|
Bart
scarfboy at gmail.com
Tue Mar 20 11:11:19 EST 2007
Indeed. To solve this, you need to remember past states one way or another. In one administration interface I've seen, state is remembered server-side for... I forget whether it was a number of actions or some time. It involved an identifier for each served page, which means you can actually *know* when a user submits something from a page displaying old state, and decide to either * set the new state as the displayed state+the change requested * set the new state as the current state + the change requested (often unpredictable) * complain "hey, you tried to alter from an old state!" * complain "hey, you tried to alter from an old state!", view the current, and ask whether you still want to apply the changes, to *that*. This is the user-friendliest if the last option may throw away ten minutes of user work. The idea of using AJAX to essentially imitate MVC is probably a workable one too, (though I still haven't checked whether there is a simple way of checking use of the back button through (ajax-less) client side scripting) If you do this, be sure to also give sane fallback behaviour to people with scripting disabled. --Bart On 3/20/07, Clodoaldo <clodoaldo.pinto.neto at gmail.com> wrote: > 2007/3/20, Kenneth Loafman <kenneth at loafman.com>: > > I'm using mod_python under Ubuntu Edgy 64, doing some basic plots of > > data and allowing users to select a point to center on a region and gen > > the next plot. All of that works as long as the user moves forward. > > The problem comes in the use of the back button. The browser merely > > displays the last page rather than rebuilding it, or at least restoring > > the variables. This leads to a lot of confusion because the server is > > on one set of plot values and the browser is now on another. This seems > > to be a common problem. Is there a solution, or should I just warn the > > user not to use the browser back button? > > How does the user select the point? Entering it in a form field? If so > save the plot values (the page state) on the page using a hidden field > inside the form: > <input type="hidden" name="variable_1" value="99.9"> > <input type="hidden" name="variable_2" value="33.3"> > > When the form is submitted those values will be available to your script. > > If you are using some Ajax scripting to let the user select the point > then adapt it to also send the current page state. > > I could not find the correct words to google. It would be something > like "page state maintenance in HTML (or HTTP)". Can someone create > the correct search words? > > Regards, > -- > Clodoaldo Pinto Neto > _______________________________________________ > Mod_python mailing list > Mod_python at modpython.org > http://mailman.modpython.org/mailman/listinfo/mod_python >
|