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= XMLRPC for Ruby

== Author and Copyright

Copyright (C) 2001-2004 by Michael Neumann (mailto:mneumann@ntecs.de)

Released under the same term of license as Ruby.

== Overview

XMLRPC is a lightweight protocol that enables remote procedure calls over

HTTP. It is defined at http://www.xmlrpc.com.

XMLRPC allows you to create simple distributed computing solutions that span

computer languages. Its distinctive feature is its simplicity compared to

other approaches like SOAP and CORBA.

The Ruby standard library package 'xmlrpc' enables you to create a server that

implements remote procedures and a client that calls them. Very little code

is required to achieve either of these.

== Example

Try the following code. It calls a standard demonstration remote procedure.

require 'xmlrpc/client'

require 'pp'

server = XMLRPC::Client.new2("http://xmlrpc-c.sourceforge.net/api/sample.php")

result = server.call("sample.sumAndDifference", 5, 3)

pp result

== Documentation

See http://www.ntecs.de/projects/xmlrpc4r. There is plenty of detail there to

use the client and implement a server.

== Features of XMLRPC for Ruby

* Extensions

* Introspection

* multiCall

* optionally nil values and integers larger than 32 Bit

* Server

* Standalone XML-RPC server

* CGI-based (works with FastCGI)

* Apache mod_ruby server

* WEBrick servlet

* Client

* synchronous/asynchronous calls

* Basic HTTP-401 Authentification

* HTTPS protocol (SSL)

* Parsers

* NQXML (NQXMLStreamParser, NQXMLTreeParser)

* Expat (XMLStreamParser, XMLTreeParser)

* REXML (REXMLStreamParser)

* xml-scan (XMLScanStreamParser)

* Fastest parser is Expat's XMLStreamParser!

* General

* possible to choose between XMLParser module (Expat wrapper) and REXML/NQXML (pure Ruby) parsers

* Marshalling Ruby objects to Hashs and reconstruct them later from a Hash

* SandStorm component architecture Client interface

== Howto

=== Client

require "xmlrpc/client"

# Make an object to represent the XML-RPC server.

server = XMLRPC::Client.new( "xmlrpc-c.sourceforge.net", "/api/sample.php")

# Call the remote server and get our result

result = server.call("sample.sumAndDifference", 5, 3)

sum = result["sum"]

difference = result["difference"]

puts "Sum: #{sum}, Difference: #{difference}"

=== Client with XML-RPC fault-structure handling

There are two possible ways, of handling a fault-structure:

==== by catching a XMLRPC::FaultException exception

require "xmlrpc/client"

# Make an object to represent the XML-RPC server.

server = XMLRPC::Client.new( "xmlrpc-c.sourceforge.net", "/api/sample.php")

begin

# Call the remote server and get our result

result = server.call("sample.sumAndDifference", 5, 3)

sum = result["sum"]

difference = result["difference"]

puts "Sum: #{sum}, Difference: #{difference}"

rescue XMLRPC::FaultException => e

puts "Error: "

puts e.faultCode

puts e.faultString

end

==== by calling "call2" which returns a boolean

require "xmlrpc/client"

# Make an object to represent the XML-RPC server.

server = XMLRPC::Client.new( "xmlrpc-c.sourceforge.net", "/api/sample.php")

# Call the remote server and get our result

ok, result = server.call2("sample.sumAndDifference", 5, 3)

if ok

sum = result["sum"]

difference = result["difference"]

puts "Sum: #{sum}, Difference: #{difference}"

else

puts "Error: "

puts result.faultCode

puts result.faultString

end

=== Client using Proxy

You can create a +Proxy+ object onto which you can call methods. This way it

looks nicer. Both forms, _call_ and _call2_ are supported through _proxy_ and

<i>proxy2</i>. You can additionally give arguments to the Proxy, which will be

given to each XML-RPC call using that Proxy.

require "xmlrpc/client"

# Make an object to represent the XML-RPC server.

server = XMLRPC::Client.new( "xmlrpc-c.sourceforge.net", "/api/sample.php")

# Create a Proxy object

sample = server.proxy("sample")

# Call the remote server and get our result

result = sample.sumAndDifference(5,3)

sum = result["sum"]

difference = result["difference"]

puts "Sum: #{sum}, Difference: #{difference}"

=== CGI-based Server

There are also two ways to define handler, the first is

like C/PHP, the second like Java, of course both ways

can be mixed:

