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Diffstat (limited to 'lib/banzai/reference_parser/base_parser.rb')
| -rw-r--r-- | lib/banzai/reference_parser/base_parser.rb | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/lib/banzai/reference_parser/base_parser.rb b/lib/banzai/reference_parser/base_parser.rb new file mode 100644 index 00000000000..3d7b9c4a024 --- /dev/null +++ b/lib/banzai/reference_parser/base_parser.rb @@ -0,0 +1,204 @@ +module Banzai + module ReferenceParser + # Base class for reference parsing classes. + # + # Each parser should also specify its reference type by calling + # `self.reference_type = ...` in the body of the class. The value of this + # method should be a symbol such as `:issue` or `:merge_request`. For + # example: + # + # class IssueParser < BaseParser + # self.reference_type = :issue + # end + # + # The reference type is used to determine what nodes to pass to the + # `referenced_by` method. + # + # Parser classes should either implement the instance method + # `references_relation` or overwrite `referenced_by`. The + # `references_relation` method is supposed to return an + # ActiveRecord::Relation used as a base relation for retrieving the objects + # referenced in a set of HTML nodes. + # + # Each class can implement two additional methods: + # + # * `nodes_user_can_reference`: returns an Array of nodes the given user can + # refer to. + # * `nodes_visible_to_user`: returns an Array of nodes that are visible to + # the given user. + # + # You only need to overwrite these methods if you want to tweak who can see + # which references. For example, the IssueParser class defines its own + # `nodes_visible_to_user` method so it can ensure users can only see issues + # they have access to. + class BaseParser + class << self + attr_accessor :reference_type + end + + # Returns the attribute name containing the value for every object to be + # parsed by the current parser. + # + # For example, for a parser class that returns "Animal" objects this + # attribute would be "data-animal". + def self.data_attribute + @data_attribute ||= "data-#{reference_type.to_s.dasherize}" + end + + def initialize(project = nil, current_user = nil) + @project = project + @current_user = current_user + end + + # Returns all the nodes containing references that the user can refer to. + def nodes_user_can_reference(user, nodes) + nodes + end + + # Returns all the nodes that are visible to the given user. + def nodes_visible_to_user(user, nodes) + projects = lazy { projects_for_nodes(nodes) } + project_attr = 'data-project' + + nodes.select do |node| + if node.has_attribute?(project_attr) + node_id = node.attr(project_attr).to_i + + if project && project.id == node_id + true + else + can?(user, :read_project, projects[node_id]) + end + else + true + end + end + end + + # Returns an Array of objects referenced by any of the given HTML nodes. + def referenced_by(nodes) + ids = unique_attribute_values(nodes, self.class.data_attribute) + + references_relation.where(id: ids) + end + + # Returns the ActiveRecord::Relation to use for querying references in the + # DB. + def references_relation + raise NotImplementedError, + "#{self.class} does not implement #{__method__}" + end + + # Returns a Hash containing attribute values per project ID. + # + # The returned Hash uses the following format: + # + # { project id => [value1, value2, ...] } + # + # nodes - An Array of HTML nodes to process. + # attribute - The name of the attribute (as a String) for which to gather + # values. + # + # Returns a Hash. + def gather_attributes_per_project(nodes, attribute) + per_project = Hash.new { |hash, key| hash[key] = Set.new } + + nodes.each do |node| + project_id = node.attr('data-project').to_i + id = node.attr(attribute) + + per_project[project_id] << id if id + end + + per_project + end + + # Returns a Hash containing objects for an attribute grouped per their + # IDs. + # + # The returned Hash uses the following format: + # + # { id value => row } + # + # nodes - An Array of HTML nodes to process. + # + # collection - The model or ActiveRecord relation to use for retrieving + # rows from the database. + # + # attribute - The name of the attribute containing the primary key values + # for every row. + # + # Returns a Hash. + def grouped_objects_for_nodes(nodes, collection, attribute) + return {} if nodes.empty? + + ids = unique_attribute_values(nodes, attribute) + + collection.where(id: ids).each_with_object({}) do |row, hash| + hash[row.id] = row + end + end + + # Returns an Array containing all unique values of an attribute of the + # given nodes. + def unique_attribute_values(nodes, attribute) + values = Set.new + + nodes.each do |node| + if node.has_attribute?(attribute) + values << node.attr(attribute) + end + end + + values.to_a + end + + # Processes the list of HTML documents and returns an Array containing all + # the references. + def process(documents) + type = self.class.reference_type + + nodes = documents.flat_map do |document| + Querying.css(document, "a[data-reference-type='#{type}'].gfm").to_a + end + + gather_references(nodes) + end + + # Gathers the references for the given HTML nodes. + def gather_references(nodes) + nodes = nodes_user_can_reference(current_user, nodes) + nodes = nodes_visible_to_user(current_user, nodes) + + referenced_by(nodes) + end + + # Returns a Hash containing the projects for a given list of HTML nodes. + # + # The returned Hash uses the following format: + # + # { project ID => project } + # + def projects_for_nodes(nodes) + @projects_for_nodes ||= + grouped_objects_for_nodes(nodes, Project, 'data-project') + end + + def can?(user, permission, subject) + Ability.abilities.allowed?(user, permission, subject) + end + + def find_projects_for_hash_keys(hash) + Project.where(id: hash.keys) + end + + private + + attr_reader :current_user, :project + + def lazy(&block) + Gitlab::Lazy.new(&block) + end + end + end +end |