question

FlexSim 2021 will only connect to a C++ dll and FlexScript.

It is theoretically possible to create a C++ dll that calls python functions. In that case, FlexSim could call a function in a C++ dll, which then calls a function in a python module (a .py or .pyd file). However, doing so requires a lot of C++ know-how.

If you want to do that, the best advice I can give is to look at how we created the PyConnector dll:

https://github.com/flexsim/FlexSimPy/tree/v23.2/PyConnector

It would be easier to create an http server with python. You can write FlexScript code to send an HTTP request to your python server. Then, as a response to the request, you could run your routing algorithm, and return some JSON. When you get the response in FlexSim, you can use JSON to parse the result:

https://docs.flexsim.com/en/23.2/Reference/CodingInFlexSim/FlexScriptAPIReference/Data/JSON.html

As an example, here is an attached python script:

routing_functions.py

If you run the python script, you can then run the following FlexScript to get a response from the server:

Http.Request request;
request.host = "localhost";
request.port = 8080;
request.path = "func_foo";
request.data = JSON.stringify([1, 2, 3, 4, 5, 6, 7]);

var response = request.sendAndWait();
var fooValue = JSON.parse(response.value);

request.path = "func_bar";
request.data = JSON.stringify(5.3);
response = request.sendAndWait();
var barValue = JSON.parse(response.value);

return [fooValue, barValue];

Note that there is some delay in creating and sending the HTTP request. If speed becomes an issue, you'd probably be able to use FlexSim's socket commands with your own protocol to get a speed improvement.