==== C/PHP-like (handler functions)

require "xmlrpc/server"

s = XMLRPC::CGIServer.new

s.add_handler("sample.sumAndDifference") do |a,b|

{ "sum" => a + b, "difference" => a - b }

end

s.serve

==== Java-like (handler classes)

require "xmlrpc/server"

s = XMLRPC::CGIServer.new

class MyHandler

def sumAndDifference(a, b)

{ "sum" => a + b, "difference" => a - b }

end

end

# NOTE: Security Hole (read below)!!!

s.add_handler("sample", MyHandler.new)

s.serve

To return a fault-structure you have to raise an FaultException e.g.:

raise XMLRPC::FaultException.new(3, "division by Zero")

===== Security Note

From Brian Candler:

Above code sample has an extremely nasty security hole, in that you can now call

any method of 'MyHandler' remotely, including methods inherited from Object

and Kernel! For example, in the client code, you can use

puts server.call("sample.send","`","ls")

(backtick being the method name for running system processes). Needless to

say, 'ls' can be replaced with something else.

The version which binds proc objects (or the version presented below in the next section)

doesn't have this problem, but people may be tempted to use the second version because it's

so nice and 'Rubyesque'. I think it needs a big red disclaimer.

From Michael:

A solution is to undef insecure methods or to use (({XMLRPC::iPIMethods})) as shown below:

class MyHandler

def sumAndDifference(a, b)

{ "sum" => a + b, "difference" => a - b }

end

end

# ... server initialization ...

s.add_handler(XMLRPC::iPIMethods("sample"), MyHandler.new)

# ...

This adds only public instance methods explicitly declared in class MyHandler

(and not those inherited from any other class).

==== With interface declarations

Code sample from the book Ruby Developer's Guide:

require "xmlrpc/server"

class Num

INTERFACE = XMLRPC::interface("num") {

meth 'int add(int, int)', 'Add two numbers', 'add'

meth 'int div(int, int)', 'Divide two numbers'

}

def add(a, b) a + b end

def div(a, b) a / b end

end

s = XMLRPC::CGIServer.new

s.add_handler(Num::INTERFACE, Num.new)

s.serve

=== Standalone server

Same as CGI-based server, only that the line

server = XMLRPC::CGIServer.new

must be changed to

server = XMLRPC::Server.new(8080)

if you want a server listening on port 8080.

The rest is the same.

=== Choosing a different XML Parser or XML Writer

The examples above all use the default parser (which is now since 1.8

REXMLStreamParser) and a default XML writer. If you want to use a different

XML parser, then you have to call the <i>set_parser</i> method of

<tt>XMLRPC::Client</tt> instances or instances of subclasses of

<tt>XMLRPC::BasicServer</tt> or by editing xmlrpc/config.rb.

Client Example:

# ...

server = XMLRPC::Client.new( "xmlrpc-c.sourceforge.net", "/api/sample.php")

server.set_parser(XMLRPC::XMLParser::XMLParser.new)

# ...

Server Example:

# ...

s = XMLRPC::CGIServer.new

s.set_parser(XMLRPC::XMLParser::XMLStreamParser.new)

# ...

or:

# ...

server = XMLRPC::Server.new(8080)

server.set_parser(XMLRPC::XMLParser::NQXMLParser.new)

# ...

Note that XMLStreamParser is incredible faster (and uses less memory) than any

other parser and scales well for large documents. For example for a 0.5 MB XML

document with many tags, XMLStreamParser is ~350 (!) times faster than

NQXMLTreeParser and still ~18 times as fast as XMLTreeParser.

You can change the XML-writer by calling method <i>set_writer</i>.

= XMLRPC for Ruby, Standard Library Documentation

== Overview

XMLRPC is a lightweight protocol that enables remote procedure calls over

HTTP. It is defined at http://www.xmlrpc.com.

XMLRPC allows you to create simple distributed computing solutions that span

computer languages. Its distinctive feature is its simplicity compared to

other approaches like SOAP and CORBA.

The Ruby standard library package 'xmlrpc' enables you to create a server that

implements remote procedures and a client that calls them. Very little code

is required to achieve either of these.

== Example

Try the following code. It calls a standard demonstration remote procedure.

require 'xmlrpc/client'

require 'pp'

server = XMLRPC::Client.new2("http://xmlrpc-c.sourceforge.net/api/sample.php")

result = server.call("sample.sumAndDifference", 5, 3)

pp result

== Documentation

See http://www.ntecs.de/projects/xmlrpc4r. There is plenty of detail there to

use the client and implement a server.

