core/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 require("ffluci.config")
  88 require("ffluci.sys")
  89
  90
  91 -- Sets privilege for given category
  92 function assign_privileges(category)
  93         local cp = ffluci.config.category_privileges
  94         if cp and cp[category] then
  95                 local u, g = cp[category]:match("([^:]+):([^:]+)")
  96                 ffluci.sys.process.setuser(u)
  97                 ffluci.sys.process.setgroup(g)
  98         end
  99 end
 100
 101 -- Dispatches the "request"
 102 function dispatch(req)
 103         request = req
 104         local m = "ffluci.controller." .. request.category .. "." .. request.module
 105         local stat, module = pcall(require, m)
 106         if not stat then
 107                 return error404()
 108         else
 109                 module.request = request
 110                 module.dispatcher = module.dispatcher or dynamic
 111                 setfenv(module.dispatcher, module)
 112                 return module.dispatcher(request)
 113         end
 114 end
 115
 116 -- Sends a 404 error code and renders the "error404" template if available
 117 function error404(message)
 118         message = message or "Not Found"
 119
 120         if not pcall(ffluci.template.render, "error404") then
 121                 ffluci.http.textheader()
 122                 print(message)
 123         end
 124         return false
 125 end
 126
 127 -- Sends a 500 error code and renders the "error500" template if available
 128 function error500(message)
 129         ffluci.http.status(500, "Internal Server Error")
 130
 131         if not pcall(ffluci.template.render, "error500", {message=message}) then
 132                 ffluci.http.textheader()
 133                 print(message)
 134         end
 135         return false
 136 end
 137
 138
 139 -- Dispatches a request depending on the PATH_INFO variable
 140 function httpdispatch()
 141         local pathinfo = os.getenv("PATH_INFO") or ""
 142         local parts = pathinfo:gmatch("/[%w-]+")
 143
 144         local sanitize = function(s, default)
 145                 return s and s:sub(2) or default
 146         end
 147
 148         local cat = sanitize(parts(), "public")
 149         local mod = sanitize(parts(), "index")
 150         local act = sanitize(parts(), "index")
 151
 152         assign_privileges(cat)
 153         dispatch({category=cat, module=mod, action=act})
 154 end
 155
 156
 157 -- Dispatchers --
 158
 159
 160 -- The Action Dispatcher searches the module for any function called
 161 -- action_"request.action" and calls it
 162 function action(request)
 163         local i18n = require("ffluci.i18n")
 164         local disp = require("ffluci.dispatcher")
 165
 166         i18n.loadc(request.category .. "_" .. request.module)
 167         local action = getfenv()["action_" .. request.action:gsub("-", "_")]
 168         if action then
 169                 action()
 170         else
 171                 disp.error404()
 172         end
 173 end
 174
 175 -- The CBI dispatcher directly parses and renders the CBI map which is
 176 -- placed in ffluci/modles/cbi/"request.module"/"request.action"
 177 function cbi(request)
 178         local i18n = require("ffluci.i18n")
 179         local disp = require("ffluci.dispatcher")
 180         local tmpl = require("ffluci.template")
 181         local cbi  = require("ffluci.cbi")
 182
 183         local path = request.category.."_"..request.module.."/"..request.action
 184
 185         i18n.loadc(request.category .. "_" .. request.module)
 186
 187         local stat, map = pcall(cbi.load, path)
 188         if stat and map then
 189                 local stat, err = pcall(map.parse, map)
 190                 if not stat then
 191                         disp.error500(err)
 192                         return
 193                 end
 194                 tmpl.render("cbi/header")
 195                 map:render()
 196                 tmpl.render("cbi/footer")
 197         elseif not stat then
 198                 disp.error500(map)
 199         else
 200                 disp.error404()
 201         end
 202 end
 203
 204 -- The dynamic dispatchers combines the action, simpleview and cbi dispatchers
 205 -- in one dispatcher. It tries to lookup the request in this order.
 206 function dynamic(request)
 207         local i18n = require("ffluci.i18n")
 208         local disp = require("ffluci.dispatcher")
 209         local tmpl = require("ffluci.template")
 210         local cbi  = require("ffluci.cbi")
 211
 212         i18n.loadc(request.category .. "_" .. request.module)
 213
 214         local action = getfenv()["action_" .. request.action:gsub("-", "_")]
 215         if action then
 216                 action()
 217                 return
 218         end
 219
 220         local path = request.category.."_"..request.module.."/"..request.action
 221         if pcall(tmpl.render, path) then
 222                 return
 223         end
 224
 225         local stat, map = pcall(cbi.load, path)
 226         if stat and map then
 227                 local stat, err = pcall(map.parse, map)
 228                 if not stat then
 229                         disp.error500(err)
 230                         return
 231                 end
 232                 tmpl.render("cbi/header")
 233                 map:render()
 234                 tmpl.render("cbi/footer")
 235                 return
 236         elseif not stat then
 237                 disp.error500(map)
 238                 return
 239         end
 240
 241         disp.error404()
 242 end
 243
 244 -- The Simple View Dispatcher directly renders the template
 245 -- which is placed in ffluci/views/"request.module"/"request.action"
 246 function simpleview(request)
 247         local i18n = require("ffluci.i18n")
 248         local tmpl = require("ffluci.template")
 249         local disp = require("ffluci.dispatcher")
 250
 251         local path = request.category.."_"..request.module.."/"..request.action
 252
 253         i18n.loadc(request.category .. "_" .. request.module)
 254         if not pcall(tmpl.render, path) then
 255                 disp.error404()
 256         end
 257 end