Lighttpd Support FastCGI (python) and LUCI(OpenWrt)

Posted on | Edited on | In

1.Backgroud

We need to use lighttpd as webserver to servive two web page:

  • FastCGI (python bottle web micro framework)
  • LUCI (openwrt’s cgi-bin/luci, which is CGI)

2. Support LUCI

After we study OpenWrt wiki docs, we know how to make lighttpd support luci.
Two key steps:

  • enable lighttpd’s “mod_cgi” module
  • tell lighttpd all requests to “cgi-bin/luci” will send to lua, lighttpd ignore them
1
2
3
4
5
6
7
8
9
# Ensure we have to enable mod_cgi, which is in conf.d
# server.modules += ( "mod_cgi" )
#
# detail see openwrt org doc: https://wiki.openwrt.org/doc/howto/luci.on.lighttpd
# 
# wang.kai@sunmedia.com.cn

# tell lighttpd to process requests using lua
cgi.assign += ( "cgi-bin/luci" => "" )

Detail see OpenWrt Wiki about LuCI on lighttpd

3. Support FastCGI

The lighttpd fastcgi configuration like this:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
# Ensure mod_fastcgi mod_rewrite  have been enabled, some modules will be enabled
# in conf.d, BSP3's configuration will have effect on this.
#
# Server.modules += ( 
#		"mod_fastcgi",
#		"mod_rewrite",
# 		)
# wang.kai@sunmedia.com.cn

var.webapp_path = "/usr/share/httpstation"
var.webapp_fcgi = "main.py"

fastcgi.server = (
	"/python_entry" => (
		"icatchtek" => (
			"bin-path" => webapp_path + "/" + webapp_fcgi,
			"socket" => "/tmp/httpstation-fcgi.socket",
			"max-procs" => 1,
			"check-local" => "disable",
		)
	),
)

# [Note]
# Python request will send to "/python_entry" + "$1", except:
# 1. document.domain + "/cgi-bin/luci"
# 2. document.domain + "/luci-static"
url.rewrite-once = (
	"^(/(?!(cgi|luci-static)).*)" => "/python_entry" + "$1",
)

3.1. fcgi server

We need to tell lighttpd:

  • “bin-path” : where lighttpd will startup executable file
  • “socket” : fast cgi use socket send/receive msg
  • “check-local” : Whether check file is existed in “server.document-root”
  • “max-procs” : lighttpd support multiple process (optional)

Lighttpd docs about FastCGI http://redmine.lighttpd.net/projects/lighttpd/wiki/Docs_ModFastCGI

3.2. URL Redirect

Because lighttpd support two web pages, we need to do something make url access ok.

3.2.1. Bottle Python Redirect

If fastcgi server work well, we need to add “/python_entry”. For example, we access “172.28.52.152/home” should be “172.28.52.152/python_entry”. We use “mod_rewrite” module to avoid this embarrassed situation. This module will pre-process URL before we really access it.

3.2.2. LUCI Redirect

We need to keep luci access like “cgi-bin/luci” and “luci-static”(which is used for js, css, etc resource files). So we use:

1
2
3
4
5
6
7
# [Note]
# Python request will send to "/python_entry" + "$1", except:
# 1. document.domain + "/cgi-bin/luci"
# 2. document.domain + "/luci-static"
url.rewrite-once = (
	"^(/(?!(cgi|luci-static)).*)" => "/python_entry" + "$1",
)

How to represent “except xxx” ?
In Reluar Expression, we use “?!“ to express except. So next regular expression is except begin with “cgi” or “luci-staic”.

^(/(?!(cgi|luci-static)).*)

0%