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Diffstat (limited to 'actionview/lib/action_view/renderer/partial_renderer.rb')
| -rw-r--r-- | actionview/lib/action_view/renderer/partial_renderer.rb | 552 |
1 files changed, 552 insertions, 0 deletions
diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb new file mode 100644 index 0000000000..cb850d75ee --- /dev/null +++ b/actionview/lib/action_view/renderer/partial_renderer.rb @@ -0,0 +1,552 @@ +# frozen_string_literal: true + +require "concurrent/map" +require "action_view/renderer/partial_renderer/collection_caching" + +module ActionView + class PartialIteration + # The number of iterations that will be done by the partial. + attr_reader :size + + # The current iteration of the partial. + attr_reader :index + + def initialize(size) + @size = size + @index = 0 + end + + # Check if this is the first iteration of the partial. + def first? + index == 0 + end + + # Check if this is the last iteration of the partial. + def last? + index == size - 1 + end + + def iterate! # :nodoc: + @index += 1 + end + end + + # = Action View Partials + # + # There's also a convenience method for rendering sub templates within the current controller that depends on a + # single object (we call this kind of sub templates for partials). It relies on the fact that partials should + # follow the naming convention of being prefixed with an underscore -- as to separate them from regular + # templates that could be rendered on their own. + # + # In a template for Advertiser#account: + # + # <%= render partial: "account" %> + # + # This would render "advertiser/_account.html.erb". + # + # In another template for Advertiser#buy, we could have: + # + # <%= render partial: "account", locals: { account: @buyer } %> + # + # <% @advertisements.each do |ad| %> + # <%= render partial: "ad", locals: { ad: ad } %> + # <% end %> + # + # This would first render <tt>advertiser/_account.html.erb</tt> with <tt>@buyer</tt> passed in as the local variable +account+, then + # render <tt>advertiser/_ad.html.erb</tt> and pass the local variable +ad+ to the template for display. + # + # == The :as and :object options + # + # By default ActionView::PartialRenderer doesn't have any local variables. + # The <tt>:object</tt> option can be used to pass an object to the partial. For instance: + # + # <%= render partial: "account", object: @buyer %> + # + # would provide the <tt>@buyer</tt> object to the partial, available under the local variable +account+ and is + # equivalent to: + # + # <%= render partial: "account", locals: { account: @buyer } %> + # + # With the <tt>:as</tt> option we can specify a different name for said local variable. For example, if we + # wanted it to be +user+ instead of +account+ we'd do: + # + # <%= render partial: "account", object: @buyer, as: 'user' %> + # + # This is equivalent to + # + # <%= render partial: "account", locals: { user: @buyer } %> + # + # == \Rendering a collection of partials + # + # The example of partial use describes a familiar pattern where a template needs to iterate over an array and + # render a sub template for each of the elements. This pattern has been implemented as a single method that + # accepts an array and renders a partial by the same name as the elements contained within. So the three-lined + # example in "Using partials" can be rewritten with a single line: + # + # <%= render partial: "ad", collection: @advertisements %> + # + # This will render <tt>advertiser/_ad.html.erb</tt> and pass the local variable +ad+ to the template for display. An + # iteration object will automatically be made available to the template with a name of the form + # +partial_name_iteration+. The iteration object has knowledge about which index the current object has in + # the collection and the total size of the collection. The iteration object also has two convenience methods, + # +first?+ and +last?