Rails - Jul 2006 - Form validation - keepin correct fields displayed on refresh

All,

I''m finally doing my first real form in Rails - the model object that 
I''m entering information for has 8 validations so far.

If I type in good values for all the fields but one, I get the pretty 
validation, and the nice field highlighting, but all of the fields are 
cleared, forcing me to retype all of that info.  That is a big drag.

Is there a standard way to get the equivalent of what we call a "form 
bean" in the Java/Struts world?

Why is the object that''s backing the form being cleared out every time
I
re-render the form after validation fails?

Has anyone implemented another object - we might call it the "view 
model," which keeps track of the state of the form until it''s 
successfully submitted?

Thanks,
Wes

-- 
Posted via http://www.ruby-forum.com/.

Wes Gamble wrote:
> All,
> 
> I''m finally doing my first real form in Rails - the model object
that
> I''m entering information for has 8 validations so far.
> 
> If I type in good values for all the fields but one, I get the pretty 
> validation, and the nice field highlighting, but all of the fields are 
> cleared, forcing me to retype all of that info.  That is a big drag.
> 
> Is there a standard way to get the equivalent of what we call a "form 
> bean" in the Java/Struts world?
> 
> Why is the object that''s backing the form being cleared out every
time I
> re-render the form after validation fails?
> 
> Has anyone implemented another object - we might call it the "view 
> model," which keeps track of the state of the form until it''s
> successfully submitted?
> 
> Thanks,
> Wes
I think I realize what I have done wrong here.  I don''t think
I''m using
read_attribute and write_attribute correctly in some of my display-only 
getters and setters and therefore, the changes are not making it into 
the attribute hash.

I will confirm.

Thanks,
Wes

-- 
Posted via http://www.ruby-forum.com/.

Wes Gamble wrote:
> Wes Gamble wrote:
>> All,
>> 
>> I''m finally doing my first real form in Rails - the model
object that
>> I''m entering information for has 8 validations so far.
>> 
>> If I type in good values for all the fields but one, I get the pretty 
>> validation, and the nice field highlighting, but all of the fields are 
>> cleared, forcing me to retype all of that info.  That is a big drag.
>> 
>> Is there a standard way to get the equivalent of what we call a
"form
>> bean" in the Java/Struts world?
>> 
>> Why is the object that''s backing the form being cleared out
every time I
>> re-render the form after validation fails?
>> 
>> Has anyone implemented another object - we might call it the "view
>> model," which keeps track of the state of the form until
it''s
>> successfully submitted?
>> 
>> Thanks,
>> Wes
> 
> I think I realize what I have done wrong here.  I don''t think
I''m using
> read_attribute and write_attribute correctly in some of my display-only 
> getters and setters and therefore, the changes are not making it into 
> the attribute hash.
> 
> I will confirm.
> 
> Thanks,
> Wes
My problem was not using write_attribute() and read_attribute() 
correctly in my object.  Hopefully, the importance of using these two 
methods will be emphasized as the need of facade columns in your model 
object is often necessary.

Wes

-- 
Posted via http://www.ruby-forum.com/.

Hi Wes,
        I am a newbie to AJAX style web development and was hoping you or
someone else could explain what facade columns are and
why/how/where are they used.

Thank you in advance,
Mathew Newton
> Wes Gamble wrote:
>> Wes Gamble wrote:
>>> All,
>>>
>>> I''m finally doing my first real form in Rails - the model
object that
>>> I''m entering information for has 8 validations so far.
>>>
>>> If I type in good values for all the fields but one, I get the
pretty
>>> validation, and the nice field highlighting, but all of the fields
are
>>> cleared, forcing me to retype all of that info.  That is a big
drag.
>>>
>>> Is there a standard way to get the equivalent of what we call a
"form
>>> bean" in the Java/Struts world?
>>>
>>> Why is the object that''s backing the form being cleared
out every time
>>> I
>>> re-render the form after validation fails?
>>>
>>> Has anyone implemented another object - we might call it the
"view
>>> model," which keeps track of the state of the form until
it''s
>>> successfully submitted?
>>>
>>> Thanks,
>>> Wes
>>
>> I think I realize what I have done wrong here.  I don''t think
I''m using
>> read_attribute and write_attribute correctly in some of my display-only
>> getters and setters and therefore, the changes are not making it into
>> the attribute hash.
>>
>> I will confirm.
>>
>> Thanks,
>> Wes
>
> My problem was not using write_attribute() and read_attribute()
> correctly in my object.  Hopefully, the importance of using these two
> methods will be emphasized as the need of facade columns in your model
> object is often necessary.
>
> Wes
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>

Wes:

Please share an example of one of your facade columns if you have the time.
I''m sure there are many that would be interested.


