用正则表达式更改URL烧瓶的路径

Question

In flask I a before_request function which does some checks and returns the user to a different url if necessary.

I have something similar to the following example which where I get request_url I now want to change this from: https://www.example.com:5000/user/profile/ to https://www.example.com:5000/us/user/profile/

@app.before_request
def check_location():
    country = request.cookies.get('country')
    if country != g.country:
        url = request.url
        url = re.sub('.com[^\/]*', '.com/us', url)
        return redirect(url, 301)

I tried some regex but this does not work when using dev server with a port. So my question is:

1. How do I write this regex a better way to get a better match.
2. Is it okay todo this with regex or does Flask have a better way?

Answer 1

Use groups:

url = "https://www.example.com:5000/user/profile/"
url = re.sub('.com[^\/]*', '\g<0>/us', url)
print url # https://www.example.com:5000/us/user/profile/

From the docs:

In addition to character escapes and backreferences as described above, \\g will use the substring matched by the group named name, as defined by the (?P...) syntax. \\g uses the corresponding group number; \\g<2> is therefore equivalent to \\2, but isn't ambiguous in a replacement such as \\g<2>0. \\20 would be interpreted as a reference to group 20, not a reference to group 2 followed by the literal character '0'. The backreference \\g<0> substitutes in the entire substring matched by the RE.