Javascipt form validation in Rails

Rails
1

Hi,

In PHP I was validating twice: client side and then server side.
Certainly
the code was not DRY but it made the user experience quicker and saved
server requests. I thought of the client side validation as optimization
of
the application. In “Agile Web D. with Rails” there is no
mention
that I can find of purely client side form validation. Is this just not
the
Rails way?

If people are still doing validation twice like I used to do then I’m
curious how they are handling it. Does it conflict with AJAX in any way?

Thanks,
Peter

2

Just thought I’d try again.

Peter

3

On Thursday 10 Nov 2005 05:57, Peter M. wrote:

In PHP I was validating twice: client side and then server side. Certainly
the code was not DRY but it made the user experience quicker and saved
server requests. I thought of the client side validation as optimization of
the application. In “Agile Web D. with Rails” there is no mention
that I can find of purely client side form validation. Is this just not the
Rails way?

If people are still doing validation twice like I used to do then I’m
curious how they are handling it. Does it conflict with AJAX in any way?

Hi Peter,

There’s various schools of thought on this, and while I don’t
necessarily
speak for “The Rails Way ™” of doing it, I think a specific
decision was
made to do it server-side only in Rails.

I think it basically stems from the fact that client-side JavaScript
validation with alert boxes and so on can get rather unwieldy, and since
you
have to do server-side validation anyway, and since rails makes it so
easy to
do the server side validation, and since validating it in two different
ways
is rather un-DRY, I think that’s essentially the reason Rails uses
server
side validation only.

I may be wrong about this, but I’m pretty sure this was what was said
the last
time this topic cropped up. Someone else please feel free to correct
me!

Having said that, I wouldn’t be surprised if someone makes a plugin to
do this
sometime, since it would probably be quite easy to automatically create
the
JavaScript validation code from the model validations themselves.

I’m not certain I’m right about all this - just trying to answer your
email
since nobody else has yet! :slight_smile:

Cheers,

~Dave

4

On Fri, 2005-11-11 at 17:42 -0200, Alessandro Cauduro wrote:

Dave,

Java/Struts (arghhhh), has a javascript error helper that generates
Javascript validation, as well as the standard server validation.

It can be nice to have this option to lower the load on the server. But it
also means that custom validations will have to be translated to Javascript,
therefore giving double the amount of work (not DRY) for the same result.

Client side validation also means you’re trusting that no-one will try
to hack your get/post requests. Thats a pretty large trust. Javascript
validations are only good for aesthetic reasons, and for situations
where you think there will be alot of mistakes (I guess, since you don’t
hit the server more than once).

-Matt B

5

Dave,

Java/Struts (arghhhh), has a javascript error helper that generates
Javascript validation, as well as the standard server validation.

It can be nice to have this option to lower the load on the server. But
it
also means that custom validations will have to be translated to
Javascript,
therefore giving double the amount of work (not DRY) for the same
result.

Alessandro

-----Mensagem original-----
De: [email protected]
[mailto:[email protected]] Em nome de Dave S.
Enviada em: sexta-feira, 11 de novembro de 2005 16:38
Para: [email protected]
Assunto: Re: [Rails] javascipt form validation in Rails

On Thursday 10 Nov 2005 05:57, Peter M. wrote:

In PHP I was validating twice: client side and then server side. Certainly
the code was not DRY but it made the user experience quicker and saved
server requests. I thought of the client side validation as optimization
of
the application. In “Agile Web D. with Rails” there is no mention
that I can find of purely client side form validation. Is this just not
the
Rails way?

If people are still doing validation twice like I used to do then I’m
curious how they are handling it. Does it conflict with AJAX in any way?

Hi Peter,

There’s various schools of thought on this, and while I don’t
necessarily
speak for “The Rails Way ™” of doing it, I think a specific
decision
was
made to do it server-side only in Rails.

I think it basically stems from the fact that client-side JavaScript
validation with alert boxes and so on can get rather unwieldy, and since
you

have to do server-side validation anyway, and since rails makes it so
easy
to
do the server side validation, and since validating it in two different
ways

is rather un-DRY, I think that’s essentially the reason Rails uses
server
side validation only.

I may be wrong about this, but I’m pretty sure this was what was said
the
last
time this topic cropped up. Someone else please feel free to correct
me!

Having said that, I wouldn’t be surprised if someone makes a plugin to
do
this
sometime, since it would probably be quite easy to automatically create
the
JavaScript validation code from the model validations themselves.

I’m not certain I’m right about all this - just trying to answer your
email
since nobody else has yet! :slight_smile:

Cheers,

~Dave

6

On 11/10/05, Peter M. [email protected] wrote:

If people are still doing validation twice like I used to do then I’m
curious how they are handling it. Does it conflict with AJAX in any way?

With AJAX you can validate once without having to define validations in
JavaScript. I’ve just published a text on exactly this subject:
http://www.bigsmoke.us/ajax-validation-in-rails/

Note that the page is untested in IE. If you find anything missing in
the
text, please let me know.

Cheers,

Rowan