class XMLRPC::BasicServer

This is the base class for all XML-RPC server-types (CGI, standalone). You can add handler and set a default handler. Do not use this server, as this is/should be an abstract class.

How the method to call is found¶ ↑

The arity (number of accepted arguments) of a handler (method or Proc object) is compared to the given arguments submitted by the client for a RPC, or Remote Procedure Call.

A handler is only called if it accepts the number of arguments, otherwise the search for another handler will go on. When at the end no handler was found, the default_handler, #set_default_handler will be called.

With this technique it is possible to do overloading by number of parameters, but only for Proc handler, because you cannot define two methods of the same name in the same class.

Constants

ERR_MC_EXPECTED_STRUCT
ERR_MC_MISSING_METHNAME
ERR_MC_MISSING_PARAMS
ERR_MC_RECURSIVE_CALL
ERR_MC_WRONG_PARAM
ERR_MC_WRONG_PARAM_PARAMS
ERR_METHOD_MISSING
ERR_UNCAUGHT_EXCEPTION

Public Class Methods

new(class_delim=".") click to toggle source

Creates a new XMLRPC::BasicServer instance, which should not be done, because XMLRPC::BasicServer is an abstract class. This method should be called from a subclass indirectly by a super call in the initialize method.

The parameter class_delim is used by #add_handler, see #add_handler, when an object is added as a handler, to delimit the object-prefix and the method-name.

# File lib/xmlrpc/server.rb, line 56
def initialize(class_delim=".")
 @handler = []
 @default_handler = nil
 @service_hook = nil
 @class_delim = class_delim
 @create = nil
 @parser = nil
 add_multicall if Config::ENABLE_MULTICALL
 add_introspection if Config::ENABLE_INTROSPECTION
end

Public Instance Methods

add_handler(prefix, obj_or_signature=nil, help=nil, &block) click to toggle source

Adds aBlock to the list of handlers, with name as the name of the method.

Parameters signature and help are used by the Introspection method if specified, where signature is either an Array containing strings each representing a type of it's signature (the first is the return value) or an Array of Arrays if the method has multiple signatures.

Value type-names are "int, boolean, double, string, Time.iso8601, base64, array, struct".

Parameter help is a String with information about how to call this method etc.

When a method fails, it can tell the client by throwing an XMLRPC::FaultException like in this example:

s.add_handler("michael.div") do |a,b|
 if b == 0
 raise XMLRPC::FaultException.new(1, "division by zero")
 else
 a / b
 end
end

In the case of b==0 the client gets an object back of type XMLRPC::FaultException that has a faultCode and faultString field.

This is the second form of ((<add_handler|XMLRPC::BasicServer#add_handler>)). To add an object write:

server.add_handler("michael", MyHandlerClass.new)

All public methods of MyHandlerClass are accessible to the XML-RPC clients by michael."name of method". This is where the class_delim in ::new plays it's role, a XML-RPC method-name is defined by prefix + class_delim + "name of method".

The third form of +add_handler is to use XMLRPC::Service::Interface to generate an object, which represents an interface (with signature and help text) for a handler class.

The interface parameter must be an instance of XMLRPC::Service::Interface. Adds all methods of obj which are defined in the interface to the server.

This is the recommended way of adding services to a server!

# File lib/xmlrpc/server.rb, line 115
def add_handler(prefix, obj_or_signature=nil, help=nil, &block)
 if block_given?
 # proc-handler
 @handler << [prefix, block, obj_or_signature, help]
 else
 if prefix.kind_of? String
 # class-handler
 raise ArgumentError, "Expected non-nil value" if obj_or_signature.nil?
 @handler << [prefix + @class_delim, obj_or_signature]
 elsif prefix.kind_of? XMLRPC::Service::BasicInterface
 # class-handler with interface
 # add all methods
 @handler += prefix.get_methods(obj_or_signature, @class_delim)
 else
 raise ArgumentError, "Wrong type for parameter 'prefix'"
 end
 end
 self
end

add_introspection() click to toggle source

Adds the introspection handlers "system.listMethods", "system.methodSignature" and "system.methodHelp", where only the first one works.

# File lib/xmlrpc/server.rb, line 236
def add_introspection
 add_handler("system.listMethods",%w(array), "List methods available on this XML-RPC server") do
 methods = []
 @handler.each do |name, obj|
 if obj.kind_of? Proc
 methods << name
 else
 obj.class.public_instance_methods(false).each do |meth|
 methods << "#{name}#{meth}"
 end
 end
 end
 methods
 end
 add_handler("system.methodSignature", %w(array string), "Returns method signature") do |meth|
 sigs = []
 @handler.each do |name, obj, sig|
 if obj.kind_of? Proc and sig != nil and name == meth
 if sig[0].kind_of? Array
 # sig contains multiple signatures, e.g. [["array"], ["array", "string"]]
 sig.each {|s| sigs << s}
 else
 # sig is a single signature, e.g. ["array"]
 sigs << sig
 end
 end
 end
 sigs.uniq! || sigs # remove eventually duplicated signatures
 end
 add_handler("system.methodHelp", %w(string string), "Returns help on using this method") do |meth|
 help = nil
 @handler.each do |name, obj, sig, hlp|
 if obj.kind_of? Proc and name == meth
 help = hlp
 break
 end
 end
 help || ""
 end
 self
end

add_multicall() click to toggle source

Adds the multi-call handler "system.multicall".

