How would you extract the GUID of an ActiveX COM DLL using only Python in a cross-platform manner?
I ran across pythoncom, which comes with pywin32. It has a LoadTypeLib function which can do just that:
import pythoncom
dll = pythoncom.LoadTypeLib("C:\\path\to\\my.dll")
print str(dll.GetLibAttr()[0])
This is better than my current solution which relies on an external CLI application, however a cross-platform solution would be even better as I don't believe pywin32 can be installed on a Linux CI easily.
I ended up using the wonderful comtypes package:
from comtypes.typeinfo import LoadTypeLibEx
lib = LoadTypeLibEx("C:\\path\to\\my.dll")
print lib.GetLibAttr().guid
The code is effectively the same; it literally calls the same LoadTypeLib from OleAut32 so it is Windows-only, however comtypes is installable through pip which makes the distribution easier.
Related
Question:
I want to compile a third-party library like Pillow or Numbpy but I want to change the name of the python27.dll to corepython27.dll. How do I do this during the compile process? Is it something I need to change in the setup.py? Or the distutils library?
I should explain that I have no experience in compiling at all. I just know that I will need to make this change as I learn more about the basics of compiling.
Explanation:
Corel's PaintShop Pro uses an embedded python interpreter to run scripts inside the program. And I would like to be able to use third-party libraries like pillow and numpy but they always fail to load. The version of python that is included with PaintShop Pro is 2.7.5. I've made sure to download the appropriate versions of these libraries but it always fails with a "DLL module doesn't exist" type error.
Using a PE viewer I was able to see that other libraries like TKinter were using imports corepython27.dll instead of python27.dll like pillow was.
Also pillow for 2.7 was using msvcr90.dll but the custom version of the tkinter library included with PSP was compiled with msvcr110.dll. Do you think this will be an issue? Do I need to compile pillow with the appropriate version of msvcr DLL? Or is matching versions (2.7) and making sure it uses the correct python.dll (corepython27.dll) the only important thing?
You can create a symbolic link named corepython27.dll showing to the installed python27.dll. You can do this in your console via the command
MKLINK <path_to_corepython.dll> <path_to_python27.dll>
In Julia I am using the module PyCall
using PyCall: #pyimport
When I then try to use the scikitlearn library's module called ensamble, there is no problem, it works and I can use the module:
#pyimport sklearn.ensemble as skle
However when I try to do the same with the PIL library or PIL library's module Images, it doesn't work.
#pyimport PIL.Image as PILI
I get the following error: ERROR: PyError (:PyImport_ImportModule)
ImportError('No module named PIL.Image',)
[inlined code] from /home/lara/.julia/v0.4/PyCall/src/exception.jl:81
in pyimport at /home/lara/.julia/v0.4/PyCall/src/PyCall.jl:387
Can someone please talk me through the steps to get this working becasue I don't see how this is different from the scikit learn library and ensamble module.
Based on discussion in the comments, the issue appears to be that PyCall is using its own Python installation which does not have the requisite library installed. There are two options:
follow these instructions to change the Python installation referenced by PyCall to your local one in /home/lara/anaconda2.
use Conda.jl to add PIL to the Conda.jl Python install:
Conda.add("Pillow") (you could probably use PIL, but Pillow is a compatible fork that is actively maintained from what I can tell)
The second option is probably slightly preferred, but if you have many packages installed already it may be simpler to try the first option (you can always switch back to the Conda.jl version if something doesn't work).
I'm trying to get libarchive module working in python 3.4 on windows.
I've installed libarchive-c with pip and all went ok but whenever I try to import it into my code or even to run it alone I'me getting error:
OSError: [WinError 126] The specified module could not be found
This is coming from ffi.py from the code below:
libarchive_path = os.environ.get('LIBARCHIVE') or find_library('archive')
libarchive = ctypes.cdll.LoadLibrary(libarchive_path)
I've never used ctypes before but if I understand correctly it is looking for external DLL. So found and installed http://gnuwin32.sourceforge.net/packages/libarchive.htm also I've added C:\Program Files (x86)\GnuWin32\bin to my %PATH% in environmental variables but it still cannot load the module. As it does not give me the name I'm not sure what module it is looking for.
