Problem with my associations Users -> Accounts -> Transactions

rubyonrails-talk
1

I have three tables: users, accounts, and transactions. Users have many accounts, accounts have many transactions. So I define my models like so:

class User < ActiveRecord::Base has_many :accounts, dependent: :destroy end

class Account < ActiveRecord::Base belongs_to :user has_many :transactions, dependent: :destroy end

class Transaction < ActiveRecord::Base belongs_to :account end

Ideally on my app. When the current_user (btw, I’m also using Devise :wink: clicks shows accounts, then clicks an account to show transactions for that page - eventually I end up on /transactions?account=2 URL. Until here works fine.

In my transactions controller, however, I was to display on that page transactions for that user (current_user) for that account (id=2). I’m not sure the correct way to do this thought. Below is what I was trying:

def index @account = current_user.accounts.find_by_id(params[:accoount]) @transactions = @account.transactions.find_all_by_account(params[:accoount]); end

…but it doesn’t work :frowning: Where am I going wrong?

2

Btw, I get the following error:

undefined method `transactions’ for nil:NilClass

To me this tells me that @account if not found, or is returning an empty array. Am I using the wrong method, or parameters?

3

Please, try Users instead of current_user, like : def index

@account = Users.accounts.find_by_id(params[:accoount])

@transactions = @account.transactions.find_all_by_account(params[:accoount]);

end

4

Aaargh!!! I see it, I didn’t type “account” correctly. I thought I was using the method incorrectly. How did I not see that for so long?! @account = Users.accounts.find_by_id(params[:accoount]) This now works - @account = current_user.accounts.find_by_id(params[:account])

5

Actually I’ve changed the whole thing to:

def index @account = current_user.accounts.find_by_id(params[:account]) @transactions = @account.transactions; end

… works fine

6

@account = Account.find(params[:account]) should also work. A possible disadvantage of this method (depending on your application) is that a manually constructed url could show an account that does not belong to the current_user.

Colin

7

Consider, though, that if for whatever reason an invalid id is passed in, @account will be nil and so @account.transactions will give you a NoMethod error.

What do you want to happen at that point?

8

Consider, though, that if for whatever reason an invalid id is passed

in, @account will be nil and so @account.transactions will give you

a NoMethod error.

What do you want to happen at that point?

Good point. Thanks, I’ll put some checking to see if account is valid or not and handle it accordingly.

9

One quick way to do that is to use plain find instead of find_by_id, thus:

@account = current_user.accounts.find(params[:account])

If a user attempts to request an account that doesn’t belong to them, this will raise ActiveRecord::RecordNotFound. The default Rails rescue_from will translate that into an HTTP 404 Not Found response.

–Matt Jones