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printenv.lua revision 1.5 
      1 -- $NetBSD: printenv.lua,v 1.5 2021/02/28 16:10:00 rillig Exp $
      2 
      3 -- this small Lua script demonstrates the use of Lua in (bozo)httpd
      4 -- it will simply output the "environment"
      5 
      6 -- Keep in mind that bozohttpd forks for each request when started in
      7 -- daemon mode, you can set global variables here, but they will have
      8 -- the same value on each invocation.  You can not keep state between
      9 -- two calls.
     10 
     11 -- You can test this example by running the following command:
     12 -- /usr/libexec/httpd -b -f -I 8080 -L test printenv.lua .
     13 -- and then navigate to: http://127.0.0.1:8080/test/printenv
     14 
     15 local httpd = require 'httpd'
     16 
     17 function escape_html(s)
     18   return s:gsub('&', '&amp;'):gsub('<', '&lt;'):gsub('>', '&gt;'):gsub('"', '&quot;')
     19 end
     20 
     21 function printenv(env, headers, query)
     22 
     23 	-- we get the "environment" in the env table, the values are more
     24 	-- or less the same as the variable for a CGI program
     25 
     26 	-- output headers using httpd.write()
     27 	-- httpd.write() will not append newlines
     28 	httpd.write("HTTP/1.1 200 Ok\r\n")
     29 	httpd.write("Content-Type: text/html\r\n\r\n")
     30 
     31 	-- output html using httpd.print()
     32 	-- you can also use print() and io.write() but they will not work with SSL
     33 	httpd.print([[
     34 		<html>
     35 			<head>
     36 				<title>Bozotic Lua Environment</title>
     37 			</head>
     38 			<body>
     39 				<h1>Bozotic Lua Environment</h1>
     40 	]])
     41 
     42 	httpd.print('module version: ' .. httpd._VERSION .. '<br>')
     43 
     44 	httpd.print('<h2>Server Environment</h2>')
     45 	-- print the list of "environment" variables
     46 	for k, v in pairs(env) do
     47 		httpd.print(escape_html(k) .. '=' .. escape_html(v) .. '<br/>')
     48 	end
     49 
     50 	httpd.print('<h2>Request Headers</h2>')
     51 	for k, v in pairs(headers) do
     52 		httpd.print(escape_html(k) .. '=' .. escape_html(v) .. '<br/>')
     53 	end
     54 
     55 	if query ~= nil then
     56 		httpd.print('<h2>Query Variables</h2>')
     57 		for k, v in pairs(query) do
     58 			httpd.print(escape_html(k) .. '=' .. escape_html(v) .. '<br/>')
     59 		end
     60 	end
     61 
     62 	httpd.print('<h2>Form Test</h2>')
     63 
     64 	httpd.print([[
     65 	<form method="POST" action="form?sender=me">
     66 	<input type="text" name="a_value">
     67 	<input type="submit">
     68 	</form>
     69 	]])
     70 	-- output a footer
     71 	httpd.print([[
     72 		</body>
     73 	</html>
     74 	]])
     75 end
     76 
     77 function form(env, header, query)
     78 
     79 	httpd.write("HTTP/1.1 200 Ok\r\n")
     80 	httpd.write("Content-Type: text/html\r\n\r\n")
     81 
     82 	if query ~= nil then
     83 		httpd.print('<h2>Form Variables</h2>')
     84 
     85 		if env.CONTENT_TYPE ~= nil then
     86 			httpd.print('Content-type: ' .. env.CONTENT_TYPE .. '<br>')
     87 		end
     88 
     89 		for k, v in pairs(query) do
     90 			httpd.print(escape_html(k) .. '=' .. escape_html(v) .. '<br/>')
     91 		end
     92 	else
     93 		httpd.print('No values')
     94 	end
     95 end
     96 
     97 -- register this handler for http://<hostname>/<prefix>/printenv
     98 httpd.register_handler('printenv', printenv)
     99 httpd.register_handler('form', form)
    100