flickr_friend.rb

#!/usr/bin/env ruby

# This script uses Selenium WebDriver and Firefox to scrape the Flickr friends
# and followers lists of a Flickr user.
# Then it groups the contacts into 3 sets: mutual friends, only followers, and
# only following.

require 'selenium-webdriver'
require 'set'
require 'optparse'

# Find the highest-numbered page by parsing the pages links.
def get_last_page web
  web.find_elements(:css, 'div.Pages a[href*="contacts/"]').map { |elem|
    elem.attribute('href').match(%r{contacts(?:/rev)?/\?page=(\d+)})[1].to_i
  }.max
end

# Parse user IDs and names from the contact list.
def get_names web
  web.find_elements(:css, 'td.contact-list-name').map { |elem|
    a_elem = elem.find_element(:tag_name, 'a')
    id = a_elem.attribute('href').match(%r{photos/(.*)/})[1]
    name = a_elem.text.strip
    { id: id, name: name }
  }
end

# Get the user name.
def get_user_name web
  m = web.current_url.match(%r{people/(.+)/contacts})
  raise 'Unable to retrieve user name. Please log in to Flickr before running this script.' unless m
  m[1]
end

# Process the contact list, returning a list of users from all the pages in
# the list.
def process_list what, web
  puts "Fetching #{what} page 1..."

  base_url = 'https://www.flickr.com/people/me/contacts/'
  base_url += 'rev/' if what == :follower
  web.get base_url
  username = get_user_name web

  last_page = get_last_page web
  names = get_names web

  # Only the first page can use people/me. Subsequent pages need the actual
  # user name.
  base_url = "https://www.flickr.com/people/#{username}/contacts/"
  base_url += 'rev/' if what == :follower

  (2..last_page).each { |page|
    puts "Fetching #{what} page #{page}..."
    web.get "#{base_url}?page=#{page}"

    names += get_names web
  }

  names
end

def show_list flist
  flist.each_with_index { |name, i|
    puts "#{i + 1}: #{name[:id]} - #{name[:name]}"
  }
end

# Wait for user to log in to Flickr, if necessary.
def check_login web
  url = 'https://www.flickr.com/people/me'
  web.get url
  m = web.current_url.match(/login\.yahoo\.com/)
  return unless m

  puts 'Please log in to Flickr'

  wait = Selenium::WebDriver::Wait.new(timeout: 900)
  wait.until { web.current_url.match(%r{flickr\.com/people}) }
end

# Use Spotlight to find the Firefox binary.
def setup_firefox_path
  firefox_app = nil
  IO.popen('mdfind "kMDItemFSName = Firefox*.app"') { |io|
    firefox_app = io.gets
  }
  raise "Can't find Firefox app bundle" unless firefox_app
  firefox_app.chomp!

  Selenium::WebDriver::Firefox::Binary.path = File.join(firefox_app, 'Contents/MacOS/firefox')
end

def parse_opts
  options = {}

  optp = OptionParser.new

  optp.banner = <<-EOM
This script uses Selenium WebDriver and Firefox to scrape the Flickr friends
and followers lists of a Flickr user.
Then it groups the contacts into 3 sets: mutual friends, only followers, and
only following.

Usage: #{File.basename $PROGRAM_NAME} [options]
  EOM

  optp.on('-h', '-?', '--help', 'Option help') {
    puts optp
    exit
  }

  optp.on('-m', '--mutual', 'Show mutual friends') {
    options[:mutual_friends] = true
  }

  optp.on('-r', '--only-friends', 'Show only-friends') {
    options[:only_friends] = true
  }

  optp.on('-o', '--only-followers', 'Show only-followers') {
    options[:only_followers] = true
  }

  optp.separator '  If none of -m/-r/-o are specified, display all 3 categories.'

  begin
    optp.parse!
  rescue OptionParser::ParseError => err
    warn "Error parsing command line: #{err}\n\n"
    warn optp
    exit 1
  end

  if !options[:mutual_friends] && !options[:only_friends] && !options[:only_followers]
    # If none of the 3 options are specified, show everything.
    options[:mutual_friends] = options[:only_friends] = options[:only_followers] = true
  end

  options
end

options = parse_opts
web = nil
begin
  setup_firefox_path
  web = Selenium::WebDriver.for :firefox

  check_login web

  following = Set.new(process_list(:following, web))
  follower = Set.new(process_list(:follower, web))

  if options[:mutual_friends]
    puts 'Mutual followers:'
    show_list(following & follower)
  end

  if options[:only_followers]
    puts 'Only followers:'
    show_list(follower - following)
  end

  if options[:only_friends]
    puts 'Only following:'
    show_list(following - follower)
  end
ensure
  web.close if web
end

__END__