Class: ViewComponent::Base

Inherits:
ActionView::Base
  • Object
show all
Includes:
ContentAreas, PolymorphicSlots, SlotableV2, Translatable, WithContentHelper
Defined in:
lib/view_component/base.rb

Constant Summary collapse

ViewContextCalledBeforeRenderError = 
Class.new(StandardError)
RESERVED_PARAMETER = 
:content

Constants included from Translatable

Translatable::HTML_SAFE_TRANSLATION_KEY

Constants included from SlotableV2

SlotableV2::RESERVED_NAMES

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from WithContentHelper

#with_content

Methods included from Translatable

#html_safe_translation, #i18n_scope, #translate

Methods included from SlotableV2

#get_slot, #set_slot

Methods included from PolymorphicSlots

included

Methods included from ContentAreas

#with

Constructor Details

#initialize ⇒ Base

Returns a new instance of Base.



185
186
 
# File 'lib/view_component/base.rb', line 185

def initialize(*)
end

Class Attribute Details

.source_location ⇒ Object 



410
411
412
 
# File 'lib/view_component/base.rb', line 410

def source_location
  @source_location
end

.virtual_path ⇒ Object 



410
411
412
 
# File 'lib/view_component/base.rb', line 410

def virtual_path
  @virtual_path
end

Instance Attribute Details

#__vc_original_view_context ⇒ Object

Returns the value of attribute __vc_original_view_context.



47
48
49
 
# File 'lib/view_component/base.rb', line 47

def __vc_original_view_context
  @__vc_original_view_context
end

Class Method Details

._deprecated_generate_mattr_accessor(name) ⇒ Object 



65
66
67
68
69
70
71
72
 
# File 'lib/view_component/base.rb', line 65

def self._deprecated_generate_mattr_accessor(name)
  define_singleton_method("generate_#{name}".to_sym) do
    generate.public_send(name)
  end
  define_singleton_method("generate_#{name}=".to_sym) do |value|
    generate.public_send("#{name}=".to_sym, value)
  end
end

._sidecar_files(extensions) ⇒ Object

EXPERIMENTAL: This API is experimental and may be removed at any time. Find sidecar files for the given extensions.

The provided array of extensions is expected to contain strings starting without the “dot”, example: `[“erb”, “haml”]`.

For example, one might collect sidecar CSS files that need to be compiled.



420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
 
# File 'lib/view_component/base.rb', line 420

def _sidecar_files(extensions)
  return [] unless source_location

  extensions = extensions.join(",")

  # view files in a directory named like the component
  directory = File.dirname(source_location)
  filename = File.basename(source_location, ".rb")
  component_name = name.demodulize.underscore

  # Add support for nested components defined in the same file.
  #
  # for example
  #
  # class MyComponent < ViewComponent::Base
  #   class MyOtherComponent < ViewComponent::Base
  #   end
  # end
  #
  # Without this, `MyOtherComponent` will not look for `my_component/my_other_component.html.erb`
  nested_component_files =
    if name.include?("::") && component_name != filename
      Dir["#{directory}/#{filename}/#{component_name}.*{#{extensions}}"]
    else
      []
    end

  # view files in the same directory as the component
  sidecar_files = Dir["#{directory}/#{component_name}.*{#{extensions}}"]

  sidecar_directory_files = Dir["#{directory}/#{component_name}/#{filename}.*{#{extensions}}"]

  (sidecar_files - [source_location] + sidecar_directory_files + nested_component_files).uniq
end

.collection_counter_parameter ⇒ Object 



629
630
631
 
# File 'lib/view_component/base.rb', line 629

def collection_counter_parameter
  "#{collection_parameter}_counter".to_sym
end

.collection_iteration_parameter ⇒ Object 



639
640
641
 
# File 'lib/view_component/base.rb', line 639

def collection_iteration_parameter
  "#{collection_parameter}_iteration".to_sym
end

.collection_parameter ⇒ Object 



624
625
626
 
# File 'lib/view_component/base.rb', line 624

def collection_parameter
  provided_collection_parameter || name && name.demodulize.underscore.chomp("_component").to_sym
end

.compile(raise_errors: false, force: false) ⇒ Object

Compile templates to instance methods, assuming they haven't been compiled already.