=begin

= xmlrpc/base64.rb

Copyright (C) 2001, 2002, 2003 by Michael Neumann (mneumann@ntecs.de)

Released under the same term of license as Ruby.

= Classes

* ((<XMLRPC::Base64>))

= XMLRPC::Base64

== Description

This class is necessary for (('xmlrpc4r')) to determine that a string should

be transmitted base64-encoded and not as a raw-string.

You can use (({XMLRPC::Base64})) on the client and server-side as a

parameter and/or return-value.

== Class Methods

--- XMLRPC::Base64.new( str, state = :dec )

Creates a new (({XMLRPC::Base64})) instance with string ((|str|)) as the

internal string. When ((|state|)) is (({:dec})) it assumes that the

string ((|str|)) is not in base64 format (perhaps already decoded),

otherwise if ((|state|)) is (({:enc})) it decodes ((|str|))

and stores it as the internal string.

--- XMLRPC::Base64.decode( str )

Decodes string ((|str|)) with base64 and returns that value.

--- XMLRPC::Base64.encode( str )

Encodes string ((|str|)) with base64 and returns that value.

== Instance Methods

--- XMLRPC::Base64#decoded

Returns the internal string decoded.

--- XMLRPC::Base64#encoded

Returns the internal string encoded with base64.

=end

module XMLRPC

class Base64

def initialize(str, state = :dec)

case state

when :enc

@str = Base64.decode(str)

when :dec

@str = str

else

raise ArgumentError, "wrong argument; either :enc or :dec"

end

def decoded

@str

end

def encoded

Base64.encode(@str)

end

def Base64.decode(str)

str.gsub(/\s+/, "").unpack("m")[0]

end

def Base64.encode(str)

[str].pack("m")

end

=begin

= xmlrpc/client.rb

Copyright (C) 2001, 2002, 2003 by Michael Neumann (mneumann@ntecs.de)

Released under the same term of license as Ruby.

= Classes

* ((<XMLRPC::Client>))

* ((<XMLRPC::Client::Proxy>))

= XMLRPC::Client

== Synopsis

require "xmlrpc/client"

server = XMLRPC::Client.new("www.ruby-lang.org", "/RPC2", 80)

begin

param = server.call("michael.add", 4, 5)

puts "4 + 5 = #{param}"

rescue XMLRPC::FaultException => e

puts "Error:"

puts e.faultCode

puts e.faultString

end

or

require "xmlrpc/client"

server = XMLRPC::Client.new("www.ruby-lang.org", "/RPC2", 80)

ok, param = server.call2("michael.add", 4, 5)

if ok then

puts "4 + 5 = #{param}"

else

puts "Error:"

puts param.faultCode

puts param.faultString

end

== Description

Class (({XMLRPC::Client})) provides remote procedure calls to a XML-RPC server.

After setting the connection-parameters with ((<XMLRPC::Client.new>)) which

creates a new (({XMLRPC::Client})) instance, you can execute a remote procedure

by sending the ((<call|XMLRPC::Client#call>)) or ((<call2|XMLRPC::Client#call2>))

message to this new instance. The given parameters indicate which method to

call on the remote-side and of course the parameters for the remote procedure.

== Class Methods

--- XMLRPC::Client.new( host=nil, path=nil, port=nil, proxy_host=nil, proxy_port=nil, user=nil, password=nil, use_ssl=false, timeout =nil)

Creates an object which represents the remote XML-RPC server on the

given host ((|host|)). If the server is CGI-based, ((|path|)) is the

path to the CGI-script, which will be called, otherwise (in the

case of a standalone server) ((|path|)) should be (({"/RPC2"})).

((|port|)) is the port on which the XML-RPC server listens.

If ((|proxy_host|)) is given, then a proxy server listening at

((|proxy_host|)) is used. ((|proxy_port|)) is the port of the

proxy server.

Default values for ((|host|)), ((|path|)) and ((|port|)) are 'localhost', '/RPC2' and

'80' respectively using SSL '443'.

If ((|user|)) and ((|password|)) are given, each time a request is send,

a Authorization header is send. Currently only Basic Authentification is

implemented no Digest.

If ((|use_ssl|)) is set to (({true})), comunication over SSL is enabled.

Note, that you need the SSL package from RAA installed.

Parameter ((|timeout|)) is the time to wait for a XML-RPC response, defaults to 30.

--- XMLRPC::Client.new2( uri, proxy=nil, timeout=nil)

--- XMLRPC::Client.new_from_uri( uri, proxy=nil, timeout=nil)

: uri

URI specifying protocol (http or https), host, port, path, user and password.

