We are looking for a C++ Soap web services framework that support RPC, preferably open source. Any recommendations?
While not FOSS another library is ATL Server library from Microsoft. It is C++ template based with some proprietary attributes by Microsoft. i.e. not standard C++
I have used SWIG to make an interface from C++ to Java or Python and then used the typical web interface support for those languages.
Since Java and Python have reflection the web services frameworks that exist for them have a much easier time passing data around.
Threading wise if your C++ code is thread safe you can let the Java server manage the creation of threads for concurrent requests etc. and just call into your C++ code using JNI.
As a bonus you can test your C++ code from Python using these same SWIG interfaces.
You can check out xmlbeansxx. This is a kind of lightweight, low level solution, compared to complete frameworks. This has advantages in some cases.
Invoking SOAP WebServices using xmlbeansxx Article
Code example is here: WsClient.cpp.
I think the way to go is to write your service in C++ (I am assuming you did all the homework and there is a good reason you want to write in C++) and then front it using an RPC server. Use something like Thrift or Protobufs for a fast RPC implementation.
Now write your web frontend in the language of your choice - python would be mine - and make RPC calls to do all your heavy lifting.
I concur with imjorge's answer and add that there's a C/C++ version of the Axis2 framework (a more flexible, extensible Axis) that does SOAP via RPC and all sorts of stuff including a bunch of the WS-* specs.
http://ws.apache.org/axis2/c/
http://code.google.com/p/staff/
Staff is Web Service Framework for C++ (service/component and client-side)/JavaScript(client-side) based on Apache Axis2/C.
Open-source, released with Apache License V2.0.