Rails Import CSV - No Route Matches - ruby-on-rails

Question

I'm very new to Rails. I'm currently trying to import data from an csv file into my rails application. However, when I followed examples and guides online, I got the error: No route matches {:action=>"import_csv", :controller=>"lists"} I've already added it in my routes.rb though. Can anyone help me check what is wrong if my codes to cause to 'no route matches' error? Below are my files:
lists_controller.rb
def import_csv
require 'fastercsv'
respond_to do |format|
#csv=params[:file].read
#n=0
#parsed_file = CSV.parse(csv)
#parsed_file.each do |row|
#user_new = User.new
#user_new.first_name = row[0]
#user_new.last_name = row[1]
#user_new.email = row[2]
#user_new.address = row[3]
#user_new.city = row[4]
#user_new.state = row[5]
#user_new.zip = row[6]
#user_new.country = row[7]
#user_new.notes = row[8]
#user_new.birthday = row[9]
#user_new.home_number = row[10]
#user_new.mobile_number = row[11]
#user_new.list_id = list_id
#user_new.save
#n=#n+1
GC.start if n%50==0
flash[:notice] = "CSV Imported Successfully, with #{n} records"
end
format.html { redirect_to lists_url }
format.json { head :no_content }
end
end
app/views/lists/show.html.erb
<%= form_for(:list, :url => list_import_csv_path, :html => {:multipart => true}) do |f| %>
<table>
<tr>
<td><label for="dump_file">Select a CSV File :</label></td>
<td ><%= file_field_tag :file %></td>
</tr>
<tr>
<td colspan='2'><%= submit_tag 'Submit' %></td>
</tr>
</table>
<% end %>
routes.rb
resources :lists do
get 'import_csv'
#match '/import_csv/:id' => 'lists#import_csv', :as => :import_csv
end
rake routes
identities GET /identities(.:format) identities#index
POST /identities(.:format) identities#create
new_identity GET /identities/new(.:format) identities#new
edit_identity GET /identities/:id/edit(.:format) identities#edit
identity GET /identities/:id(.:format) identities#show
PUT /identities/:id(.:format) identities#update
DELETE /identities/:id(.:format) identities#destroy
newsletter_cancel GET /newsletters/:newsletter_id/cancel(.:format) newsletters#cancel
newsletters GET /newsletters(.:format) newsletters#index
POST /newsletters(.:format) newsletters#create
new_newsletter GET /newsletters/new(.:format) newsletters#new
edit_newsletter GET /newsletters/:id/edit(.:format) newsletters#edit
newsletter GET /newsletters/:id(.:format) newsletters#show
PUT /newsletters/:id(.:format) newsletters#update
DELETE /newsletters/:id(.:format) newsletters#destroy
list_import_csv GET /lists/:list_id/import_csv(.:format) lists#import_csv
lists GET /lists(.:format) lists#index
POST /lists(.:format) lists#create
new_list GET /lists/new(.:format) lists#new
edit_list GET /lists/:id/edit(.:format) lists#edit
list GET /lists/:id(.:format) lists#show
PUT /lists/:id(.:format) lists#update
DELETE /lists/:id(.:format) lists#destroy
users GET /users(.:format) users#index
POST /users(.:format) users#create
new_user GET /users/new(.:format) users#new
edit_user GET /users/:id/edit(.:format) users#edit
user GET /users/:id(.:format) users#show
PUT /users/:id(.:format) users#update
DELETE /users/:id(.:format) users#destroy

Answer 1

Your form is submitted with a POST, while the route is for a GET. Either pass :method => :get to the form_for helper, or change your route to post (I would prefer the former though, since you're requesting data, not changing anything on the server).
To specify GET method for a form, you would do
<%= form_for (:list, :url => list_import_csv_path, :method => :get, :html => {:multipart => true}) do |f| %>
I'm also not sure if it's a good idea to force start garbage collection - it'd kill your performance if it kicks in while processing requests. Leftover objects should get garbage collected automatically.
I'd also extract the User export part (probably into a static method on the User model):
require 'faster_csv'
class User < ActiveRecord::Base
...
def self.import_from_csv(file)
CSV.parse(file).each do |row|
u = User.new(:first_name => row[0], :last_name => row[1] ...etc)
return false if !u.save
end
end
end
Then, in the controller:
def import_csv
respond_to do |format|
if !User.import_from_csv(params[:file])
format.html { render :show, :error => "Some error here" }
format.json { render :json => "Some error here", :status => :unprocessable_entity }
else
format.html { redirect_to lists_url, :notice => "Import successful!" }
format.json { :head => :ok }
end
end
end

Answer 2

Use post instead of get in your config/routes.rb.