Do as much work as possible in this step, as doing so reduces the amount of work done each time a component is rendered.



528
529
530
 
# File 'lib/view_component/base.rb', line 528

def compile(raise_errors: false, force: false)
  compiler.compile(raise_errors: raise_errors, force: force)
end

.compiled? ⇒ Boolean

Returns:

  • (Boolean) 


519
520
521
 
# File 'lib/view_component/base.rb', line 519

def compiled?
  compiler.compiled?
end

.compiler ⇒ Object 



533
534
535
 
# File 'lib/view_component/base.rb', line 533

def compiler
  @__vc_compiler ||= Compiler.new(self)
end

.config ⇒ Object 



22
23
24
 
# File 'lib/view_component/base.rb', line 22

def config
  @config ||= ViewComponent::Config.defaults
end

.counter_argument_present? ⇒ Boolean

Returns:

  • (Boolean) 


634
635
636
 
# File 'lib/view_component/base.rb', line 634

def counter_argument_present?
  initialize_parameter_names.include?(collection_counter_parameter)
end

.format ⇒ Object 



544
545
546
 
# File 'lib/view_component/base.rb', line 544

def format
  :html
end

.identifier ⇒ Object 



549
550
551
 
# File 'lib/view_component/base.rb', line 549

def identifier
  source_location
end

.inherited(child) ⇒ Object 



475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
 
# File 'lib/view_component/base.rb', line 475

def inherited(child)
  # Compile so child will inherit compiled `call_*` template methods that
  # `compile` defines
  compile

  # Give the child its own personal #render_template_for to protect against the case when
  # eager loading is disabled and the parent component is rendered before the child. In
  # such a scenario, the parent will override ViewComponent::Base#render_template_for,
  # meaning it will not be called for any children and thus not compile their templates.
  if !child.instance_methods(false).include?(:render_template_for) && !child.compiled?
    child.class_eval <<~RUBY, __FILE__, __LINE__ + 1
      def render_template_for(variant = nil)
        # Force compilation here so the compiler always redefines render_template_for.
        # This is mostly a safeguard to prevent infinite recursion.
        self.class.compile(raise_errors: true, force: true)
        # .compile replaces this method; call the new one
        render_template_for(variant)
      end
    RUBY
  end

  # If Rails application is loaded, add application url_helpers to the component context
  # we need to check this to use this gem as a dependency
  if defined?(Rails) && Rails.application && !(child < Rails.application.routes.url_helpers)
    child.include Rails.application.routes.url_helpers
  end

  # Derive the source location of the component Ruby file from the call stack.
  # We need to ignore `inherited` frames here as they indicate that `inherited`
  # has been re-defined by the consuming application, likely in ApplicationComponent.
  child.source_location = caller_locations(1, 10).reject { |l| l.label == "inherited" }[0].path

  # Removes the first part of the path and the extension.
  child.virtual_path = child.source_location.gsub(
    /(.*#{Regexp.quote(ViewComponent::Base.config.view_component_path)})|(\.rb)/, ""
  )

  # Set collection parameter to the extended component
  child.with_collection_parameter provided_collection_parameter

  super
end

.iteration_argument_present? ⇒ Boolean

Returns:

  • (Boolean) 


644
645
646
 
# File 'lib/view_component/base.rb', line 644

def iteration_argument_present?
  initialize_parameter_names.include?(collection_iteration_parameter)
end

.short_identifier ⇒ Object

Provide identifier for ActionView template annotations



470
471
472
 
# File 'lib/view_component/base.rb', line 470

def short_identifier
  @short_identifier ||= defined?(Rails.root) ? source_location.sub("#{Rails.root}/", "") : source_location
end

.strip_trailing_whitespace(value = true) ⇒ Object

Strips trailing whitespace from templates before compiling them.

“`ruby class MyComponent < ViewComponent::Base

strip_trailing_whitespace

end “`

Parameters:

  • value (Boolean) (defaults to: true) —

    Whether or not to strip newlines.



