LookupError: unknown encoding: string_escape when running scons command

Question

I am following this tutorial to build the IoTivity Base Android API:

https://wiki.iotivity.org/android_build_instructions#android_example_apps

I downloaded the IoTivity project from here:

https://iotivity.org/downloads

I am at the step where I use the command to build IoTivity for Android:

scons TARGET_OS=android

And I get the output:

scons: Reading SConscript files ... LookupError: unknown encoding:
string_escape:   File
"C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\SConstruct",
line 28:
    SConscript('build_common/SConscript')   File "c:\users\darius\appdata\local\programs\python\python37-32\lib\site-packages\scons\SCons\Script\SConscript.py",
line 667:
    return method(*args, **kw)   File "c:\users\darius\appdata\local\programs\python\python37-32\lib\site-packages\scons\SCons\Script\SConscript.py",
line 604:
    return _SConscript(self.fs, *files, **subst_kw)   File "c:\users\darius\appdata\local\programs\python\python37-32\lib\site-packages\scons\SCons\Script\SConscript.py",
line 285:
    call_stack[-1].globals)   File "C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\build_common\SConscript",
line 559:
    user_prefix = env.get('BUILD_DIR').encode('string_escape')

I am on a Windows machine, using Command Prompt.

I tried the solutions in this post:

Python 2.7 : LookupError: unknown encoding: cp65001

But it did not help. I am new to Python. Can someone help?

EDIT

After changing to Python 2.7.16, I now get this output instead:

scons: Reading SConscript files ...

*********************** Error ************************
*                                                    *
* Please make sure that 7-zip is in your System PATH *
*                                                    *
******************************************************

NameError: name 'host_arch' is not defined:   File
"C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\SConstruct",
line 28:
    SConscript('build_common/SConscript')   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
667:
    return method(*args, **kw)   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
604:
    return _SConscript(self.fs, *files, **subst_kw)   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
285:
    call_stack[-1].globals)   File "C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\build_common\SConscript",
line 795:
    env.SConscript(target_os + '/SConscript')   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
604:
    return _SConscript(self.fs, *files, **subst_kw)   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
285:
    call_stack[-1].globals)   File "C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\build_common\android\SConscript",
line 19:
    SConscript('#/extlibs/android/ndk/SConscript')   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
667:
    return method(*args, **kw)   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
604:
    return _SConscript(self.fs, *files, **subst_kw)   File "c:\python27\lib\site-packages\scons\SCons\Script\SConscript.py", line
285:
    call_stack[-1].globals)   File "C:\Users\Darius\Downloads\iotivity-1.3.1.tar\iotivity-1.3.1\iotivity-1.3.1\extlibs\android\ndk\SConscript", line 24:
    if host_arch in ['x86_64']:

I did add my 7-zip folder path to PATH environment variable and restarted, but I still get this message. Not sure why it's even required though..

Answer 1

Looking at the error it looks like iotivity is using string_escape which isn't supported under python 3.*.

You'll need to install python 2.7 then:

py -3 -mpip uninstall scons
py -2 -mpip install -U pip setuptools wheel
py -2 -mpip install scons

Then try again.