Making ugly code more beautiful using Python's with statement

My task was to ensure that the correct language is set when sending out emails.

My first iteration used following code:

#Remember the current language
current_lang = get_current_lang()

#Set language by uid if possible
user_lang = get_lang_by_uid(uid)
if user_lang:
    set_current_lang(user_lang)

#… MAIL CODE … 

#Revert back to old language
set_current_lang(current_lang)

Now this is fine and well, but not that clean, especially when you have to use it in multiple places. I knew there must be a better way to do this. After some iterations I came up with this marvel:

with set_lang_by_uid(uid):
    #… MAIL CODE …

A one liner that I can use everywhere!

The implementation of set_lang_by_uid

Implementing set_lang_by_uid is trivial - that's the great thing about using the with statement!

Here's how it's implemented:

from contextlib import contextmanager

@contextmanager
def set_lang_by_uid(uid):
    user_lang = get_lang_by_uid(uid)
    if user_lang:
        current_lang = get_current_lang()
        set_current_lang(user_lang)
        yield
        set_current_lang(current_lang)
    else:
        yield

More references

Check out my older writing on the with statement:

• Implementing file locks using Python's with statement
• Python's with statement