Consuming Python COM Server from .NET

Question

I wanted to implement python com server using win32com extensions. Then consume the server from within the .NET. I used the following example to implement the com server and it runs without a problem but when I try to consume it using C# I got FileNotFoundException with the following message "Retrieving the COM class factory for component with CLSID {676E38A6-7FA7-4BFF-9179-AE959734DEBB} failed due to the following error: 8007007e." . I posted the C# code as well.I wonder if I'm missing something I would appreciate any help. Thanks, Sarah ``` #PythonCOMServer.py import pythoncom class PythonUtilities: _public_methods_ = [ 'SplitString' ] _reg_progid_ = "PythonDemos.Utilities" # NEVER copy the following ID # Use"print pythoncom.CreateGuid()" to make a new one. _reg_clsid_ = pythoncom.CreateGuid() print _reg_clsid_ def SplitString(self, val, item=None): import string if item != None: item = str(item) return string.split(str(val), item) # Add code so that when this script is run by # Pyt…

Accepted Answer

A COM server is just a piece of software (a DLL or an executable) that will accept remote procedure calls (RPC) through a defined protocol. Part of the protocol says that the server must have a unique ID, stored in the Windows' registry. In our case, this means that you have "registered" a server that is not existing. Thus the error (component not found).

So, it should be something like this (as usual, this is untested code!):

```
import pythoncom

class HelloWorld:
    _reg_clsctx_ = pythoncom.CLSCTX_LOCAL_SERVER
    _reg_clsid_ = "{B83DD222-7750-413D-A9AD-01B37021B24B}"
    _reg_desc_ = "Python Test COM Server"
    _reg_progid_ = "Python.TestServer"
    _public_methods_ = ['Hello']
    _public_attrs_ = ['softspace', 'noCalls']
    _readonly_attrs_ = ['noCalls']
    # for Python 3.7+
    _reg_verprogid_ = "Python.TestServer.1"
    _reg_class_spec_ = "HelloWorldCOM.HelloWorld"

def __init__(self):
        self.softspace = 1
        self.noCalls = 0

def Hello(self, who):
        self.noCalls = self.noCalls + 1
        # insert "softspace" number of spaces
        return "Hello" + " " * self.softspace + str(who)

if __name__ == '__main__':
    if '--register' in sys.argv[1:] or '--unregister' in sys.argv[1:]:
        import win32com.server.register
        win32com.server.register.UseCommandLine(HelloWorld)
    else:
        # start the server.
        from win32com.server import localserver
        localserver.serve(['{B83DD222-7750-413D-A9AD-01B37021B24B}'])
```

Then you should run from the command line (assuming the script is called HelloWorldCOM.py):

```
HelloWorldCOM.py --register
HelloWorldCOM.py
```

Class HelloWorld is the actual implementation of the server. It expose one method (Hello) and a couple of attributes, one of the two is read-only. With the first command, you register the server; with the second one, you run it and then it becomes available to usage from other applications.

Consuming Python COM Server from .NET

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