python - 为什么我无法安装 flask (PIP 错误)？

Question

我无法安装 Flask 或几乎任何其他模块。
我的操作系统:Ubuntu 14.04 LTS(32 位)。
Ubuntu 预装了 Python2 和 Python3。
当我使用 flask 时，我尝试使用以下命令安装它:

pip3 install flask

这是终端的输出:

root@Ashu-linx:/var/www# pip3 install flask
Downloading/unpacking flask
Downloading Flask-2.0.1-py3-none-any.whl (94kB): 94kB downloaded
Downloading/unpacking itsdangerous>=2.0 (from flask)
Downloading itsdangerous-2.0.1-py3-none-any.whl
Downloading/unpacking Jinja2>=3.0 (from flask)
Downloading Jinja2-3.0.1-py3-none-any.whl (133kB): 133kB downloaded
Downloading/unpacking Werkzeug>=2.0 (from flask)
Downloading Werkzeug-2.0.1-py3-none-any.whl (288kB): 288kB downloaded
Downloading/unpacking click>=7.1.2 (from flask)
Downloading click-8.0.1-py3-none-any.whl (97kB): 97kB downloaded
Cleaning up...
Exception:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2482, in _dep_map
return self.__dep_map
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2344, in __getattr__
raise AttributeError(attr)
AttributeError: _DistInfoDistribution__dep_map

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/pip/basecommand.py", line 122, in main
status = self.run(options, args)
File "/usr/lib/python3/dist-packages/pip/commands/install.py", line 278, in run
requirement_set.prepare_files(finder, force_root_egg_info=self.bundle, 
bundle=self.bundle)
File "/usr/lib/python3/dist-packages/pip/req.py", line 1266, in prepare_files
req_to_install.extras):
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2291, in requires
dm = self._dep_map
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2484, in _dep_map
self.__dep_map = self._compute_dependencies()
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2517, in 
_compute_dependencies
common = frozenset(reqs_for_extra(None))
File "/usr/lib/python3/dist-packages/pkg_resources.py", line 2514, in reqs_for_extra
if req.marker_fn(override={'extra':extra}):
File "/usr/share/python-wheels/setuptools-3.3-py2.py3-none- 
any.whl/_markerlib/markers.py", line 113, in marker_fn
return eval(compiled_marker, environment)
File "<environment marker>", line 1, in <module>
NameError: name 'platform_system' is not defined

Storing debug log for failure in /root/.pip/pip.log

然后我在以下帮助下检查了我的 PIP 版本:

pip3 --version

输出是:

pip 1.5.4 from /usr/lib/python3/dist-packages (python 3.4)

然后我想到了先更新它:

pip install --upgrade pip

然后它给了我以下错误:

Cannot fetch index base URL https://pypi.python.org/simple/
Could not find any downloads that satisfy the requirement pip in 
/usr/lib/python2.7/dist-packages
Downloading/unpacking pip
Cleaning up...
No distributions at all found for pip in /usr/lib/python2.7/dist-packages
Storing debug log for failure in /root/.pip/pip.log

然后我在网上搜索了这个错误，发现一个stackoverflow page
并找到以下命令:

pip install --index-url=https://pypi.python.org/simple/flask

然后我运行了相同的命令，但出现了警告:

You must give at least one requirement to install (see "pip help install")

有人能告诉我现在该怎么办吗？
我已阅读 Flask 安装指南，但对我没有帮助。

Answer 1

File "<environment marker>", line 1, in <module>
NameError: name 'platform_system' is not defined

这意味着您使用的 pip 版本(在 Python 3.4 中)对于模块的较新版本来说太旧了。
解决方案是升级 pip，但您最终升级了 Python 2 pip。
确保您的目标是正确的 pip 的最佳方法是像这样运行它:

python3 -m pip install --upgrade pip

或者，

pip3 install --upgrade pip

在 Windows 中，

py -3.4 -m pip install --upgrade pip