Sylvain Wallez wrote:
Reinhard Poetz wrote:
Vilya Harvey wrote:
Reinhard P�tz wrote:
Imagine following scenario: You have a service layer that is exposed
as web services. cForms already does as much validation as possible
but some complex checks can only be performed by the backend.
If I call a webservice (via Axis client) this webservice can return
errors (how this is done hasn't been defined yet).
Are there any best practices or experiences how to map errors coming
from the service or domain layer to cForms widgets? (The error has
to appear at widget level.)
In your flowscript, you can create your own ValidationError object
and explicitly set that on the apppropriate widget.
What we did was to define our own type of exception which included
information about all validation errors that were found, then wrote a
simple(-ish) flowscript function which handled looking up the
relevant widgets, creating the error objects and setting them into
the widgets.
Thank you!
This means that the service layer is aware of which widgets exist? I'm
not sure if I (and especially my customer) likes this bi-directional
dependency...
Nono! Your validation code has to catch the exception and translate it
into a validation error. This means you can have "regular" validation
errors (i.e. the backend could be reached but detected invalid data) and
communication-level errors, e.g. "could not validate data, try again
later".
let's try to express this using some pseudo-code:
var form = new Form(...);
var businessObject = getBusinessObjectFromServiceLayer();
form.load(businessObject);
form.show(...);
form.save(businessObject);
var errorType;
try {
saveBusinessObjectInBackend(businessObject);
} catch(ex) {
errorType = ex.getErrorType();
}
if(errorType == "user.already.exists") {
form.lookupWidget("user").setValidationError("User already exists!");
}
form.show(...);
Do you mean something like this? The problem with this is that the service layer
can return *a lot* of different error types and I would have to write dozens of
ifs ... :-(
--
Reinhard P�tz Independant Consultant, Trainer & (IT)-Coach
{Software Engineering, Open Source, Web Applications, Apache Cocoon}
web(log): http://www.poetz.cc
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