Importing external module in IronPython

Question

I'm currently working on an application written in C#, which I'm embedding IronPython in. I generally have no problems about it, but there's one thing that I don't know how to deal with.

I want to import an external module into the script. How can I do that? Simple import ext_lib doesn't work. Should I add a path to the lib to sys.path? Maybe it is possible to copy the lib's .py file into app directory and import from there?

EDIT: I finally chosen another solution - compiled my script with py2exe and I'm just running it from main C# app with Process (without using IronPython).

Anyway, thanks for help ;)

Solution 1

Before compiling a script with the PythonEngine, I add the script's directory to the engine's search path. This is what I do in the C# code:

string dir = Path.GetDirectoryName(scriptPath);                       
ICollection<string> paths = engine.GetSearchPaths();

if (!String.IsNullOrWhitespace(dir))
{
    paths.Add(dir);
}
else
{
    paths.Add(Environment.CurrentDirectory);
}
engine.SetSearchPaths(paths);

Now if the libraries are in the directory where the scripts, which you are executing, reside they will be importable.

Solution 2

Chances are that your path is set up incorrectly. From the IronPython FAQ:

How do I use CPython standard libraries?

To tell IronPython where the Python standard library is, you can add the "lib" directory of CPython to IronPython's path. To do this, put the following code into IronPython's "site.py" file (replace c:\python24\lib with your actual path to the CPython lib directory):

import sys
sys.path.append(r"c:\python24\lib")

Also, if you're getting import errors in CPython for a script that you do have on your computer, 99% of the time it's a path issue there too.

Solution 3

If you have installed IronPython from NuGet packages and you want modules from the CPython Standard Library then the best way to do it is by installing the IronPython.StdLib NuGet package which is from the same authors of IronPython.

Comments

[DaveS]

if I were to remove a directory from paths after calling SetSearchPaths(paths), would the engine know? I have a similar setup but I expect multiple scripts to be run from various locations. So I want to remove the script's search path after that particular script has been executed.

[FabioSpaghetti]

​I don't understand if these 2 lines import sys to IronPython ? if so, why is sys imported before indicating the directory ?​