Validation discussions frequently bring up the concept of populating beans
with potentially invalid data then calling a bean.validate() function, but
something doesn't quite feel right about it for me.
If I have a date field in my bean, then I would like it to be a real date
value (or an empty string meaning null), or if I have a numeric field in my
bean then I want it to be a real numeric value. Allowing them to be anything
entered by a user just doesn't feel right - but that is just where my head
is at right now.
I have been handling general add/edit forms as follows (it's a bit of a long
story ...)
I create a "FormHelper" object that is aware of all fields on the form
(including hidden, visible and dynamic fields). It knows how to transform
database data or objects into form field values and visa versa.
For a User add/edit form I would have a UserFormHelper with some functions
as follows:
* setField(name,value)
* getField(name)
Functions to set/get form field values.
* initialiseFields()
This initialises an internal struct with all of the fields in the form. It
sets each of the fields to their initial value. These values would be for
"add/new" forms. This function essentially defines the fields that are
permitted in the form. The field names exactly match the actual form field
names. This is called from the init() function and has code that looks like:
<cfset setField("userId",0)>
<cfset setField("firstName","")>
<cfset setField("lastName","")>
* loadByUsedId(userId)
This initialises the helper fields from the database. But this could also be
something like loadByUserBean(user). This calls the setField() function for
each field, but with the value from the database/bean. This is used for an
"edit" form.
* loadByEvent(event)
This initialises the helper fields from an "event", which is just the
combined form and url scopes. This is used when attempting to save a form.
The submitted form values are passed into the helper via this function.
* validate()
This validates the form data. This may also populate beans and call their
validate() functions, but this helper validation is aware of the entire form
which may span multiple bean types. This function sets errors inside the
helper.
* save()
Calls validate() and if no errors, performs the save (via
services/gateways). If errors during the save occur, then additional errors
may be set.
I would generally use the helper as follows:
* newUser event:
<cfset helper = createObject("component","UserFormHelper").init()>
In the form, use code such as:
<cfset userId = helper.getField("userId")>
<input type="hidden" name="userId" value="#userId#">
<cfset firstName = helper.getField("firstName")>
<input type="hidden" name="firstName" value="#userId#">
* editUser event:
<cfset userId = event.get("userId")>
<cfset helper = createObject("component","UserFormHelper").init()>
<cfset helper.loadByUserId(userId)>
Then the form display code is the same as above.
* saveUser event:
<cfset helper = createObject("component","UserFormHelper").init()>
<cfset helper.loadByEvent(event)>
<cfset helper.save()>
<cfif not helper.hasErrors()>
<cfset userId = helper.getField("userId")>
<cflocation
url="/some/dir/index.cfm?event=editUser&userId=#userId#">
</cfif>
<!---
Then display the same form again, but with error messages. The helper has a
function getErrors() which returns a collection of formfield error messages.
--->
The helper manages the data with the form display in mind. It holds any
submitted invalid data which is redisplayed exactly as entered back onto the
form when errors occur, it also prepares data for display - such as
converting datetime fields from the database into the correct display values
for the form. Essentially it is a representation of the form as the server
sees it - without the UI - just a bunch of name/value pairs.
I have a base FormHelper that all other form helpers extend, so there is not
much work in setting up new forms.
Overall this has been working out quite nicely for me, but would love to
hear others ideas.
Kevan
-----Original Message-----
From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of
Michael Sharman
Sent: Wednesday, 24 September 2008 3:28 PM
To: CFCDev
Subject: [CFCDEV] Using object "getters" after form validation fails
Hi guys,
I'm after some suggestions for a quite common scenario. I have a site
where users are registered (i.e. they have a profile) and have the
option of updating their details after logging in.
I load the "update" form's controls from a User.cfc
e.g. <input type="text" name="email" id="email"
value="#oUser.getEmail()#" />
Now when the form gets submitted validation takes place and if that
validation fails the update form is reloaded with an error message.
The problem is that I want to display the new information that the
user has entered even though it hasn't yet been updated in the
database.
I feel I can't update the User objects "state" if the validation fails
as the user may navigate away from the update form and as the rest of
the site depends on the User object's information this would be
potentially incorrect.
Would I be looking at some kind of memento pattern here? Some kind of
a global #request.input# struct? How do people get around this,
hopefully without complicating/messing up views with a cfparam for
each User property etc
Thanks
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