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SearchObserver starting point
class SearchObserver < ActiveRecord::Observer
observe :topic, :post, :user, :category
def self.scrub_html_for_search(html)
HtmlScrubber.scrub(html)
end
def self.update_index(table, id, search_data)
table_name = "#{table}_search_data"
foreign_key = "#{table}_id"
# Would be nice to use AR here but not sure how to execut Postgres functions
# when inserting data like this.
rows = Post.exec_sql_row_count("UPDATE #{table_name} SET search_data = TO_TSVECTOR('english', ?) WHERE #{foreign_key} = ?", search_data, id)
if rows == 0
Post.exec_sql("INSERT INTO #{table_name} (#{foreign_key}, search_data) VALUES (?, TO_TSVECTOR('english', ?))", id, search_data)
end
rescue
# don't allow concurrency to mess up saving a post
end
def self.update_posts_index(post_id, cooked, title, category)
search_data = scrub_html_for_search(cooked) << " " << title
search_data << " " << category if category
update_index('post', post_id, search_data)
end
def self.update_users_index(user_id, username, name)
search_data = username.dup << " " << (name || "")
update_index('user', user_id, search_data)
end
def self.update_categories_index(category_id, name)
update_index('category', category_id, name)
end
def after_save(obj)
if obj.class == Post && obj.cooked_changed?
category_name = obj.topic.category.name if obj.topic.category
SearchObserver.update_posts_index(obj.id, obj.cooked, obj.topic.title, category_name)
end
if obj.class == User && (obj.username_changed? || obj.name_changed?)
SearchObserver.update_users_index(obj.id, obj.username, obj.name)
end
if obj.class == Topic && obj.title_changed?
if obj.posts
post = obj.posts.where(post_number: 1).first
if post
category_name = obj.category.name if obj.category
SearchObserver.update_posts_index(post.id, post.cooked, obj.title, category_name)
end
end
end
if obj.class == Category && obj.name_changed?
SearchObserver.update_categories_index(obj.id, obj.name)
end
end
class HtmlScrubber < Nokogiri::XML::SAX::Document
attr_reader :scrubbed
def initialize
@scrubbed = ""
end
def self.scrub(html)
me = new
parser = Nokogiri::HTML::SAX::Parser.new(me)
begin
copy = "<div>"
copy << html unless html.nil?
copy << "</div>"
parser.parse(html) unless html.nil?
end
me.scrubbed
end
def start_element(name, attributes=[])
attributes = Hash[*attributes.flatten]
if attributes["alt"]
scrubbed << " "
scrubbed << attributes["alt"]
scrubbed << " "
end
if attributes["title"]
scrubbed << " "
scrubbed << attributes["title"]
scrubbed << " "
end
end
def characters(string)
scrubbed << " "
scrubbed << string
scrubbed << " "
end
end
end
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