53 lines
3.1 KiB
HTML
53 lines
3.1 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<head>
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<meta name="author" content="Basho Technologies" />
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<meta name="description" content="Webmachine's approach to resource functions and referential transparency" />
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<meta name="keywords" content="webmachine http rest web" />
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<meta http-equiv="content-type" content="text/html;charset=utf-8" />
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<link rel="stylesheet" href="css/style-1c.css" type="text/css" />
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<title>Webmachine's approach to resource functions and referential transparency</title>
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</head>
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<body>
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<div id="content">
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<h1><span class="hr"></span><a href="/">webmachine</a></h1>
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<ul id="top">
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<li><a href="/">Home</a></li>
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<li><a href="http://bitbucket.org/justin/webmachine/">Source Code</a></li>
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<li><a href="contact.html">Contact</a></li>
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</ul>
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<div id="left">
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<h3>Webmachine's approach to resource functions and referential transparency</h3>
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<p>
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Webmachine goes to great lengths to help your <a href="resources.html">resource functions</a> to be as referentially transparent as possible. By "referentially transparent" we mean that given the same input <code> {ReqData, Context} </code> the function will return the same output <code> {Result, ReqData, Context} </code> and that side effects will be insignificant from the point of view of Webmachine's execution.
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</p>
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<p>
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We don't try to force you into pure referential transparency; we give you as big a hole as you want via <code>Context</code>. As that term is application-specific, you can put database handles, server process identifiers, or anything else you like in there and we won't try to stop you.
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</p>
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<p>
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However, all Webmachine really cares about is the rest of the terms. Since resource functions are generally referentially transparent at least with regard to those terms, many things are easier -- testing, <a href="debugging.html">debugging</a>, and even static analysis and reasoning about your Web application.
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</p>
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<p>
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Note that there is one important exception to this. The <a href="streambody.html">streamed body feature</a> exists to allow resources to consume or produce request/response bodies a hunk at a time without ever having the whole thing in memory. While the continuation-passing style used in the streaming API is friendly to general functional analysis, due to the necessary side-effect of reading or writing to sockets the stream bodies cannot be treated in quite the same way as other uses of the <code>ReqData</code> interface. Luckily, it is easy to inspect a <code>ReqData</code> to see if this is the case in any individual resource or request instance.
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</p>
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</div>
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<div id="footer">
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</div>
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</div>
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<script type="text/javascript">
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var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
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document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
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</script>
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<script type="text/javascript">
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try {
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var pageTracker = _gat._getTracker("UA-4979965-5");
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pageTracker._trackPageview();
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} catch(err) {}</script>
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</body>
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</html>
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