aboutsummaryrefslogtreecommitdiffstats
path: root/actionview/lib/action_view/base.rb
blob: 5253ef7b0cae9a570949ed5aa59011b95c027170 (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
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
# frozen_string_literal: true

require "active_support/core_ext/module/attr_internal"
require "active_support/core_ext/module/attribute_accessors"
require "active_support/ordered_options"
require "active_support/deprecation"
require "action_view/log_subscriber"
require "action_view/helpers"
require "action_view/context"
require "action_view/template"
require "action_view/lookup_context"

module ActionView #:nodoc:
  # = Action View Base
  #
  # Action View templates can be written in several ways.
  # If the template file has a <tt>.erb</tt> extension, then it uses the erubi[https://rubygems.org/gems/erubi]
  # template system which can embed Ruby into an HTML document.
  # If the template file has a <tt>.builder</tt> extension, then Jim Weirich's Builder::XmlMarkup library is used.
  #
  # == ERB
  #
  # You trigger ERB by using embeddings such as <tt><% %></tt>, <tt><% -%></tt>, and <tt><%= %></tt>. The <tt><%= %></tt> 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 <tt><% %></tt>, and the name is written using the output embedding tag <tt><%= %></tt>. 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+.
  #
  # When on a line that only contains whitespaces except for the tag, <tt><% %></tt> suppresses leading and trailing whitespace,
  # including the trailing newline. <tt><% %></tt> and <tt><%- -%></tt> are the same.
  # Note however that <tt><%= %></tt> and <tt><%= -%></tt> are different: only the latter removes trailing whitespaces.
  #
  # === 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 %>
  #
  # The local variables passed to sub templates can be accessed as a hash using the <tt>local_assigns</tt> hash. This lets you access the
  # variables as:
  #
  #   Headline: <%= local_assigns[:headline] %>
  #
  # This is useful in cases where you aren't sure if the local variable has been assigned. Alternatively, you could also use
  # <tt>defined? headline</tt> to first check if the variable has been assigned before using it.
  #
  # === 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 do
  #     xml.h1(@person.name)
  #     xml.p(@person.bio)
  #   end
  #
  # would produce something like:
  #
  #   <div>
  #     <h1>David Heinemeier Hansson</h1>
  #     <p>A product of Danish Design during the Winter of '79...</p>
  #   </div>
  #
  # Here is 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"
  #
  #       @recent_items.each do |item|
  #         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
  #
  # For more information on Builder please consult the {source
  # code}[https://github.com/jimweirich/builder].
  class Base
    include Helpers, ::ERB::Util, Context

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

    # How to complete the streaming when an exception occurs.
    # This is our best guess: first try to close the attribute, then the tag.
    cattr_accessor :streaming_completion_on_exception, default: %("><script>window.location = "/500.html"</script></html>)

    # Specify whether rendering within namespaced controllers should prefix
    # the partial paths for ActiveModel objects with the namespace.
    # (e.g., an Admin::PostsController would render @post using /admin/posts/_post.erb)
    cattr_accessor :prefix_partial_path_with_controller_namespace, default: true

    # Specify default_formats that can be rendered.
    cattr_accessor :default_formats

    # Specify whether an error should be raised for missing translations
    cattr_accessor :raise_on_missing_translations, default: false

    # Specify whether submit_tag should automatically disable on click
    cattr_accessor :automatically_disable_submit_tag, default: true

    class_attribute :_routes
    class_attribute :logger

    class << self
      delegate :erb_trim_mode=, to: "ActionView::Template::Handlers::ERB"

      def cache_template_loading
        ActionView::Resolver.caching?
      end

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

      def xss_safe? #:nodoc:
        true
      end

      def with_empty_template_cache # :nodoc:
        subclass = Class.new(self) {
          # We can't implement these as self.class because subclasses will
          # share the same template cache as superclasses, so "changed?" won't work
          # correctly.
          define_method(:compiled_method_container)           { subclass }
          define_singleton_method(:compiled_method_container) { subclass }
        }
      end

      def changed?(other) # :nodoc:
        compiled_method_container != other.compiled_method_container
      end
    end

    attr_reader :view_renderer, :lookup_context
    attr_internal :config, :assigns

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

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

    # :stopdoc:

    def self.build_lookup_context(context)
      case context
      when ActionView::Renderer
        context.lookup_context
      when Array
        ActionView::LookupContext.new(context)
      when ActionView::PathSet
        ActionView::LookupContext.new(context)
      when nil
        ActionView::LookupContext.new([])
      else
        raise NotImplementedError, context.class.name
      end
    end

    def self.empty
      with_view_paths([])
    end

    def self.with_view_paths(view_paths, assigns = {}, controller = nil)
      with_context ActionView::LookupContext.new(view_paths), assigns, controller
    end

    def self.with_context(context, assigns = {}, controller = nil)
      new context, assigns, controller
    end

    NULL = Object.new

    # :startdoc:

    def initialize(lookup_context = nil, assigns = {}, controller = nil, formats = NULL) #:nodoc:
      @_config = ActiveSupport::InheritableOptions.new

      unless formats == NULL
        ActiveSupport::Deprecation.warn <<~eowarn.squish
        Passing formats to ActionView::Base.new is deprecated
        eowarn
      end

      case lookup_context
      when ActionView::LookupContext
        @lookup_context = lookup_context
      else
        ActiveSupport::Deprecation.warn <<~eowarn.squish
        ActionView::Base instances should be constructed with a lookup context,
        assignments, and a controller.
        eowarn
        @lookup_context = self.class.build_lookup_context(lookup_context)
      end

      @view_renderer = ActionView::Renderer.new @lookup_context
      @current_template = nil

      @cache_hit = {}
      assign(assigns)
      assign_controller(controller)
      _prepare_context
    end

    def _run(method, template, locals, buffer, &block)
      _old_output_buffer, _old_virtual_path, _old_template = @output_buffer, @virtual_path, @current_template
      @current_template = template
      @output_buffer = buffer
      send(method, locals, buffer, &block)
    ensure
      @output_buffer, @virtual_path, @current_template = _old_output_buffer, _old_virtual_path, _old_template
    end

    def compiled_method_container
      if self.class == ActionView::Base
        ActiveSupport::Deprecation.warn <<~eowarn.squish
          ActionView::Base instances must implement `compiled_method_container`
          or use the class method `with_empty_template_cache` for constructing
          an ActionView::Base instances that has an empty cache.
        eowarn
      end

      self.class
    end

    def in_rendering_context(options)
      old_view_renderer  = @view_renderer
      old_lookup_context = @lookup_context

      if !lookup_context.html_fallback_for_js && options[:formats]
        formats = Array(options[:formats])
        if formats == [:js]
          formats << :html
        end
        @lookup_context = lookup_context.with_prepended_formats(formats)
        @view_renderer = ActionView::Renderer.new @lookup_context
      end

      yield @view_renderer
    ensure
      @view_renderer = old_view_renderer
      @lookup_context = old_lookup_context
    end

    ActiveSupport.run_load_hooks(:action_view, self)
  end
end