You can use : <META http-equiv="Pragma" content="no-cache"> <META http-equiv="Cache-Control" content="no-store, no-cache, must-revalidate, post-check=0, pre-check=0"> <META http-equiv="Expires" content="0">
With this tags in your header, a lot of browsers will not keep the page in their cache. So when the user will use the back button, the browser will re-submit the request to the server. It can help to know where the user is in your webapp. Arnaud > -----Message d'origine----- > De : apachep2 [mailto:[EMAIL PROTECTED] > Envoye : mardi 11 mars 2003 16:15 > A : 'Struts Users Mailing List' > Objet : RE: The Back button on on multi-page forms ?????? > > > Does IRS give me a chance hitting Back, re-filing last year's tax form > and re-submitting it? :) > > -----Original Message----- > From: Bueno Carlos M [mailto:[EMAIL PROTECTED] > Sent: March 10, 2003 10:27 PM > To: 'Struts Users Mailing List' > Subject: RE: The Back button on on multi-page forms ?????? > > I may be way off here, but how about coding defensively? This > isn't some > special java-struts problem; it's the price of maintaining > the illusion > of a > session over HTTP. > > Form tokens are a good idea but the user can and will click that pesky > back > button to change what they inputted. One of two things will > happen: the > browser calls up the form from cache and fills in the values > or it makes > a > new HTTP request, which will give them a blank form. Since they have > already > submitted once, you have that data somewhere. So.... populate the dang > form > if the data exists. Simple? Simple. > > It doesn't have to be complicated. A properly-built state machine (ie, > your > session or action code) should ignore input that can corrupt its > internals. > Check the state you are about to change -- if it's already changed, go > to > the next step, merge it or whatever is the Right Thing To Do. > If you app > is > so fragile that someone clicking ye olde back button will > mess things up > you > should look for ways to improve and simplify your design, not some > clever > client hack. > > My reasoning is this: as soon as you plug one hole another > will open up. > Say > you disable the back button. What happens if the user clicks submit > twice? > What happens if they press CTRL-N and now have two windows > with the same > session? > > 1. Users will always do what you don't expect. > > 2. The average user is pretty dumb. > > 3. Half of all users are even dumber than *that*. > > 4. Browsers work for them, not for you. > > -- los > > -----Original Message----- > From: Andrew Hill [mailto:[EMAIL PROTECTED] > Sent: Monday, March 10, 2003 9:39 PM > To: Struts Users Mailing List > Subject: RE: The Back button on on multi-page forms ?????? > > > <snip> > Remember that the back button does not contact the server > </snip> > > Some do sometimes - but Im not sure under what cicumstances - probably > depends on what sort of caching setting you have set up in > your browser > - > and what browser it is - and the alignment of neptune and saturn etc.. > (ie: > nothing you can rely on server side). Ive seen it happen. > > At the moment Im using the evil javascript location.replace trick to > avoid > pages going into the history where possible. People who hit the back > button > end up back on the login page... > > I really wanted to give them an electric shock to help the > "back is bad" > concept sink in properly, but alas! - the hardware isnt in place to > administer this form of 'interactive user training' :-( > > -----Original Message----- > From: David Graham [mailto:[EMAIL PROTECTED] > Sent: Tuesday, 11 March 2003 06:17 > To: [EMAIL PROTECTED] > Subject: RE: The Back button on on multi-page forms ?????? > > > Then that is a browser specific issue. When I hit the back button in > Opera, > all of the form fields are just how I entered them. Remember that the > back > button does not contact the server so Struts has nothing to do with > this. > > David > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > >Reply-To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > >To: "Struts Users Mailing List" <[EMAIL PROTECTED]> > >Subject: RE: The Back button on on multi-page forms ?????? > >Date: Mon, 10 Mar 2003 16:08:10 -0600 > > > >sorry, I think we are going in circles..... > > > >This is a multipage form (3 to be exact but with only one > actionform), > BUT > >my whole original issue