+. In the case of the example above, the template would be fed +ad_iteration+. + # For backwards compatibility the +partial_name_counter+ is still present and is mapped to the iteration's + # +index+ method. + # + # The <tt>:as</tt> option may be used when rendering partials. + # + # You can specify a partial to be rendered between elements via the <tt>:spacer_template</tt> option. + # The following example will render <tt>advertiser/_ad_divider.html.erb</tt> between each ad partial: + # + # <%= render partial: "ad", collection: @advertisements, spacer_template: "ad_divider" %> + # + # If the given <tt>:collection</tt> is +nil+ or empty, <tt>render</tt> will return +nil+. This will allow you + # to specify a text which will be displayed instead by using this form: + # + # <%= render(partial: "ad", collection: @advertisements) || "There's no ad to be displayed" %> + # + # NOTE: Due to backwards compatibility concerns, the collection can't be one of hashes. Normally you'd also + # just keep domain objects, like Active Records, in there. + # + # == \Rendering shared partials + # + # Two controllers can share a set of partials and render them like this: + # + # <%= render partial: "advertisement/ad", locals: { ad: @advertisement } %> + # + # This will render the partial <tt>advertisement/_ad.html.erb</tt> regardless of which controller this is being called from. + # + # == \Rendering objects that respond to +to_partial_path+ + # + # Instead of explicitly naming the location of a partial, you can also let PartialRenderer do the work + # and pick the proper path by checking +to_partial_path+ method. + # + # # @account.to_partial_path returns 'accounts/account', so it can be used to replace: + # # <%= render partial: "accounts/account", locals: { account: @account} %> + # <%= render partial: @account %> + # + # # @posts is an array of Post instances, so every post record returns 'posts/post' on +to_partial_path+, + # # that's why we can replace: + # # <%= render partial: "posts/post", collection: @posts %> + # <%= render partial: @posts %> + # + # == \Rendering the default case + # + # If you're not going to be using any of the options like collections or layouts, you can also use the short-hand + # defaults of render to render partials. Examples: + # + # # Instead of <%= render partial: "account" %> + # <%= render "account" %> + # + # # Instead of <%= render partial: "account", locals: { account: @buyer } %> + # <%= render "account", account: @buyer %> + # + # # @account.to_partial_path returns 'accounts/account', so it can be used to replace: + # # <%= render partial: "accounts/account", locals: { account: @account} %> + # <%= render @account %> + # + # # @posts is an array of Post instances, so every post record returns 'posts/post' on +to_partial_path+, + # # that's why we can replace: + # # <%= render partial: "posts/post", collection: @posts %> + # <%= render @posts %> + # + # == \Rendering partials with layouts + # + # Partials can have their own layouts applied to them. These layouts are different than the ones that are + # specified globally for the entire action, but they work in a similar fashion. Imagine a list with two types + # of users: + # + # <%# app/views/users/index.html.erb %> + # Here's the administrator: + # <%= render partial: "user", layout: "administrator", locals: { user: administrator } %> + # + # Here's the editor: + # <%= render partial: "user", layout: "editor", locals: { user: editor } %> + # + # <%# app/views/users/_user.html.erb %> + # Name: <%= user.name %> + # + # <%# app/views/users/_administrator.html.erb %> + # <div id="administrator"> + # Budget: $<%= user.budget %> + # <%= yield %> + # </div> + # + # <%# app/views/users/_editor.html.erb %> + # <div id="editor"> + # Deadline: <%= user.deadline %> + # <%= yield %> + # </div> + # + # ...this will return: + # + # Here's the administrator: + # <div id="administrator"> + # Budget: $<%= user.budget %> + # Name: <%= user.name %> + # </div> + # + # Here's the editor: + # <div id="editor"> + # Deadline: <%= user.deadline %> + # Name: <%= user.name %> + # </div> + # + # If a collection is given, the layout will be rendered once for each item in + # the collection. For example, these two snippets have the same output: + # + # <%# app/views/users/_user.html.erb %> + # Name: <%= user.name %> + # + # <%# app/views/users/index.html.erb %> + # <%# This does not use layouts %> + # <ul> + # <% users.each do |user| -%> + # <li> + # <%= render partial: "user", locals: { user: user } %> + # </li> + # <% end -%> + # </ul> + # + # <%# app/views/users/_li_layout.html.erb %> + # <li> + # <%= yield %> + # </li> + # + # <%# app/views/users/index.html.erb %> + # <ul> + # <%= render partial: "user", layout: "li_layout", collection: users %> + # </ul> + # + # Given two users whose names are Alice and Bob, these snippets return: + # + # <ul> + # <li> + # Name: Alice + # </li> + # <li> + # Name: Bob + # </li> + # </ul> + # + # The current object being rendered, as well as the object_counter, will be + # available as local variables inside the