Mercurial Hosting > luan

local Io = require "luan:Io"
local Html = require "luan:Html"
local Http = require "luan:web/Http"
local Shared = require "site:/Shared"


function service()
	Io.stdout = Http.response.text_writer()
%>
<html>
<head>
	<% Html.simply_html_head() %>
	<title>Luan Tutorial</title>
</head>
<body>

<div container>
<% Shared.header() %>
<h1 margin-bottom="1em">Luan Tutorial</h1>


<p>Create a file <b>hello.luan</b> containing:</p>

<p><tt><pre><%=Html.encode[[
	%>
	Hello World
	<%
]]%></pre></tt></p>

<p>To run this, type <b>luan file:hello</b> on the command line.  This should print <b>Hello World</b>.</p>

<p>The syntax here is based on <a href="http://en.wikipedia.org/wiki/JavaServer_Pages">JSP</a>.  Let's change it a little:</p>

<p><tt><pre><%=Html.encode[[
	name = "Bob"
	%>
	Hello <%= name %>
	<%
]]%></pre></tt></p>

<p>This should print <b>Hello Bob</b>.  Now let's try a more conventional approach:</p>

<p><tt><pre>
	local Io = require "luan:Io"
	local print = Io.print

	print("Hello World")
</pre></tt></p>

<p>In Luan, a function call with one string argument doesn't require parenthesis, so <b>print("Hello World")</b> is the same as <b>print "Hello World"</b> and <b>require "luan:Io"</b> is the same as <b>require("luan:Io")</b>.  Both <b>require</b> and <b>print</b> are functions.</p>

<p>The <b>require</b> function takes a <a href="http://en.wikipedia.org/wiki/Uniform_resource_identifier">URI</a> as an argument.  Examples of URIs are "<b>luan:Io</b>" and "<b>file:hello</b>".  <b>require</b> is used to import a module, which is returned from the <b>require</b> function call.  In the case above, we assign the module to the local variable <b>Io</b>.  The function <b>print</b> is a member of this module.  We could have done <b>Io.print("Hello World")</b> but instead we chose to assign <b>print</b> to a local variable and use that to call the function.</p>

<p>Luan starts with only two defined functions: <b>require</b> and <b>java</b>.  You will use <b>require</b> to import whatever you need.  This is a little more work, but makes it clear in each file where each function comes from.</p>

<p>Let's a make fancier version:</p>

<p><tt><pre>
	local Io = require "luan:Io"
	local print = Io.print

	function hello(name)
		print("Hello "..name)
	end

	hello("Bob")
</pre></tt></p>

<p>The <b>..</b> operator does concatenation.  This will print <b>Hello Bob</b>.</p>

<p>Now let's make a web page.  First we need a directory for our website.  So create a directory <b>site</b>.  In this directory, create a file <b>hi.luan</b> containing:

<p><tt><pre><%=Html.encode[[
	local Io = require "luan:Io"
	local Http = require "luan:web/Http"

	function service()
		Io.stdout = Http.response.text_writer()
		%>
		<html>
			<body>
				Hello World
			</body>
		</html>
		<%
	end
]]%></pre></tt></p>

<p>Now go back to the parent directory and do <b>luan luan:web/serve file:site</b>.  This will run the Luan web server on port 8080.  Try going to <a href="http://localhost:8080/">http://localhost:8080/</a>.  You should see the directory.  If you click on <b>hi.luan</b> you will see the source.  But if you remove the <b>.luan</b> and just go to <a href="http://localhost:8080/hi">http://localhost:8080/hi</a> then you will run the program which will generate the web page.</p>

<p>The Luan webserver looks for function named <b>service</b> in the file and calls it to generate the page.  Code of the form <b><%=Html.encode[[%>...<%]]%></b> writes its output to <b>Io.stdout</b> which by default is the standard output of the command line.  So in <b>service</b> one usually starts by setting <b>Io.stdout</b> to a <tt>text_writer</tt> which writes its output to the HTTP response (to the web browser).</p>

<p>You can find this example and others in the <a href="examples">examples directory</a>.  Take a look at <a href="examples/hi2.luan">hi2.luan</a> next.  Remember to remove the <b>.luan</b> from the URL to run the code.  And by the way, you can see the source for this page at <a href="tutorial.html.luan">tutorial.html.luan</a>.</p>

<p>So now you have built your website and you want to publish it to the web.  If you have your own domain, create a CNAME record for it pointing to <b>s1.luanhost.com</b>.  If you don't have a domain, just use a domain like <b>bob.s1.luanhost.com</b> (anything of the form <b>*.s1.luanhost.com</b>).  Assuming your directory is <b>site</b> and you will use the password <b>secret</b>, do the following from the command line:

<p><tt><pre>
	luan luan:host/push bob.s1.luanhost.com secret site
</pre></tt></p>

<p>The form is <b>luan luan:host/push domain password directory</b>.  If you change your site, just run this again and your site will be updated.  To delete your site, do <b>luan luan:host/delete domain password</b>.</p>

<p>Hopefully this short tutorial gave you an idea of how to use Luan to make a website.</p>

</div>

<% Html.simply_html_body_bottom() %>
</body>
</html>
<%
end
author	Franklin Schmidt <fschmidt@gmail.com>
date	Mon, 11 May 2015 15:29:29 -0600
parents	322c03d85ada
children	2b9bc97f0439