How to make it work on Windows?

[NosIreland]

Hi,
I want to use this in my code but getting problems to make it work on windows with python 3.4
I've installed it with pip without a problem but whenever I use import libarchive it fails with:
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. I 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 of the module, I'm not sure what module it is looking for. What am I missing?

[pombredanne]

Sorry that I dropped the ball on the related #8 and #16 tickets....

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
With MinGW32 build instructions there: https://github.com/nexB/scancode-thirdparty-src/blob/master/libarchive/build.sh#L47

The way scancode loads the library is a tad more engaged since it is the same code for Win/Linux/mac.
You can see it there:
https://github.com/nexB/scancode-toolkit/blob/develop/src/extractcode/libarchive2.py#L64
Note that this is NOT using python-libarchive-c yet but a different/custom ctypes binding for now. Until I have time to fix things. At least it gives you access to a Win DLL and an example on how to load it correctly.

[NosIreland]

Thanks for replay I'll see if I can make it work :)

[pombredanne]

I also posted a reply at http://stackoverflow.com/questions/37165002/using-libarchive-in-python-on-windows I assume that this is you on both places. ;)

[Zitrax]

Any possibility/plan of getting a pip install setting it all up to work without any additional manual steps on Windows ?

[Changaco]

@Zitrax Yes, someone just has to step up and do the work. I'm busy and I don't use Windows so it probably won't be me (except perhaps if someone proposes to pay me to get it done).

[HatScripts]

I have prebuilt Windows binaries for another project here:
https://github.com/nexB/scancode-toolkit/tree/develop/src/extractcode/bin/win-32/bin

404... 😢

[pombredanne]

@HatScripts https://github.com/nexB/scancode-toolkit/tree/9e04eb55cd4a049409b86dac0b76445d87474c3a/plugins/extractcode-libarchive-win_amd64/src/extractcode_libarchive/lib

[HatScripts]

@pombredanne Thanks for that.

I still can't figure out how to make it work. I assume I need the libarchive.dll file, so I've tried adding that to my PATH, and also setting the LIBARCHIVE environment variable to point to it, but I get this error upon trying to import libarchive:

Traceback (most recent call last):
  File "D:/IdeaProjects/Python/Downloader/libarchive_test.py", line 4, in <module>
    import libarchive
  File "...\AppData\Local\Programs\Python\Python36\lib\site-packages\libarchive\__init__.py", line 1, in <module>
    from .entry import ArchiveEntry
  File "...\AppData\Local\Programs\Python\Python36\lib\site-packages\libarchive\entry.py", line 6, in <module>
    from . import ffi
  File "...\AppData\Local\Programs\Python\Python36\lib\site-packages\libarchive\ffi.py", line 27, in <module>
    libarchive = ctypes.cdll.LoadLibrary(libarchive_path)
  File "...\AppData\Local\Programs\Python\Python36\lib\ctypes\__init__.py", line 426, in LoadLibrary
    return self._dlltype(name)
  File "...\AppData\Local\Programs\Python\Python36\lib\ctypes\__init__.py", line 348, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: [WinError 193] %1 is not a valid Win32 application

What am I doing wrong?

[pombredanne]

It is kinda hard to figure out short of looking at your code. Is this public? And FWIW, the build I listed above needs ALL the DLLs, not just libarchive.dll.

[MartinFalatic]

From your development branch I see:

Windows 64-bit libraries: https://github.com/nexB/scancode-toolkit/tree/develop/plugins/extractcode-libarchive-win_amd64/src/extractcode_libarchive/lib

Windows 32-bit libraries: https://github.com/nexB/scancode-toolkit/tree/develop/plugins/extractcode-libarchive-win32/src/extractcode_libarchive/lib

Judging by the error, I would think @HatScripts needs the Win32 libraries.

Well, I get the same error and I'm using Windows 10 x64 to try this out, and I've tried both libraries (that are in their folders with all the related libraries)

[MartinFalatic]

Oh. @pombredanne, the full contents of the libarchive libraries those two folders are completely byte-identical, and both appear to actually be the Win32 builds of these DLLs. The setup.cfg files do differ, but that doesn't seem to have had the desired effect when you built them.

Looking at the other library folders, libmagic is similarly afflicted.

The 7z library is the only one with distinct 32-bit and 64-bit binaries present.

This is all as seen on the develop branch here:

https://github.com/nexB/scancode-toolkit/tree/develop/plugins

[MartinFalatic]

Well, almost three hours later and I finally built a version of the libarchive binary from scratch that loaded.... but doesn't work enough to pass more than a few tests. That's an utterly miserable experience for something that should be precompiled to begin with.

[bicobus]

@pombredanne Would it be possible for you to include you build scripts to this project's setup.py? So that whenever somebody do a pip install libarchive-c, the build system triggers if libarchive isn't already present on the host system.

This would help with using external build system like azure-pipelines or appveyor.