Class: UrlTracker::Server

Inherits:
Object
  • Object
show all
Includes:
SocketCommunication
Defined in:
lib/url_tracker/server.rb

Overview

Class that waits for messages on a given socket and responds back to clients. It can track URLs, list currently tracked URLs and stop tracking. The interval between consecutive checks for change in the pages is customizable.

Constant Summary

Constants included from SocketCommunication

UrlTracker::SocketCommunication::InvalidSocketError, UrlTracker::SocketCommunication::MAX_CONN_QUEUE, UrlTracker::SocketCommunication::MAX_MESSAGE_LENGTH

Instance Attribute Summary

Attributes included from SocketCommunication

#path

Instance Method Summary collapse

Methods included from SocketCommunication

#bind, #close_connection, #connect, #next_message, #wait_for_connection, #write

Constructor Details

#initialize(logger = Logger.new(STDERR)) ⇒ Server

Initializes a new server which logs its activities using the passed logger object. Defaults to Ruby’s Logger class. Log level defaults to Logger::INFO and you can override it by setting the URL_TRACKER_DEBUG environment variable



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# File 'lib/url_tracker/server.rb', line 17

def initialize(logger=Logger.new(STDERR))
  setup_signals
  @logger = logger
  @logger.level = level_from_env || Logger::INFO
end

Instance Method Details

#list ⇒ Object

List tracked URLs



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# File 'lib/url_tracker/server.rb', line 52

def list
  UrlTracker.list_all
end

#loop_forever ⇒ Object

Main server method. Loops forever, waiting for new connections, and checking new messages. Takes the appropriate action according to what is received, such as a new URL to track.



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# File 'lib/url_tracker/server.rb', line 26

def loop_forever
  running = true

  while wait_for_connection
    @logger.info("New client connected")
    command, *arguments = next_message.split
    @logger.debug "#{command} received"
    response = case command
      when /^track$/i    then track(arguments.first)
      when /^list$/i     then list
      when /^release$/i  then release(arguments.first)
    end

    write(response) unless response.nil?
  end
rescue => e
  @logger.error("An error occurred when waiting for new connections!\n\t#{e.inspect}\n\t#{e.backtrace.join("\n\t")}")
end

#release(uri) ⇒ Object

Release an URL



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# File 'lib/url_tracker/server.rb', line 57

def release(uri)
  @logger.info("Releasing URL #{uri}")
  UrlTracker.release_uri(uri)
end

#run(params) ⇒ Object

Runs the server, according to the argv options passed. Possible options:

-s, --socket [FILE] #=> Uses FILE as socket file for communication
-f, --fork          #=> Forks and works as a daemon

params can also be a hash, containing the parsed information to the server.



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# File 'lib/url_tracker/server.rb', line 69

def run(params)
  @logger.info "UrlTracker #{UrlTracker::VERSION} starting. Log level is #{@logger.level.inspect}."

  options = parse(params)
  @socket_file = options.socket_file
  @pid         = nil

  bind(@socket_file)

  @logger.info "Server starting at socket #{Pathname.new(@socket_file).realpath.to_s}"

  if options.fork
    @pid = fork { loop_forever }
    @logger.info "Forking to background. Child pid #{@pid}"
  else
    loop_forever
  end
end

#stop ⇒ Object

Stops the current server



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# File 'lib/url_tracker/server.rb', line 89

def stop
  @pid ? Process.kill('TERM', @pid) : close_connection
end

#track(uri) ⇒ Object

Track an URL



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# File 'lib/url_tracker/server.rb', line 46

def track(uri)
  @logger.info("Tracking URL #{uri}")
  UrlTracker.track_uri(uri)
end