undefined method `fql_query' for nil:NilClass - ruby-on-rails

With the koala gem I am trying to count checkins for a page. I am using rails.
In my user.rb I have a method for getting a new connection to the Facebook graph:
class User < ActiveRecord::Base
def facebook
#facebook ||= Koala::Facebook::API.new(oauth_token)
end
end
In my school.rb I have a method for counting the checkins:
class school < ActiveRecord::Base
def count_checkins(name)
checkins = #facebook.fql_query("SELECT checkins FROM page WHERE name = #{name}")
end
end
And I am calling it from the view like this:
<%= #school.count_checkins(#school.name) %>
But I get the following error:
undefined method `fql_query' for nil:NilClass
Dont really understand why I get this error, any help would be wonderful.

It looks like you haven't actually created the #facebook object inside your School model. We'd need to see the rest of your school.rb file to know for sure. I'd suggest you create the object inside your School.initialize() method like so:
def initialize(oauth_token)
unless oauth_token.nil?
#facebook = Koala::facebook::API.new(oauth_token)
end
end
In order for this to work, you'll need to pass the desired oauth_token to your School.new() call. Then you'll have one #facebook object for each School.
Edit
After looking at the gist, I realized that you had actually intantiated a User object, and called the facebook method on that. That is actually the better way to do it. The problem is, you're using #current_user, which would have to be setup as a property of the school model. You probably meant to use the helper function current_user instead.
def count_checkins(name)
u = current_user
u.#facebook.fql_query("SELECT checkins FROM page WHERE name = #{name}")
end
Try that and see what happens. At the very least, you should get a different error message.
Edit 2
So, now I'm thinking the current_user function should be called in controller code, not model code. This is because the current user is something that doesn't really exist except as part of an active request. Therefore, we should take User u as a parameter to the count_checkins function like so:
def count_checkins(name, u)
u.facebook.fql_query("SELECT checkins FROM page WHERE name = #{name}")
end
You'll need to change the code where you call count_checkins() too:
count_checkins(name, current_user)
That should do it. Let's see!

Related

Monkeypatch ActiveRecord::FinderMethods

I'm trying to monkey patch ActiveRecord::FinderMethods in order to use hashed ids for my models. So for example User.find(1) becomes User.find("FEW"). Sadly my overwritten method doesn't get called. Any ideas how to overwrite the find_one method?
module ActiveRecord
module FinderMethods
alias_method :orig_find_one, :find_one
def find_one(id)
if id.is_a?(String)
orig_find_one decrypt_id(id)
else
orig_find_one(id)
end
end
end
end
Here's an article that discusses how to actually do what you want by overriding the User.primary_key method like:
class User
self.primary_key = 'hashed_id'
end
Which would allow you to call User.find and pass it the "hashed_id":
http://ruby-journal.com/how-to-override-default-primary-key-id-in-rails/
So, it's possible.
That said, I would recommend against doing that, and instead using something like User.find_by_hashed_id. The only difference is that this method will return nil when a result is not found instead of throwing an ActiveRecord::RecordNotFound exception. You could throw this manually in your controller:
def show
#user = User.find_by_hashed_id(hashed_id)
raise ActiveRecord::RecordNotFound.new if #user.nil?
... continue processing ...
end
Finally, one other note to make this easier on you -- Rails also has a method you can override in your model, to_param, to tell it what property to use when generating routes. By default, of course, it users the id, but you would probably want to use the hashed_id.
class User
def to_param
self.hashed_id
end
end
Now, in your controller, params[:id] will contain the hashed_id instead of the id.
def show
#user = User.find_by_hashed_id(params[:id])
raise ActiveRecord::RecordNotFound.new if #user.nil?
... continue processing ...
end
I agree that you should be careful when doing this, but it is possible.
If you have a method decode_id that converts a hashed ID back to the original id, then the following will work:
In User.rb
# Extend AR find method to allow finding records by an encoded string id:
def self.find(*ids)
return super if ids.length > 1
# Note the short-circuiting || to fall-back to default behavior
find_by(id: decode_id(ids[0])) || super
end
Just make sure that decode_id returns nil if it's passed an invalid hash. This way you can find by Hashed ID and standard ID, so if you had a user with id 12345, then the following:
User.find(12345)
User.find("12345")
User.find(encode_id(12345))
Should all return the same user.

