[Mailman-Developers] Re: GET vs POST (was Re: subscription confirmations)

[Jay R. Ashworth]

On Thu, Jul 19, 2001 at 04:35:47PM +0530, Satya wrote:
> >On 7/18/01 9:51 PM, "J C Lawrence" <claw@2wire.com> wrote:
> >> http://www.google.com/search?q=beej+site%3Awww.kanga.nu
> >
> >Wait. Are we allowed to put this in an e-mail? Shouldn't JC have had to put
> >it on a web page and post a URL to the page with the link on it?
> 
> This got me thinking. I haven't been following this discussion too
> closely, but it strikes me that a GET like the above should return the
> same thing given the same parameters. This is what "side
> effects" should mean.
> 
> If it's a confirmation, the second time you try to GET the URL, you'll
> (well, should) get an error saying "already confirmed". Thus,
> side-effect. State change.
> 
> A search URL like the one above doesn't cause any state change (except
> maybe counter/stats), so should be okay.
> 
> Not easy (or maybe even possible) to distinguish those by a program,
> though.

Correct.  This is the underlying reason for the W3C recommendation
(pronouncement?).  The fence they build is "if it ain't a post, it's
not allowed to do anything you weren't expecting."

Whether that was acceptable In The Real World was the debate we were
having -- it requires an (potentially not acceptable to the user) extra
action to do what is desired (in this case, unsubbing from a list).

Cheers,
-- jra
-- 
Jay R. Ashworth                                                jra@baylink.com
Member of the Technical Staff     Baylink                             RFC 2100
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