月歸檔：四月 2007

By Kevin Marshall

The Basics
APIs(application programming interface)

three architectures:
Representational State Transfer (REST)
Simple Object Access Protocol (SOAP)
Extensible Markup Language Remote Procedural(XML-RPC)
(SOAP grew out of XML-RPC)

SOAP
Web service signatures are really just data types that the service either expects or returns.
WSDL(Web Service Description Language)
a WSDL file is an XML document that defines the interface to a SOAP service.

REST
URL, http
The world wide web itself can be considered a REST system.

Searching Yahoo using REST
need:
1.Connect( net lib)
2.store
3.Parse results ( REXML lib)

Yahoo! web service API (up to 5,000 requests/IP per day)

Google AJAX Search API

use the CGI library to escape our search term, ensuring that the search term is safe for use in our HTTP GET request:
query = CGI.escape("SEARCH TEXT")

https://www.google.com/accounts/NewAccount?continue=http://api.google.com/createkey&followup=http://api.google.com/createkey:

Searching Google Using SOAP or SOAP with WSDL Files
UTF-8 can contain special characters that Ruby can’t handle in a string, causing our driver to throw an XSD::ValueSpaceError error upon invocation. To avoid this problem, we manually set our encoding to UTF-8 using the XSD library.
XSD::Charset.encoding = ‘UTF8′

Displaying Photos from Flickr Using XML-RPC

Building Web Service Servers
Make sure you turn off layouts for the methods you’ll be using in your service
Associate RXML templates with the methods in your controllers, instead of RHTML templates
xml is an XML document object that’s available in any RXML template
xml.name("Kevin", :id => 1, "age" => "31")
# creates <name id="1" age="31">Kevin</name>

 xml.exampledata do
     xml.name("Kevin")
 end
 # creates <exampledata><name>Kevin</name></exampledata>

SOAP and XML-RPC Web Service Servers
ActionWebService (AWS)
 script/generate web_service YOURSERVICE YOURMETHOD1 YOURMETHOD2

 three dispatching options, :direct, :delegated, or :layered.
web_service_dispatching_mode:direct
:delegated or :layered is the best way to go for any large or complex web service
With :delegated, clients use a distinct URL for each method in the API
With :layered, clients use the same URL for all attached methods and rely on AWS to route the request based on information passed in its header

:expects and :returns symbols
Ruby types (:string, :int, :bool, :float, :time, :datetime, :date, and :base64), or the names of ActiveRecord::Base or ActionWebService::Struct classes (for example, Greeting or Account), or a single element array to represent arrays of objects (for example, [:string] to represent an array of Strings or [Account] to represent an array of ActionWebService::Struct Account objects).

 raise "Access denied!"

with <Programming Ruby 2nd>
Ruby Basic

                   Variables        &nb[-aa--]sp;          Constants and
Local          Global        Instance Class    Class Names
name           $debug        @name    @@total  PI

fish_and_chips $CUSTOMER     @point_1 @@symtab FeetPerMile
x_axis         $_            @X       @@N      String
thx1138        $plan9        @_       @@x_pos  MyClass
_26            $Global       @plan9   @@SINGLE JazzSong

statement modi?ers
puts "Danger, Will Robinson" if radiation > 3000
square = square*square while square < 1000

Regular Expressions
In Ruby, you typically create a regular expression by writing a pattern
between slash characters (/pattern/).

/P(erl|ython)/
This pipe character means “either the thing on the right or the thing on the left,” in this case either Perl or Python.
 /ab+c/ matches a string containing an a followed by one or more b’s, followed by a c.
/ab*c/ creates a regular expression that matches one a, zero or more b’s, and one c.

\s, which matches a whitespace character (space, tab, newline, and so on);
\d, which matches any digit;
\w, which matches any character that may appear in a typical word.
A dot ( . ) matches (almost) any character.

if line =~ /Perl|Python/

line.sub(/Perl/, ‘Ruby’)    # replace first ‘Perl’ with ‘Ruby’
line.gsub(/Python/, ‘Ruby’) # replace every ‘Python’ with ‘Ruby’

Blocks and Iterators
{ puts "Hello" }      # this is a block
do                    ###
  club.enroll(person)   # and so is this
  person.socialize      #
end                   ###

    def call_block
      puts "Start of method"
      yield
      yield
      puts "End of method"
    end
    call_block { puts "In the block" }
produces:
    Start of method
    In the block
    In the block
    End of method

def call_block
  yield("hello", 99)
end
call_block {|str, num| … }

iterators: methods that return successive elements from some kind of collection, such as an array.
   animals = %w( ant bee cat dog elk )  # create an array
   animals.each {|animal| puts animal } # iterate over the contents
# within class Array…
def each
  for each element    # <– not valid Ruby
    yield(element)
  end
end

Reading and ’Riting
puts writes its arguments, adding a newline after each.
print also writes its arguments, but with no newline.
printf, which prints its arguments under the control of a format stringejfkldfjai