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     = function(...) return ffluci.model.uci.get(...) or "" end,
  56         controller = os.getenv("SCRIPT_NAME"),
  57         media      = ffluci.config.main.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(v:sub(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         c = c or 1
 124         ffluci.fs.writefile("/tmp/"..tostring(c), template)
 125         c = c+1
 126
 127         return template
 128 end
 129
 130 -- Oldstyle render shortcut
 131 function render(name, scope, ...)
 132         scope = scope or getfenv(2)
 133         local s, t = pcall(Template, name)
 134         if not s then
 135                 error(t)
 136         else
 137                 t:render(scope, ...)
 138         end
 139 end
 140
 141
 142 -- Template class
 143 Template = ffluci.util.class()
 144
 145 -- Shared template cache to store templates in to avoid unnecessary reloading
 146 Template.cache = {}
 147
 148
 149 -- Constructor - Reads and compiles the template on-demand
 150 function Template.__init__(self, name)
 151         if self.cache[name] then
 152                 self.template = self.cache[name]
 153         else
 154                 self.template = nil
 155         end
 156
 157         -- Create a new namespace for this template
 158         self.viewns = {}
 159
 160         -- Copy over from general namespace
 161         for k, v in pairs(viewns) do
 162                 self.viewns[k] = v
 163         end
 164
 165         -- If we have a cached template, skip compiling and loading
 166         if self.template then
 167                 return
 168         end
 169
 170         -- Compile and build
 171         local sourcefile   = viewdir .. name .. ".htm"
 172         local compiledfile = viewdir .. name .. ".lua"
 173         local err
 174
 175         if compiler_mode == "file" then
 176                 local tplmt = ffluci.fs.mtime(sourcefile)
 177                 local commt = ffluci.fs.mtime(compiledfile)
 178
 179                 -- Build if there is no compiled file or if compiled file is outdated
 180                 if ((commt == nil) and not (tplmt == nil))
 181                 or (not (commt == nil) and not (tplmt == nil) and commt < tplmt) then
 182                         local compiled = compile(ffluci.fs.readfile(sourcefile))
 183                         ffluci.fs.writefile(compiledfile, compiled)
 184                         self.template, err = loadstring(compiled)
 185                 else
 186                         self.template, err = loadfile(compiledfile)
 187                 end
 188
 189         elseif compiler_mode == "none" then
 190                 self.template, err = loadfile(self.compiledfile)
 191
 192         elseif compiler_mode == "memory" then
 193                 self.template, err = loadstring(compile(ffluci.fs.readfile(sourcefile)))
 194
 195         end
 196
 197         -- If we have no valid template throw error, otherwise cache the template
 198         if not self.template then
 199                 error(err)
 200         else
 201                 self.cache[name] = self.template
 202         end
 203 end
 204
 205
 206 -- Renders a template
 207 function Template.render(self, scope)
 208         scope = scope or getfenv(2)
 209
 210         -- Save old environment
 211         local oldfenv = getfenv(self.template)
 212
 213         -- Put our predefined objects in the scope of the template
 214         ffluci.util.resfenv(self.template)
 215         ffluci.util.updfenv(self.template, scope)
 216         ffluci.util.updfenv(self.template, self.viewns)
 217
 218         -- Now finally render the thing
 219         self.template()
 220
 221         -- Reset environment
 222         setfenv(self.template, oldfenv)
 223 end