Tapestry Fixed Control Name Fixin

Have you ever had a problems with Tapestry5 ValidationTracker service? When after zone update inside a form you are trying to submit this form, validation fails and all specified form values inside updated zone disappear? No? Then try this demo, choose country, then city(name is empty), submit => validation fails, city value is missed.

Tapestry Render Deferred Fixin

Tapestry5 pages consists of a set of components placed on this page. When client request comes to the server this components will render themselves in the same order they was placed on the page. The rendering of each component is divided into a number of phases (Component Rendering) but all this phases are triggered within its component rendering. So, what if there is a dependency of component-A in some setup logic of component-B? No problem, when their order is <component-B> => <component-A>. But what will happen if their order is <component-A> => <component-B>? Component-A will have invalid data from component-B(it hasn't initialized itself yet). There is a solution in Label component from tapestry-core. It defers "for" attribute rendering using Heartbeat service.

Tapestry Ajax Upload Fixin

Do you have problems with file uploading when using it with ajax requests?
The issue is that ajax file uploading isn't transparently supported. There are some approaches to solve this issue. I will use jQuery as client side framework and Tapestry5 as server side for all examples.

1. Using advantages of html5 http://www.w3.org/TR/XMLHttpRequest2/#interface-formdata

The main idea is to use special JS interface called FormData. We can create it from existing form element and it will copy all data from it or we can create empty FormData and fill it from scratch. Then we can use it in ajax request and it will work.

... in almost all modern browsers: Chrome 7+, FF 4.0, IE 10+(really?), Opera 12+, Safari 5+. But what about old browsers?

2. Using usual form submission in iframe.
The idea is to emulate asynchronous request via form submission in separate iframe. We just need to create iframe and form targeted to this iframe, attach file inputs to newly created form, copy input values from original form to new as hidden fields, and submit this form as usual. Response from server will be automatically loaded in iframe body.


In this case we should also improve server logic to think about such request as ajax request. And don't forget about escaping.