第一章《Flask Web开发》：安装flask

flaskGithub

阿里云服务器
Python

1.1 使用虚拟环境

我已经安装好了：

$  virtualenv --version
 15.1.0

安装了Git，也是第一次用。

git clone https://github.com/miguelgrinberg/flasky.git
cd flasky/
git checkout 1a

当我试图按照书上从GitHub上下载示例代码的时候，出现了下面的报错：

Initialized empty Git repository in /home/zhouyunlai/Python/project.git/flasky/.git/
error:  while accessing https://github.com/miguelgrinberg/flasky.git/info/refs

fatal: HTTP request failed

查了之后可能是HTTPS协议不行，用Git协议，在GitHub上获取Git协议地址：

Git协议与HTTPS协议

    git clone git@github.com:miguelgrinberg/flasky.git

得到了如下报错：

Initialized empty Git repository in /home/zhouyunlai/Python/flasky/.git/
The authenticity of host 'github.com (13.229.188.59)' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'github.com,13.229.188.59' (RSA) to the list of known hosts.
Permission denied (publickey).
fatal: The remote end hung up unexpectedly

看了github提示Permission denied (publickey)，如何才能解决？按照里面的步骤配置了一下GitHub的SSH Keys，试了一下

  git clone git@github.com:miguelgrinberg/flasky.git

还是不行：

Initialized empty Git repository in /home/zhouyunlai/Python/flasky/.git/
Warning: Permanently added the RSA host key for IP address '52.74.223.119' to the list of known hosts.
Connection closed by 52.74.223.119
fatal: The remote end hung up unexpectedly

查了git push 时出现Connection closed by remote host文章没看完，就把下面的代码输进去了 ：

  ssh git@github.com -vT

输出一堆结果。然后再试一下，可以了：

git clone git@github.com:miguelgrinberg/flasky.git
Initialized empty Git repository in /home/zhouyunlai/Python/flasky/.git/
remote: Counting objects: 896, done.
remote: Total 896 (delta 0), reused 0 (delta 0), pack-reused 895
Receiving objects: 100% (896/896), 179.20 KiB, done.
Resolving deltas: 100% (541/541), done.

接着按步骤来：

   $ virtualenv venv
New python executable in /home/zhouyunlai/Python/flasky/venv/bin/python
/home/zhouyunlai/Python/flasky/venv/bin/python: error while loading shared libraries: libpython2.7.so.1.0: cannot open shared object file: No such file or directory
ERROR: The executable /home/zhouyunlai/Python/flasky/venv/bin/python is not functioning
ERROR: It thinks sys.prefix is u'/home/zhouyunlai/Python/flasky' (should be u'/home/zhouyunlai/Python/flasky/venv')
ERROR: virtualenv is not compatible with this system or executable

不出所料，每一个新的命令都会报错。看了廖雪峰的virtualenv还是不管用。

你不是没有libpython2.7.so.1.0 吗？我找几个出来：

find / -name libpython2.7.so.1.0
/usr/local/aegis/PythonLoader/lib/libpython2.7.so.1.0
/usr/local/aegis/PythonLoader/libpython2.7.so.1.0
/root/miniconda2/lib/libpython2.7.so.1.0
/root/miniconda2/pkgs/python-2.7.14-hc2b0042_21/lib/libpython2.7.so.1.0

然后

  export LD_LIBRARY_PATH="/root/miniconda2/lib"

$virtualenv venv
New python executable in /home/zhouyunlai/Python/flasky/venv/bin/python
Installing setuptools, pip, wheel...done.

至少没报错了。

在使用虚拟环境之前，需要先激活：

  source venv/bin/activate

命令行前面出现了（venv），应该可以了。

1.2 使用pip安装Python包

在虚拟环境中安装Flask

$ pip install flask

启动Python解释器，尝试导入Flask

$python
Python 2.7.14 |Anaconda, Inc.| (default, Oct 16 2017, 17:29:19) 
[GCC 7.2.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import flask

没有报错，成功了。可以学习第二章了。

今天的工作完成，回到全局Python解释器中；

  deactivate

Linux及Git介绍
阿里云 linux搭建git服务器
《Flask Web Development》第1章 安装Flask

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