src/ffluci/template.lua

   1 --[[
   2 FFLuCI - Template Parser
   3
   4 Description:
   5 A template parser supporting includes, translations, Lua code blocks
   6 and more. It can be used either as a compiler or as an interpreter.
   7
   8 FileId: $Id$
   9
  10 License:
  11 Copyright 2008 Steven Barth <steven@midlink.org>
  12
  13 Licensed under the Apache License, Version 2.0 (the "License");
  14 you may not use this file except in compliance with the License.
  15 You may obtain a copy of the License at
  16
  17         http://www.apache.org/licenses/LICENSE-2.0
  18
  19 Unless required by applicable law or agreed to in writing, software
  20 distributed under the License is distributed on an "AS IS" BASIS,
  21 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  22 See the License for the specific language governing permissions and
  23 limitations under the License.
  24
  25 ]]--
  26 module("ffluci.template", package.seeall)
  27
  28 require("ffluci.config")
  29 require("ffluci.util")
  30 require("ffluci.fs")
  31 require("ffluci.i18n")
  32 require("ffluci.model.uci")
  33
  34 viewdir = ffluci.fs.dirname(ffluci.util.__file__()) .. "view/"
  35
  36
  37 -- Compile modes:
  38 -- none:        Never compile, only use precompiled data from files
  39 -- memory:      Always compile, do not save compiled files, ignore precompiled
  40 -- file:        Compile on demand, save compiled files, update precompiled
  41 compiler_mode = "memory"
  42
  43
  44 -- This applies to compiler modes "always" and "smart"
  45 --
  46 -- Produce compiled lua code rather than lua sourcecode
  47 -- WARNING: Increases template size heavily!!!
  48 -- This produces the same bytecode as luac but does not have a strip option
  49 compiler_enable_bytecode = false
  50
  51
  52 -- Define the namespace for template modules
  53 viewns = {
  54         translate  = ffluci.i18n.translate,
  55         config     = ffluci.model.uci.get,
  56         controller = os.getenv("SCRIPT_NAME"),
  57         media      = ffluci.config.mediaurlbase,
  58         write      = io.write,
  59         include    = function(name) Template(name):render(getfenv(2)) end,
  60 }
  61
  62 -- Compiles a given template into an executable Lua module
  63 function compile(template)
  64         -- Search all <% %> expressions (remember: Lua table indexes begin with #1)
  65         local function expr_add(command)
  66                 table.insert(expr, command)
  67                 return "<%" .. tostring(#expr) .. "%>"
  68         end
  69
  70         -- As "expr" should be local, we have to assign it to the "expr_add" scope
  71         local expr = {}
  72         ffluci.util.extfenv(expr_add, "expr", expr)
  73
  74         -- Save all expressiosn to table "expr"
  75         template = template:gsub("<%%(.-)%%>", expr_add)
  76
  77         local function sanitize(s)
  78                 s = ffluci.util.escape(s)
  79                 s = ffluci.util.escape(s, "'")
  80                 s = ffluci.util.escape(s, "\n")
  81                 return s
  82         end
  83
  84         -- Escape and sanitize all the template (all non-expressions)
  85         template = sanitize(template)
  86
  87         -- Template module header/footer declaration
  88         local header = "write('"
  89         local footer = "')"
  90
  91         template = header .. template .. footer
  92
  93         -- Replacements
  94         local r_include = "')\ninclude('%s')\nwrite('"
  95         local r_i18n    = "'..translate('%1','%2')..'"
  96         local r_uci     = "'..config('%1','%2','%3')..'"
  97         local r_pexec   = "'..%s..'"
  98         local r_exec    = "')\n%s\nwrite('"
  99
 100         -- Parse the expressions
 101         for k,v in pairs(expr) do
 102                 local p = v:sub(1, 1)
 103                 local re = nil
 104                 if p == "+" then
 105                         re = r_include:format(sanitize(string.sub(v, 2)))
 106                 elseif p == ":" then
 107                         re = sanitize(v):gsub(":(.-) (.+)", r_i18n)
 108                 elseif p == "~" then
 109                         re = sanitize(v):gsub("~(.-)%.(.-)%.(.+)", r_uci)
 110                 elseif p == "=" then
 111                         re = r_pexec:format(string.sub(v, 2))
 112                 else
 113                         re = r_exec:format(v)
 114                 end
 115                 template = template:gsub("<%%"..tostring(k).."%%>", re)
 116         end
 117
 118         if compiler_enable_bytecode then
 119                 tf = loadstring(template)
 120                 template = string.dump(tf)
 121         end
 122
 123         return template
 124 end
 125
 126 -- Oldstyle render shortcut
 127 function render(name, ...)
 128         local s, t = pcall(Template, name)
 129         if not s then
 130                 error("Unable to load template: " .. name)
 131         else
 132                 t:render(...)
 133         end
 134 end
 135
 136
 137 -- Template class
 138 Template = ffluci.util.class()
 139
 140 -- Shared template cache to store templates in to avoid unnecessary reloading
 141 Template.cache = {}
 142
 143
 144 -- Constructor - Reads and compiles the template on-demand
 145 function Template.__init__(self, name)
 146         if self.cache[name] then
 147                 self.template = self.cache[name]
 148         else
 149                 self.template = nil
 150         end
 151
 152         -- Create a new namespace for this template
 153         self.viewns = {}
 154
 155         -- Copy over from general namespace
 156         for k, v in pairs(viewns) do
 157                 self.viewns[k] = v
 158         end
 159
 160         -- If we have a cached template, skip compiling and loading
 161         if self.template then
 162                 return
 163         end
 164
 165         -- Compile and build
 166         local sourcefile   = viewdir .. name .. ".htm"
 167         local compiledfile = viewdir .. name .. ".lua"
 168
 169         if compiler_mode == "file" then
 170                 local tplmt = ffluci.fs.mtime(sourcefile)
 171                 local commt = ffluci.fs.mtime(compiledfile)
 172
 173                 -- Build if there is no compiled file or if compiled file is outdated
 174                 if ((commt == nil) and not (tplmt == nil))
 175                 or (not (commt == nil) and not (tplmt == nil) and commt < tplmt) then
 176                         local compiled = compile(ffluci.fs.readfile(sourcefile))
 177                         ffluci.fs.writefile(compiledfile, compiled)
 178                         self.template = loadstring(compiled)
 179                 else
 180                         self.template = loadfile(compiledfile)
 181                 end
 182
 183         elseif compiler_mode == "none" then
 184                 self.template = loadfile(self.compiledfile)
 185
 186         elseif compiler_mode == "memory" then
 187                 self.template = loadstring(compile(ffluci.fs.readfile(sourcefile)))
 188
 189         else
 190                 error("Invalid compiler mode: " .. compiler_mode)
 191
 192         end
 193
 194         -- If we have no valid template throw error, otherwise cache the template
 195         if not self.template then
 196                 error("Unable to load template: " .. name)
 197         else
 198                 self.cache[name] = self.template
 199         end
 200 end
 201
 202
 203 -- Renders a template
 204 function Template.render(self, scope)
 205         scope = scope or getfenv(2)
 206
 207         -- Save old environment
 208         local oldfenv = getfenv(self.template)
 209
 210         -- Put our predefined objects in the scope of the template
 211         ffluci.util.updfenv(self.template, scope)
 212         ffluci.util.updfenv(self.template, self.viewns)
 213
 214         -- Now finally render the thing
 215         self.template()
 216
 217         -- Reset environment
 218         setfenv(self.template, oldfenv)
 219 end