Two columns must not equal each other in Rails
I'm creating a social network in Rails and I have a model like this:
create_table "friendships", :force => true do |t|
t.integer "user1_id"
t.integer "user2_id"
t.boolean "hasaccepted"
t.datetime "created_at"
t.datetime "updated_at"
end
The problem is that you cannot add yourself as friend, so I tried this in my model:
def validate
if :user1_id == :user2_id
record.errors.add "You cannot add yourself as a friend."
return false
end
end
And I have this in my controller:
def addfriend
if params[:id]
@friendship = Friendship.new()
@friendship.user1_id = session[:user]
@friendship.user2_id = params[:id]
respond_to do |format|
if @friendship.save
format.html { redirect_to "/" } # Yes, SO users, I will fix this redirect later and it is not important for now.
format.xml { render :xml => @friendship, :status => :created }
else
开发者_如何学Go format.html { redirect_to "/" }
format.xml { render :xml => @friendship.errors, :status => :unprocessable_entity }
end
end
end
end
(where session[:user]
is the uid of the currently signed in user)
However, when I go to http://localhost:3000/profile/addfriend/2.xml
while I'm signed in as user 2
, Rails returns me the new Friendship
, instead of an error message, and when I take a look at my database, the Friendship
is also there (and it shouldn't). Can someone please explain me how to fix this? Thanks
Try it like this:
class Friendship < ActiveRecord::Base
validate :cannot_add_self
private
def cannot_add_self
errors.add(:user2_id, 'You cannot add yourself as a friend.') if user1_id == user2_id
end
end
if :user1_id == :user2_id
That's always gonna be false - you're comparing the symbols. It's the same as writing if "user1_id" == "user2_id"
.
You should write it as if user1_id == user2_id
to compare the values of the columns.
more fun:
validates :user1_id, exclusion: { in: ->(friendship) { [friendship.user2_id] }, message: "Stop it or you'll go blind." }
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