Example: https://user:password@host:port/path

: proxy

Is of the form "host:port".

: timeout

Defaults to 30.

--- XMLRPC::Client.new3( hash={} )

--- XMLRPC::Client.new_from_hash( hash={} )

Parameter ((|hash|)) has following case-insensitive keys:

* host

* path

* port

* proxy_host

* proxy_port

* user

* password

* use_ssl

* timeout

Calls ((<XMLRPC::Client.new>)) with the corresponding values.

== Instance Methods

--- XMLRPC::Client#call( method, *args )

Invokes the method named ((|method|)) with the parameters given by

((|args|)) on the XML-RPC server.

The parameter ((|method|)) is converted into a (({String})) and should

be a valid XML-RPC method-name.

Each parameter of ((|args|)) must be of one of the following types,

where (({Hash})), (({Struct})) and (({Array})) can contain any of these listed ((:types:)):

* (({Fixnum})), (({Bignum}))

* (({TrueClass})), (({FalseClass})) ((({true})), (({false})))

* (({String})), (({Symbol}))

* (({Float}))

* (({Hash})), (({Struct}))

* (({Array}))

* (({Date})), (({Time})), (({XMLRPC::DateTime}))

* (({XMLRPC::Base64}))

* A Ruby object which class includes XMLRPC::Marshallable (only if Config::ENABLE_MARSHALLABLE is (({true}))).

That object is converted into a hash, with one additional key/value pair "___class___" which contains the class name

for restoring later that object.

The method returns the return-value from the RPC

((-stands for Remote Procedure Call-)).

The type of the return-value is one of the above shown,

only that a (({Bignum})) is only allowed when it fits in 32-bit and

that a XML-RPC (('dateTime.iso8601')) type is always returned as

a ((<(({XMLRPC::DateTime}))|URL:datetime.html>)) object and

a (({Struct})) is never returned, only a (({Hash})), the same for a (({Symbol})), where

always a (({String})) is returned.

A (({XMLRPC::Base64})) is returned as a (({String})) from xmlrpc4r version 1.6.1 on.

If the remote procedure returned a fault-structure, then a

(({XMLRPC::FaultException})) exception is raised, which has two accessor-methods

(({faultCode})) and (({faultString})) of type (({Integer})) and (({String})).

--- XMLRPC::Client#call2( method, *args )

The difference between this method and ((<call|XMLRPC::Client#call>)) is, that

this method do ((*not*)) raise a (({XMLRPC::FaultException})) exception.

The method returns an array of two values. The first value indicates if

the second value is a return-value ((({true}))) or an object of type

(({XMLRPC::FaultException})).

Both are explained in ((<call|XMLRPC::Client#call>)).

Simple to remember: The "2" in "call2" denotes the number of values it returns.

--- XMLRPC::Client#multicall( *methods )

You can use this method to execute several methods on a XMLRPC server which supports

the multi-call extension.

Example:

s.multicall(

['michael.add', 3, 4],

['michael.sub', 4, 5]

)

# => [7, -1]

--- XMLRPC::Client#multicall2( *methods )

Same as ((<XMLRPC::Client#multicall>)), but returns like ((<XMLRPC::Client#call2>)) two parameters

instead of raising an (({XMLRPC::FaultException})).

--- XMLRPC::Client#proxy( prefix, *args )

Returns an object of class (({XMLRPC::Client::Proxy})), initialized with

((|prefix|)) and ((|args|)). A proxy object returned by this method behaves

like ((<XMLRPC::Client#call>)), i.e. a call on that object will raise a

(({XMLRPC::FaultException})) when a fault-structure is returned by that call.

--- XMLRPC::Client#proxy2( prefix, *args )

Almost the same like ((<XMLRPC::Client#proxy>)) only that a call on the returned

(({XMLRPC::Client::Proxy})) object behaves like ((<XMLRPC::Client#call2>)), i.e.

a call on that object will return two parameters.

--- XMLRPC::Client#call_async(...)

--- XMLRPC::Client#call2_async(...)

--- XMLRPC::Client#multicall_async(...)

--- XMLRPC::Client#multicall2_async(...)

--- XMLRPC::Client#proxy_async(...)

--- XMLRPC::Client#proxy2_async(...)

In contrast to corresponding methods without "_async", these can be

called concurrently and use for each request a new connection, where the

non-asynchronous counterparts use connection-alive (one connection for all requests)

if possible.

