Manlio Perillo manlio_perillo at libero.it
Wed Dec 12 22:18:31 CET 2007

Ian Bicking ha scritto:
> [...]
>> The gateway is not required to remove HTTP_CONTENT_TYPE and 
>> at least this is what CGI says (and WSGI says nothing about this).
>> In fact in mod_wsgi for Nginx I don't remove these two variables, 
>> since it requires extra code (but I will remove them, if there is a 
>> good reason for doing so).
> I never really read through the spec for this, but by convention all 
> servers I know of do remove these.  Having the same header show up in 
> multiple places seems dangerous (where the two values may not match, 
> especially if the request has one of those keys rewritten).  

Well, with mod_wsgi for nginx an user *can* rewrite *every* variable 
passed to the WSGI environment (with the exception of the variables in 
the wsgi namespace, SCRIPT_NAME and PATH_INFO) using the `wsgi_var` 
directive (to be precise in the current version the user can not 
override HTTP_ variables since the `wsgi_var` variables are inserted in 
the enviroment dictionary before the HTTP_ variables, but I'm going to 
change this right now).

WSGI variables are all added using the `wsgi_var` directive.

> And of 
> course it's not much code to remove them.  There's some things that 
> technically are okay with WSGI, but in practice are bad (like leaving 
> out QUERY_STRING, which can cause very weird bugs due to how the cgi 
> module was written).

QUERY_STRING can be a problem for me, since I don't add to the 
environment dictionary empty variables, with the exception of 

Well, not a real problem, since it easy to make sure that it is always 
present in the WSGI environment dictionary.

By the way: the CGI spec 
requires QUERY_STRING to be *alway* present, but the WSGI spec allows it 
to be absent.

P.S.: I'm reading the cgi module and it only uses argv[1]:
       if sys.argv[1:]:
           qs = sys.argv[1]

       I'm not sure to understand.

       Moreover in mod_wsgi for nginx, I call PySys_SetArgv, so the WSGI
       application sees the command line options passed to nginx.

Thanks  Manlio Perillo

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