573
574
575
 
# File 'lib/view_component/base.rb', line 573

def strip_trailing_whitespace(value = true)
  self.__vc_strip_trailing_whitespace = value
end

.strip_trailing_whitespace? ⇒ Boolean

Whether trailing whitespace will be stripped before compilation.

Returns:

  • (Boolean) 


580
581
582
 
# File 'lib/view_component/base.rb', line 580

def strip_trailing_whitespace?
  __vc_strip_trailing_whitespace
end

.type ⇒ Object

we'll eventually want to update this to support other types



539
540
541
 
# File 'lib/view_component/base.rb', line 539

def type
  "text/html"
end

.validate_collection_parameter!(validate_default: false) ⇒ Object

Ensure the component initializer accepts the collection parameter. By default, we don't validate that the default parameter name is accepted, as support for collection rendering is optional.

Raises:

  • (ArgumentError) 


590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
 
# File 'lib/view_component/base.rb', line 590

def validate_collection_parameter!(validate_default: false)
  parameter = validate_default ? collection_parameter : provided_collection_parameter

  return unless parameter
  return if initialize_parameter_names.include?(parameter)

  # If Ruby can't parse the component class, then the initalize
  # parameters will be empty and ViewComponent will not be able to render
  # the component.
  if initialize_parameters.empty?
    raise ArgumentError, "The #{self} initializer is empty or invalid." \
      "It must accept the parameter `#{parameter}` to render it as a collection.\n\n" \
      "To fix this issue, update the initializer to accept `#{parameter}`.\n\n" \
      "See https://viewcomponent.org/guide/collections.html for more information on rendering collections."
  end

  raise ArgumentError, "The initializer for #{self} doesn't accept the parameter `#{parameter}`, " \
    "which is required in order to render it as a collection.\n\n" \
    "To fix this issue, update the initializer to accept `#{parameter}`.\n\n" \
    "See https://viewcomponent.org/guide/collections.html for more information on rendering collections."
end

.validate_initialization_parameters! ⇒ Object

Ensure the component initializer doesn't define invalid parameters that could override the framework's methods.

Raises:



616
617
618
619
620
621
 
# File 'lib/view_component/base.rb', line 616

def validate_initialization_parameters!
  return unless initialize_parameter_names.include?(RESERVED_PARAMETER)

  raise ViewComponent::ComponentError, "#{self} initializer can't accept the parameter `#{RESERVED_PARAMETER}`, as it will override a " \
    "public ViewComponent method. To fix this issue, rename the parameter."
end

.with_collection(collection, **args) ⇒ Object

Render a component for each element in a collection ([documentation](/guide/collections)):

“`ruby render(ProductsComponent.with_collection(@products, foo: :bar)) “`

Parameters:

  • collection (Enumerable) —

    A list of items to pass the ViewComponent one at a time.

  • args (Arguments) —

    Arguments to pass to the ViewComponent every time.



463
464
465
 
# File 'lib/view_component/base.rb', line 463

def with_collection(collection, **args)
  Collection.new(self, collection, **args)
end

.with_collection_parameter(parameter) ⇒ Object

Set the parameter name used when rendering elements of a collection ([documentation](/guide/collections)):

“`ruby with_collection_parameter :item “`

Parameters:

  • parameter (Symbol) —

    The parameter name used when rendering elements of a collection.



560
561
562
 
# File 'lib/view_component/base.rb', line 560

def with_collection_parameter(parameter)
  @provided_collection_parameter = parameter
end

Instance Method Details

#_output_postamble ⇒ String

EXPERIMENTAL: Optional content to be returned after the rendered template.

Returns:

  • (String) 


157
158
159
 
# File 'lib/view_component/base.rb', line 157

def _output_postamble
  ""
end

#before_render ⇒ void

This method returns an undefined value.

Called before rendering the component. Override to perform operations that depend on having access to the view context, such as helpers.



165
166
167
 
# File 'lib/view_component/base.rb', line 165

def before_render
  before_render_check
end

#before_render_check ⇒ void

Deprecated.

Use `#before_render` instead. Will be removed in v3.0.0.

