在激活/停用虚拟环境时可以自动更改PYTHONPATH吗？

Question

我想在一个特定的虚拟环境中使用与平常不同的PYTHONPATH。请问我该如何自动设置这个？我知道可以修改bin/activate文件，但有没有更好或者更标准的方法呢？

Answer 1

这里是被修改过的 bin/activate 文件，供你参考。它能正确设置 PYTHONPATH，但取消设置的功能不太好用。

# This file must be used with "source bin/activate" *from bash*
# you cannot run it directly

deactivate () {
    if [ -n "$_OLD_VIRTUAL_PATH" ] ; then
        PATH="$_OLD_VIRTUAL_PATH"
        export PATH
        unset _OLD_VIRTUAL_PATH
    fi  

    # This should detect bash and zsh, which have a hash command that must
    # be called to get it to forget past commands.  Without forgetting
    # past commands the $PATH changes we made may not be respected
    if [ -n "$BASH" -o -n "$ZSH_VERSION" ] ; then
        hash -r
    fi  

    if [ -n "$_OLD_VIRTUAL_PS1" ] ; then
        PS1="$_OLD_VIRTUAL_PS1"
        export PS1 
        unset _OLD_VIRTUAL_PS1
    fi  

    if [ -n "$_OLD_PYTHONPATH" ] ; then
        PYTHONPATH="$_OLD_PYTHONPATH"
        export PYTHONPATH 
        unset _OLD_PYTHONPATH
    fi  

    unset VIRTUAL_ENV
    if [ ! "$1" = "nondestructive" ] ; then
    # Self destruct!
        unset deactivate
    fi  
}

# unset irrelavent variables
deactivate nondestructive
VIRTUAL_ENV="env_location" # Anonymized
export VIRTUAL_ENV

_OLD_VIRTUAL_PATH="$PATH"
PATH="$VIRTUAL_ENV/bin:$PATH"
export PATH

_OLD_VIRTUAL_PS1="$PS1"
if [ "`basename \"$VIRTUAL_ENV\"`" = "__" ] ; then
    # special case for Aspen magic directories
    # see http://www.zetadev.com/software/aspen/
    PS1="[`basename \`dirname \"$VIRTUAL_ENV\"\``] $PS1"
else
    PS1="(`basename \"$VIRTUAL_ENV\"`)$PS1"
fi
export PS1

# This should detect bash and zsh, which have a hash command that must
# be called to get it to forget past commands.  Without forgetting
# past commands the $PATH changes we made may not be respected
if [ -n "$BASH" -o -n "$ZSH_VERSION" ] ; then
    hash -r
fi

_OLD_PYTHONPATH="$PYTHONPATH"
PYTHONPATH="new_pythonpath" #Anonymized
export PYTHONPATH

Answer 2

这个django-users帖子可能会对你帮助很大。它建议使用virtualenvwrapper来管理虚拟环境，这样你就可以使用add2virtualenv这个命令了。使用这个命令时，当你的环境处于激活状态时，你只需要输入：

add2virtualenv directory1 directory2 ...

就可以把目录添加到当前环境的pythonpath中。

它会自动处理在切换环境时的PATH变化，完全不需要什么复杂的操作。就这样，搞定了！