Class: ViewComponent::Base

Inherits:
ActionView::Base
  • Object
show all
Includes:
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

Constructor Details

#initialize ⇒ Base

Returns a new instance of Base.



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# File 'lib/view_component/base.rb', line 156

def initialize(*)
end

Class Attribute Details

.config ⇒ ViewComponent::Config

Returns the current config.

Returns:



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

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

.source_location ⇒ Object 



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# File 'lib/view_component/base.rb', line 356

def source_location
  @source_location
end

.virtual_path ⇒ Object 



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# File 'lib/view_component/base.rb', line 356

def virtual_path
  @virtual_path
end

Instance Attribute Details

#__vc_original_view_context ⇒ Object

Returns the value of attribute __vc_original_view_context.



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

def __vc_original_view_context
  @__vc_original_view_context
end

Class Method Details

.collection_counter_parameter ⇒ Object 



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

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

.collection_iteration_parameter ⇒ Object 



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# File 'lib/view_component/base.rb', line 584

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

.collection_parameter ⇒ Object 



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# File 'lib/view_component/base.rb', line 569

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.



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# File 'lib/view_component/base.rb', line 473

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

.compiled? ⇒ Boolean

Returns:

  • (Boolean) 


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

def compiled?
  compiler.compiled?
end

.compiler ⇒ Object 



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# File 'lib/view_component/base.rb', line 478

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

.counter_argument_present? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/view_component/base.rb', line 579

def counter_argument_present?
  initialize_parameter_names.include?(collection_counter_parameter)
end

.format ⇒ Object 



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# File 'lib/view_component/base.rb', line 489

def format
  :html
end

.identifier ⇒ Object 



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# File 'lib/view_component/base.rb', line 494

def identifier
  source_location
end

.inherited(child) ⇒ Object 



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# File 'lib/view_component/base.rb', line 420

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) 


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# File 'lib/view_component/base.rb', line 589

def iteration_argument_present?
  initialize_parameter_names.include?(collection_iteration_parameter)
end

.short_identifier ⇒ Object

Provide identifier for ActionView template annotations



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# File 'lib/view_component/base.rb', line 415

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

.sidecar_files(extensions) ⇒ Object

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.

Parameters:

  • extensions (Array<String>) —

    Extensions of which to return matching sidecar files.



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# File 'lib/view_component/base.rb', line 365

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

.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.



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# File 'lib/view_component/base.rb', line 518

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) 


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# File 'lib/view_component/base.rb', line 525

def strip_trailing_whitespace?
  __vc_strip_trailing_whitespace
end

.type ⇒ Object

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



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# File 'lib/view_component/base.rb', line 484

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) 


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

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) || splatted_keyword_argument_present?

  # 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:



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

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.



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# File 'lib/view_component/base.rb', line 408

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.



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# File 'lib/view_component/base.rb', line 505

def with_collection_parameter(parameter)
  @provided_collection_parameter = parameter
end

Instance Method Details

#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.



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# File 'lib/view_component/base.rb', line 144

def before_render
  # 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) 


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# File 'lib/view_component/base.rb', line 179

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



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# File 'lib/view_component/base.rb', line 236

def format
  @__vc_variant if defined?(@__vc_variant)
end

#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) 


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# File 'lib/view_component/base.rb', line 198

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

#output_postamble ⇒ String

Optional content to be returned after the rendered template.

Returns:

  • (String) 


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# File 'lib/view_component/base.rb', line 136

def output_postamble
  ""
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`.



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

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) 


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# File 'lib/view_component/base.rb', line 151

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) 


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# File 'lib/view_component/base.rb', line 71

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?
    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.



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# File 'lib/view_component/base.rb', line 127

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) 


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# File 'lib/view_component/base.rb', line 244

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.



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

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



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# File 'lib/view_component/base.rb', line 229

def view_cache_dependencies
  []
end

#virtual_path ⇒ Object

Exposes .virtual_path as an instance method



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# File 'lib/view_component/base.rb', line 223

def virtual_path
  self.class.virtual_path
end