0 Preface
RPC yes Remote Procedure Call Abbreviation , Translated into Chinese ： Remote method call .
stay Python in , We can use XML-RPC Protocols create their own cross platform , Language independent server .XML Remote Procedure Call, namely XML Remote method call .
XML-RPC Published in 1998 year , It is a set that allows to run on different operating systems 、 The program implementation in different environments is based on Internet Specification of procedure call and a series of implementation . This remote procedure call uses http As a transport protocol ,XML As the encoding format of transmission information .
XML-RPC The definition of is kept as simple as possible , But it can also transmit 、 Handle 、 Return complex data structures .XML- RPC（http://www.xmlrpc.com） By UserLand Software（UserLand Software） Of Dave Winer And Microsoft Co publish [2]. Later in the new features are constantly introduced under , This standard gradually evolved into today's SOAP agreement .XML-RPC Is a remote procedure call method , It uses HTTP Delivered XML As a carrier . With it , The client can call methods with parameters on the remote server （ The server to URI name ） And get structured data .
The simple understanding is ： Define data as XML Format , adopt HTTP Protocol for remote transmission .
1 The server
stay Python in ,
xmlrpc The module is a collection XML-RPC Server and client implementation module package . These modules are :
We use
SimpleXMLRPCServer To create
SimpleXMLRPCSERVER example , And tell it to listen for incoming requests . Next , We define some functions as part of the service and register them , So that the server knows how to call it .
Create a
xmlrpc_server.py file . In the following example , We use SimpleXMLRPCServer Instance creation server , And register some predefined and customized functions . Last , We put the server into an infinite loop to receive and respond to requests .
from xmlrpc.server import SimpleXMLRPCServer
from xmlrpc.server import SimpleXMLRPCRequestHandler
class RequestHandler(SimpleXMLRPCRequestHandler):
rpc_paths = ('/RPC2',)
with SimpleXMLRPCServer(('localhost', 9000), requestHandler=RequestHandler) as server:
server.register_introspection_functions()
# Register len() function;
server.register_function(len)
# Register a function under a different name
@server.register_function(name='rmndr')
def remainder_function(x, y):
return x // y
# Register a function under function.__name__.
@server.register_function
def modl(x, y):
return x % y
server.serve_forever()
XML-RPC It allows us to easily construct a simple remote call service . All you need to do is create a server instance , By its way
register_function() To register functions , Then use the method
serve_forever() To start it .
Once the above server is started , You can call through the client program , The program can refer to functions and make function calls .
2 Running client
Create a
xmlrpc_client.py file ：
import xmlrpc.client
s = xmlrpc.client.ServerProxy('http://localhost:9000')
print(s.len("Yuzhou1su"))
print(s.rmndr(1024,128))
print(s.modl(7,3))
# Print list of available methods
print(s.system.listMethods()) The following output can be seen in the terminal
$ python xmlrpc_client.py
9
8
1
['len', 'modl', 'rmndr', 'system.listMethods', 'system.methodHelp', 'system.methodSignature']- The first result ： character string Yuzhou1su The length is 9
- Second result ：1024 Divide 128 The result of the division of is 8
- The third result ：7 Divide 3 The remainder is 1
- The last line ： Output system method
summary
XML-RPC Of shortcoming ：
- Its performance is not high
- Transmission of other data formats is not supported . as well as XML-RPC All data will be serialized into XML Format , So it will be slower than other methods
- And it can't protect against maliciously constructed data .
XML-RPC Of advantage ：
- Through the encapsulation of program language , Realize the call of remote object .
however , The advantage of this simple coding is that many other programming languages can understand . Use XML-RPC Words , The client program can adopt Python Other languages , You can also visit Service for .
Put aside XML-RPC Don't say the limitations of , If you need it fast but not perfect （quick and dirty） The way Implement a remote procedure call system , So learn about XML-RPC It's still worth it . Many times it's simple Our plan is good enough . in addition ,JSON-RPC Its principle is similar .
- xmlrpc --- XMLRPC Server and client modules
- adopt XML-RPC Realize simple remote call
- xmlrpc.client — XML-RPC Client class library
