gitlab-org--gitlab-foss/lib/banzai/object_renderer.rb
Adam Buckland ace833b31d Add indication for closed or merged issuables in GFM
Example: for issues that are closed, the links will now show '[closed]'
following the issue number. This is done as post-process after the markdown has
been loaded from the cache as the status of the issue may change between
the cache being populated and the content being displayed.

In order to avoid N+1 queries problem when rendering notes ObjectRenderer
populates the cache of referenced issuables for all notes at once,
before the post processing phase.

As a part of this change, the Banzai BaseParser#grouped_objects_for_nodes
method has been refactored to return a Hash utilising the node itself as the
key, since this was a common pattern of usage for this method.
2017-04-07 14:31:43 -05:00

87 lines
3 KiB
Ruby

module Banzai
# Class for rendering multiple objects (e.g. Note instances) in a single pass,
# using +render_field+ to benefit from caching in the database. Rendering and
# redaction are both performed.
#
# The unredacted HTML is generated according to the usual +render_field+
# policy, so specify the pipeline and any other context options on the model.
#
# The *redacted* (i.e., suitable for use) HTML is placed in an attribute
# named "redacted_<foo>", where <foo> is the name of the cache field for the
# chosen attribute.
#
# As an example, rendering the attribute `note` would place the unredacted
# HTML into `note_html` and the redacted HTML into `redacted_note_html`.
class ObjectRenderer
attr_reader :project, :user
# project - A Project to use for redacting Markdown.
# user - The user viewing the Markdown/HTML documents, if any.
# context - A Hash containing extra attributes to use during redaction
def initialize(project, user = nil, redaction_context = {})
@project = project
@user = user
@redaction_context = redaction_context
end
# Renders and redacts an Array of objects.
#
# objects - The objects to render.
# attribute - The attribute containing the raw Markdown to render.
#
# Returns the same input objects.
def render(objects, attribute)
documents = render_documents(objects, attribute)
documents = post_process_documents(documents, objects, attribute)
redacted = redact_documents(documents)
objects.each_with_index do |object, index|
redacted_data = redacted[index]
object.__send__("redacted_#{attribute}_html=", redacted_data[:document].to_html.html_safe)
object.user_visible_reference_count = redacted_data[:visible_reference_count]
end
end
private
def render_documents(objects, attribute)
pipeline = HTML::Pipeline.new([])
objects.map do |object|
pipeline.to_document(Banzai.render_field(object, attribute))
end
end
def post_process_documents(documents, objects, attribute)
# Called here to populate cache, refer to IssuableExtractor docs
IssuableExtractor.new(project, user).extract(documents)
documents.zip(objects).map do |document, object|
context = context_for(object, attribute)
Banzai::Pipeline[:post_process].to_document(document, context)
end
end
# Redacts the list of documents.
#
# Returns an Array containing the redacted documents.
def redact_documents(documents)
redactor = Redactor.new(project, user)
redactor.redact(documents)
end
# Returns a Banzai context for the given object and attribute.
def context_for(object, attribute)
base_context.merge(object.banzai_render_context(attribute))
end
def base_context
@base_context ||= @redaction_context.merge(
current_user: user,
project: project,
skip_redaction: true
)
end
end
end