Class: Droonga::Watcher

Inherits:
Object
  • Object
show all
Defined in:
lib/droonga/watcher.rb

Constant Summary collapse

EXACT_MATCH = 
false

Instance Method Summary collapse

Constructor Details

#initialize(context) ⇒ Watcher

Returns a new instance of Watcher.



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# File 'lib/droonga/watcher.rb', line 22

def initialize(context)
  @context = context

  @subscriber_table = @context["Subscriber"]
  @query_table      = @context["Query"]
  @keyword_table    = @context["Keyword"]
end

Instance Method Details

#eval_condition(condition, words) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 154

def eval_condition(condition, words)
  case condition
  when Hash
    # todo
  when String
    words[condition]
  when Array
    case condition.first
    when "||"
      condition[1..-1].each do |element|
        return true if eval_condition(element, words)
      end
      false
    when "&&"
      condition[1..-1].each do |element|
        return false unless eval_condition(element, words)
      end
      true
    when "-"
      return false unless eval_condition(condition[1], words)
      condition[2..-1].each do |element|
        return false if eval_condition(element, words)
      end
      true
    end
  end
end

#feed(request, &block) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 95

def feed(request, &block)
  targets = request[:targets]

  hits = []
  targets.each do |key, target|
    scan_body(hits, target)
  end
  hits.uniq! # hits may be duplicated if multiple targets are matched

  publish(hits, request, &block)
end

#pick_keywords(memo, condition) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 107

def pick_keywords(memo, condition)
  case condition
  when Hash
    memo << condition["query"]
  when String
    memo << condition
  when Array
    condition[1..-1].each do |element|
      pick_keywords(memo, element)
    end
  end
  memo
end

#publish(hits, request) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 182

def publish(hits, request)
  routes = {}
  hits.each do |query|
    subscribers = @subscriber_table.select do |subscriber|
      subscriber.subscriptions =~ query
    end
    subscribers.each do |subscriber|
      route = subscriber.route.key
      routes[route] ||= []
      routes[route] << subscriber.key.key
    end
=begin
# "group" version. This is slower than above...
    route_records = subscribers.group("route",
                                      :max_n_sub_records => subscribers.size)
    route_records.each do |route_record|
      route = route_record._key
      routes[route] ||= []
      route_record.sub_records.each do |subscriber|
        routes[route] << subscriber.key.key
      end
    end
=end
  end
  routes.each do |route, subscribers|
    yield(route, subscribers)
  end
end

#query_match(query, keywords) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 138

def query_match(query, keywords)
  return true unless EXACT_MATCH
  @conditions = {} unless @conditions
  condition = @conditions[query.id]
  unless condition
    condition = JSON.parse(query.key)
    @conditions[query.id] = condition
    # CAUTION: @conditions can be huge.
  end
  words = {}
  keywords.each do |keyword|
    words[keyword.key] = true
  end
  eval_condition(condition, words)
end

#scan_body(hits, body) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 121

def scan_body(hits, body)
  trimmed = body.strip
  candidates = {}
  # FIXME scan reports the longest keyword matched only
  @keyword_table.scan(trimmed).each do |keyword, word, start, length|
    @query_table.select do |query|
      query.keywords =~ keyword
    end.each do |record|
      candidates[record.key] ||= []
      candidates[record.key] << keyword
    end
  end
  candidates.each do |query, keywords|
    hits << query if query_match(query, keywords)
  end
end

#subscribe(request) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 30

def subscribe(request)
  subscriber = request[:subscriber]
  condition  = request[:condition]
  query      = request[:query]
  route      = request[:route]

  # XXX better validation and error class must be written!!
  if subscriber.nil? or subscriber.empty? or condition.nil? or
     query.nil? or route.nil?
    raise "invalid request"
  end
  raise "too long query" if query.size > 4095

  query_record = @query_table[query]
  unless query_record
    keywords = pick_keywords([], condition)
    query_record = @query_table.add(query, :keywords => keywords)
  end
  subscriber_record = @subscriber_table[subscriber]
  if subscriber_record
    subscriptions = subscriber_record.subscriptions
    unless subscriptions.include?(query_record)
      subscriptions << query_record
      subscriber_record.subscriptions = subscriptions
    end
    subscriber_record.last_modified = Time.now
  else
    @subscriber_table.add(subscriber,
                          :subscriptions => [query_record],
                          :route => route,
                          :last_modified => Time.now)
  end
end

#unsubscribe(request) ⇒ Object 



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# File 'lib/droonga/watcher.rb', line 64

def unsubscribe(request)
  subscriber = request[:subscriber]
  query      = request[:query]

  if subscriber.nil? or subscriber.empty?
    raise "invalid request"
  end

  subscriber_record = @subscriber_table[subscriber]
  return unless subscriber_record

  if query.nil? or query.empty?
    delete_subscriber(subscriber_record)
  else
    query_record = @query_table[query]
    return unless query_record

    subscriptions = subscriber_record.subscriptions
    new_subscriptions = subscriptions.select do |subscription|
      subscription != query_record
    end

    if new_subscriptions.empty?
      delete_subscriber(subscriber_record)
    else
      subscriber_record.subscriptions = new_subscriptions
      sweep_orphan_queries(subscriptions)
    end
  end
end