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Problem

You need to convert a string to all uppercase or all lowercase.

Solution

Use httpd_util:to_upper or httpd_util:to_lower from the OTP httpd_util module. (Yes, I know that these would make more sense in the string module!)

 
1> httpd_utils:to_upper("hello").
"HELLO"
2> httpd_utils:to_lower("ERLANG").
"erlang"

The httpd_util module contains a dog's breakfast of functionality that probably belong in other modules, but that have not been added due to backwards-compatibility concerns.