aboutsummaryrefslogtreecommitdiffstats
path: root/actionpack/lib/action_view/base.rb
blob: 7488127e35150fd61206028e5a9ef6b947753ff5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
require 'active_support/core_ext/module/attr_internal'
require 'active_support/core_ext/module/delegation'
require 'active_support/core_ext/class/attribute'
require 'active_support/core_ext/array/wrap'
require 'active_support/ordered_options'
require 'action_view/log_subscriber'

module ActionView #:nodoc:
  # = Action View Base
  #
  # Action View templates can be written in several ways. If the template file has a <tt>.erb</tt> (or <tt>.rhtml</tt>) extension then it uses a mixture of ERb
  # (included in Ruby) and HTML. If the template file has a <tt>.builder</tt> (or <tt>.rxml</tt>) extension then Jim Weirich's Builder::XmlMarkup library is used.
  #
  # == ERB
  #
  # You trigger ERB by using embeddings such as <% %>, <% -%>, and <%= %>. The <%= %> tag set is used when you want output. Consider the
  # following loop for names:
  #
  #   <b>Names of all the people</b>
  #   <% @people.each do |person| %>
  #     Name: <%= person.name %><br/>
  #   <% end %>
  #
  # The loop is setup in regular embedding tags <% %> and the name is written using the output embedding tag <%= %>. Note that this
  # is not just a usage suggestion. Regular output functions like print or puts won't work with ERB templates. So this would be wrong:
  #
  #   <%# WRONG %>
  #   Hi, Mr. <% puts "Frodo" %>
  #
  # If you absolutely must write from within a function use +concat+.
  #
  # <%- and -%> suppress leading and trailing whitespace, including the trailing newline, and can be used interchangeably with <% and %>.
  #
  # === Using sub templates
  #
  # Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The
  # classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts):
  #
  #   <%= render "shared/header" %>
  #   Something really specific and terrific
  #   <%= render "shared/footer" %>
  #
  # As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the
  # result of the rendering. The output embedding writes it to the current template.
  #
  # But you don't have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance
  # variables defined using the regular embedding tags. Like this:
  #
  #   <% @page_title = "A Wonderful Hello" %>
  #   <%= render "shared/header" %>
  #
  # Now the header can pick up on the <tt>@page_title</tt> variable and use it for outputting a title tag:
  #
  #   <title><%= @page_title %></title>
  #
  # === Passing local variables to sub templates
  #
  # You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values:
  #
  #   <%= render "shared/header", { :headline => "Welcome", :person => person } %>
  #
  # These can now be accessed in <tt>shared/header</tt> with:
  #
  #   Headline: <%= headline %>
  #   First name: <%= person.first_name %>
  #
  # If you need to find out whether a certain local variable has been assigned a value in a particular render call,
  # you need to use the following pattern:
  #
  #   <% if local_assigns.has_key? :headline %>
  #     Headline: <%= headline %>
  #   <% end %>
  #
  # Testing using <tt>defined? headline</tt> will not work. This is an implementation restriction.
  #
  # === Template caching
  #
  # By default, Rails will compile each template to a method in order to render it. When you alter a template,
  # Rails will check the file's modification time and recompile it in development mode.
  #
  # == Builder
  #
  # Builder templates are a more programmatic alternative to ERB. They are especially useful for generating XML content. An XmlMarkup object
  # named +xml+ is automatically made available to templates with a <tt>.builder</tt> extension.
  #
  # Here are some basic examples:
  #
  #   xml.em("emphasized")                              # => <em>emphasized</em>
  #   xml.em { xml.b("emph & bold") }                   # => <em><b>emph &amp; bold</b></em>
  #   xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a>
  #   xml.target("name"=>"compile", "option"=>"fast")   # => <target option="fast" name="compile"\>
  #                                                     # NOTE: order of attributes is not specified.
  #
  # Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
  #
  #   xml.div {
  #     xml.h1(@person.name)
  #     xml.p(@person.bio)
  #   }
  #
  # would produce something like:
  #
  #   <div>
  #     <h1>David Heinemeier Hansson</h1>
  #     <p>A product of Danish Design during the Winter of '79...</p>
  #   </div>
  #
  # A full-length RSS example actually used on Basecamp:
  #
  #   xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
  #     xml.channel do
  #       xml.title(@feed_title)
  #       xml.link(@url)
  #       xml.description "Basecamp: Recent items"
  #       xml.language "en-us"
  #       xml.ttl "40"
  #
  #       for item in @recent_items
  #         xml.item do
  #           xml.title(item_title(item))
  #           xml.description(item_description(item)) if item_description(item)
  #           xml.pubDate(item_pubDate(item))
  #           xml.guid(@person.firm.account.url + @recent_items.url(item))
  #           xml.link(@person.firm.account.url + @recent_items.url(item))
  #
  #           xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
  #         end
  #       end
  #     end
  #   end
  #
  # More builder documentation can be found at http://builder.rubyforge.org.
  class Base
    include Helpers, Rendering, Partials, ::ERB::Util, Context

    # Specify the proc used to decorate input tags that refer to attributes with errors.
    cattr_accessor :field_error_proc
    @@field_error_proc = Proc.new{ |html_tag, instance| "<div class=\"field_with_errors\">#{html_tag}</div>".html_safe }

    class_attribute :helpers
    class_attribute :_routes

    class << self
      delegate :erb_trim_mode=, :to => 'ActionView::Template::Handlers::ERB'
      delegate :logger, :to => 'ActionController::Base', :allow_nil => true

      def cache_template_loading
        ActionView::Resolver.caching?
      end

      def cache_template_loading=(value)
        ActionView::Resolver.caching = value
      end
    end

    attr_accessor :_template
    attr_internal :request, :controller, :config, :assigns, :lookup_context

    delegate :formats, :formats=, :locale, :locale=, :view_paths, :view_paths=, :to => :lookup_context

    delegate :request_forgery_protection_token, :params, :session, :cookies, :response, :headers,
             :flash, :action_name, :controller_name, :to => :controller

    delegate :logger, :to => :controller, :allow_nil => true

    def self.xss_safe? #:nodoc:
      true
    end

    def self.process_view_paths(value)
      value.is_a?(PathSet) ?
        value.dup : ActionView::PathSet.new(Array.wrap(value))
    end

    def assign(new_assigns) # :nodoc:
      @_assigns = new_assigns.each { |key, value| instance_variable_set("@#{key}", value) }
    end

    def initialize(lookup_context = nil, assigns_for_first_render = {}, controller = nil, formats = nil) #:nodoc:
      assign(assigns_for_first_render)
      self.helpers = Module.new unless self.class.helpers

      @_config = {}
      @_content_for  = Hash.new { |h,k| h[k] = ActiveSupport::SafeBuffer.new }
      @_virtual_path = nil
      @output_buffer = nil

      if @_controller = controller
        @_request = controller.request if controller.respond_to?(:request)
        @_config  = controller.config.inheritable_copy if controller.respond_to?(:config)
      end

      @_lookup_context = lookup_context.is_a?(ActionView::LookupContext) ?
        lookup_context : ActionView::LookupContext.new(lookup_context)
      @_lookup_context.formats = formats if formats
    end

    def store_content_for(key, value)
      @_content_for[key] = value
    end

    def controller_path
      @controller_path ||= controller && controller.controller_path
    end

    def controller_prefixes
      @controller_prefixes ||= controller && controller._prefixes
    end

    ActiveSupport.run_load_hooks(:action_view, self)
  end
end