使用virtualenvwrapper(Linux + Windows)

生活的问题在于，你永远不知道下一个到来的是什么问题。开发亦然。之前Python都是用一个运行环境，偶尔用一下virtualenv，直到开始在windows调试python才不得不来学习virtualenvwrapper。

简介

Virtualenvwrapper解决的主要问题是和virtualenv一样的，但是它弥补了virtualenv无法统一管理环境的缺点。

安装

virtualenvwrapper安装方式还是比较简单的。

Linux

1.安装

pip install virtualenvwrapper

2.设置环境变量

export WORKON_HOME=~/Envs
export PROJECT_HOME=$HOME/pyproj
source /usr/bin/virtualenvwrapper.sh

建议添加到自启动脚本中~/.bashrc 或 ~/.profile。

Windows

windows下直接安装virtualenvwrapper似乎不能运行。
我搜索到有独立的安装包，也能通过pip安装。https://github.com/davidmarble/virtualenvwrapper-win。

1.安装

# using pip
pip install virtualenvwrapper-win

# using easy_install
easy_install virtualenvwrapper-win

# from source
git clone git://github.com/davidmarble/virtualenvwrapper-win.git
cd virtualenvwrapper-win
python setup.py install

2.设置环境变量（可选）

Optional: Add an environment variable WORKON_HOME to specify the path to store environments. By default, this is `%USERPROFILE%\Envs`。

3.可能出现的错误

  File "D:\Python\Python27\Lib\mimetypes.py", line 249, in enum_types
        ctype = ctype.encode(default_encoding) # omit in 3.x!
UnicodeDecodeError: 'ascii' codec can't decode byte 0xb0 in position 1: ordinal not in range(128)

原因是某些程序（阿里旺旺）写了一些中文键值到注册表里。具体看http://pcliuyang.blog.51cto.com/8343567/1339637

解决方法：打开Python27/Lib/mimetypes.py，找到default_encoding = sys.getdefaultencoding()一行，在它前面添加如下代码：

# begin fix bug
if sys.getdefaultencoding() != 'gbk':
        reload(sys)
        sys.setdefaultencoding('gbk')
# end

命令

主要命令Linux和windows是一致的，部分有出入。

主要命令

mkvirtualenv <name>
Create a new virtualenv environment named . The environment will
be created in WORKON_HOME.

lsvirtualenv
List all of the enviornments stored in WORKON_HOME.

rmvirtualenv <name>
Remove the environment . Uses folder_delete.bat.

workon [<name>]
If is specified, activate the environment named (change
the working virtualenv to ). If a project directory has been
defined, we will change into it. If no argument is specified, list the
available environments. One can pass additional option -c after
virtualenv name to cd to virtualenv directory if no projectdir is set.

deactivate
Deactivate the working virtualenv and switch back to the default system
Python.

add2virtualenv <full or relative path>
If a virtualenv environment is active, appends to
virtualenv_path_extensions.pth inside the environment’s site-packages,
which effectively adds to the environment’s PYTHONPATH.
If a virtualenv environment is not active, appends to
virtualenv_path_extensions.pth inside the default Python’s
site-packages. If doesn’t exist, it will be created.

其他命令

cdproject
If a virtualenv environment is active and a projectdir has been defined,
change the current working directory to active virtualenv’s project directory.
cd- will return you to the last directory you were in before calling
cdproject.

cdsitepackages
If a virtualenv environment is active, change the current working
directory to the active virtualenv’s site-packages directory. If
a virtualenv environment is not active, change the current working
directory to the default Python’s site-packages directory. cd-
will return you to the last directory you were in before calling
cdsitepackages.

cdvirtualenv
If a virtualenv environment is active, change the current working
directory to the active virtualenv base directory. If a virtualenv
environment is not active, change the current working directory to
the base directory of the default Python. cd- will return you
to the last directory you were in before calling cdvirtualenv.

lssitepackages
If a virtualenv environment is active, list that environment’s
site-packages. If a virtualenv environment is not active, list the
default Python’s site-packages. Output includes a basic listing of
the site-packages directory, the contents of easy-install.pth,
and the contents of virtualenv_path_extensions.pth (used by
add2virtualenv).

setprojectdir(win)/setvirtualenvproject(Linux)
这两个命令功能相同，但是格式不同。setprojectdir只需要一个参数，指定工程主目录。setvirtualenvproject需要两个参数，参数一指定虚拟环境目录，参数二指定工程主目录。参数可省略，省略时使用当前的虚拟环境和当前目录。

# setvirtualenvproject 用法示例
$ mkproject myproj
New python executable in myproj/bin/python
Installing setuptools.............................................
..................................................................
..................................................................
done.
Creating /Users/dhellmann/Devel/myproj
(myproj)$ mkvirtualenv myproj_new_libs
New python executable in myproj/bin/python
Installing setuptools.............................................
..................................................................
..................................................................
done.
Creating /Users/dhellmann/Devel/myproj
(myproj_new_libs)$ setvirtualenvproject $VIRTUAL_ENV $(pwd)

toggleglobalsitepackages
If a virtualenv environment is active, toggle between having the
global site-packages in the PYTHONPATH or just the virtualenv’s
site-packages.

whereis <file>
A script included for convenience. Returns directory locations
of file and file with any executable extensions. So you can call
whereis python to find all executables starting with python or
whereis python.exe for an exact match.

mkproject(Only in Linux)
项目将创建到PROJECT_HOME目录下，实际上相当于在某个目录下，建了一个环境。