What am I missing?
(disclaimer) I contribute to https://github.com/Changaco/python-libarchive-c and I maintain https://github.com/nexB/scancode-toolkit
Both contain a ctypes binding for libarchive, though ScanCode is for extraction only.
My answer here is for python-libarchive-c, but ScanCode contains some of the DLL you are looking for so I am lacing in a bit of both.
To get python-libarchive-c going on Windows you need a libarchive DLL and its deps that can then be loaded.
There are no pre-built DLLs bundled in python-libarchive-c but I have prebuilt Windows binaries for another project here:
https://github.com/nexB/scancode-toolkit/tree/develop/src/extractcode/bin/win-32/bin
The corresponding source code is there: https://github.com/nexB/scancode-thirdparty-src
And you have MinGW32 build instructions there if you want to rebuild from source yourself: https://github.com/nexB/scancode-thirdparty-src/blob/master/libarchive/build.sh#L47
In general to load a DLL from a path -- assuming that the var libarchive contains the full path to that DLL -- use this:
lib = ctypes.CDLL(libarchive)
Now this is for Scancode. For python-libarchive-c, you could try to set the LIBARCHIVE variable to point the path of your DLL with:
set LIBARCHIVE="C:\.....\libarchive.dll"
Then start Python, import the library and use it.
NB: I did not test this (yet) , but this should work. IF not please file a bug.
I did not run any test on Python 3.4 either. I use primarily Python 2.7.
But the DLL and the code is not Python 2.7-specific at all.
FWIW, the way scancode loads the library is a tad more engaged since it can from the same code load DLLs Win/Linux/Mac for specific 32 or 64 bits archs using conventional locations. You can see the code in action there:
https://github.com/nexB/scancode-toolkit/blob/develop/src/extractcode/libarchive2.py#L64
ScanCode is NOT using python-libarchive-c ATM yet but a different/custom ctypes binding focused on a more specific use case of extraction only. At least it gives you access to a Win DLL and its deps (or instruction a build them) and an example on how to load it correctly.
/HTH
I want to use the Cantera library in python. I have been using it for C++ and I am linking my adding these couple lines to my makefile:
CANT_LIB = $HOME/usr/local/Cantera201/lib/
CANT_INC = $HOME/usr/local/Cantera201/include/ -I $HOME/usr/local/Cantera201/include/cantera \
with CANT_LIB and CANT_INC being called when compiling.
I have very limited experience with python. Is there an equivalent to linking libraries in python? I have tried adding the cantera path to PYTHONPATH but it did not work. I am working on a Linux server on which I do not have access to super user and python 2.6.6.
You need to install Cantera's Python module to use it, the raw C/C++ libraries aren't enough. If you install using the directions on their website it should be installed to the appropriate Python site-packages directory automatically, and available for use with just import cantera.
Im my Python file, I have imported the win32gui module like this:
import win32gui
I have also downloaded win32gui but don't know how to make my script run. How can I run my Python script which imports win32gui? When I run it, I get:
ImportError: No module named win32gui
Sorry for the newbie question but I'm trying to learn Python so don't know much about it.
When on a windows platform, I usually go for the executables. They should work all the time. Try perhaps one of the files listed here:
http://sourceforge.net/projects/pywin32/files/pywin32/Build216/
It's the most recent build. Choose the one appropriate to your Python's version.
this is a module from Marc Hammond's well-known pywin32 extension module, you can also get the source and compile it quite easily (I found I needed to do this because I needed a 64 bit build and couldn't find one at the time). The mercurial address to get it is:
http://pywin32.hg.sourceforge.net:8000/hgroot/pywin32/pywin32
there are visual studio project files in the .\pywin32\win32 directory...