This method returns an undefined value.

Called after rendering the component.



173
174
175
 
# File 'lib/view_component/base.rb', line 173

def before_render_check
  # noop
end

#controller ⇒ ActionController::Base

The current controller. Use sparingly as doing so introduces coupling that inhibits encapsulation & reuse, often making testing difficult.

Returns:

  • (ActionController::Base) 


208
209
210
211
212
213
214
215
216
217
218
219
220
221
 
# File 'lib/view_component/base.rb', line 208

def controller
  if view_context.nil?
    raise(
      ViewContextCalledBeforeRenderError,
      "`#controller` can't be used during initialization, as it depends " \
      "on the view context that only exists once a ViewComponent is passed to " \
      "the Rails render pipeline.\n\n" \
      "It's sometimes possible to fix this issue by moving code dependent on " \
      "`#controller` to a `#before_render` method: https://viewcomponent.org/api.html#before_render--void."
    )
  end

  @__vc_controller ||= view_context.controller
end

#format ⇒ Object

For caching, such as #cache_if



265
266
267
268
 
# File 'lib/view_component/base.rb', line 265

def format
  # Ruby 2.6 throws a warning without checking `defined?`, 2.7 doesn't
  @__vc_variant if defined?(@__vc_variant)
end

#generate_distinct_locale_files ⇒ Object

Deprecated.

Use `#generate.distinct_locale_files` instead. Will be removed in v3.0.0.



74
 
# File 'lib/view_component/base.rb', line 74

_deprecated_generate_mattr_accessor :distinct_locale_files

#generate_locale ⇒ Object

Deprecated.

Use `#generate.locale` instead. Will be removed in v3.0.0.



75
 
# File 'lib/view_component/base.rb', line 75

_deprecated_generate_mattr_accessor :locale

#generate_sidecar ⇒ Object

Deprecated.

Use `#generate.sidecar` instead. Will be removed in v3.0.0.



76
 
# File 'lib/view_component/base.rb', line 76

_deprecated_generate_mattr_accessor :sidecar

#generate_stimulus_controller ⇒ Object

Deprecated.

Use `#generate.stimulus_controller` instead. Will be removed in v3.0.0.



77
 
# File 'lib/view_component/base.rb', line 77

_deprecated_generate_mattr_accessor :stimulus_controller

#helpers ⇒ ActionView::Base

A proxy through which to access helpers. Use sparingly as doing so introduces coupling that inhibits encapsulation & reuse, often making testing difficult.

Returns:

  • (ActionView::Base) 


227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
 
# File 'lib/view_component/base.rb', line 227

def helpers
  if view_context.nil?
    raise(
      ViewContextCalledBeforeRenderError,
      "`#helpers` can't be used during initialization, as it depends " \
      "on the view context that only exists once a ViewComponent is passed to " \
      "the Rails render pipeline.\n\n" \
      "It's sometimes possible to fix this issue by moving code dependent on " \
      "`#helpers` to a `#before_render` method: https://viewcomponent.org/api.html#before_render--void."
    )
  end

  # Attempt to re-use the original view_context passed to the first
  # component rendered in the rendering pipeline. This prevents the
  # instantiation of a new view_context via `controller.view_context` which
  # always returns a new instance of the view context class.
  #
  # This allows ivars to remain persisted when using the same helper via
  # `helpers` across multiple components and partials.
  @__vc_helpers ||= __vc_original_view_context || controller.view_context
end

#render(options = {}, args = {}, &block) ⇒ Object

Re-use original view_context if we're not rendering a component.

This prevents an exception when rendering a partial inside of a component that has also been rendered outside of the component. This is due to the partials compiled template method existing in the parent `view_context`,

and not the component's `view_context`.



195
196
197
198
199
200
201
202
 
# File 'lib/view_component/base.rb', line 195

def render(options = {}, args = {}, &block)
  if options.respond_to?(:set_original_view_context)
    options.set_original_view_context(self.__vc_original_view_context)
    super
  else
    __vc_original_view_context.render(options, args, &block)
  end
end

#render? ⇒ Boolean

Override to determine whether the ViewComponent should render.

