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diff --git a/docs/en/cowboy/2.0/guide/overview/index.html b/docs/en/cowboy/2.0/guide/overview/index.html deleted file mode 100644 index fb4e5cee..00000000 --- a/docs/en/cowboy/2.0/guide/overview/index.html +++ /dev/null @@ -1,297 +0,0 @@ -<!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: Request overview</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>Request overview</span></h1> - -<div class="paragraph"><p>This chapter explains the different steps a request
-goes through until a response is sent, along with
-details of the Cowboy implementation.</p></div>
-<div class="sect1">
-<h2 id="_request_response">Request/response</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>As you already know, HTTP clients connect to the server and
-send a request for a resource; the server then sends a
-response containing the resource if it could obtain it.</p></div>
-<div class="paragraph"><p>Before the server can send the resource, however, it
-needs to perform many different operations to read the
-request, find the resource, prepare the response being
-sent and often other related operations the user can
-add like writing logs.</p></div>
-<div class="paragraph"><p>Requests take the following route in Cowboy:</p></div>
-<div class="imageblock">
-<div class="content">
-<img src="../http_req_resp.png" alt="HTTP request/response flowchart" />
-</div>
-</div>
-<div class="paragraph"><p>This shows the default middlewares, but they may be
-configured differently in your setup. The dark green
-indicates the points where you can hook your own code,
-the light green is the Cowboy code that you can of
-course configure as needed.</p></div>
-<div class="paragraph"><p>The <code>acceptor</code> is the part of the server that accepts
-the connection and create an Erlang process to handle
-it. The <code>parser</code> then starts reading from the socket
-and handling requests as they come until the socket
-is closed.</p></div>
-<div class="paragraph"><p>A response may be sent at many different points in the
-life of the request. If Cowboy can’t parse the request,
-it gives up with an error response. If the router can’t
-find the resource, it sends a not found error. Your
-own code can of course send a response at any time.</p></div>
-<div class="paragraph"><p>When a response is sent, you can optionally modify it
-or act upon it by enabling the <code>onresponse</code> hook. By
-default the response is sent directly to the client.</p></div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_and_then">And then?</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>Behavior depends on what protocol is in use.</p></div>
-<div class="paragraph"><p>HTTP/1.0 can only process one request per connection,
-so Cowboy will close the connection immediately after
-it sends the response.</p></div>
-<div class="paragraph"><p>HTTP/1.1 allows the client to request that the server
-keeps the connection alive. This mechanism is described
-in the next section.</p></div>
-<div class="paragraph"><p>HTTP/2 is designed to allow sending multiple requests
-asynchronously on the same connection. Details on what
-this means for your application is described in this
-chapter.</p></div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_keep_alive_http_1_1">Keep-alive (HTTP/1.1)</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>With HTTP/1.1, the connection may be left open for
-subsequent requests to come. This mechanism is called
-<code>keep-alive</code>.</p></div>
-<div class="paragraph"><p>When the client sends a request to the server, it includes
-a header indicating whether it would like to leave the
-socket open. The server may or may not accept, indicating
-its choice by sending the same header in the response.</p></div>
-<div class="paragraph"><p>Cowboy will include this header automatically in all
-responses to HTTP/1.1 requests. You can however force
-the closing of the socket if you want. When Cowboy sees
-you want to send a <code>connection: close</code> header, it will
-not override it and will close the connection as soon
-as the reply is sent.</p></div>
-<div class="paragraph"><p>This snippet will force Cowboy to close the connection.</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="color: #009900">Req2</span> <span style="color: #990000">=</span> <span style="font-weight: bold"><span style="color: #000000">cowboy_req:reply</span></span>(<span style="color: #993399">200</span>, [
- {<span style="color: #990000"><<</span><span style="color: #FF0000">"connection"</span><span style="color: #990000">>></span>, <span style="color: #990000"><<</span><span style="color: #FF0000">"close"</span><span style="color: #990000">>></span>},
-], <span style="color: #990000"><<</span><span style="color: #FF0000">"Closing the socket in 3.. 2.. 1.."</span><span style="color: #990000">>></span>, <span style="color: #009900">Req</span>)<span style="color: #990000">.</span></tt></pre></div></div>
-<div class="paragraph"><p>Cowboy will only accept a certain number of new requests
-on the same connection. By default it will run up to 100
-requests. This number can be changed by setting the
-<code>max_keepalive</code> configuration value when starting an
-HTTP 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">cowboy:start_http</span></span>(<span style="color: #FF6600">my_http_listener</span>, <span style="color: #993399">100</span>, [{<span style="color: #FF6600">port</span>, <span style="color: #993399">8080</span>}], [
- {<span style="color: #FF6600">env</span>, [{<span style="color: #FF6600">dispatch</span>, <span style="color: #009900">Dispatch</span>}]},
- {<span style="color: #FF6600">max_keepalive</span>, <span style="color: #993399">5</span>}
-])<span style="color: #990000">.</span></tt></pre></div></div>
-<div class="paragraph"><p>Cowboy implements the keep-alive mechanism by reusing
-the same process for all requests. This allows Cowboy
-to save memory. This works well because most code will
-not have any side effect impacting subsequent requests.
-But it also means you need to clean up if you do have
-code with side effects. The <code>terminate/3</code> function can
-be used for this purpose.</p></div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_pipelining_http_1_1">Pipelining (HTTP/1.1)</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>While HTTP is designed as a sequential protocol, with
-the client sending a request and then waiting for the
-response from the server, nothing prevents the client
-from sending more requests to the server without waiting
-for the response, due to how sockets work. The server
-still handles the requests sequentially and sends the
-responses in the same order.</p></div>
-<div class="paragraph"><p>This mechanism is called pipelining. It allows reducing
-latency when a client needs to request many resources
-at the same time. This is used by browsers when requesting
-static files for example.</p></div>
-<div class="paragraph"><p>This is handled automatically by the server.</p></div>
-</div>
-</div>
-<div class="sect1">
-<h2 id="_asynchronous_requests_http_2">Asynchronous requests (HTTP/2)</h2>
-<div class="sectionbody">
-<div class="paragraph"><p>In HTTP/2, the client can send a request at any time.
-And the server can send a response at any time too.</p></div>
-<div class="paragraph"><p>This means for example that the client does not need
-to wait for a request to be fully sent to send another,
-it is possible to interleave a request with the request
-body of another request. The same is true with responses.
-Responses may also be sent in a different order.</p></div>
-<div class="paragraph"><p>Because requests and responses are fully asynchronous,
-Cowboy creates a new process for each request, and these
-processes are managed by another process that handles the
-connection itself.</p></div>
-<div class="paragraph"><p>HTTP/2 servers may also decide to send resources to the
-client before the client requests them. This is especially
-useful for sending static files associated with the HTML
-page requested, as this reduces the latency of the overall
-response. Cowboy does not support this particular mechanism
-at this point, however.</p></div>
-</div>
-</div>
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