清单 1. skokie-lookup.rb

#!/usr/bin/ruby

require 'net/http'

if ARGV.length == 0
  puts "#{$0}: You must enter at least one argument."
  exit
end

output = ""

# Set up our regular expressions
not_in_collection_re = /class="yourEntryWouldBeHereData"/ix
on_shelf_re = /CHECK SHELF/ix
checked_out_re = /DUE /ix

# Iterate through each of our arguments
ARGV.each do |isbn|

  # Ignore non-ISBN arguments
  if not isbn.match(/[0-9xX]{10}/)
    output << "ISBN #{isbn} is invalid.\n"
    next
  end

  # Ask the library what it knows about our ISBN
  response = Net::HTTP.get_response('catalog.skokie.lib.il.us',
                                    "/search~S4/i?SEARCH=#{isbn}")

  # Check our regular expressions against the HTML response
  if not_in_collection_re.match(response.body)
    output << "ISBN #{isbn} is not in the Skokie collection.\n"
  elsif on_shelf_re.match(response.body)
    output << "ISBN #{isbn} is on the shelf.\n"
  elsif checked_out_re.match(response.body)
    output << "ISBN #{isbn} is currently checked out.\n"
  else
    output << "ISBN #{isbn} response: Unparseable!\n"
  end
end

# Show everyone what we've learned
puts output

清单 2. combined-lookup.rb

#!/usr/bin/ruby

require 'net/http'
require 'rexml/document'

if ARGV.length == 0
  puts "#{$0}: You must enter at least one argument."
  exit
end

output = ""

# Set up our regular expressions
not_in_collection_re = /class="yourEntryWouldBeHereData"/ix
on_shelf_re = /CHECK\s+SHELF/ix
checked_out_re = /DUE /ix

# Iterate through each of our arguments
ARGV.each do |isbn|

  # Ignore non-ISBN arguments
  if not isbn.match(/[0-9xX]{10}/)
    output << "ISBN #{isbn} is invalid.\n"
    next
  end

  output << "ISBN: #{isbn}\n"

  # ------------------------------------------------------------
  # Amazon
  # ------------------------------------------------------------

  # Put together an Amazon parameter string
  amazon_params = {'Service' => 'AWSECommerceService',
    'Operation' => 'ItemLookup',
    'AWSAccessKeyId' => 'XXX',
    'ItemId' => isbn,
    'ResponseGroup' => 'Medium,OfferFull',
    'MerchantId' => 'All'}.map {|key,value| "#{key}=#{value}"}.join("&")

  # Ask Amazon what it knows about our ISBN
  amazon_response = Net::HTTP.get_response('webservices.amazon.com',
                                           '/onca/xml?' << amazon_params)

  xml = REXML::Document.new(amazon_response.body)

  # Get the lowest new, used, and collectible prices
  new_price =
xml.root.elements["Items/Item/OfferSummary/LowestNewPrice/FormattedPrice"]
  if new_price.nil?
    output << "\tNew: None available\n"
  else
    output << "\tNew: #{new_price.text}\n"
  end

  used_price =
xml.root.elements["Items/Item/OfferSummary/LowestUsedPrice/FormattedPrice"]
  if used_price.nil?
    output << "\tUsed: None available\n"
  else
    output << "\tUsed: #{used_price.text}\n"
  end

  collectible_price =
xml.root.elements["Items/Item/OfferSummary/LowestCollectiblePrice/FormattedPrice"]
  if collectible_price.nil?
    output << "\tCollectible: None available\n"
  else
    output << "\tCollectible: #{collectible_price.text}\n"
  end

  # ------------------------------------------------------------
  # Library
  # ------------------------------------------------------------

  # Ask the library what it knows about our ISBN
  library_response = Net::HTTP.get_response('catalog.skokie.lib.il.us',
                                    "/search~S4/i?SEARCH=#{isbn}")

  # Check our regular expressions against the HTML response
  if not_in_collection_re.match(library_response.body)
    output << "\tLibrary: Not in the Skokie collection.\n"
  elsif checked_out_re.match(library_response.body)
    output << "\tLibrary: Checked out.\n"
  elsif on_shelf_re.match(library_response.body)
    output << "\tLibrary: On the shelf.\n"
  else
    output << "\tLibrary: Unparseable response\n"
  end
end

