(), any()}]</h3>

<p>The environment variable.</p>

<p>One is created for every request. It is passed to each middleware module executed and subsequently returned, optionally with its contents modified.</p>

<h2 id="callbacks">Callbacks</h2>

<h3 id="execute">execute(Req, Env) -> {ok, Req, Env} | {suspend, Module, Function, Args} | {halt, Req} | {error, StatusCode, Req}</h3>

<p>Types:</p>

<ul>
<li>Req = cowboy_req:req()</li>
<li>Env = env()</li>
<li>Module = module()</li>
<li>Function = atom()</li>
<li>Args = [any()]</li>
<li>StatusCode = cowboy:http_status()</li>
</ul>

<p>Execute the middleware.</p>

<p>The <code>ok</code> return value indicates that everything went well and that Cowboy should continue processing the request. A response may or may not have been sent.</p>

<p>The <code>suspend</code> return value will hibernate the process until an Erlang message is received. Note that when resuming, any previous stacktrace information will be gone.</p>

<p>The <code>halt</code> return value stops Cowboy from doing any further processing of the request, even if there are middlewares that haven't been executed yet. The connection may be left open to receive more requests from the client.</p>

<p>The <code>error</code> return value sends an error response identified by the <code>StatusCode</code> and then proceeds to terminate the connection. Middlewares that haven't been executed yet will not be called.</p>


<!-- a.code -->
</div>

<div class="span3 sidecol">
<div class="input-append">
<form id="form-search" class="form-search" action="#">
	<input id="input-search" type="text" placeholder="Function search" autocomplete="off" autofocus class="input-medium search-query span2">
	<button type="submit" class="btn btn-success">Go</button>
</form>
</div>

<h3 id="docs-nav">Navigation</h3>

<h3>See also</h3><ul><li><a href="/docs/en/cowboy/1.0/guide/">User Guide</a></li><li><a href="/docs/en/cowboy/1.0/index.html">README</a></li></ul>

<h3>Version select</h3>
<ul>

	<li><a href="/docs/en/cowboy/1.0/manual/"><strong>1.0</strong></a></li>

	<li><a href="/docs/en/cowboy/HEAD/manual/"><strong>HEAD</strong></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 &copy; Nine Nines 2012-2014</p>
            </div>
          </div>
        </div>
      </footer>

    <!-- Javascript -->
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
    <script src="/js/bootstrap-carousel.js"></script>
    <script src="/js/bootstrap-dropdown.js"></script>
    <script src="/js/custom.js"></script>


<script type="text/javascript" src="/js/shCore.js"></script>
<script type="text/javascript" src="/js/shlang/shBrushBash.js"></script>
<script type="text/javascript" src="/js/shlang/shBrushErlang.js"></script>
<script type="text/javascript" src="/js/shlang/shBrushJScript.js"></script>
<script type="text/javascript" src="/js/shlang/shBrushPlain.js"></script>
<script type="text/javascript">SyntaxHighlighter.all();</script>

<script type="text/javascript" src="/js/fuse.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
	var f;

	$.getJSON("/docs/db.json", function(data){
		f = new Fuse(data, {keys: ["n"], threshold: 0.3});
		$("<ul id=\"search-results\">").insertAfter("#form-search");
	});

	$("#input-search").keyup(function(e){if(f){if (e.which != 13 ){
		var results = f.search($(this).val());
		if (results.length == 0){
			$("#form-search").attr("action", "#");
		}else{
			$("#form-search").attr("action", results[0].l);
		}

		$("#search-results").empty();
		for (var i = 0; i < 10 && i < results.length; i++){
			$("<li><a href=\"" + results[i].l + "\">" + results[i].n + "</a></li>")
				.appendTo("#search-results");
		}
	}}});
});
</script>

  </body>
</html>