[IronPython] Embedding IronPython and calling python functions from C#

Patrick van der Willik patrick at toolmaker.nl
Tue Jun 16 01:26:17 CEST 2009


The actual code that uses these variables from within a script looks 
like this:
def OnConnect(user):
    s = "The value of x: " + str(x)
    user.Send(s, True) 
    user.Receiver = "user_username"
    return True

And the complete exception is:
[ERROR] [16-6-2009 1:18:16] An error occured while attempting to accept 
a new connection. Error: name 'x' is not defined
[ERROR] [16-6-2009 1:18:16] Stacktrace:    at 
IronPython.Runtime.PythonContext.MissingName(SymbolId name)
   at Microsoft.Scripting.Runtime.ModuleGlobalWrapper.GetCachedValue()
   at Microsoft.Scripting.Runtime.ModuleGlobalWrapper.get_CurrentValue()
   at S$2.OnConnect$6(Object user)
   at _stub_$17##8(Closure , CallSite , Object , User )
   at Microsoft.Scripting.Actions.MatchCaller.Call2[T0,T1,TRet](Func`4 
target, CallSite site, Object[] args)
   at Microsoft.Scripting.Actions.CallSite`1.UpdateAndExecute(Object[] args)
   at 
Microsoft.Scripting.Actions.UpdateDelegates.Update2[T,T0,T1,TRet](CallSite 
site, T0 arg0, T1 arg1)
   at System.Boolean(User)(Object[] , User )
   at TestProject.Users.ConnectionManager.AcceptNewConnnections() in 
C:\Users\Patrick\Documents\Visual Studio 
2008\Projects\test\TestProject\Users\ConnectionManager.cs
:line 108

Weird thing is: If I use GetVariable, it works fine. The call is done at 
a later location in the program that where I do the SetVariable, but the 
script scope hasn't ben changed in the meantime.