On 7/14/06, Wes Gamble <weyus@att.net> wrote:
>
> Wes Gamble wrote:
> > Wes Gamble wrote:
> >> All,
> >>
> >> I''m finally doing my first real form in Rails - the model
object that
> >> I''m entering information for has 8 validations so far.
> >>
> >> If I type in good values for all the fields but one, I get the
pretty
> >> validation, and the nice field highlighting, but all of the fields
are
> >> cleared, forcing me to retype all of that info.  That is a big
drag.
> >>
> >> Is there a standard way to get the equivalent of what we call a
"form
> >> bean" in the Java/Struts world?
> >>
> >> Why is the object that''s backing the form being cleared
out every time
> I
> >> re-render the form after validation fails?
> >>
> >> Has anyone implemented another object - we might call it the
"view
> >> model," which keeps track of the state of the form until
it''s
> >> successfully submitted?
> >>
> >> Thanks,
> >> Wes
> >
> > I think I realize what I have done wrong here.  I don''t think
I''m using
> > read_attribute and write_attribute correctly in some of my
display-only
> > getters and setters and therefore, the changes are not making it into
> > the attribute hash.
> >
> > I will confirm.
> >
> > Thanks,
> > Wes
>
> My problem was not using write_attribute() and read_attribute()
> correctly in my object.  Hopefully, the importance of using these two
> methods will be emphasized as the need of facade columns in your model
> object is often necessary.
>
> Wes
>
> --
> Posted via http://www.ruby-forum.com/.
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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unknown wrote:
> Hi Wes,
>         I am a newbie to AJAX style web development and was hoping you 
> or
> someone else could explain what facade columns are and
> why/how/where are they used.
> 
> Thank you in advance,
> Mathew Newton
Mathew,

Basically, any time that you have to customize the look and feel of a 
column from the DB, you will have to do something like this.

Here''s the real live example I just figured out (although I''m
still
having some issues with the validation :]).

I have a legacy DB schema that contains one field for an email called 
"fromLine".
The fromLine field is formatted as:
"Name of person" <email address>

But I want to display this information and allow for data entry with two 
fields - one for name and one for email address.  So in order to do 
that, I need to split up (to read) and merge together (to write) the 
name and email address in order to interact correctly with my DB column.

Here''s what you have in the view:

<TD class="list-label"><LABEL
for="email_from">From (name):</LABEL></TD>
<TD><%= text_field(:current_job, ''from_name'')
%></TD>

<TD class="list-label"><LABEL
for="email_from_email">From (email
address):</LABEL></TD>
<TD><%= text_field(:current_job, ''from_email'')
%></TD>

Here''s what you have to do in the model to make this work - notice the 
use of read_attribute and write_attribute - you have to do this because 
the form helpers interact with the actual DB attributes, not the custom 
ones that you create in the model.  The attributes hash persists no 
matter what happens. If you have errors, my understanding is that the 
object that you get in your view is a brand new object when you 
redisplay the page, so it isn''t enough to just reference your custom 
attributes (because they would be empty since it''s a new object).

Basically, you have to use the attribute hash to "hold" your custom 
stuff.  Attributes that aren''t modified just go directly to the 
attribute hash.

public
  def from_name
    line = read_attribute(:fromLine)
    if (! line.nil?) && (md = line.match(/"(.*)"/))
      md[1]
    else
      ''''
    end
  end

  public
  def from_name=(name)
    line = "\"#{name}\" <#{self.from_email}>"
    self.fromLine = line
  end

  public
  def from_email
    line = read_attribute(:fromLine)
    if (! line.nil?) && (md = line.match(/<(.*)>/))
      md[1]
    else
      ''''
    end
  end

  public
  def from_email=(email)
    line = "\"#{self.from_name}\" <#{email}>"
    self.fromLine = line
  end

  public
  def fromLine=(line)
    write_attribute(:fromLine, line)
  end

HTH,
Wes

-- 
Posted via http://www.ruby-forum.com/.

The thing that tripped me up was that because I couldn''t see any data,
I
thought that my custom getters weren''t being called when I refreshed
the
page.

But in fact, my custom getters were being called, but the data that they 
were referencing was empty, because they were being called on a _brand 
new_ object.

You can see that the object in your view is different every time by 
putting:

<%= "Object id: " + @your_object_name.object_id.to_s %>

into your page and POSTing with errors.  You will see a different object 
id every time.

Wes

-- 
Posted via http://www.ruby-forum.com/.

On the other hand, you may not want to listen to me since now NONE of my 
validations appear to be running.

Sigh.  I still love Rails, but why does it have to be such a rocky road 
for me :)?

WG

-- 
Posted via http://www.ruby-forum.com/.