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Refactor compiler and template to use requested details
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@sfnelson
sfnelson committed Nov 8, 2024
1 parent 86b0149 commit 5e13764
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Showing 11 changed files with 188 additions and 103 deletions.
4 changes: 4 additions & 0 deletions docs/CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,10 @@ nav_order: 5

*Stephen Nelson*

* BREAKING: Use ActionView's `lookup_context` for picking templates instead of the request format.

*Stephen Nelson*

* Ensure HTML output safety wrapper is used for all inline templates.

*Joel Hawksley*
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22 changes: 12 additions & 10 deletions lib/view_component/base.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
require "view_component/errors"
require "view_component/inline_template"
require "view_component/preview"
require "view_component/request_details"
require "view_component/slotable"
require "view_component/slotable_default"
require "view_component/template"
Expand Down Expand Up @@ -63,6 +64,8 @@ def set_original_view_context(view_context)
self.__vc_original_view_context = view_context
end

using RequestDetails

# Entrypoint for rendering components.
#
# - `view_context`: ActionView context from calling view
Expand Down Expand Up @@ -90,13 +93,12 @@ def render_in(view_context, &block)
# For i18n
@virtual_path ||= virtual_path

# For template variants (+phone, +desktop, etc.)
@__vc_variant ||= @lookup_context.variants.first
# Describes the inferred request constraints (locales, formats, variants)
@__vc_requested_details ||= @lookup_context.vc_requested_details

# 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 DuplicateContentError.new(self.class.name)
Expand All @@ -108,7 +110,7 @@ def render_in(view_context, &block)
before_render

if render?
rendered_template = render_template_for(@__vc_variant, __vc_request&.format&.to_sym).to_s
rendered_template = render_template_for(@__vc_requested_details).to_s

# Avoid allocating new string when output_preamble and output_postamble are blank
if output_preamble.blank? && output_postamble.blank?
Expand Down Expand Up @@ -156,7 +158,7 @@ def render_parent_to_string
target_render = self.class.instance_variable_get(:@__vc_ancestor_calls)[@__vc_parent_render_level]
@__vc_parent_render_level += 1

target_render.bind_call(self, @__vc_variant)
target_render.bind_call(self, @__vc_requested_details)
ensure
@__vc_parent_render_level -= 1
end
Expand Down Expand Up @@ -267,11 +269,11 @@ def view_cache_dependencies
[]
end

# For caching, such as #cache_if
# Expected by ActionView::Template::Renderable
#
# @private
def format
@__vc_variant if defined?(@__vc_variant)
nil
end

# The current request. Use sparingly as doing so introduces coupling that
Expand Down Expand Up @@ -328,7 +330,7 @@ def content_evaluated?
end

def maybe_escape_html(text)
return text if __vc_request && !__vc_request.format.html?
return text if @current_template && !@current_template.html?
return text if text.blank?

if text.html_safe?
Expand Down Expand Up @@ -517,12 +519,12 @@ def inherited(child)
# 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, format = nil)
def render_template_for(requested_details)
# 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, format)
render_template_for(requested_details)
end
RUBY
end
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86 changes: 42 additions & 44 deletions lib/view_component/compiler.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -55,6 +55,23 @@ def compile(raise_errors: false, force: false)
end
end

# @return all matching compiled templates, in priority order based on the requested details from LookupContext
#
# @param [ActionView::TemplateDetails::Requested] requested_details i.e. locales, formats, variants
def find_templates_for(requested_details)
filtered_templates = @templates.select do |template|
template.details.matches?(requested_details)
end

if filtered_templates.count > 1
filtered_templates.sort_by! do |template|
template.details.sort_key_for(requested_details)
end
end

filtered_templates
end

private

attr_reader :templates
Expand All @@ -64,40 +81,25 @@ def define_render_template_for
template.compile_to_component
end

method_body =
if @templates.one?
@templates.first.safe_method_name_call
elsif (template = @templates.find(&:inline?))
template.safe_method_name_call
else
branches = []

