Referrer key missing form os.environ dictionary?

[Grant Edwards]

On 2013-09-25, Steven D'Aprano <steve+comp.lang.python at pearwood.info> wrote:
> On Wed, 25 Sep 2013 17:04:55 +0300, ?????????? wrote:
>
>> 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.

And of course that's bolloks:

   Python 2.7.5 (default, Aug 29 2013, 15:13:35) 
   [GCC 4.6.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import os
   >>> os.environ.get('HTTP_REFERER','UnkownRef')
   'UnkownRef'
   >>> 

   Python 3.2.5 (default, Aug 29 2013, 15:19:46) 
   [GCC 4.6.3] on linux2
   Type "help", "copyright", "credits" or "license" for more information.
   >>> import os
   >>> os.environ.get('HTTP_REFERER','UnkownRef')
   'UnkownRef'
   >>> 

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

It is.

> The Referer is not an environment variable.

It is when you're writing a CGI app.

> How would your shell know what URL you were just browsing?

Because the HTTP server sets those environment variables before
invoking the CGI app.

-- 
Grant Edwards               grant.b.edwards        Yow! Boy, am I glad it's
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