was: > > > >When they hit the back button the original form content IS either > absent or > >different to their last entries (I do a reset in the actionform0. > > > >Am I doing something wrong or is this a fact of life with the back > button. > > > >ron > > > >-----Original Message----- > >From: David Graham [mailto:[EMAIL PROTECTED] > >Sent: Monday, March 10, 2003 3:49 PM > >To: [EMAIL PROTECTED] > >Subject: RE: The Back button on on multi-page forms ?????? > > > > > >If this is a multi-page form, then don't use tokens and let them use > the > >back button to correct the data. If it's a single page form, use > tokens > >and > >provide an update form where they can correct any mistakes > they made on > the > >add form. The difference is that the multi-page form will be > accumulating > >data in the session rather than immediately inserting it in the > database. > > > >David > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > >Reply-To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > > >To: "Struts Users Mailing List" <[EMAIL PROTECTED]> > > >Subject: RE: The Back button on on multi-page forms ?????? > > >Date: Mon, 10 Mar 2003 15:36:25 -0600 > > > > > >I completely understand your example and how validation works..... > > > > > >In my example, the error is not a validation error, it is a user > error > >(as > > >my example said a wrong phone number) > > >Say he/she typed in a home phone number and wants to go back and > change > >it > > >to his work phone. > > >The user instinctively will hit the back button. > > >That's where my problem starts.......... > > > > > >ron > > > > > >-----Original Message----- > > >From: David Graham [mailto:[EMAIL PROTECTED] > > >Sent: Monday, March 10, 2003 3:27 PM > > >To: [EMAIL PROTECTED] > > >Subject: RE: The Back button on on multi-page forms ?????? > > > > > > > > >1. User submits form with invalid data. > > >2. Form bean's validate() method returns ActionErrors > > >3. Struts *forwards* the request back to the input page with errors > > >4. Input page displays errors. > > >5. User submits form again, if invalid goto step 1. > > > > > >There is no valid reason for the user to use the back button to > correct > > >data. Tokens prevent the user from submitting the same form twice. > > > > > >David > > > > > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > >Reply-To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > > > >To: "Struts Users Mailing List" <[EMAIL PROTECTED]> > > > >Subject: RE: The Back button on on multi-page forms ?????? > > > >Date: Mon, 10 Mar 2003 15:07:40 -0600 > > > > > > > >So, how can they correct a user error (i.e wrong phone number) on > the > > > >previous page, and resubmit the form? > > > > > > > >R > > > > > > > >-----Original Message----- > > > >From: David Graham [mailto:[EMAIL PROTECTED] > > > >Sent: Monday, March 10, 2003 3:01 PM > > > >To: [EMAIL PROTECTED] > > > >Subject: RE: The Back button on on multi-page forms ?????? > > > > > > > > > > > >Pressing the back button does not contact the server and thus > cannot > >post > > > >any information. When the user submits the form again, > their token > >will > > >be > > > >invalid and your action will prevent a duplicate post. > > > > > > > >David > > > > > > > > > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > > >Reply-To: "Struts Users Mailing List" > ><[EMAIL PROTECTED]> > > > > >To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > > > > >Subject: RE: The Back button on on multi-page forms ?????? > > > > >Date: Mon, 10 Mar 2003 14:40:43 -0600 > > > > > > > > > >Maybe I'm dumb, but it is not apparent to me how the "token" is > used > >to > > > > >make > > > > >the back button post the correct form information. > > > > > > > > > >R > > > > > > > > > >-----Original Message----- > > > > >From: David Graham [mailto:[EMAIL PROTECTED] > > > > >Sent: Monday, March 10, 2003 12:48 PM > > > > >To: [EMAIL PROTECTED] > > > > >Subject: RE: The Back button on on multi-page forms ?????? > > > > > > > > > > > > > > >You'll notice that I also pointed you to the struts-example app > that > > > >shows > > > > >you how to use the methods you found in the javadoc. > > > > > > > > > >David > > > > > > > > > > > > > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > > > >Reply-To: "Struts Users Mailing List" > > ><[EMAIL PROTECTED]> > > > > > >To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > > > > > >Subject: