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added tutorial
author Franklin Schmidt <fschmidt@gmail.com>
date Wed, 22 Apr 2015 20:38:48 -0600
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children 4118eb51c816
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381:83efd1e3685c 382:8557581740db
1 local Io = require "luan:Io"
2 local Html = require "luan:Html"
3 local Http = require "luan:web/Http"
4
5 function service()
6 Io.stdout = Http.response.text_writer()
7 Io.stdout = Http.response.text_writer()
8 Html.simply_html_page{
9 head = function() %>
10 <title>Luan Tutorial</title>
11 <% end;
12 body = function() %>
13
14 <div container>
15 <div><small><a href="/">Luan</a></small></div>
16 <h1 margin-bottom="1em">Luan Tutorial</h1>
17
18
19 <p>Create a file <b>hello.luan</b> containing:</p>
20
21 <p><tt><pre><%=Html.encode[[
22 %>
23 Hello World
24 <%
25 ]]%></pre></tt></p>
26
27 <p>To run this, type <b>luan file:hello</b> on the command line. This should print <b>Hello World</b>.</p>
28
29 <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>
30
31 <p><tt><pre><%=Html.encode[[
32 name = "Bob"
33 %>
34 Hello <%= name %>
35 <%
36 ]]%></pre></tt></p>
37
38 <p>This should print <b>Hello Bob</b>. Now let's try a more conventional approach:</p>
39
40 <p><tt><pre>
41 local Io = require "luan:Io"
42 local print = Io.print
43
44 print("Hello World")
45 </pre></tt></p>
46
47 <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>
48
49 <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>
50
51 <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>
52
53 <p>Let's a make fancier version:</p>
54
55 <p><tt><pre>
56 local Io = require "luan:Io"
57 local print = Io.print
58
59 function hell(name)
60 print("Hello "..name)
61 end
62
63 hello("Bob")
64 </pre></tt></p>
65
66 <p>The <b>..</b> operator does concatenation. This will print <b>Hello Bob</b>.</p>
67
68 <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:
69
70 <p><tt><pre><%=Html.encode[[
71 local Io = require "luan:Io"
72 local Http = require "luan:web/Http"
73
74 function service()
75 Io.stdout = Http.response.text_writer()
76 %>
77 <html>
78 <body>
79 Hello World
80 </body>
81 </html>
82 <%
83 end
84 ]]%></pre></tt></p>
85
86 <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>
87
88 <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>
89
90 <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>
91
92 <p>So now you have built your website and you want 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:
93
94 <p><tt><pre>
95 luan luan:host/push bob.s1.luanhost.com secret site
96 </pre></tt></p>
97
98 <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>
99
100 <p>Hopefully this short tutorial gave you an idea of how to use Luan to make a website.</p>
101
102 </div>
103
104 <% end;
105 }
106 end