src/ffluci/dispatcher.lua

   1 --[[
   2 FFLuCI - Dispatcher
   3
   4 Description:
   5 The request dispatcher and module dispatcher generators
   6
   7
   8 The dispatching process:
   9     For a detailed explanation of the dispatching process we assume:
  10     You have installed the FFLuCI CGI-Dispatcher in /cgi-bin/ffluci
  11
  12         To enforce a higher level of security only the CGI-Dispatcher
  13         resides inside the web server's document root, everything else
  14         stays inside an external directory, we assume this is /lua/ffluci
  15         for this explanation.
  16
  17     All controllers and action are reachable as sub-objects of /cgi-bin/ffluci
  18     as if they were virtual folders and files
  19         e.g.: /cgi-bin/ffluci/public/info/about
  20               /cgi-bin/ffluci/admin/network/interfaces
  21         and so on.
  22
  23     The PATH_INFO variable holds the dispatch path and
  24         will be split into three parts: /category/module/action
  25
  26     Category:   This is the category in which modules are stored in
  27                                 By default there are two categories:
  28                                 "public" - which is the default public category
  29                                 "admin"  - which is the default protected category
  30
  31                                 As FFLuCI itself does not implement authentication
  32                                 you should make sure that "admin" and other sensitive
  33                                 categories are protected by the webserver.
  34
  35                                 E.g. for busybox add a line like:
  36                                 /cgi-bin/ffluci/admin:root:$p$root
  37                                 to /etc/httpd.conf to protect the "admin" category
  38
  39
  40         Module:         This is the controller which will handle the request further
  41                                 It is always a submodule of ffluci.controller, so a module
  42                                 called "helloworld" will be stored in
  43                                 /lua/ffluci/controller/helloworld.lua
  44                                 You are free to submodule your controllers any further.
  45
  46         Action:         This is action that will be invoked after loading the module.
  47                     The kind of how the action will be dispatched depends on
  48                                 the module dispatcher that is defined in the controller.
  49                                 See the description of the default module dispatcher down
  50                                 on this page for some examples.
  51
  52
  53     The main dispatcher at first searches for the module by trying to
  54         include ffluci.controller.category.module
  55         (where "category" is the category name and "module" is the module name)
  56         If this fails a 404 status code will be send to the client and FFLuCI exits
  57
  58         Then the main dispatcher calls the module dispatcher
  59         ffluci.controller.category.module.dispatcher with the request object
  60         as the only argument. The module dispatcher is then responsible
  61         for the further dispatching process.
  62
  63
  64 FileId:
  65 $Id$
  66
  67 License:
  68 Copyright 2008 Steven Barth <steven@midlink.org>
  69
  70 Licensed under the Apache License, Version 2.0 (the "License");
  71 you may not use this file except in compliance with the License.
  72 You may obtain a copy of the License at
  73
  74         http://www.apache.org/licenses/LICENSE-2.0
  75
  76 Unless required by applicable law or agreed to in writing, software
  77 distributed under the License is distributed on an "AS IS" BASIS,
  78 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  79 See the License for the specific language governing permissions and
  80 limitations under the License.
  81
  82 ]]--
  83
  84 module("ffluci.dispatcher", package.seeall)
  85 require("ffluci.http")
  86 require("ffluci.template")
  87
  88
  89 -- Dispatches the "request"
  90 function dispatch(req)
  91         request = req
  92         local m = "ffluci.controller." .. request.category .. "." .. request.module
  93         local stat, module = pcall(require, m)
  94         if not stat then
  95                 return error404()
  96         else
  97                 module.request = request
  98                 module.dispatcher = module.dispatcher or dynamic
  99                 setfenv(module.dispatcher, module)
 100                 return module.dispatcher(request)
 101         end
 102 end
 103
 104 -- Sends a 404 error code and renders the "error404" template if available
 105 function error404(message)
 106         message = message or "Not Found"
 107
 108         if not pcall(ffluci.template.render, "error404") then
 109                 ffluci.http.textheader()
 110                 print(message)
 111         end
 112         return false
 113 end
 114
 115 -- Sends a 500 error code and renders the "error500" template if available
 116 function error500(message)
 117         ffluci.http.status(500, "Internal Server Error")
 118
 119         if not pcall(ffluci.template.render, "error500") then
 120                 ffluci.http.textheader()
 121                 print(message)
 122         end
 123         return false
 124 end
 125
 126
 127 -- Dispatches a request depending on the PATH_INFO variable
 128 function httpdispatch()
 129         local pathinfo = os.getenv("PATH_INFO") or ""
 130         local parts = pathinfo:gmatch("/[%w-]+")
 131
 132         local sanitize = function(s, default)
 133                 return s and s:sub(2) or default
 134         end
 135
 136         local cat = sanitize(parts(), "public")
 137         local mod = sanitize(parts(), "index")
 138         local act = sanitize(parts(), "index")
 139
 140         dispatch({category=cat, module=mod, action=act})
 141 end
 142
 143
 144 -- Dispatchers --
 145
 146
 147 -- The Action Dispatcher searches the module for any function called
 148 -- action_"request.action" and calls it
 149 function action(request)
 150         local i18n = require("ffluci.i18n")
 151         local disp = require("ffluci.dispatcher")
 152
 153         i18n.loadc(request.module)
 154         local action = getfenv()["action_" .. request.action:gsub("-", "_")]
 155         if action then
 156                 action()
 157         else
 158                 disp.error404()
 159         end
 160 end
 161
 162 -- The CBI dispatcher directly parses and renders the CBI map which is
 163 -- placed in ffluci/modles/cbi/"request.module"/"request.action"
 164 function cbi(request)
 165         local i18n = require("ffluci.i18n")
 166         local disp = require("ffluci.dispatcher")
 167         local tmpl = require("ffluci.template")
 168         local cbi  = require("ffluci.cbi")
 169
 170         i18n.loadc(request.module)
 171
 172         stat, map = pcall(cbi.load, request.module.."/"..request.action)
 173         if stat then
 174                 tmpl.render("header")
 175                 map:render()
 176                 tmpl.render("footer")
 177         else
 178                 disp.error404()
 179         end
 180 end
 181
 182 -- The dynamic dispatchers combines the action, simpleview and cbi dispatchers
 183 -- in one dispatcher. It tries to lookup the request in this order.
 184 function dynamic(request)
 185         local i18n = require("ffluci.i18n")
 186         local disp = require("ffluci.dispatcher")
 187         local tmpl = require("ffluci.template")
 188         local cbi  = require("ffluci.cbi")
 189
 190         i18n.loadc(request.module)
 191
 192         local action = getfenv()["action_" .. request.action:gsub("-", "_")]
 193         if action then
 194                 action()
 195                 return
 196         end
 197
 198         if pcall(tmpl.render, request.module .. "/" .. request.action) then
 199                 return
 200         end
 201
 202         stat, map = pcall(cbi.load, request.module.."/"..request.action)
 203         if stat then
 204                 tmpl.render("header")
 205                 map:render()
 206                 tmpl.render("footer")
 207                 return
 208         end
 209
 210         disp.error404()
 211 end
 212
 213 -- The Simple View Dispatcher directly renders the template
 214 -- which is placed in ffluci/views/"request.module"/"request.action"
 215 function simpleview(request)
 216         local i18n = require("ffluci.i18n")
 217         local tmpl = require("ffluci.template")
 218         local disp = require("ffluci.dispatcher")
 219
 220         i18n.loadc(request.module)
 221         if not pcall(tmpl.render, request.module .. "/" .. request.action) then
 222                 disp.error404()
 223         end
 224 end