libs/web: add the ability for maps to push error messages to the global page header
[project/luci.git] / libs / web / luasrc / dispatcher.lua
index 12093fe..3d0db5a 100644 (file)
@@ -25,14 +25,18 @@ limitations under the License.
 ]]--
 
 --- LuCI web dispatcher.
-local fs = require "luci.fs"
+local fs = require "nixio.fs"
 local sys = require "luci.sys"
 local init = require "luci.init"
 local util = require "luci.util"
 local http = require "luci.http"
+local nixio = require "nixio", require "nixio.util"
 
 module("luci.dispatcher", package.seeall)
-context = luci.util.threadlocal()
+context = util.threadlocal()
+uci = require "luci.model.uci"
+i18n = require "luci.i18n"
+_M.fs = fs
 
 authenticator = {}
 
@@ -47,7 +51,26 @@ local fi
 -- @param ...  Virtual path
 -- @return             Relative URL
 function build_url(...)
-       return luci.http.getenv("SCRIPT_NAME") .. "/" .. table.concat(arg, "/")
+       local path = {...}
+       local url = { http.getenv("SCRIPT_NAME") or "" }
+
+       local k, v
+       for k, v in pairs(context.urltoken) do
+               url[#url+1] = "/;"
+               url[#url+1] = http.urlencode(k)
+               url[#url+1] = "="
+               url[#url+1] = http.urlencode(v)
+       end
+
+       local p
+       for _, p in ipairs(path) do
+               if p:match("^[a-zA-Z0-9_%-%.%%/,;]+$") then
+                       url[#url+1] = "/"
+                       url[#url+1] = p
+               end
+       end
+
+       return table.concat(url, "")
 end
 
 --- Send a 404 error code and render the "error404" template if available.
@@ -69,12 +92,17 @@ end
 -- @param message      Custom error message (optional)#
 -- @return                     false
 function error500(message)
-       luci.http.status(500, "Internal Server Error")
-
-       require("luci.template")
-       if not luci.util.copcall(luci.template.render, "error500", {message=message}) then
+       luci.util.perror(message)
+       if not context.template_header_sent then
+               luci.http.status(500, "Internal Server Error")
                luci.http.prepare_content("text/plain")
                luci.http.write(message)
+       else
+               require("luci.template")
+               if not luci.util.copcall(luci.template.render, "error500", {message=message}) then
+                       luci.http.prepare_content("text/plain")
+                       luci.http.write(message)
+               end
        end
        return false
 end
@@ -82,35 +110,42 @@ end
 function authenticator.htmlauth(validator, accs, default)
        local user = luci.http.formvalue("username")
        local pass = luci.http.formvalue("password")
-       
+
        if user and validator(user, pass) then
                return user
        end
-       
+
        require("luci.i18n")
        require("luci.template")
        context.path = {}
        luci.template.render("sysauth", {duser=default, fuser=user})
        return false
-       
+
 end
 
 --- Dispatch an HTTP request.
 -- @param request      LuCI HTTP Request object
-function httpdispatch(request)
+function httpdispatch(request, prefix)
        luci.http.context.request = request
-       context.request = {}
-       local pathinfo = request:getenv("PATH_INFO") or ""
 
-       for node in pathinfo:gmatch("[^/]+") do
-               table.insert(context.request, node)
+       local r = {}
+       context.request = r
+       local pathinfo = http.urldecode(request:getenv("PATH_INFO") or "", true)
+
+       if prefix then
+               for _, node in ipairs(prefix) do
+                       r[#r+1] = node
+               end
        end
 
-       local stat, err = util.copcall(dispatch, context.request)
-       if not stat then
-               error500(err)
+       for node in pathinfo:gmatch("[^/]+") do
+               r[#r+1] = node
        end
-       
+
+       local stat, err = util.coxpcall(function()
+               dispatch(context.request)
+       end, error500)
+
        luci.http.close()
 