should bookmark.id return nil

hey guys so i'm having issues adding a Like/Dislike function to my bookmarks on my page.
basically i have a snippet of code given to me that lives in my User model:
def liked(bookmark)
likes.where(bookmark_id: bookmark.id).first
end
however when i am running the server and clicking on the topic to show the associated bookmarks, i keep getting the
undefined method `id' for nil:NilClass
my question is... firstly what is going wrong here? and secondly, whats the difference between bookmark_id and bookmark.id?
im pretty sure id doesn't exist for bookmark... and if not... how would i add it?
ive tried via migration, unfortunately nothing great came from that
use this code:
def liked(bookmark)
likes.where(bookmark_id: bookmark.id).first if bookmark.present?
end
You are getting id for nil:NilClass error due to object is not present.i.e bookmark object is nil.
bookmark_id is the field name for the bookmark class.And bookmark.id returns the id of the bookmark object, only if the object is present.
bookmark.id raises an exception.
Ensure bookmark instance is passed to the liked method and is not nil
You need to ensure that your bookmark argument is not nil.
You could try the following code
def liked(bookmark)
likes.where(bookmark_id: bookmark.try(:id)).first
end
or an even better version
def liked(bookmark)
likes.find_by(bookmark_id: bookmark.try(:id))
end
Above code will return a nil object or first like
To answer your second question, bookmark_id is an column name here for your Like model whereas bookmark.id is a method call on bookmark object.
You can try the following.
def liked(bookmark)
likes.where(bookmark_id: bookmark.id).try(:first) unless bookmark.blank?
end

Rails getting access to current user

I'm trying to save in Note which Employee was the last editor of a `Note'
In a View, I'm able to access the current employee like this:
<h4><%= current_user.employee.id%></h4>
But, in a Model, I can't use current_user.employee.id.
So, I'm trying this in the User model:
def self.current
Thread.current[:user]
end
def self.current=(user)
Thread.current[:user] = user
end
And this in the Note model:
before_create :record_update
before_update :record_update
protected
def record_update
self.lasteditor_id = User.current.employee.id unless User.current.employee.id.nil?
end
What I'm getting is the last User in the Users table.
Thanks for the help!
current_user gets the logged in user information from the session. You cannot access session variables from model. If you want to update the Note model with the Last employee who viewed it, do it in your controller(most likely show action of your note or any other action you think would be right)
def show
#note = Note.find(params[:id])
#note.update_atribute(:last_viewed_by, current_user.id)
end
You code might look different from above. But this is the idea

Rails: activeadmin overriding create action

I have an activeadmin resource which has a belongs_to :user relationship.
When I create a new Instance of the model in active admin, I want to associate the currently logged in user as the user who created the instance (pretty standard stuff I'd imagine).
So... I got it working with:
controller do
def create
#item = Item.new(params[:item])
#item.user = current_curator
super
end
end
However ;) I'm just wondering how this works? I just hoped that assigning the #item variable the user and then calling super would work (and it does). I also started looking through the gem but couldn't see how it was actually working.
Any pointers would be great. I'm assuming this is something that InheritedResources gives you?
Thanks!
I ran into a similar situation where I didn't really need to completely override the create method. I really only wanted to inject properties before save, and only on create; very similar to your example. After reading through the ActiveAdmin source, I determined that I could use before_create to do what I needed:
ActiveAdmin.register Product do
before_create do |product|
product.creator = current_user
end
end
Another option:
def create
params[:item].merge!({ user_id: current_curator.id })
create!
end
You are right active admin use InheritedResources, all other tools you can see on the end of the page.
As per the AA source code this worked for me:
controller do
def call_before_create(offer)
end
end

Rails scope model data by user_id

I have a Rails application where a user longs in and I have the user_id in the session. The next step is to create a scope for all model data shown to the user where data.user_id = session[:user_id].
I know I can do the following in each of my controllers
Controller.find_all_by_user_id(session[:user_id])
Yet to me it seems there is probably a better solution. I found the possibility to add a scope to the model, yet the session is not known here and MVC pattern wise it is probably not a good idea to have it there. Is there a solution to apply such a user_id restriction to all data coming from the models or should I just use the find_all_by_user_id for every controller function that has userdata in it?
If I understand you correctly you want to access some data by user_id. Which means that you can define relationship in the user model as has_many :this_and_that or something like that. It it is right, then you can create a before_filter or even better a function in your application controller in which you get your current user instance. Trough this instance, you can access all available data to that user. You can even make that function a helper function, and you can use that in a view.
#User.erb
has_many :other_data
#ApplicationConroller.erb
def current_user
#current_user ||= User.find_by_id(session[:user_id])
end
#OtherControllers
def index
#other_datas = current_user.other_datas
end
You can have before_filter :load_user_data, :if => current_user or something like that.
Method will look like that:
def load_user_data
#data = ModelName.where(user_id: session[:user_id])
end
#data will be ActiveRecord::Relation and will be chainable. Also using find_all_by_user_id in each controller not that bad, if you really need it.

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