python - Pip error: Microsoft Visual C++ 14.0 is required

Question

I just ran the following command:

pip install -U steem

and the installation worked well until it failed to install pycrypto. Afterwards I did the

pip install cryptography

command because I thought it was the missing package. So my question is, how I can install steem without the pycrypto-error (or the pycrypto-package in addition) and how to uninstall the cryptography-Package which I don't need. (I'm using Windows 7 and Python 3)

Requirement already up-to-date: python-dateutil in c:users***appdatalo
calprogramspythonpython36libsite-packages (from dateparser->maya->steem)
...
Installing collected packages: urllib3, idna, chardet, certifi, requests, pycryp
to, funcy, w3lib, voluptuous, diff-match-patch, scrypt, prettytable, appdirs, la
ngdetect, ruamel.yaml, humanize, tzlocal, regex, dateparser, pytzdata, pendulum,
maya, ecdsa, pylibscrypt, ujson, toolz, steem
Running setup.py install for pycrypto ... error
Complete output from command c:users***appdatalocalprogramspytho
npython36python.exe -u -c "import setuptools, tokenize;__file__='C:\Users\
***~1\AppData\Local\Temp\pip-build-k6flhu5k\pycrypto\setup.py';f=getattr(
tokenize, 'open', open)(__file__);code=f.read().replace('
', '
');f.close();
exec(compile(code, __file__, 'exec'))" install --record C:Users***N~1AppDat
aLocalTemppip-igpkll6u-recordinstall-record.txt --single-version-externally-
managed --compile:
running install
running build
running build_py
...
building 'Crypto.Random.OSRNG.winrandom' extension
error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual
C++ Build Tools": http://landinghub.visualstudio.com/visual-cpp-build-tools

----------------------------------------
Command "c:users***appdatalocalprogramspythonpython36python.exe -u
-c "import setuptools, tokenize;__file__='C:\Users\***N~1\AppData\Local\
Temp\pip-build-k6flhu5k\pycrypto\setup.py';f=getattr(tokenize, 'open', open)(
__file__);code=f.read().replace('
', '
');f.close();exec(compile(code,   __fil
e__, 'exec'))" install --record C:Users***N~1AppDataLocalTemppip-igpkll6
u-recordinstall-record.txt --single-version-externally-managed --compile"   faile
d with error code 1 in C:Users***N~1AppDataLocalTemppip-build-    k6flhu5kp
ycrypto

Answer 1

You need to install Microsoft Visual C++ 14.0 to install pycrypto:

error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual
C++ Build Tools": http://landinghub.visualstudio.com/visual-cpp-build-tools

In the comments you ask which link to use. Use the link to Visual C++ 2015 Build Tools. That will install Visual C++ 14.0 without installing Visual Studio.

In the comments you ask about methods of installing pycrypto that do not require installing a compiler. The binaries in the links appear to be for earlier versions of Python than you are using. One link is to a binary in a DropBox account.

I do not recommend downloading binary versions of cryptography libraries provided by third parties. The only way to guarantee that you are getting a version of pycrypto that is compatible with your version of Python and has not been built with any backdoors is to build it from the source.

After you have installed Visual C++, just re-run the original command:

pip install -U steem

To find out what the various install options mean, run this command:

pip help install

The help for the -U option says

-U, --upgrade        Upgrade all specified packages to the newest available
                     version. The handling of dependencies depends on the
                     upgrade-strategy used.

If you do not already have the steem library installed, you can run the command without the -U option.