        --context._disable_memtrace()
@@ -119,95 +154,186 @@ end
 --- Dispatches a LuCI virtual path.
 -- @param request      Virtual path
 function dispatch(request)
-       --context._disable_memtrace = require "luci.debug".trap_memtrace()
+       --context._disable_memtrace = require "luci.debug".trap_memtrace("l")
        local ctx = context
        ctx.path = request
-       
-       require "luci.i18n".setlanguage(require "luci.config".main.lang)
-       
+       ctx.urltoken   = ctx.urltoken or {}
+
+       local conf = require "luci.config"
+       assert(conf.main,
+               "/etc/config/luci seems to be corrupt, unable to find section 'main'")
+
+       local lang = conf.main.lang or "auto"
+       if lang == "auto" then
+               local aclang = http.getenv("HTTP_ACCEPT_LANGUAGE") or ""
+               for lpat in aclang:gmatch("[%w-]+") do
+                       lpat = lpat and lpat:gsub("-", "_")
+                       if conf.languages[lpat] then
+                               lang = lpat
+                               break
+                       end
+               end
+       end
+       require "luci.i18n".setlanguage(lang)
+
        local c = ctx.tree
        local stat
        if not c then
                c = createtree()
        end
-       
+
        local track = {}
        local args = {}
-       context.args = args
+       ctx.args = args
+       ctx.requestargs = ctx.requestargs or args
        local n
+       local t = true
+       local token = ctx.urltoken
+       local preq = {}
+       local freq = {}
 
        for i, s in ipairs(request) do
-               c = c.nodes[s]
-               n = i
-               if not c then
-                       break
+               local tkey, tval
+               if t then
+                       tkey, tval = s:match(";(%w+)=([a-fA-F0-9]*)")
                end
 
-               util.update(track, c)
-               
-               if c.leaf then
-                       break
+               if tkey then
+                       token[tkey] = tval
+               else
+                       t = false
+                       preq[#preq+1] = s
+                       freq[#freq+1] = s
+                       c = c.nodes[s]
+                       n = i
+                       if not c then
+                               break
+                       end
+
+                       util.update(track, c)
+
+                       if c.leaf then
+                               break
+                       end
                end
        end
 
        if c and c.leaf then
                for j=n+1, #request do
-                       table.insert(args, request[j])
+                       args[#args+1] = request[j]
+                       freq[#freq+1] = request[j]
                end
        end
 