layout template under the same names + # as available in the partial. + # + # You can also apply a layout to a block within any template: + # + # <%# app/views/users/_chief.html.erb %> + # <%= render(layout: "administrator", locals: { user: chief }) do %> + # Title: <%= chief.title %> + # <% end %> + # + # ...this will return: + # + # <div id="administrator"> + # Budget: $<%= user.budget %> + # Title: <%= chief.name %> + # </div> + # + # As you can see, the <tt>:locals</tt> hash is shared between both the partial and its layout. + # + # If you pass arguments to "yield" then this will be passed to the block. One way to use this is to pass + # an array to layout and treat it as an enumerable. + # + # <%# app/views/users/_user.html.erb %> + # <div class="user"> + # Budget: $<%= user.budget %> + # <%= yield user %> + # </div> + # + # <%# app/views/users/index.html.erb %> + # <%= render layout: @users do |user| %> + # Title: <%= user.title %> + # <% end %> + # + # This will render the layout for each user and yield to the block, passing the user, each time. + # + # You can also yield multiple times in one layout and use block arguments to differentiate the sections. + # + # <%# app/views/users/_user.html.erb %> + # <div class="user"> + # <%= yield user, :header %> + # Budget: $<%= user.budget %> + # <%= yield user, :footer %> + # </div> + # + # <%# app/views/users/index.html.erb %> + # <%= render layout: @users do |user, section| %> + # <%- case section when :header -%> + # Title: <%= user.title %> + # <%- when :footer -%> + # Deadline: <%= user.deadline %> + # <%- end -%> + # <% end %> + class PartialRenderer < AbstractRenderer + include CollectionCaching + + PREFIXED_PARTIAL_NAMES = Concurrent::Map.new do |h, k| + h[k] = Concurrent::Map.new + end + + def initialize(*) + super + @context_prefix = @lookup_context.prefixes.first + end + + def render(context, options, block) + setup(context, options, block) + @template = find_partial + + @lookup_context.rendered_format ||= begin + if @template && @template.formats.present? + @template.formats.first + else + formats.first + end + end + + if @collection + render_collection + else + render_partial + end + end + + private + + def render_collection + instrument(:collection, count: @collection.size) do |payload| + return nil if @collection.blank? + + if @options.key?(:spacer_template) + spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals) + end + + cache_collection_render(payload) do + @template ? collection_with_template : collection_without_template + end.join(spacer).html_safe + end + end + + def render_partial + instrument(:partial) do |payload| + view, locals, block = @view, @locals, @block + object, as = @object, @variable + + if !block && (layout = @options[:layout]) + layout = find_template(layout.to_s, @template_keys) + end + + object = locals[as] if object.nil? # Respect object when object is false + locals[as] = object if @has_object + + content = @template.render(view, locals) do |*name| + view._layout_for(*name, &block) + end + + content = layout.render(view, locals) { content } if layout + payload[:cache_hit] = view.view_renderer.cache_hits[@template.virtual_path] + content + end + end + + # Sets up instance variables needed for rendering a partial. This method + # finds the options and details and extracts them. The method also contains + # logic that handles the type of object passed in as the partial. + # + # If +options[:partial]+ is a string, then the <tt>@path</tt> instance variable is + # set to that string. Otherwise, the +options[:partial]+ object must + # respond to +to_partial_path+ in order to setup the path. + def setup(context, options, block) + @view = context + @options = options + @block = block + + @locals = options[:locals] ? options[:locals].symbolize_keys : {} + @details = extract_details(options) + + prepend_formats(options[:formats]) + + partial = options[:partial] + + if String === partial + @has_object = options.key?(:object) + @object = options[:object] + @collection = collection_from_options + @path = partial + else + @has_object = true + @object = partial + @collection = collection_from_object || collection_from_options + + if @collection + paths = @collection_data = @collection.map { |o| partial_path(o) } + @path = paths.uniq.one? ? paths.first : nil + else + @path = partial_path + end + end + + if as = options[:as] + raise_invalid_option_as(as) unless /\A[a-z_]\w*\z/.match?