gitlab-org--gitlab-foss/app/models/concerns/cache_markdown_field.rb
Patrick Bajao 2eecfd8f9d Use Redis for CacheMarkDownField on non AR models
This allows using `CacheMarkdownField` for models that are not backed
by ActiveRecord.

When the including class inherits `ActiveRecord::Base` we include
`Gitlab::MarkdownCache::ActiveRecord::Extension`. This will cause the
markdown fields to be rendered and the generated HTML stored in a
`<field>_html` attribute on the record. We also store the version
used for generating the markdown.

All other classes that include this model will include the
`Gitlab::MarkdownCache::Redis::Extension`. This add the `<field>_html`
attributes to that model and will generate the html in them. The
generated HTML will be cached in redis under the key
`markdown_cache:<class>:<id>`. The class this included in must
therefore respond to `id`.
2019-06-05 13:19:59 +08:00

148 lines
5.2 KiB
Ruby

# frozen_string_literal: true
# This module takes care of updating cache columns for Markdown-containing
# fields. Use like this in the body of your class:
#
# include CacheMarkdownField
# cache_markdown_field :foo
# cache_markdown_field :bar
# cache_markdown_field :baz, pipeline: :single_line
# cache_markdown_field :baz, whitelisted: true
#
# Corresponding foo_html, bar_html and baz_html fields should exist.
module CacheMarkdownField
extend ActiveSupport::Concern
# changes to these attributes cause the cache to be invalidates
INVALIDATED_BY = %w[author project].freeze
def skip_project_check?
false
end
# Returns the default Banzai render context for the cached markdown field.
def banzai_render_context(field)
raise ArgumentError.new("Unknown field: #{field.inspect}") unless
cached_markdown_fields.markdown_fields.include?(field)
# Always include a project key, or Banzai complains
project = self.project if self.respond_to?(:project)
group = self.group if self.respond_to?(:group)
context = cached_markdown_fields[field].merge(project: project, group: group)
# Banzai is less strict about authors, so don't always have an author key
context[:author] = self.author if self.respond_to?(:author)
context[:markdown_engine] = :common_mark
context
end
# Update every column in a row if any one is invalidated, as we only store
# one version per row
def refresh_markdown_cache
options = { skip_project_check: skip_project_check? }
updates = cached_markdown_fields.markdown_fields.map do |markdown_field|
[
cached_markdown_fields.html_field(markdown_field),
Banzai::Renderer.cacheless_render_field(self, markdown_field, options)
]
end.to_h
updates['cached_markdown_version'] = latest_cached_markdown_version
updates.each { |field, data| write_markdown_field(field, data) }
end
def refresh_markdown_cache!
updates = refresh_markdown_cache
save_markdown(updates)
end
def cached_html_up_to_date?(markdown_field)
return false if cached_html_for(markdown_field).nil? && __send__(markdown_field).present? # rubocop:disable GitlabSecurity/PublicSend
html_field = cached_markdown_fields.html_field(markdown_field)
markdown_changed = markdown_field_changed?(markdown_field)
html_changed = markdown_field_changed?(html_field)
latest_cached_markdown_version == cached_markdown_version &&
(html_changed || markdown_changed == html_changed)
end
def invalidated_markdown_cache?
cached_markdown_fields.html_fields.any? {|html_field| attribute_invalidated?(html_field) }
end
def attribute_invalidated?(attr)
__send__("#{attr}_invalidated?") # rubocop:disable GitlabSecurity/PublicSend
end
def cached_html_for(markdown_field)
raise ArgumentError.new("Unknown field: #{markdown_field}") unless
cached_markdown_fields.markdown_fields.include?(markdown_field)
__send__(cached_markdown_fields.html_field(markdown_field)) # rubocop:disable GitlabSecurity/PublicSend
end
def latest_cached_markdown_version
@latest_cached_markdown_version ||= (Gitlab::MarkdownCache::CACHE_COMMONMARK_VERSION << 16) | local_version
end
def local_version
# because local_markdown_version is stored in application_settings which
# uses cached_markdown_version too, we check explicitly to avoid
# endless loop
return local_markdown_version if respond_to?(:has_attribute?) && has_attribute?(:local_markdown_version)
settings = Gitlab::CurrentSettings.current_application_settings
# Following migrations are not properly isolated and
# use real models (by calling .ghost method), in these migrations
# local_markdown_version attribute doesn't exist yet, so we
# use a default value:
# db/migrate/20170825104051_migrate_issues_to_ghost_user.rb
# db/migrate/20171114150259_merge_requests_author_id_foreign_key.rb
if settings.respond_to?(:local_markdown_version)
settings.local_markdown_version
else
0
end
end
included do
cattr_reader :cached_markdown_fields do
Gitlab::MarkdownCache::FieldData.new
end
if self < ActiveRecord::Base
include Gitlab::MarkdownCache::ActiveRecord::Extension
else
prepend Gitlab::MarkdownCache::Redis::Extension
end
end
class_methods do
private
# Specify that a field is markdown. Its rendered output will be cached in
# a corresponding _html field. Any custom rendering options may be provided
# as a context.
def cache_markdown_field(markdown_field, context = {})
cached_markdown_fields[markdown_field] = context
html_field = cached_markdown_fields.html_field(markdown_field)
invalidation_method = "#{html_field}_invalidated?".to_sym
# The HTML becomes invalid if any dependent fields change. For now, assume
# author and project invalidate the cache in all circumstances.
define_method(invalidation_method) do
invalidations = changed_markdown_fields & [markdown_field.to_s, *INVALIDATED_BY]
invalidations.delete(markdown_field.to_s) if changed_markdown_fields.include?("#{markdown_field}_html")
!invalidations.empty? || !cached_html_up_to_date?(markdown_field)
end
end
end
end