# File lib/xmlrpc/server.rb, line 191
def add_multicall
 add_handler("system.multicall", %w(array array), "Multicall Extension") do |arrStructs|
 unless arrStructs.is_a? Array
 raise XMLRPC::FaultException.new(ERR_MC_WRONG_PARAM, "system.multicall expects an array")
 end
 arrStructs.collect {|call|
 if call.is_a? Hash
 methodName = call["methodName"]
 params = call["params"]
 if params.nil?
 multicall_fault(ERR_MC_MISSING_PARAMS, "Missing params")
 elsif methodName.nil?
 multicall_fault(ERR_MC_MISSING_METHNAME, "Missing methodName")
 else
 if methodName == "system.multicall"
 multicall_fault(ERR_MC_RECURSIVE_CALL, "Recursive system.multicall forbidden")
 else
 unless params.is_a? Array
 multicall_fault(ERR_MC_WRONG_PARAM_PARAMS, "Parameter params have to be an Array")
 else
 ok, val = call_method(methodName, *params)
 if ok
 # correct return value
 [val]
 else
 # exception
 multicall_fault(val.faultCode, val.faultString)
 end
 end
 end
 end
 else
 multicall_fault(ERR_MC_EXPECTED_STRUCT, "system.multicall expected struct")
 end
 }
 end # end add_handler
 self
end

get_default_handler() click to toggle source

Returns the default-handler, which is called when no handler for a method-name is found.

It is either a Proc object or nil.

# File lib/xmlrpc/server.rb, line 170
def get_default_handler
 @default_handler
end

get_service_hook() click to toggle source

Returns the service-hook, which is called on each service request (RPC) unless it's nil.

# File lib/xmlrpc/server.rb, line 137
def get_service_hook
 @service_hook
end

process(data) click to toggle source

# File lib/xmlrpc/server.rb, line 283
def process(data)
 method, params = parser().parseMethodCall(data)
 handle(method, *params)
end

set_default_handler(&handler) click to toggle source

Sets handler as the default-handler, which is called when no handler for a method-name is found.

handler is a code-block.

The default-handler is called with the (XML-RPC) method-name as first argument, and the other arguments are the parameters given by the client-call.

If no block is specified the default of XMLRPC::BasicServer is used, which raises a XMLRPC::FaultException saying "method missing".

# File lib/xmlrpc/server.rb, line 185
def set_default_handler(&handler)
 @default_handler = handler
 self
end

set_service_hook(&handler) click to toggle source

A service-hook is called for each service request (RPC).

You can use a service-hook for example to wrap existing methods and catch exceptions of them or convert values to values recognized by XMLRPC.

You can disable it by passing nil as the handler parameter.

The service-hook is called with a Proc object along with any parameters.

An example:

server.set_service_hook {|obj, *args|
 begin
 ret = obj.call(*args) # call the original service-method
 # could convert the return value
 rescue
 # rescue exceptions
 end
}

# File lib/xmlrpc/server.rb, line 161
def set_service_hook(&handler)
 @service_hook = handler
 self
end

Private Instance Methods

call_method(methodname, *args) click to toggle source

# File lib/xmlrpc/server.rb, line 334
def call_method(methodname, *args)
 begin
 [true, dispatch(methodname, *args)]
 rescue XMLRPC::FaultException => e
 [false, e]
 rescue Exception => e
 [false, XMLRPC::FaultException.new(ERR_UNCAUGHT_EXCEPTION, "Uncaught exception #{e.message} in method #{methodname}")]
 end
end

check_arity(obj, n_args) click to toggle source

Returns true, if the arity of obj matches n_args

# File lib/xmlrpc/server.rb, line 322
def check_arity(obj, n_args)
 ary = obj.arity
 if ary >= 0
 n_args == ary
 else
 n_args >= (ary+1).abs
 end
end

dispatch(methodname, *args) click to toggle source

# File lib/xmlrpc/server.rb, line 294
def dispatch(methodname, *args)
 for name, obj in @handler
 if obj.kind_of? Proc
 next unless methodname == name
 else
 next unless methodname =~ /^#{name}(.+)$/
 next unless obj.respond_to? 1ドル
 obj = obj.method(1ドル)
 end
 if check_arity(obj, args.size)
 if @service_hook.nil?
 return obj.call(*args)
 else
 return @service_hook.call(obj, *args)
 end
 end
 end
 if @default_handler.nil?
 raise XMLRPC::FaultException.new(ERR_METHOD_MISSING, "Method #{methodname} missing or wrong number of parameters!")
 else
 @default_handler.call(methodname, *args)
 end
end

handle(methodname, *args) click to toggle source

# File lib/xmlrpc/server.rb, line 344
def handle(methodname, *args)
 create().methodResponse(*call_method(methodname, *args))
end

multicall_fault(nr, str) click to toggle source

# File lib/xmlrpc/server.rb, line 290
def multicall_fault(nr, str)
 {"faultCode" => nr, "faultString" => str}
end