+       ctx.requestpath = ctx.requestpath or freq
+       ctx.path = preq
+
        if track.i18n then
                require("luci.i18n").loadc(track.i18n)
        end
-       
+
        -- Init template engine
-       if not track.notemplate then
+       if (c and c.index) or not track.notemplate then
                local tpl = require("luci.template")
-               local viewns = setmetatable({}, {__index=_G})
-               tpl.context.viewns = viewns
-               viewns.write       = luci.http.write
-               viewns.include     = function(name) tpl.Template(name):render(getfenv(2)) end
-               viewns.translate   = function(...) return require("luci.i18n").translate(...) end
-               viewns.striptags   = util.striptags
-               viewns.controller  = luci.http.getenv("SCRIPT_NAME")
-               viewns.media       = luci.config.main.mediaurlbase
-               viewns.resource    = luci.config.main.resourcebase
-               viewns.REQUEST_URI = (luci.http.getenv("SCRIPT_NAME") or "") .. (luci.http.getenv("PATH_INFO") or "")
-       end
-       
+               local media = track.mediaurlbase or luci.config.main.mediaurlbase
+               if not pcall(tpl.Template, "themes/%s/header" % fs.basename(media)) then
+                       media = nil
+                       for name, theme in pairs(luci.config.themes) do
+                               if name:sub(1,1) ~= "." and pcall(tpl.Template,
+                                "themes/%s/header" % fs.basename(theme)) then
+                                       media = theme
+                               end
+                       end
+                       assert(media, "No valid theme found")
+               end
+
+               tpl.context.viewns = setmetatable({
+                  write       = luci.http.write;
+                  include     = function(name) tpl.Template(name):render(getfenv(2)) end;
+                  translate   = function(...) return require("luci.i18n").translate(...) end;
+                  export      = function(k, v) if tpl.context.viewns[k] == nil then tpl.context.viewns[k] = v end end;
+                  striptags   = util.striptags;
+                  pcdata      = util.pcdata;
+                  media       = media;
+                  theme       = fs.basename(media);
+                  resource    = luci.config.main.resourcebase
+               }, {__index=function(table, key)
+                       if key == "controller" then
+                               return build_url()
+                       elseif key == "REQUEST_URI" then
+                               return build_url(unpack(ctx.requestpath))
+                       else
+                               return rawget(table, key) or _G[key]
+                       end
+               end})
+       end
+
        track.dependent = (track.dependent ~= false)
        assert(not track.dependent or not track.auto, "Access Violation")
-       
+
        if track.sysauth then
                local sauth = require "luci.sauth"
-               
+
                local authen = type(track.sysauth_authenticator) == "function"
                 and track.sysauth_authenticator
                 or authenticator[track.sysauth_authenticator]
-                
+
                local def  = (type(track.sysauth) == "string") and track.sysauth
                local accs = def and {track.sysauth} or track.sysauth
-               local sess = ctx.authsession or luci.http.getcookie("sysauth")
-               sess = sess and sess:match("^[A-F0-9]+$")
-               local user = sauth.read(sess)
-               
+               local sess = ctx.authsession
+               local verifytoken = false
+               if not sess then
+                       sess = luci.http.getcookie("sysauth")
+                       sess = sess and sess:match("^[a-f0-9]*$")
+                       verifytoken = true
+               end
+
+               local sdat = sauth.read(sess)
+               local user
+
+               if sdat then
+                       sdat = loadstring(sdat)
+                       setfenv(sdat, {})
+                       sdat = sdat()
+                       if not verifytoken or ctx.urltoken.stok == sdat.token then
+                               user = sdat.user
+                       end
+               else
+                       local eu = http.getenv("HTTP_AUTH_USER")
+                       local ep = http.getenv("HTTP_AUTH_PASS")
+                       if eu and ep and luci.sys.user.checkpasswd(eu, ep) then
+                               authen = function() return eu end
+                       end
+               end
+
                if not util.contains(accs, user) then
                        if authen then
+                               ctx.urltoken.stok = nil
                                local user, sess = authen(luci.sys.user.checkpasswd, accs, def)
                                if not user or not util.contains(accs, user) then
                                        return
                                else
                                        local sid = sess or luci.sys.uniqueid(16)
-                                       luci.http.header("Set-Cookie", "sysauth=" .. sid.."; path=/")
                                        if not sess then
-                                               sauth.write(sid, user)
+                                               local token = luci.sys.uniqueid(16)
+                                               sauth.write(sid, util.get_bytecode({
+                                                       user=user,
+                                                       token=token,
+                                                       secret=luci.sys.uniqueid(16)
+                                               }))
+                                               ctx.urltoken.stok = token
                                        end
+                                       luci.http.header("Set-Cookie", "sysauth=" .. sid.."; path="..build_url())
                                        ctx.authsession = sid
+                                       ctx.authuser = user
                                end
                        else
                                luci.http.status(403, "Forbidden")
                                return
                        end
+               else
+                       ctx.authsession = sess
+                       ctx.authuser = user
                end
        end
 
@@ -219,22 +345,46 @@ function dispatch(request)
                luci.sys.process.setuser(track.setuser)
        end
 
