SSL backend error when using OpenSSL

Question

I was trying to install pycurl in a virtualenv using pip and I got this error

ImportError: pycurl: libcurl link-time ssl backend (openssl) is different from compile-time ssl backend (none/other)

I read some documentation saying that "To fix this, you need to tell setup.py what SSL backend is used" (source) although I am not sure how to do this since I installed pycurl using pip.

How can I specify the SSL backend when installing pycurl with pip?

Thanks

Answer 1

The method to fix the pycurl after Mac OS High Sierra update:

1. Reinstall the curl libraries to use OpenSSL instead of SecureTransport

   brew install curl --with-openssl
   

2. Install pycurl with correct build-time environment and paths

   export PYCURL_SSL_LIBRARY=openssl
   pip uninstall pycurl 
   pip install --no-cache-dir --global-option=build_ext --global-option="-L/usr/local/opt/openssl/lib" --global-option="-I/usr/local/opt/openssl/include" --user pycurl
   

Answer 2

Following worked for me with Python3.6

MacOS High-Sierra

sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-openssl" pycurl 

CentOS 7

sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-nss" pycurl

Answer 3

With OSX 10.13, a brew-installed openSSL, and virtualenv, I was successful with:

workon ..your-environment-here..
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=openssl
export LDFLAGS=-L/usr/local/opt/openssl/lib;export CPPFLAGS=-I/usr/local/opt/openssl/include;pip install pycurl --compile --no-cache-dir

Answer 4

After reading their INSTALLATION file, I was able to solve my problem by setting an environment variable and did a reinstall

• remove existing pycurl installation

  pip uninstall pycurl

• export variable with your link-time ssl backend (which is openssl above)

  export PYCURL_SSL_LIBRARY=openssl

• then, re-install pycurl

  pip install pycurl

There could be other solution out there but this works perfectly for me on a virtualenv and pip installation.

Answer 5

You can download the tar.gz file from here. Then extract it into a folder. You'll find a setup.py file there. Run the command over there that the site mentioned. For example:

python setup.py --with-[ssl|gnutls|nss] install

FYI: I tried to install pycurl at my windows, but I couldn't. But did it on my linux.

Answer 6

pip install -U pip

if [ "$(curl --version | grep NSS 2>/dev/null)" ]; then
    pip install --compile --install-option="--with-nss" pycurl
else
    pip install --compile --install-option="--with-openssl" pycurl
fi