Handling server side failures

[johncorro]

I'm new to Laszlo and was looking to develop an app w/ Struts at the Controller and Laszlo at the View. There are several concerns looming in my head mostly revolving around form-handling. Can someone point me to an example of the following sequence:

1. User navigates to some url w/ a form (myform.lzx for example)

2. A Laszlo view retrieves information from a datasource (let's say it's a JSP view whose content is in XML format) and populates the info into a Lazlo form.

3. The user makes some changes to the data and submits the Laszlo form.

4. The underlying Action class (or generic servlet) recieves the HTTP post'ed data and attempts to perform some operation. The operation fails and a collection of error message(s) are compiled and sent back in the HTTP response.

5. The error message(s) is displayed to the user.

Something I'm specifically having a hard time wrapping my head is in step 3. Is my understanding correct that Laszlo issues a "behind-the-scenes" HTTP post? I'm getting the impression that the view doesn't actually refresh like how an HTML page would refresh when you submitted a form.

Thanks for any help!

[antun]

Is my understanding correct that Laszlo issues a "behind-the-scenes" HTTP post?

That's exactly right. There is no page refresh (and you wouldn't want one either in your case).

Typically in your LZX you would write some script that submitted the form entries (using a dataset as a medium), and you would use the dataset's ondata event to find out when the script on the server had responded with XML data (e.g. saying <message response="ok" /> or providing information on missing fields).

You could then read the information from the dataset and present that to the user.

-Antun