(as.to_s) + as = as.to_sym + end + + if @path + @variable, @variable_counter, @variable_iteration = retrieve_variable(@path, as) + @template_keys = retrieve_template_keys + else + paths.map! { |path| retrieve_variable(path, as).unshift(path) } + end + + self + end + + def collection_from_options + if @options.key?(:collection) + collection = @options[:collection] + collection ? collection.to_a : [] + end + end + + def collection_from_object + @object.to_ary if @object.respond_to?(:to_ary) + end + + def find_partial + find_template(@path, @template_keys) if @path + end + + def find_template(path, locals) + prefixes = path.include?(?/) ? [] : @lookup_context.prefixes + @lookup_context.find_template(path, prefixes, true, locals, @details) + end + + def collection_with_template + view, locals, template = @view, @locals, @template + as, counter, iteration = @variable, @variable_counter, @variable_iteration + + if layout = @options[:layout] + layout = find_template(layout, @template_keys) + end + + partial_iteration = PartialIteration.new(@collection.size) + locals[iteration] = partial_iteration + + @collection.map do |object| + locals[as] = object + locals[counter] = partial_iteration.index + + content = template.render(view, locals) + content = layout.render(view, locals) { content } if layout + partial_iteration.iterate! + content + end + end + + def collection_without_template + view, locals, collection_data = @view, @locals, @collection_data + cache = {} + keys = @locals.keys + + partial_iteration = PartialIteration.new(@collection.size) + + @collection.map do |object| + index = partial_iteration.index + path, as, counter, iteration = collection_data[index] + + locals[as] = object + locals[counter] = index + locals[iteration] = partial_iteration + + template = (cache[path] ||= find_template(path, keys + [as, counter, iteration])) + content = template.render(view, locals) + partial_iteration.iterate! + content + end + end + + # Obtains the path to where the object's partial is located. If the object + # responds to +to_partial_path+, then +to_partial_path+ will be called and + # will provide the path. If the object does not respond to +to_partial_path+, + # then an +ArgumentError+ is raised. + # + # If +prefix_partial_path_with_controller_namespace+ is true, then this + # method will prefix the partial paths with a namespace. + def partial_path(object = @object) + object = object.to_model if object.respond_to?(:to_model) + + path = if object.respond_to?(:to_partial_path) + object.to_partial_path + else + raise ArgumentError.new("'#{object.inspect}' is not an ActiveModel-compatible object. It must implement :to_partial_path.") + end + + if @view.prefix_partial_path_with_controller_namespace + prefixed_partial_names[path] ||= merge_prefix_into_object_path(@context_prefix, path.dup) + else + path + end + end + + def prefixed_partial_names + @prefixed_partial_names ||= PREFIXED_PARTIAL_NAMES[@context_prefix] + end + + def merge_prefix_into_object_path(prefix, object_path) + if prefix.include?(?/) && object_path.include?(?/) + prefixes = [] + prefix_array = File.dirname(prefix).split("/") + object_path_array = object_path.split("/")[0..-3] # skip model dir & partial + + prefix_array.each_with_index do |dir, index| + break if dir == object_path_array[index] + prefixes << dir + end + + (prefixes << object_path).join("/") + else + object_path + end + end + + def retrieve_template_keys + keys = @locals.keys + keys << @variable if @has_object || @collection + if @collection + keys << @variable_counter + keys << @variable_iteration + end + keys + end + + def retrieve_variable(path, as) + variable = as || begin + base = path[-1] == "/" ? "" : File.basename(path) + raise_invalid_identifier(path) unless base =~ /\A_?(.*?)(?:\.\w+)*\z/ + $1.to_sym + end + if @collection + variable_counter = :"#{variable}_counter" + variable_iteration = :"#{variable}_iteration" + end + [variable, variable_counter, variable_iteration] + end + + IDENTIFIER_ERROR_MESSAGE = "The partial name (%s) is not a valid Ruby identifier; " \ + "make sure your partial name starts with underscore." + + OPTION_AS_ERROR_MESSAGE = "The value (%s) of the option `as` is not a valid Ruby identifier; " \ + "make sure it starts with lowercase letter, " \ + "and is followed by any combination of letters, numbers and underscores." + + def raise_invalid_identifier(path) + raise ArgumentError.new(IDENTIFIER_ERROR_MESSAGE % (path)) + end + + def raise_invalid_option_as(as) + raise ArgumentError.new(OPTION_AS_ERROR_MESSAGE % (as)) + end + end +end |