# Newbie - Params passed to new **URL:** \ **Category:** Rails\ **Created:** [June 7, 2007, 10:48pm UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265 "2007-06-07T22:48:38Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 7, 2007, 10:48pm UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/1 "2007-06-07T22:48:38Z")
My understanding is that “params” is a hash containing the parameters passed to a controller. So within a method, I should be able to do: contact = Contact.new( params ) but I get the error “undefined method `action=’” When I use: contact = Contact.new( :name =\> params[:name], :address =\> params[:address] ) everything is fine. But this of course becomes a problem when I have many parameters. I thought ActiveRecord’s new() would automatically throw out parameters that weren’t part of the data structure. I suppose I’m missing something obvious, but I can’t figure it out. Thanks! ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 7, 2007, 10:50pm UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/2 "2007-06-07T22:50:39Z")
> params[:address] ) > > everything is fine. But this of course becomes a problem when I have > many parameters. I thought ActiveRecord’s new() would automatically > throw out parameters that weren’t part of the data structure. I > suppose I’m missing something obvious, but I can’t figure it out. I don’t think it does… but I’ve never really looked. Typically in your example above I see things like: contact = Contact.new( params[:contact] ) so the form variables have names such as “params[:contact][:name]” etc… That way you only deal with what you want. Look into the form helper calls for more info. ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 7, 2007, 10:51pm UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/3 "2007-06-07T22:51:39Z")
Mojave wrote: > params[:address] ) > > everything is fine. But this of course becomes a problem when I have > many parameters. I thought ActiveRecord’s new() would automatically > throw out parameters that weren’t part of the data structure. I > suppose I’m missing something obvious, but I can’t figure it out. No, what you need to do is “scope” the params. So that in your form you have etc. Then you may use Contact.new(params[:contact]) in your controller. The point being that everything related to a contact is put into the params[:contact] hash. If you use the built in helpers for creating your input tags, you get the “scoping” for free. – Cheers, - Jacob A. ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 8, 2007, 12:16am UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/4 "2007-06-08T00:16:48Z")
On Jun 7, 1:55 pm, Jacob A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > contact = Contact.new( :name =\> params[:name], :address =\> > > everything related to a contact is put into the params[:contact] hash. > > If you use the built in helpers for creating your input tags, you get > > the “scoping” for free. > > – > Cheers, > > - Jacob A. Thanks for both responses. I’m creating a contact via an Ajax call, not using a form. The url is “/contact/add?name=joe&address=Broadway” - so in this case, I should scope it with “/contact/add? contact[name]=joe&contact[address]=Broadway” - is that right? That seems to be a little excessive, but I suppose cleaner. ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 8, 2007, 1:47am UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/5 "2007-06-08T01:47:56Z")
Or even better yet use: \<% form\_for :contact, contacts\_path() do |form| %\> Name: \<%= form.text\_field :name, :size =\> 40 %\> ... ... instead of \<% form\_tag … %\> … … ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 8, 2007, 12:28am UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/6 "2007-06-08T00:28:49Z")
> > Contact.new(params[:contact]) in your controller. The point being that > > I’m creating a contact via an Ajax call, not using a form. The url is > > “/contact/add?name=joe&address=Broadway” - so in this case, I should > > scope it with “/contact/add? > > contact[name]=joe&contact[address]=Broadway” - is that right? > > That seems to be a little excessive, but I suppose cleaner. Or just pull out what you want and name it explicitly in your controller like you had been doing… Or do something with Contact.column\_names to dynamically pull what you want out of params or something… ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 8, 2007, 5:42am UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/7 "2007-06-08T05:42:32Z")
Mojave wrote: > On Jun 7, 1:55 pm, Jacob A. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > contact = Contact.new( :name =\> params[:name], :address =\> > > > everything related to a contact is put into the params[:contact] hash. > > > If you use the built in helpers for creating your input tags, you get > > > the “scoping” for free. > > > > – > > Cheers, > > > > - Jacob A. > > Thanks for both responses. > > I’m creating a contact via an Ajax call, not using a form. The url is > “/contact/add?name=joe&address=Broadway” - so in this case, I should > scope it with “/contact/add? > contact[name]=joe&contact[address]=Broadway” - is that right? > > That seems to be a little excessive, but I suppose cleaner. This might be a good time to look into routing ([http://api.rubyonrails.org/classes/ActionController/Routing.html](http://api.rubyonrails.org/classes/ActionController/Routing.html)). You should be able to create a creative route to handle the details (I haven’t tested this, so no promises): map.connect ‘/contact/add?name=:contact[name]&address=:contact[address]’, :controller =\> contact, :action =\> add At least this way you keep the url ugliness from your customer. Otherwise, you can always setup something like: map.connect ‘/contact/add?\*details’, :controller =\> contact, :action =\> add and then your contact details will be passed in their own variable. The problem I’ve found with params is that it ends up containing a lot of details about the rails transaction that you, most likely, don’t need. Also, there’s nothing wrong with parsing out the params and then creating the row. Don’t worry, Ruby won’t bite! 😉 -Josh ---
**Author:** ![Mojave](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/58f4c7/32.png) [@Mojave](https://www.ruby-forum.com/u/Mojave)\ **Post date:** [June 8, 2007, 1:14pm UTC](https://www.ruby-forum.com/t/newbie-params-passed-to-new/106265/8 "2007-06-08T13:14:11Z")
I’m not exactly sure of the value of routing here. The form will be POSTed and the user will never see them in the url. Also, while you should indeed scope your form params by nesting them, you shouldn’t be writing the html code manually. Use rails’ built-in form helpers. They are abundant.Start by reading the documentation for form\_for. Then you can indeed simply use contact = Contact.new(params[:contact]). Also, ActiveRecord will indeed bork if fed params that don’t match up with the model’s attributes.