Patrick

Michael Foord wrote:
> Patrick van der Willik wrote:
>> Alright, that actually really worked pretty good, and I finally got 
>> it all working as it should. However, I'm running into 1 more little 
>> issue, now I need to go the other way around aswell. I have several 
>> functions marked in my application as PythonExportable. In a certain 
>> startup phase of the application, after creating the IronPython 
>> hosting environment, I walk over all these classes using Reflection, 
>> take the tagged functions and put these into my IP scope.
>>
>> However, my simple tests for some reason cause my SetVariable() calls 
>> to not work. I added 2 tests to my scripts, one where I add a 
>> variable into the scope and another one where I add a delegate. 
>> However, in both cases, whenever I use these variables from within my 
>> scripts, they don't seem to work. Code:
>>                Func<string> test = new Func<string>(Test);
>>                scope.SetVariable("x", 10);
>>                scope.SetVariable("Test", test);
>>
>> Accessing them in my scripts have the effect of triggering an 
>> exception that shows that x is undefined.
>
> Can you show the actual code that attempts to use them and the actual 
> exception message raised.
>
> Michael
>
>>
>> Some insights into this would be of great help.
>>
>> Patrick
>>
>> Michael Foord wrote:
>>> See this section of my hosting article:
>>>
>>> http://www.voidspace.org.uk/ironpython/hosting_api.shtml#functions-as-delegates 
>>>
>>>
>>> You cast the function to a delegate as you fetch it out of the scope.
>>>
>>> Michael
>>>
>>> Patrick van der Willik wrote:
>>>> I'm a bit late with responding to this as I was kinda busy. I used 
>>>> the code that was given Stephen and it seems to run properly 
>>>> without throwing exceptions. However, I created a little 
>>>> autoexec.py file with a simple function in it with 2 parameters.
>>>>
>>>> The main problem here is: How do I call the function through the 
>>>> scope? I used engine.CreateScope() to create myself a new scope, 
>>>> but from there on, I'm basically lost(again). What I basically want 
>>>> to do, is call my function 'add' with 2 parameters(say, 10 and 15). 
>>>> The modules itself are loaded into a ScriptSource.
>>>>
>>>> Thanks,
>>>> Patrick
>>>>
>>>> Lepisto, Stephen P wrote:
>>>>>
>>>>> What I do when I want to work with python modules from embedded 
>>>>> IronPython is set the IronPython search path with the path of the 
>>>>> module to load then  create and execute a small python script that 
>>>>> loads the main python modules into the current scope.
>>>>>
>>>>>  
>>>>>
>>>>> string moduleName = Path.GetFileName(modulePath);
>>>>>
>>>>> string path = Path.GetDirectoryName(modulePath);
>>>>>
>>>>>  
>>>>>
>>>>> ICollection<string> paths = _pythonEngine.GetSearchPaths();
>>>>>
>>>>> if (!paths.Contains(path))
>>>>>
>>>>> {
>>>>>
>>>>>     paths.Add(path);
>>>>>
>>>>>     _pythonEngine.SetSearchPaths(paths);
>>>>>
>>>>> }
>>>>>
>>>>> string modInvoke = String.Format("import {0}\nfrom {0} import 
>>>>> *\n", moduleName);
>>>>>
>>>>> ScriptSource source = 
>>>>> _pythonEngine.CreateScriptSourceFromString(modInvoke,
>>>>>
>>>>>                                                                  
>>>>> Microsoft.Scripting.SourceCodeKind.Statements);
>>>>>
>>>>>  
>>>>>
>>>>> Where modulePath is the full path to the python module or package 
>>>>> to load.
>>>>>
>>>>>  
>>>>>
>>>>> I can then invoke methods or access attributes using the 
>>>>> IronPython scope.  In this way, I can interact with the python 
>>>>> modules for as long as necessary before closing down the 
>>>>> scope/engine.
>>>>>
>>>>>  
>>>>>
>>>>>  
>>>>>
>>>>> *From:* users-bounces at lists.ironpython.com 
>>>>> [mailto:users-bounces at lists.ironpython.com] *On Behalf Of *Dody 
>>>>> Gunawinata
>>>>> *Sent:* Thursday, June 11, 2009 9:09 AM
>>>>> *To:* Discussion of IronPython
>>>>> *Subject:* Re: [IronPython] Embedding IronPython and calling 
>>>>> python functions from C#
>>>>>
>>>>>  
>>>>>
>>>>> You can read all yours file scripts, then using StringBuilder to 
>>>>> combine then and call CreateScriptSourceFromString()
>>>>>
>>>>> Then you can call your functions within the combined scripts 
>>>>> normally. Pretty much you are creating a giant source code on the 
>>>>> fly.
>>>>>
>>>>>  
>>>>>
>>>>> On Thu, Jun 11, 2009 at 5:32 PM, Patrick van der Willik 
>>>>> <patrick at toolmaker.nl <mailto:patrick at toolmaker.nl>> wrote:
>>>>>
>>>>> I'm currently attempting to embed the IronPython 2 runtimes into 
>>>>> an existing application written in C#. However, I find the amount 
>>>>> of documentation lacking on what I'm trying to do. I currently 
>>>>> have a proof-of-concept version which uses Lua and LuaInterface, 
>>>>> but the people who have to write the scripts dislike Lua(Well, 
>>>>> more hate it with a passion) and would love to see this working 
>>>>> with Python.
>>>>>
>>>>> My host application is a networked application that must trigger 
>>>>> certain scripts functions on events generated by the connected 
>>>>> clients. The idea is that when my application starts, it will load 
>>>>> the IronPython script environment, launches an 'autoexec.py' which 
>>>>> will load various other scripts files and do some housekeeping. 
>>>>> Once this all is completed, it will start listening to incoming 
>>>>> connections. However, in various scenarios, the application has to 
>>>>> trigger scripted functions when data is received from a client. 
>>>>> Which script function is called is different per client and per 
>>>>> event. I have events for connecting, logging on, disconnecting and 
>>>>> a set of data specific events after receiving data. This highly 
>>>>> depends on the received packets.
>>>>>
>>>>> My question here is: How do I embed IronPython in such a fashion 
>>>>> that I can load my scripts and then trigger various functions 
>>>>> within that? I've seen many examples that just call 
>>>>> CreateScriptSourceFromString() or File each time in which just 1 
>>>>> piece of code is implemented. This is not suitable for the needs 
>>>>> here because the scripted systems can become quite complex.
>>>>>
>>>>> With regards,
>>>>> Patrick
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at lists.ironpython.com <mailto:Users at lists.ironpython.com>
>>>>> http://lists.ironpython.com/listinfo.cgi/users-ironpython.com
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> -- 
>>>>> nomadlife.org <http://nomadlife.org>
>>>>>
>>>>> ------------------------------------------------------------------------ 
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at lists.ironpython.com
>>>>> http://lists.ironpython.com/listinfo.cgi/users-ironpython.com
>>>>>   
>>>>
>>>> ------------------------------------------------------------------------ 
>>>>
>>>>
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>>>>   
>>>
>>>
>>
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>
>




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