-       if c and type(c.target) == "function" then
-               context.dispatched = c
-               
+       local target = nil
+       if c then
+               if type(c.target) == "function" then
+                       target = c.target
+               elseif type(c.target) == "table" then
+                       target = c.target.target
+               end
+       end
+
+       if c and (c.index or type(target) == "function") then
+               ctx.dispatched = c
+               ctx.requested = ctx.requested or ctx.dispatched
+       end
+
+       if c and c.index then
+               local tpl = require "luci.template"
+
+               if util.copcall(tpl.render, "indexer", {}) then
+                       return true
+               end
+       end
+
+       if type(target) == "function" then
                util.copcall(function()
-                       local oldenv = getfenv(c.target)
+                       local oldenv = getfenv(target)
                        local module = require(c.module)
                        local env = setmetatable({}, {__index=
-                               
+
                        function(tbl, key)
-                               return rawget(tbl, key) or module[key] or oldenv[key] 
+                               return rawget(tbl, key) or module[key] or oldenv[key]
                        end})
 
-                       setfenv(c.target, env)
+                       setfenv(target, env)
                end)
-               
-               c.target(unpack(args))
+
+               if type(c.target) == "table" then
+                       target(c.target, unpack(args))
+               else
+                       target(unpack(args))
+               end
        else
                error404()
        end
@@ -243,8 +393,8 @@ end
 --- Generate the dispatching index using the best possible strategy.
 function createindex()
        local path = luci.util.libpath() .. "/controller/"
-       local suff = ".lua"
-       
+       local suff = { ".lua", ".lua.gz" }
+
        if luci.util.copcall(require, "luci.fastindex") then
                createindex_fastindex(path, suff)
        else
@@ -254,17 +404,19 @@ end
 
 --- Generate the dispatching index using the fastindex C-indexer.
 -- @param path         Controller base directory
--- @param suffix       Controller file suffix
-function createindex_fastindex(path, suffix)
+-- @param suffixes     Controller file suffixes
+function createindex_fastindex(path, suffixes)
        index = {}
-               
+
        if not fi then
                fi = luci.fastindex.new("index")
-               fi.add(path .. "*" .. suffix)
-               fi.add(path .. "*/*" .. suffix)
+               for _, suffix in ipairs(suffixes) do
+                       fi.add(path .. "*" .. suffix)
+                       fi.add(path .. "*/*" .. suffix)
+               end
        end
        fi.scan()
-       
+
        for k, v in pairs(fi.indexes) do
                index[v[2]] = v[1]
        end
@@ -272,43 +424,56 @@ end
 
 --- Generate the dispatching index using the native file-cache based strategy.
 -- @param path         Controller base directory
--- @param suffix       Controller file suffix
-function createindex_plain(path, suffix)
+-- @param suffixes     Controller file suffixes
+function createindex_plain(path, suffixes)
+       local controllers = { }
+       for _, suffix in ipairs(suffixes) do
+               nixio.util.consume((fs.glob(path .. "*" .. suffix)), controllers)
+               nixio.util.consume((fs.glob(path .. "*/*" .. suffix)), controllers)
+       end
+
        if indexcache then
-               local cachedate = fs.mtime(indexcache)
-               if cachedate and cachedate > fs.mtime(path) then
+               local cachedate = fs.stat(indexcache, "mtime")
+               if cachedate then
+                       local realdate = 0
+                       for _, obj in ipairs(controllers) do
+                               local omtime = fs.stat(path .. "/" .. obj, "mtime")
+                               realdate = (omtime and omtime > realdate) and omtime or realdate
+                       end
 
-                       assert(
-                               sys.process.info("uid") == fs.stat(indexcache, "uid")
-                               and fs.stat(indexcache, "mode") == "rw-------",
-                               "Fatal: Indexcache is not sane!"
-                       )
+                       if cachedate > realdate then
+                               assert(
+                                       sys.process.info("uid") == fs.stat(indexcache, "uid")
+                                       and fs.stat(indexcache, "modestr") == "rw-------",
+                                       "Fatal: Indexcache is not sane!"
+                               )
 