# Show everyone what we've learned
puts output

清单 3. xmlrpc-lookup.rb

#!/usr/bin/ruby

require 'net/http'
require 'rexml/document'
require 'xmlrpc/server'

# Set our regular expressions
not_in_collection_re = /class="yourEntryWouldBeHereData"/ix
on_shelf_re = /CHECK\s+SHELF/ix
checked_out_re = /DUE /ix

# ------------------------------------------------------------
# XML-RPC
# ------------------------------------------------------------

# Start an HTTP server on port 8080, to listen for clients
server = XMLRPC::Server.new(8080)

server.add_handler(name="atf.books",
                   signature=['array', 'array']) do |isbns|

  output = [ ]

  # Iterate through each of our arguments
  isbns.each do |isbn|

    isbn_output = {'ISBN' => isbn}

    # Ignore non-ISBN arguments
    if not isbn.match(/^[0-9xX]{10}$/)
      isbn_output['message'] = "ISBN #{isbn} is invalid."
      output << isbn_output
      next
    end

    # ------------------------------------------------------------
    # Amazon
    # ------------------------------------------------------------

    # Put together an Amazon parameter string
    amazon_params = {'Service' => 'AWSECommerceService',
      'Operation' => 'ItemLookup',
      'AWSAccessKeyId' => 'XXX',
      'ItemId' => isbn,
      'ResponseGroup' => 'Medium,OfferFull',
      'MerchantId' => 'All'}.map {|key,value|
"#{key}=#{value}"}.join("&")

    # Ask Amazon what it knows about our ISBN
    amazon_response = Net::HTTP.get_response('webservices.amazon.com',
                                             '/onca/xml?' <<
amazon_params)

    xml = REXML::Document.new(amazon_response.body)

    # Get the lowest new, used, and collectible prices
    new_price =
xml.root.elements["Items/Item/OfferSummary/LowestNewPrice/FormattedPrice"]
    if new_price.nil?
      isbn_output['New'] = "None available"
    else
      isbn_output['New'] = new_price.text
    end

    used_price =
xml.root.elements["Items/Item/OfferSummary/LowestUsedPrice/FormattedPrice"]
    if used_price.nil?
      isbn_output['Used'] = "None available"
    else
      isbn_output['Used'] = used_price.text
    end

    collectible_price =
xml.root.elements["Items/Item/OfferSummary/LowestCollectiblePrice/FormattedPrice"]
    if collectible_price.nil?
      isbn_output['Collectible'] = "None available"
    else
      isbn_output['Collectible'] = collectible_price.text
    end

    # ------------------------------------------------------------
    # Library
    # ------------------------------------------------------------

    # Ask the library what it knows about our ISBN
    library_response = Net::HTTP.get_response('catalog.skokie.lib.il.us',
                                              "/search~S4/i?SEARCH=#{isbn}")

    # Check our regular expressions against the HTML response
    if not_in_collection_re.match(library_response.body)
      isbn_output['Library'] = "Library: Not in the Skokie collection."
    elsif checked_out_re.match(library_response.body)
      isbn_output['Library'] = "Checked out."
    elsif on_shelf_re.match(library_response.body)
      isbn_output['Library'] = "On the shelf."
    else
      isbn_output['Library'] = "Unparseable response."
    end

    output << isbn_output
  end

  output
end

server.serve

清单 4. xmlrpc-lookup-client.rb

#!/usr/bin/ruby

require 'xmlrpc/client'

# Get the ISBNs from the command line
isbns = ARGV

# Connect to the server
server = XMLRPC::Client.new2("http://127.0.0.1:8080/", nil, 120)

# Send the ISBNs, and catch any faults that we find
begin
  results = server.call("atf.books", isbns)
rescue XMLRPC::FaultException => e
  puts "Error:"
  puts e.faultCode
  puts e.faultString
end

# Display the results!
results.each do |result|
  result.each do |key, value|
    if key == "ISBN"
      puts "ISBN: #{value}\n"
    else
      puts "\t#{key}: #{value}\n"
    end
  end
end