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mustache.rb
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mustache.rb
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require 'mustache/enumerable'
require 'mustache/template'
require 'mustache/context'
require 'mustache/settings'
# Mustache is the base class from which your Mustache subclasses
# should inherit (though it can be used on its own).
#
# The typical Mustache workflow is as follows:
#
# * Create a Mustache subclass: class Stats < Mustache
# * Create a template: stats.mustache
# * Instantiate an instance: view = Stats.new
# * Render that instance: view.render
#
# You can skip the instantiation by calling `Stats.render` directly.
#
# While Mustache will do its best to load and render a template for
# you, this process is completely customizable using a few options.
#
# All settings can be overriden at the class level.
#
# For example, going with the above example, we can use
# `Stats.template_path = "/usr/local/templates"` to specify the path
# Mustache uses to find templates.
#
# Here are the available options:
#
# * template_path
#
# The `template_path` setting determines the path Mustache uses when
# looking for a template. By default it is "."
# Setting it to /usr/local/templates, for example, means (given all
# other settings are default) a Mustache subclass `Stats` will try to
# load /usr/local/templates/stats.mustache
#
# * template_extension
#
# The `template_extension` is the extension Mustache uses when looking
# for template files. By default it is "mustache"
#
# * template_file
#
# You can tell Mustache exactly which template to use with this
# setting. It can be a relative or absolute path.
#
# * template
#
# Sometimes you want Mustache to render a string, not a file. In those
# cases you may set the `template` setting. For example:
#
# >> Mustache.render("Hello {{planet}}", :planet => "World!")
# => "Hello World!"
#
# The `template` setting is also available on instances.
#
# view = Mustache.new
# view.template = "Hi, {{person}}!"
# view[:person] = 'Mom'
# view.render # => Hi, mom!
#
# * view_namespace
#
# To make life easy on those developing Mustache plugins for web frameworks or
# other libraries, Mustache will attempt to load view classes (i.e. Mustache
# subclasses) using the `view_class` class method. The `view_namespace` tells
# Mustache under which constant view classes live. By default it is `Object`.
#
# * view_path
#
# Similar to `template_path`, the `view_path` option tells Mustache where to look
# for files containing view classes when using the `view_class` method.
#
class Mustache
# Instantiates an instance of this class and calls `render` with
# the passed args.
#
# @return A rendered String version of a template.
def self.render(*args)
new.render(*args)
end
# Parses our fancy pants template file and returns normal file with
# all special {{tags}} and {{#sections}}replaced{{/sections}}.
#
# Examples
#
# @view.render("Hi {{thing}}!", :thing => :world)
#
# View.template = "Hi {{thing}}!"
# @view = View.new
# @view.render(:thing => :world)
#
# @param [String,Hash] data A String template or a Hash context.
# If a Hash is given, we'll try to figure
# out the template from the class.
# @param [Hash] ctx A Hash context if `data` is a String template.
#
# @return [String] Returns a rendered version of a template.
def render(data = template, ctx = {})
case data
when Hash
ctx = data
when Symbol
self.template_name = data
end
tpl = case data
when Hash
templateify(template)
when Symbol
templateify(template)
else
templateify(data)
end
return tpl.render(context) if ctx == {}
begin
context.push(ctx)
tpl.render(context)
ensure
context.pop
end
end
# Context accessors.
#
# Example:
# view = Mustache.new
# view[:name] = "Jon"
# view.template = "Hi, {{name}}!"
# view.render # => "Hi, Jon!"
def [](key)
context[key.to_sym]
end
def []=(key, value)
context[key.to_sym] = value
end
# A helper method which gives access to the context at a given time.
# Kind of a hack for now, but useful when you're in an iterating section
# and want access to the hash currently being iterated over.
def context
@context ||= Context.new(self)
end
# Given a file name and an optional context, attempts to load and
# render the file as a template.
def self.render_file(name, context = {})
render(partial(name), context)
end
# Given a file name and an optional context, attempts to load and
# render the file as a template.
def render_file(name, context = {})
self.class.render_file(name, context)
end
# Given a name, attempts to read a file and return the contents as a
# string. The file is not rendered, so it might contain
# {{mustaches}}.
#
# Call `render` if you need to process it.
def self.partial(name)
File.read("#{template_path}/#{name}.#{template_extension}")
end
# Override this in your subclass if you want to do fun things like
# reading templates from a database. It will be rendered by the
# context, so all you need to do is return a string.
def partial(name)
self.class.partial(name)
end
# Override this to provide custom escaping.
#
# Example:
#
# class PersonView < Mustache
# def escapeHTML(str)
# my_html_escape_method(str)
# end
# end
#
# @param [String] str String to escape.
#
# @return [String] Escaped HTML.
def escapeHTML(str)
CGI.escapeHTML(str)
end
# Has this instance or its class already compiled a template?
def compiled?
(@template && @template.is_a?(Template)) || self.class.compiled?
end
private
# When given a symbol or string representing a class, will try to produce an
# appropriate view class.
# e.g.
# Mustache.view_namespace = Hurl::Views
# Mustache.view_class(:Partial) # => Hurl::Views::Partial
def self.view_class(name)
name = classify(name.to_s)
# Emptiness begets emptiness.
return Mustache if name.to_s.empty?
name = "#{view_namespace}::#{name}"
const = rescued_const_get(name)
return const if const
const_from_file(name)
end
def self.rescued_const_get name
const_get(name, true) || Mustache
rescue NameError
nil
end
def self.const_from_file name
file_name = underscore(name)
file_path = "#{view_path}/#{file_name}.rb"
return Mustache unless File.exists?(file_path)
require file_path.chomp('.rb')
rescued_const_get(name)
end
# Has this template already been compiled? Compilation is somewhat
# expensive so it may be useful to check this before attempting it.
def self.compiled?
@template.is_a? Template
end
# template_partial => TemplatePartial
# template/partial => Template::Partial
def self.classify(underscored)
underscored.split('/').map do |namespace|
namespace.split(/[-_]/).map do |part|
part[0] = part.chars.first.upcase
part
end.join
end.join('::')
end
# TemplatePartial => template_partial
# Template::Partial => template/partial
# Takes a string but defaults to using the current class' name.
def self.underscore(classified = name)
classified = superclass.name if classified.to_s.empty?
string = classified.dup.split("#{view_namespace}::").last
string.split('::').map do |part|
part[0] = part[0].downcase
part.gsub(/[A-Z]/) { |s| "_" << s.downcase }
end.join('/')
end
# @param [Template,String] obj Turns `obj` into a template
def self.templateify(obj)
obj.is_a?(Template) ? obj : Template.new(obj)
end
def templateify(obj)
self.class.templateify(obj)
end
# Return the value of the configuration setting on the superclass, or return
# the default.
#
# @param [Symbol] attr_name Name of the attribute. It should match
# the instance variable.
# @param [Object] default Default value to use if the superclass does
# not respond.
#
# @return Inherited or default configuration setting.
def self.inheritable_config_for(attr_name, default)
superclass.respond_to?(attr_name) ? superclass.send(attr_name) : default
end
end