Note, that you have to use Threads to call these methods concurrently.

The following example calls two methods concurrently:

Thread.new {

p client.call_async("michael.add", 4, 5)

}

Thread.new {

p client.call_async("michael.div", 7, 9)

}

--- XMLRPC::Client#timeout

--- XMLRPC::Client#user

--- XMLRPC::Client#password

Return the corresponding attributes.

--- XMLRPC::Client#timeout= (new_timeout)

--- XMLRPC::Client#user= (new_user)

--- XMLRPC::Client#password= (new_password)

Set the corresponding attributes.

--- XMLRPC::Client#set_writer( writer )

Sets the XML writer to use for generating XML output.

Should be an instance of a class from module (({XMLRPC::XMLWriter})).

If this method is not called, then (({XMLRPC::Config::DEFAULT_WRITER})) is used.

--- XMLRPC::Client#set_parser( parser )

Sets the XML parser to use for parsing XML documents.

Should be an instance of a class from module (({XMLRPC::XMLParser})).

If this method is not called, then (({XMLRPC::Config::DEFAULT_PARSER})) is used.

--- XMLRPC::Client#cookie

--- XMLRPC::Client#cookie= (cookieString)

Get and set the HTTP Cookie header.

--- XMLRPC::Client#http_header_extra= (additionalHeaders)

Set extra HTTP headers that are included in the request.

--- XMLRPC::Client#http_header_extra

Access the via ((<XMLRPC::Client#http_header_extra=>)) assigned header.

--- XMLRPC::Client#http_last_response

Returns the (({Net::HTTPResponse})) object of the last RPC.

= XMLRPC::Client::Proxy

== Synopsis

require "xmlrpc/client"

server = XMLRPC::Client.new("www.ruby-lang.org", "/RPC2", 80)

michael = server.proxy("michael")

michael2 = server.proxy("michael", 4)

# both calls should return the same value '9'.

p michael.add(4,5)

p michael2.add(5)

== Description

Class (({XMLRPC::Client::Proxy})) makes XML-RPC calls look nicer!

You can call any method onto objects of that class - the object handles

(({method_missing})) and will forward the method call to a XML-RPC server.

Don't use this class directly, but use instead method ((<XMLRPC::Client#proxy>)) or

((<XMLRPC::Client#proxy2>)).

== Class Methods

--- XMLRPC::Client::Proxy.new( server, prefix, args=[], meth=:call, delim="." )

Creates an object which provides (({method_missing})).

((|server|)) must be of type (({XMLRPC::Client})), which is the XML-RPC server to be used

for a XML-RPC call. ((|prefix|)) and ((|delim|)) will be prepended to the methodname

called onto this object.

Parameter ((|meth|)) is the method (call, call2, call_async, call2_async) to use for

a RPC.

((|args|)) are arguments which are automatically given

to every XML-RPC call before the arguments provides through (({method_missing})).

== Instance Methods

Every method call is forwarded to the XML-RPC server defined in ((<new|XMLRPC::Client::Proxy#new>)).

Note: Inherited methods from class (({Object})) cannot be used as XML-RPC names, because they get around

(({method_missing})).

= History

$Id$

=end

module XMLRPC

# Constructors -------------------------------------------------------------------

def new2(uri, proxy=nil, timeout=nil)

begin

url = URI(uri)

rescue URI::InvalidURIError => e

raise ArgumentError, e.message, e.backtrace

end

unless URI::HTTP === url

raise ArgumentError, "Wrong protocol specified. Only http or https allowed!"

end

proto = url.scheme

user = url.user

passwd = url.password

host = url.host

port = url.port

path = url.path.empty? ? nil : url.request_uri

proxy_host, proxy_port = (proxy || "").split(":")

proxy_port = proxy_port.to_i if proxy_port

self.new(host, path, port, proxy_host, proxy_port, user, passwd, (proto == "https"), timeout)

end

alias new_from_uri new2

def new3(hash={})

# convert all keys into lowercase strings

h = {}

hash.each { |k,v| h[k.to_s.downcase] = v }

self.new(h['host'], h['path'], h['port'], h['proxy_host'], h['proxy_port'], h['user'], h['password'],

h['use_ssl'], h['timeout'])

end

alias new_from_hash new3

# Attribute Accessors -------------------------------------------------------------------

# add additional HTTP headers to the request

# makes last HTTP response accessible

# Cookie support

# Call methods --------------------------------------------------------------

# Multicall methods --------------------------------------------------------------

# Proxy generating methods ------------------------------------------