Re: Techniques for Sequence of Pages

>Now, on to a different way to handle multistep forms.
>
>URL examples:
>checkout/1
>checkout/2
>checkout/3
>
>In this case only "checkout" is defined in the nav object, so the 1, 2 and 3 are
>"leftovers" after nav->getlocation  is called. The first leftover is returned by
>nav->getargs(1), for example 1, 2 or 3.
>Using the same nav path for all steps means that the same set of config, lib, content
>and action files are used for all the steps, so inside each of them there is a
>select/case tree that looks at getargs(1) and produces the appropriate result for each
>step. This is useful for multistep forms where some or much of the logic can be reused
>between steps.
>
>The form for each step uses the same -formaction as -actionpath, which is a bit
>contrary to the above description. So the form doesn't actually advance to the next
>step upon submission, but instead the action file redirects to the next step if the
>submission is successful. This gives clean URLs that correspond to the actual current
>step in the multistep form no matter if the form is successful or not, and it also
>makes it really easy to go backwards in the chain simply by redirecting to the
>previous step. The form posts are also "refresh safe" that way.
>With this method it's also easy to handle multistep forms that branch off or skip
>steps.
>
>
>Some code samples that hopefully illustrates this
>
>
>config_checkout.inc (just the beginning)
>-------------------
>var('checkout_stage'=1);
>if($nav -> getargs -> size && $nav -> getargs(1) -> size);
>   $checkout_stage = integer($nav -> getargs(1));
>/if;
>
>var('ordersent'=false);
>
>// then configure some forms depending on current $checkout_stage
>// ...
>
>
>action_checkout.inc (sample code)
>-------------------
>var('continue'=true);
>
>// handle abnormal flow first
>if(action_param('button_prev') -> size);
>   // Got to previous step
>   $continue=false;
>   redirect_url(($nav -> url ) + ($checkout_stage - 1));
>/if;
>
>
>// perform actions
>select($checkout_stage);
>case(1);
>   // update cart contents
>   // ...
>case(2);
>   // update shipping and payment details  
>   // ...
>case(3);
>   if($continue);
>       // add order
>       inline($db_connect);
>       var('updatefields'=$s_checkoutform -> updatefields);
>       $db_order -> addrecord($s_checkoutform -> updatefields);
>
>       var('order_id'=$db_order -> keyvalue);
>      
>       if($db_order -> error_code);
>           $continue = false;
>           $message_form -> insert('error'='COuld not cerate order ');
>       /if;
>
>       if($continue && $order_id > 0);
>           // add order items
>           // ...
>       /if;
>       $ordersent = true;
>
>       /inline;
>   /if;
>/select;
>
>// follow normal flow
>if(action_param('button_next') -> size
>   && $checkout_stage < 3
>   && $continue);
>   // Go to next step
>   redirect_url(($nav -> url ) + ($checkout_stage + 1));
>/if;