@templates.each do |template|
conditional =
if template.inline_call?
"variant&.to_sym == #{template.variant.inspect}"
else
[
template.default_format? ? "(format == #{ViewComponent::Base::VC_INTERNAL_DEFAULT_FORMAT.inspect} || format.nil?)" : "format == #{template.format.inspect}",
template.variant.nil? ? "variant.nil?" : "variant&.to_sym == #{template.variant.inspect}"
].join(" && ")
end

branches << [conditional, template.safe_method_name_call]
end
@component.silence_redefinition_of_method(:render_template_for)

out = branches.each_with_object(+"") do |(conditional, branch_body), memo|
memo << "#{(!memo.present?) ? "if" : "elsif"} #{conditional}\n #{branch_body}\n"
if @templates.one?
template = @templates.first
safe_call = template.safe_method_name_call
@component.define_method(:render_template_for) do |_|
@current_template = template
instance_exec(&safe_call)
end
else
compiler = self
@component.define_method(:render_template_for) do |details|
if (@current_template = compiler.find_templates_for(details).first)
instance_exec(&@current_template.safe_method_name_call)
else
raise MissingTemplateError.new(self.class.name, details)
end
out << "else\n #{templates.find { _1.variant.nil? && _1.default_format? }.safe_method_name_call}\nend"
end

@component.silence_redefinition_of_method(:render_template_for)
@component.class_eval <<-RUBY, __FILE__, __LINE__ + 1
def render_template_for(variant = nil, format = nil)
#{method_body}
end
RUBY
end

def template_errors
Expand Down Expand Up @@ -168,15 +170,18 @@ def template_errors

def gather_templates
@templates ||=
begin
if @component.inline_template.present?
[Template::Inline.new(
component: @component,
inline_template: @component.inline_template
)]
else
path_parser = ActionView::Resolver::PathParser.new
templates = @component.sidecar_files(
ActionView::Template.template_handler_extensions
).map do |path|
details = path_parser.parse(path).details
out = Template::File.new(component: @component, path: path, details: details)

out
Template::File.new(component: @component, path: path, details: details)
end

component_instance_methods_on_self = @component.instance_methods(false)
Expand All @@ -186,17 +191,10 @@ def gather_templates
).flat_map { |ancestor| ancestor.instance_methods(false).grep(/^call(_|$)/) }
.uniq
.each do |method_name|
templates << Template::InlineCall.new(
component: @component,
method_name: method_name,
defined_on_self: component_instance_methods_on_self.include?(method_name)
)
end

if @component.inline_template.present?
templates << Template::Inline.new(
templates << Template::InlineCall.new(
component: @component,
inline_template: @component.inline_template
method_name: method_name,
defined_on_self: component_instance_methods_on_self.include?(method_name)
)
end

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16 changes: 16 additions & 0 deletions lib/view_component/errors.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -38,6 +38,22 @@ def initialize(example)
end
end

class MissingTemplateError < StandardError
MESSAGE =
"No templates for COMPONENT match the request DETAIL.\n\n" \
"To fix this issue, provide a suitable template."

def initialize(component, request_detail)
detail = {
locale: request_detail.locale,
formats: request_detail.formats,
variants: request_detail.variants,
handlers: request_detail.handlers
}
super(MESSAGE.gsub("COMPONENT", component).gsub("DETAIL", detail.inspect))
end
end

class DuplicateContentError < StandardError
MESSAGE =
"It looks like a block was provided after calling `with_content` on COMPONENT, " \
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30 changes: 30 additions & 0 deletions lib/view_component/request_details.rb
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Original file line number Diff line number Diff line change
@@ -0,0 +1,30 @@
# frozen_string_literal: true

module ViewComponent
# LookupContext computes and encapsulates @details for each request
# so that it doesn't need to be recomputed on each partial render.
# This data is wrapped in ActionView::TemplateDetails::Requested and
# used by instances of ActionView::Resolver to choose which template
# best matches the request.
#
# ActionView considers this logic internal to template/partial resolution.
# We're exposing it to the compiler via `refine` so that ViewComponent
# can match Rails' template picking logic.
module RequestDetails
refine ActionView::LookupContext do
# Return an abstraction for matching and sorting available templates
# based on the current lookup context details.
#
# @return ActionView::TemplateDetails::Requested
# @see ActionView::LookupContext#detail_args_for
# @see ActionView::FileSystemResolver#_find_all
def vc_requested_details(user_details = {})
# The hash `user_details` would normally be the standard arguments that
# `render` accepts, but there's currently no mechanism for users to
# provide these when calling render on a ViewComponent.
details, cached = detail_args_for(user_details)
cached || ActionView::TemplateDetails::Requested.new(**details)
end
end
end
end
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