Accept parameters only from POST request in python

Question

Is there a way to accept parameters only from POST request? If I use cgi.FieldStorage() from cgi module, it accepts parameters from both GET and POST request.

Do you mean python cgi module? If yes, no problem to avoid it. I just want a way to do what I asked. — stdio, Jun 28 '11 at 21:22
Yes, it is possible, but the way to do it depends on what web framework you are using. — ʇsәɹoɈ, Jun 28 '11 at 22:38

SingleNegationElimination · Accepted Answer · 2011-06-28T22:45:24.657

By default, most things in the cgi module merge os.environ['QUERY_STRING'] and sys.stdin (in the format suggested by os.environ['CONTENT_TYPE']). So the simple solution would be to modify os.environ, or rather, provide an alternative, with no query string.

# make a COPY of the environment
environ = dict(os.environ)
# remove the query string from it
del environ['QUERY_STRING']
# parse the environment
form = cgi.FieldStorage(environ=environ)
# form contains no arguments from the query string!

Ignacio Vazquez-Abrams suggests avoiding the cgi module altogether; modern python web apps should usually adhere to the WSGI interface. That might instead look like:

import webob
def application(environ, start_response):
    req = webob.Request(environ)
    if req.method == 'POST':
        # do something with req.POST

# still a CGI application:
if __name__ == '__main__':
    import wsgiref.handlers
    wsgiref.handlers.CGIHandler().run(application)

Perfect! They are both good ways, but I prefer don't use external modules in this case, so I'll use the first way. Thanks a lot! — stdio, Jun 28 '11 at 23:37
That's unfortunate. An amazing amount of work is totally boilerplate when dealing with web-apps. `webob` is about the thinnest veneer of a no-framework framework around for wsgi (it's even less magical than `cgi` but is generally more useful). You really should build your app on top of a solid framework and focus on the actual *problem you're trying to solve* — SingleNegationElimination, Jun 29 '11 at 00:40

score 0 · Answer 2 · answered Jun 28 '11 at 21:24

0

From the documentation, I think you can do the following:

form = cgi.FieldStorage()
if isinstance(form["key"], cgi.FieldStorage):
     pass #handle field

This code is untested.

answered Jun 28 '11 at 21:24

Jasmijn

9,370
2
29
43

This seems a way to reject "key" parameter and I don't want this. I want to accept a parameter only from POST request and not GET. – stdio Jun 28 '11 at 21:38
This is supposed to to only handle POST requests. URL parameters in GET requests use `cgi.MiniFieldStorage`. It might not be fail safe (for example, for when you come across a POST request with URL parameters), but it's a quick fix. – Jasmijn Jun 28 '11 at 21:45
Mmm...I tried (with both POST and GET request), but it doesn't work, I don't get anything. – stdio Jun 28 '11 at 21:58

Accept parameters only from POST request in python

2 Answers2