RE: The Back button on on multi-page forms ?????? > > > > > >Date: Mon, 10 Mar 2003 12:39:51 -0600 > > > > > > > > > > > >Khalid > > > > > > > > > > > >I will share anything I find. > > > > > > > > > > > >Have not got too much help so far..... > > > > > > > > > > > >I am digging into the "tokens" > > > > > > > > > > > >Javadoc does not say much !! > > > > > > > > > > > >Ron > > > > > > > > > > > >-----Original Message----- > > > > > >From: Khalid K. [mailto:[EMAIL PROTECTED] > > > > > >Sent: Monday, March 10, 2003 12:25 PM > > > > > >To: [EMAIL PROTECTED] > > > > > >Subject: Re: The Back button on on multi-page forms ?????? > > > > > > > > > > > > > > > > > >Hello Ron, > > > > > > > > > > > >We have an application that has the same problem. if you got > the > > >"back" > > > > > >button issue resloved, could you please share the code sample > ?? > > > > > >I checked the java doc, and it looks like > "isValidToken" is in > 1.1, > > >and > > > > >not > > > > > >in 1.0.2. > > > > > > > > > > > >Thanks! > > > > > > > > > > > >Khalid > > > > > > > > > > > >----- Original Message ----- > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > > > >To: "Struts Users Mailing List" > <[EMAIL PROTECTED]> > > > > > >Sent: Monday, March 10, 2003 10:14 AM > > > > > >Subject: RE: The Back button on on multi-page forms > > > > > > > > > > > > > > > > > > > I get the picture....thanks anyway. > > > > > > > > > > > > > > -----Original Message----- > > > > > > > From: David Graham [mailto:[EMAIL PROTECTED] > > > > > > > Sent: Monday, March 10, 2003 12:04 PM > > > > > > > To: [EMAIL PROTECTED] > > > > > > > Subject: RE: The Back button on on multi-page forms > > > > > > > > > > > > > > > > > > > > > See the Action class' javadoc for details. > > > > > > > > > > > > > > David > > > > > > > > > > > > > > > > > > > > > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > > > > > >Reply-To: "Struts Users Mailing List" > > > > ><[EMAIL PROTECTED]> > > > > > > > >To: "Struts Users Mailing List" > ><[EMAIL PROTECTED]> > > > > > > > >Subject: RE: The Back button on on multi-page forms > > > > > > > >Date: Mon, 10 Mar 2003 11:54:32 -0600 > > > > > > > > > > > > > > > >Thanks for the tip on tokens.... > > > > > > > > > > > > > > > >I'm not familiar (yet) with tokens. > > > > > > > >Are these new in 1.1 or have they always been > there..... I > have > > >to > > > > >use > > > > > > > >Struts 1.0. > > > > > > > > > > > > > > > >Ron > > > > > > > > > > > > > > > >-----Original Message----- > > > > > > > >From: David Graham [mailto:[EMAIL PROTECTED] > > > > > > > >Sent: Monday, March 10, 2003 10:24 AM > > > > > > > >To: [EMAIL PROTECTED] > > > > > > > >Subject: Re: The Back button on on multi-page forms > > > > > > > > > > > > > > > > > > > > > > > >See the Action class' javadoc for the token > methods and the > > > > > >struts-example > > > > > > > >app for how to use them. > > > > > > > > > > > > > > > >David > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >From: "Ron Day" <[EMAIL PROTECTED]> > > > > > > > > >Reply-To: "Struts Users Mailing List" > > > > > ><[EMAIL PROTECTED]> > > > > > > > > >To: "Struts Users Mailing List" > > ><[EMAIL PROTECTED]> > > > > > > > > >Subject: The Back button on on multi-page forms > > > > > > > > >Date: Mon, 10 Mar 2003 10:05:16 -0600 > > > > > > > > > > > > > > > > > >Anyone have any ideas or best practises on how > to handle > the > > >use > > > > > > > >(mis-use) > > > > > > > > >of the browser back button on multi-page forms. > > > > > > > > > > > > > > > > > >My forms work fine and validate Ok, but if the back > button is > > > >used > > > > > >the > > > > > > > > >forms > > > > > > > > >are not re-populated properly. In particular anything > that > >was > > >in > > > > >the > > > > > > > > >reset, > > > > > > > > >seems to be used when the form appears after the back > button > >is > > > > >used. > > > > > > > > > > > > > > > > > >ron > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > >--------------------------------------------------------------------- > > > > > > > > >To unsubscribe, e-mail: > > > >[EMAIL PROTECTED] > > > > > > > > >For additional commands, e-mail: > > > > >[EMAIL PROTECTED] > > > > > > > > > > > > > > > > > > > > > > > > > >_________________________________________________________________ > > > > > > > >Add photos to your messages with MSN 8. 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