-                       index = loadfile(indexcache)()
-                       return index
-               end             
+                               index = loadfile(indexcache)()
+                               return index
+                       end
+               end
        end
-       
-       index = {}
 
-       local controllers = util.combine(
-               luci.fs.glob(path .. "*" .. suffix) or {},
-               luci.fs.glob(path .. "*/*" .. suffix) or {}
-       )
+       index = {}
 
        for i,c in ipairs(controllers) do
-               local module = "luci.controller." .. c:sub(#path+1, #c-#suffix):gsub("/", ".")
+               local module = "luci.controller." .. c:sub(#path+1, #c):gsub("/", ".")
+               for _, suffix in ipairs(suffixes) do
+                       module = module:gsub(suffix.."$", "")
+               end
+
                local mod = require(module)
                local idx = mod.index
-               
+
                if type(idx) == "function" then
                        index[module] = idx
                end
        end
-       
+
        if indexcache then
-               fs.writefile(indexcache, util.get_bytecode(index))
-               fs.chmod(indexcache, "a-rwx,u+rw")
+               local f = nixio.open(indexcache, "w", 600)
+               f:writeall(util.get_bytecode(index))
+               f:close()
        end
 end
 
@@ -318,16 +483,18 @@ function createtree()
        if not index then
                createindex()
        end
-       
+
        local ctx  = context
        local tree = {nodes={}}
-       
+       local modi = {}
+
        ctx.treecache = setmetatable({}, {__mode="v"})
        ctx.tree = tree
-       
+       ctx.modifiers = modi
+
        -- Load default translation
-       require "luci.i18n".loadc("default")
-       
+       require "luci.i18n".loadc("base")
+
        local scope = setmetatable({}, {__index = luci.dispatcher})
 
        for k, v in pairs(index) do
@@ -335,10 +502,32 @@ function createtree()
                setfenv(v, scope)
                v()
        end
-       
+
+       local function modisort(a,b)
+               return modi[a].order < modi[b].order
+       end
+
+       for _, v in util.spairs(modi, modisort) do
+               scope._NAME = v.module
+               setfenv(v.func, scope)
+               v.func()
+       end
+
        return tree
 end
 
+--- Register a tree modifier.
+-- @param      func    Modifier function
+-- @param      order   Modifier order value (optional)
+function modifier(func, order)
+       context.modifiers[#context.modifiers+1] = {
+               func = func,
+               order = order or 0,
+               module
+                       = getfenv(2)._NAME
+       }
+end
+
 --- Clone a node of the dispatching tree to another position.
 -- @param      path    Virtual path destination
 -- @param      clone   Virtual path source
@@ -349,33 +538,24 @@ function assign(path, clone, title, order)
        local obj  = node(unpack(path))
        obj.nodes  = nil
        obj.module = nil
-       
+
        obj.title = title
        obj.order = order
-       
-       local c = context.tree
-       for k, v in ipairs(clone) do
-               if not c.nodes[v] then
-                       c.nodes[v] = {nodes={}}
-               end
 
-               c = c.nodes[v]
-       end
-       
-       setmetatable(obj, {__index = c})
-       
+       setmetatable(obj, {__index = _create_node(clone)})
+
        return obj
 end
 
 --- Create a new dispatching node and define common parameters.
 -- @param      path    Virtual path
--- @param      target  Target function to call when dispatched. 
+-- @param      target  Target function to call when dispatched.
 -- @param      title   Destination node title
 -- @param      order   Destination node order value (optional)
 -- @return                     Dispatching tree node
 function entry(path, target, title, order)
        local c = node(unpack(path))
-       
+
        c.target = target
        c.title  = title
        c.order  = order
@@ -384,14 +564,21 @@ function entry(path, target, title, order)
        return c
 end
 
