“SSL certificate verify failed” using pip to insta

问题:

I am trying to install the Scrapy package (among others) for python using pip. I have tried doing the installation using python 3 and python 2, I have installed/upgraded the setuptools like so: $ pip3 install --upgrade setuptools, I have tried to use the --trusted-host option like so: $ pip3 install --trusted-host pypi.python.org Scrapy. But I always get the same error message when I run $ pip3 install Scrapy. The complete output is this:

Collecting Scrapy
  Using cached Scrapy-1.3.2-py2.py3-none-any.whl
Collecting PyDispatcher>=2.0.5 (from Scrapy)
  Using cached PyDispatcher-2.0.5.tar.gz
Collecting service-identity (from Scrapy)
  Using cached service_identity-16.0.0-py2.py3-none-any.whl
Collecting pyOpenSSL (from Scrapy)
  Using cached pyOpenSSL-16.2.0-py2.py3-none-any.whl
Collecting w3lib>=1.15.0 (from Scrapy)
  Using cached w3lib-1.17.0-py2.py3-none-any.whl
Collecting parsel>=1.1 (from Scrapy)
  Using cached parsel-1.1.0-py2.py3-none-any.whl
Collecting queuelib (from Scrapy)
  Using cached queuelib-1.4.2-py2.py3-none-any.whl
Requirement already satisfied: six>=1.5.2 in /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages (from Scrapy)
Collecting Twisted>=13.1.0 (from Scrapy)
  Using cached Twisted-17.1.0.tar.bz2
    Complete output from command python setup.py egg_info:
    Download error on https://pypi.python.org/simple/incremental/: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749) -- Some packages may not be found!
    Couldn't find index page for 'incremental' (maybe misspelled?)
    Download error on https://pypi.python.org/simple/: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749) -- Some packages may not be found!
    No local packages or working download links found for incremental>=16.10.1
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/gy/5xt04_452z791v1qjs1yzxkh0000gn/T/pip-build-nkv4jozy/Twisted/setup.py", line 21, in <module>
        setuptools.setup(**_setup["getSetupArgs"]())
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/distutils/core.py", line 108, in setup
        _setup_distribution = dist = klass(attrs)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/setuptools/dist.py", line 317, in __init__
        self.fetch_build_eggs(attrs['setup_requires'])
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/setuptools/dist.py", line 372, in fetch_build_eggs
        replace_conflicting=True,
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pkg_resources/__init__.py", line 851, in resolve
        dist = best[req.key] = env.best_match(req, ws, installer)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1123, in best_match
        return self.obtain(req, installer)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1135, in obtain
        return installer(requirement)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/setuptools/dist.py", line 440, in fetch_build_egg
        return cmd.easy_install(req)
      File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/setuptools/command/easy_install.py", line 668, in easy_install
        raise DistutilsError(msg)
    distutils.errors.DistutilsError: Could not find suitable distribution for Requirement.parse('incremental>=16.10.1')

    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/gy/5xt04_452z791v1qjs1yzxkh0000gn/T/pip-build-nkv4jozy/Twisted/

I am on a mac OS version 10.12.1 and am using python 3.6. Does anybody know a solution to this problem?

回答1:

pip install --trusted-host pypi.python.org autopep8 (any package name)

This command will add pypi.python.org to the trusted sources and will install all the required package.

I ran into the error myself and typing this command helped me install all the pip packages of python.

回答2:

As stated here https://bugs.python.org/issue28150 in previous versions of python Apple supplied the OpenSSL packages but does not anymore.

Running the command pip install certifi and then pip install Scrapy fixed it for me

回答3:

One note on the above answers: it is no longer sufficient to add just pypi.python.org to the trusted-hosts in the case where you are behind an HTTPS-intercepting proxy (we have zScaler).

I currently have the following in my pip.ini:

trusted-host = pypi.python.org pypi.org files.pythonhosted.org

Running pip -v install pkg will give you some hints as to which hosts might need to be added.

回答4:

Something to try --- tell python to not use https with the index directive and a http:// address (not https://)

pip install --index-url=http://pypi.python.org/simple/ --trusted-host pypi.python.org  Scrapy

You may be behind a corporate firewall and Ive have experiences where even the above failed, though Im not going to pretend like I know enough about firewalls or SSL to understand why. In that case the only way I was able to get around that was to get a certificate file and pass it to python. See kenorb’s answer here for details.

回答5:

You can try sudo apt-get upgrade to get the latest packages. It fixed the issue on my machine.

回答6:

It looks like they are also using pypi.org now. I added the following to %appdata%\pip\pip.ini and was able to download my packages from behind an HTTPS-intercepting proxy:

trusted-host = pypi.python.org files.pythonhosted.org pypi.org

回答7:

It seems that Scrapy fails because installing Twisted fails, which fails because incremental fails. Running pip install --upgrade pip && pip install --upgrade incremental fixed this for me.

回答8:

If adding pypi.python.org as a trusted host does not work, you try adding files.pythonhosted.org. For example

python -m pip install --upgrade --trusted-host files.pythonhosted.org <package-name>

回答9:

If you're using python3, you can try this too:

python3 -m pip install --upgrade Scrapy --trusted-host pypi.org --trusted-host files.pythonhosted.org