Referrer key missing form os.environ dictionary?

[Νίκος]

Στις 25/9/2013 5:01 μμ, ο/η Chris “Kwpolska” Warrick έγραψε:
> On Wed, Sep 25, 2013 at 2:45 PM, Νίκος <nikos.gr33k at gmail.com> wrote:
>> Hello, i decided am ong other os.environ variables to also grab the
>> 'HTTP_REFERER' fiel but when i try to run my script i was seeing a KeyError
>> complaining that 'HTTP_REFERER' didnt exist.
>>
>> So, to see what existed in the os.environ dictionary i issues a print(
>> os.environ ) to see all available keys and their values:
>
> The Referer header is not mandatory by any means.  Your client
> probably does not send it.
>
I would like to check for its existence and retrieve it if possible, if 
its not there then default to the string "UnKnown Ref".

I try to do this with:

referer = os.environ.get('HTTP_REFERER', 'UnknownRef')

but that doesn't return anything either.

Can you verify that its the correct way to grab the referral string?