B2B Integration : A Practical Guide to Collaborative E-commerce

84 B2B Integration — A Practical Guide to Collaborative E-commerce
RPC Client
Calling
Code
RPC
Interface
Client
Stub
RPC
Runtime
jk %.
Apparent Path of
Procedure Call
•
Apparent Path
of Data
Return Data
Input Arguments
RPC Server
Remote
Procedure
RPC
Interface
Server
Runtime
RPC Runtime
Figure 3.23. — Real and apparent paths of RPC call and data flow
RPC-based integration can either be synchronous or asynchronous in
nature. A synchronous function or method call will hold up the execution
of an application while it awaits a response from the remote method.
As an example, assume that there is a remote procedure for retrieving
customer information. The details of the RPC are given in Table 3.1.
XML-based RPCs
B2B applications that communicate using RPC can fully leverage XMLbased
technology to communicate in a standard way over the Internet
using HTTP. RPCs, based on XML, work by encoding the RPC request
from the client to the remote server in an XML message (see Figure 3.24).
The message is then sent over the Internet to the server. On receiving
the message, the server decodes it, executes the remote procedure and
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