Best practise for setting default URL parameters in the controller

[Bizt]

I've been trying to set default URL parameters in the controller, which will also be used within the view. This is what I've got:

@params = params

defaults = { :date_from => '21/1/21014', :date_to => '21/2/21014', :data=>"Expense" }
if @params.any?
  @params = defaults.merge(@params)
else
  @params = defaults
end

.. seems messy, and doesn't work :( When params are present it still uses the default params. Not sure where it's going wrong and search on google yields many varieties. I know using default values in methods is something that I will repeat again so I was wondering what the best practise is for handling this. Thanks

[Colin Law]

On 2 February 2014 06:22, Bizt <marty...@gmail.com> wrote:
> I've been trying to set default URL parameters in the controller, which will
> also be used within the view. This is what I've got:
>
> @params = params
>
> defaults = { :date_from => '21/1/21014', :date_to => '21/2/21014',
> :data=>"Expense" }
> if @params.any?
> @params = defaults.merge(@params)
> else
> @params = defaults
> end
>
> .. seems messy, and doesn't work :( When params are present it still uses
> the default params.

That is likely because it should be params not @params. I don't think
you need the .any? test either, just let it merge the empty hash into
defaults.

If you need to do this in more than one controller method then use a
before filter.

Colin

[Frederick Cheung]

It doesn't work because @params isn't where params are stored. Params is never empty (at a minimum :controller and :action are set) so you can get rid of the else

You could update params in place , ie params.merge!(...).

Personally I wouldn't do this. I'd be more likely to have a controller method called something like get_date_range that would get the dates from params that would do things like parse the strings into actual dates and/or replace missing params with defaults.

Fred

[Colin Law]

On 2 February 2014 13:57, Frederick Cheung <frederic...@gmail.com> wrote:
> ...

> You could update params in place , ie params.merge!(...).

Would that not use the value from defaults if it was already present in params?

>
> Personally I wouldn't do this. I'd be more likely to have a controller method called something like get_date_range that would get the dates from params that would do things like parse the strings into actual dates and/or replace missing params with defaults.

+1

Colin

[Frederick Cheung]

On Sunday, February 2, 2014 2:10:10 PM UTC, Colin Law wrote:
> On 2 February 2014 13:57, Frederick Cheung <frederic...@gmail.com> wrote:
>
> > ...
>
> > You could update params in place , ie params.merge!(...).
>
>
>
> Would that not use the value from defaults if it was already present in params?
>

I was assuming this was after checking that params didn't have the values in question, although if not you could use reverse_merge!

Fred

[Dave Aronson]

On Sun, Feb 2, 2014 at 5:02 AM, Colin Law <cla...@gmail.com> wrote:

> That is likely because it should be params not @params.

But:

> On 2 February 2014 06:22, Bizt <marty...@gmail.com> wrote:

....

>> This is what I've got:
>>
>> @params = params

so @params should work the same as params. Not sure why he's
bothering to copy it into an @-var, tho; maybe he wants access to it
in a view....

-Dave

--
Dave Aronson, the T. Rex of Codosaurus LLC (codosaur.us),
freelance software developer, and creator of these sites:
PullRequestRoulette.com, blog.codosaur.us, & Dare2XL.com.

[Hassan Schroeder]

On Sat, Feb 1, 2014 at 10:22 PM, Bizt <marty...@gmail.com> wrote:
> I've been trying to set default URL parameters in the controller, which will
> also be used within the view.

> ... so I was wondering what the best practise is for handling this.

Personally, I'd say "best practice" is "don't do that" :-)

Instead of passing raw params to a view, build your model object
(or a service object) with them and pass that in. And if you need
defaults for missing attributes specified, the model/s.o. would be
a better place for them.

FWIW,
--
Hassan Schroeder ------------------------ hassan.s...@gmail.com
http://about.me/hassanschroeder
twitter: @hassan