+--- Fetch or create a dispatching node without setting the target module or
+-- enabling the node.
+-- @param      ...             Virtual path
+-- @return                     Dispatching tree node
+function get(...)
+       return _create_node({...})
+end
+
 --- Fetch or create a new dispatching node.
 -- @param      ...             Virtual path
 -- @return                     Dispatching tree node
 function node(...)
-       local c = _create_node(arg)
+       local c = _create_node({...})
 
        c.module = getfenv(2)._NAME
-       c.path = arg
        c.auto = nil
 
        return c
@@ -401,19 +588,20 @@ function _create_node(path, cache)
        if #path == 0 then
                return context.tree
        end
-       
+
        cache = cache or context.treecache
        local name = table.concat(path, ".")
        local c = cache[name]
-       
+
        if not c then
+               local new = {nodes={}, auto=true, path=util.clone(path)}
                local last = table.remove(path)
+
                c = _create_node(path, cache)
-               
-               local new = {nodes={}, auto=true}
+
                c.nodes[last] = new
                cache[name] = new
-               
+
                return new
        else
                return c
@@ -425,8 +613,12 @@ end
 --- Create a redirect to another dispatching node.
 -- @param      ...             Virtual path destination
 function alias(...)
-       local req = arg
-       return function()
+       local req = {...}
+       return function(...)
+               for _, r in ipairs({...}) do
+                       req[#req+1] = r
+               end
+
                dispatch(req)
        end
 end
@@ -435,75 +627,201 @@ end
 -- @param      n               Number of path values to replace
 -- @param      ...             Virtual path to replace removed path values with
 function rewrite(n, ...)
-       local req = arg
-       return function()
-               for i=1,n do 
-                       table.remove(context.path, 1)
+       local req = {...}
+       return function(...)
+               local dispatched = util.clone(context.dispatched)
+
+               for i=1,n do
+                       table.remove(dispatched, 1)
                end
-               
-               for i,r in ipairs(req) do
-                       table.insert(context.path, i, r)
+
+               for i, r in ipairs(req) do
+                       table.insert(dispatched, i, r)
                end
-               
-               dispatch()
+
+               for _, r in ipairs({...}) do
+                       dispatched[#dispatched+1] = r
+               end
+
+               dispatch(dispatched)
+       end
+end
+
+
+local function _call(self, ...)
+       if #self.argv > 0 then
+               return getfenv()[self.name](unpack(self.argv), ...)
+       else
+               return getfenv()[self.name](...)
        end
 end
 
 --- Create a function-call dispatching target.
--- @param      name    Target function of local controller 
+-- @param      name    Target function of local controller
 -- @param      ...             Additional parameters passed to the function
 function call(name, ...)
-       local argv = {...}
-       return function() return getfenv()[name](unpack(argv)) end
+       return {type = "call", argv = {...}, name = name, target = _call}
+end
+
+
+local _template = function(self, ...)
+       require "luci.template".render(self.view)
 end
 
 --- Create a template render dispatching target.
 -- @param      name    Template to be rendered
 function template(name)
-       return function()
-               require("luci.template")
-               luci.template.render(name)
-       end
+       return {type = "template", view = name, target = _template}
 end
 
---- Create a CBI model dispatching target.
--- @param      model   CBI model tpo be rendered
-function cbi(model)
-       return function(...)
-               require("luci.cbi")
-               require("luci.template")
 
