python 虛擬環境下安裝flask read time out
第一種解決方法：設定time out 的時間：pip install --default-tiemout=100 Flask
還是報錯，於是嘗試第二種方案，採用國內映象：
pip install -i http://mirrors.aliyun.com/pypi/simple/ Flask
還是有問題，錯誤如下：
The repository located at mirrors.aliyun.com is not a trusted or secure host and is being ignored. If this repository is available via HTTPS it is recommended to use HTTPS instead, otherwise you may silence this warning and allow it anyways with '--trusted-host mirrors.aliyun.com'.
Could not find a version that satisfies the requirement Flask (from versions: )
No matching distribution found for Flask
You are using pip version 9.0.1, however version 18.0 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
說這個地址是不可信的，於是新增信任：--trusted-host=mirrors.aliyun.com
完整命令：pip install --trusted-host=mirrors.aliyun.com -i http://mirrors.aliyun.com/pypi/simple/ Flask
前路坎坷啊 又有新錯誤了，
Running setup.py install for MarkupSafe ... error
Exception:
Traceback (most recent call last):
File "d:\python\myflask\venv\lib\site-packages\pip\compat\__init__.py", line 73, in console_to_str
return s.decode(sys.__stdout__.encoding)
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb6 in position 33: invalid start byte
安裝依賴包，MarkupSafe 報錯了，是由於windows 命令字元問題，百度說改配置檔案，