18265a4a16d82fe4325d792d00a03e2b85de5cbe
[project/luci.git] / 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, scope, ...)
128 scope = scope or getfenv(2)
129 local s, t = pcall(Template, name)
130 if not s then
131 error("Unable to load template: " .. name)
132 else
133 t:render(scope, ...)
134 end
135 end
136
137
138 -- Template class
139 Template = ffluci.util.class()
140
141 -- Shared template cache to store templates in to avoid unnecessary reloading
142 Template.cache = {}
143
144
145 -- Constructor - Reads and compiles the template on-demand
146 function Template.__init__(self, name)
147 if self.cache[name] then
148 self.template = self.cache[name]
149 else
150 self.template = nil
151 end
152
153 -- Create a new namespace for this template
154 self.viewns = {}
155
156 -- Copy over from general namespace
157 for k, v in pairs(viewns) do
158 self.viewns[k] = v
159 end
160
161 -- If we have a cached template, skip compiling and loading
162 if self.template then
163 return
164 end
165
166 -- Compile and build
167 local sourcefile = viewdir .. name .. ".htm"
168 local compiledfile = viewdir .. name .. ".lua"
169
170 if compiler_mode == "file" then
171 local tplmt = ffluci.fs.mtime(sourcefile)
172 local commt = ffluci.fs.mtime(compiledfile)
173
174 -- Build if there is no compiled file or if compiled file is outdated
175 if ((commt == nil) and not (tplmt == nil))
176 or (not (commt == nil) and not (tplmt == nil) and commt < tplmt) then
177 local compiled = compile(ffluci.fs.readfile(sourcefile))
178 ffluci.fs.writefile(compiledfile, compiled)
179 self.template = loadstring(compiled)
180 else
181 self.template = loadfile(compiledfile)
182 end
183
184 elseif compiler_mode == "none" then
185 self.template = loadfile(self.compiledfile)
186
187 elseif compiler_mode == "memory" then
188 self.template = loadstring(compile(ffluci.fs.readfile(sourcefile)))
189
190 else
191 error("Invalid compiler mode: " .. compiler_mode)
192
193 end
194
195 -- If we have no valid template throw error, otherwise cache the template
196 if not self.template then
197 error("Unable to load template: " .. name)
198 else
199 self.cache[name] = self.template
200 end
201 end
202
203
204 -- Renders a template
205 function Template.render(self, scope)
206 scope = scope or getfenv(2)
207
208 -- Save old environment
209 local oldfenv = getfenv(self.template)
210
211 -- Put our predefined objects in the scope of the template
212 ffluci.util.resfenv(self.template)
213 ffluci.util.updfenv(self.template, scope)
214 ffluci.util.updfenv(self.template, self.viewns)
215
216 -- Now finally render the thing
217 self.template()
218
219 -- Reset environment
220 setfenv(self.template, oldfenv)
221 end