-               maps = luci.cbi.load(model, ...)
+local function _cbi(self, ...)
+       local cbi = require "luci.cbi"
+       local tpl = require "luci.template"
+       local http = require "luci.http"
+
+       local config = self.config or {}
+       local maps = cbi.load(self.model, ...)
+
+       local state = nil
+
+       for i, res in ipairs(maps) do
+               res.flow = config
+               local cstate = res:parse()
+               if cstate and (not state or cstate < state) then
+                       state = cstate
+               end
+       end
+
+       local function _resolve_path(path)
+               return type(path) == "table" and build_url(unpack(path)) or path
+       end
+
+       if config.on_valid_to and state and state > 0 and state < 2 then
+               http.redirect(_resolve_path(config.on_valid_to))
+               return
+       end
+
+       if config.on_changed_to and state and state > 1 then
+               http.redirect(_resolve_path(config.on_changed_to))
+               return
+       end
+
+       if config.on_success_to and state and state > 0 then
+               http.redirect(_resolve_path(config.on_success_to))
+               return
+       end
+
+       if config.state_handler then
+               if not config.state_handler(state, maps) then
+                       return
+               end
+       end
+
+       http.header("X-CBI-State", state or 0)
+
+       if not config.noheader then
+               tpl.render("cbi/header", {state = state})
+       end
+
+       local redirect
+       local messages
+       local applymap   = false
+       local pageaction = true
+       local parsechain = { }
+
+       for i, res in ipairs(maps) do
+               if res.apply_needed and res.parsechain then
+                       local c
+                       for _, c in ipairs(res.parsechain) do
+                               parsechain[#parsechain+1] = c
+                       end
+                       applymap = true
+               end
+
+               if res.redirect then
+                       redirect = redirect or res.redirect
+               end
 
-               for i, res in ipairs(maps) do
-                       res:parse()
+               if res.pageaction == false then
+                       pageaction = false
                end
 
-               luci.template.render("cbi/header")
-               for i, res in ipairs(maps) do
-                       res:render()
+               if res.message then
+                       messages = messages or { }
+                       messages[#messages+1] = res.message
                end
-               luci.template.render("cbi/footer")
+       end
+
+       for i, res in ipairs(maps) do
+               res:render({
+                       firstmap   = (i == 1),
+                       applymap   = applymap,
+                       redirect   = redirect,
+                       messages   = messages,
+                       pageaction = pageaction,
+                       parsechain = parsechain
+               })
+       end
+
+       if not config.nofooter then
+               tpl.render("cbi/footer", {
+                       flow       = config,
+                       pageaction = pageaction,
+                       redirect   = redirect,
+                       state      = state,
+                       autoapply  = config.autoapply
+               })
        end
 end
 
---- Create a CBI form model dispatching target.
--- @param      model   CBI form model tpo be rendered
-function form(model)
-       return function(...)
-               require("luci.cbi")
-               require("luci.template")
+--- Create a CBI model dispatching target.
+-- @param      model   CBI model to be rendered
+function cbi(model, config)
+       return {type = "cbi", config = config, model = model, target = _cbi}
+end
 
-               maps = luci.cbi.load(model, ...)
 
-               for i, res in ipairs(maps) do
-                       res:parse()
-               end
+local function _arcombine(self, ...)
+       local argv = {...}
+       local target = #argv > 0 and self.targets[2] or self.targets[1]
+       setfenv(target.target, self.env)
+       target:target(unpack(argv))
+end
+
+--- Create a combined dispatching target for non argv and argv requests.
+-- @param trg1 Overview Target
+-- @param trg2 Detail Target
+function arcombine(trg1, trg2)
+       return {type = "arcombine", env = getfenv(), target = _arcombine, targets = {trg1, trg2}}
+end
 
-               luci.template.render("header")
-               for i, res in ipairs(maps) do
-                       res:render()
+
+local function _form(self, ...)
+       local cbi = require "luci.cbi"
+       local tpl = require "luci.template"
+       local http = require "luci.http"
+
+       local maps = luci.cbi.load(self.model, ...)
+       local state = nil
+
+       for i, res in ipairs(maps) do
+               local cstate = res:parse()
+               if cstate and (not state or cstate < state) then
+                       state = cstate
                end
-               luci.template.render("footer")
        end
+
+       http.header("X-CBI-State", state or 0)
+       tpl.render("header")
+       for i, res in ipairs(maps) do
+               res:render()
+       end
+       tpl.render("footer")
+end
+
+--- Create a CBI form model dispatching target.
+-- @param      model   CBI form model tpo be rendered
+function form(model)
+       return {type = "cbi", model = model, target = _form}
 end