Returns:

  • (Boolean) 


180
181
182
 
# File 'lib/view_component/base.rb', line 180

def render?
  true
end

#render_in(view_context, &block) ⇒ String

Entrypoint for rendering components.

  • `view_context`: ActionView context from calling view

  • `block`: optional block to be captured within the view context

Returns HTML that has been escaped by the respective template handler.

Returns:

  • (String) 


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
 
# File 'lib/view_component/base.rb', line 87

def render_in(view_context, &block)
  self.class.compile(raise_errors: true)

  @view_context = view_context
  self.__vc_original_view_context ||= view_context

  @output_buffer = ActionView::OutputBuffer.new

  @lookup_context ||= view_context.lookup_context

  # required for path helpers in older Rails versions
  @view_renderer ||= view_context.view_renderer

  # For content_for
  @view_flow ||= view_context.view_flow

  # For i18n
  @virtual_path ||= virtual_path

  # For template variants (+phone, +desktop, etc.)
  @__vc_variant ||= @lookup_context.variants.first

  # For caching, such as #cache_if
  @current_template = nil unless defined?(@current_template)
  old_current_template = @current_template
  @current_template = self

  if block && defined?(@__vc_content_set_by_with_content)
    raise ArgumentError, "It looks like a block was provided after calling `with_content` on #{self.class.name}, " \
      "which means that ViewComponent doesn't know which content to use.\n\n" \
      "To fix this issue, use either `with_content` or a block."
  end

  @__vc_content_evaluated = false
  @__vc_render_in_block = block

  before_render

  if render?
    # Ensure `content` is evaluated before rendering the template, this is
    # needed so slots and other side-effects are performed before the
    # component template is evaluated.
    content if self.class.use_consistent_rendering_lifecycle

    render_template_for(@__vc_variant).to_s + _output_postamble
  else
    ""
  end
ensure
  @current_template = old_current_template
end

#render_parent ⇒ Object

Subclass components that call `super` inside their template code will cause a double render if they emit the result:

“`erb <%= super %> # double-renders <% super %> # does not double-render “`

Calls `super`, returning `nil` to avoid rendering the result twice.



148
149
150
151
152
 
# File 'lib/view_component/base.rb', line 148

def render_parent
  mtd = @__vc_variant ? "call_#{@__vc_variant}" : "call"
  method(mtd).super_method.call
  nil
end

#request ⇒ ActionDispatch::Request

The current request. Use sparingly as doing so introduces coupling that inhibits encapsulation & reuse, often making testing difficult.

Returns:

  • (ActionDispatch::Request) 


286
287
288
 
# File 'lib/view_component/base.rb', line 286

def request
  @request ||= controller.request if controller.respond_to?(:request)
end

#set_original_view_context(view_context) ⇒ void

This method returns an undefined value.

Components render in their own view context. Helpers and other functionality require a reference to the original Rails view context, an instance of `ActionView::Base`. Use this method to set a reference to the original view context. Objects that implement this method will render in the component's view context, while objects that don't will render in the original view context so helpers, etc work as expected.

Parameters:

  • view_context (ActionView::Base) —

    The original view context.



58
59
60
 
# File 'lib/view_component/base.rb', line 58

def set_original_view_context(view_context)
  self.__vc_original_view_context = view_context
end

#view_cache_dependencies ⇒ Object

For caching, such as #cache_if



258
259
260
 
# File 'lib/view_component/base.rb', line 258

def view_cache_dependencies
  []
end

#virtual_path ⇒ Object

Exposes .virtual_path as an instance method



252
253
254
 
# File 'lib/view_component/base.rb', line 252

def virtual_path
  self.class.virtual_path
end

#with_variant(variant) ⇒ self

Deprecated.

Will be removed in v3.0.0.

Use the provided variant instead of the one determined by the current request.

Parameters:

  • variant (Symbol) —

    The variant to be used by the component.

Returns:

  • (self) 


275
276
277
278
279
 
# File 'lib/view_component/base.rb', line 275

def with_variant(variant)
  @__vc_variant = variant

  self
end