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stringdnslualua-patterns

how to extract the domain from a URL

I need to extract domain (four.five) from URL (one.two.three.four.five) in a Lua string variable.

I can't seem to find a function to do this in Lua.

EDIT:

By the time the URL gets to me, the http stuff has already been stripped off. So, some examples are: 

a) safebrowsing.google.com 
b) i2.cdn.turner.com 
c) powerdns.13854.n7.nabble.com

so my result should be: 

a) google.com
b) turner.com
c) nabble.com
Solution

  • This should work:

    local url = "foo.bar.google.com"
local domain = url:match("[%w%.]*%.(%w+%.%w+)")
print(domain)

    Output:google.com

    The pattern [%w%.]*%.(%w+%.%w+) looks for the content after the second dot . from the end.