Defining custom methods in Rails

Question

I have just started using Rails and I am trying to build a banking app. I am having trouble setting up transactions between accounts.

I have currently scaffolded Transaction and Account. In my transaction page I can create a list of transaction with each transaction containing information about the source account, amount to transfer and the destination account. However, at the end of the page I would like a link or a button that processes all the transactions on the page and clears the page. Thus, modifying all the specified account balances.

Below is the steps I took in going about it.

1) In transaction model (transaction.rb model) define process method

class Transaction < ActiveRecord::Base
    def proc (transaction) 
        # Code processes transactions
        @account = Account.find(transaction.from_account)
        @account.balance = @account.balance - transaction.amount
        @account.update_attributes(params[:account]) #update the new balance
end
end

2) Then create a method in transaction controller call execute

def execute
      @transaction = Transaction.find(params[:id])
    proc (@transaction)
    @transaction.destroy

      respond_to do |format|
      format.html { redirect_to transactions_url }
      format.json { head :no_content }
  end

3) Then define the a link to display on the transaction page (shown below):

<% @transactions.each do |transaction| %>
  <tr>
    <td><%= transaction.from_account %></td>
    <td><%= transaction.amount %></td>
    <td><%= transaction.to_account %></td>
    <td><%= link_to 'Execute', transaction, confirm: 'Are you sure?', method: :execute %></td>
    <td><%= link_to 'Show', transaction %></td>
    <td><%= link_to 'Edit', edit_transaction_path(transaction) %></td>
    <td><%= link_to 'Destroy', transaction, confirm: 'Are you sure?', method: :delete %></td>
    <td><%= transaction.id%></td>
 </tr>
<% end %>

4) But when I click the Execute link I get the routing error: [POST] "/transactions/6"

Currently my routes(routes.rb) are setup as follows:

resources :transactions do
       member do
       post :execute
       end
   end

  resources :accounts

How do I setup the routes so that it may process my method? Thanks in advance

Answer 1

What you're trying to do here is not add a new method, but a new 'HTTP verb'. Don't do it. You'll likely receive a nasty message like this:

    !! Unexpected error while processing request: EXECUTE, accepted HTTP methods are OPTIONS,
 GET, HEAD, POST, PUT, DELETE, TRACE, CONNECT, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, 
UNLOCK, VERSION-CONTROL, REPORT, CHECKOUT, CHECKIN, UNCHECKOUT, MKWORKSPACE, UPDATE, LABEL,
 MERGE, BASELINE-CONTROL, MKACTIVITY, ORDERPATCH, ACL, SEARCH, and PATCH

In the console run ' rake routes ' and be sure you have the route for execute registered. Something like:

execute_transaction

Then update your execute link and replace 'transaction' with the proper path finder, and set the method to :post instead.

link_to "Execute", execute_transaction_path(transaction), method: :post

Answer 2

Small difference: change the method name from a symbol to a string.

resources :transactions do
  member do
    post "execute"
  end
end

Checkout the Rails Routing Guide