I've a user profile (with name, logo, about_me) which is created after user creation(using Devise). Profile table uses user_id as Primary key.
Now I want that whenever the user creates/updates a post, while filling in form some details are taken from profile, so profile data or #profile be available in post form as I cannot expose my model in form.
To set post.myname attribute in create and #update I'm doing this:
#myprofile = Profile.find_by_user_id(current_user)
write_attribute(:myname, #myprofile.name)
I read from various sources but what's the best solution of the 4 given and if anyone can back with easy code as I do not want to do something extensive? Thanks in advance.
1)Form Hidden fields - Like get the profile data as above in hash in #edit and then pass through form and access fields in #update but that way we will pass each field separately. Can one #myprofile be passed?
2)Session - I feel if profile data is stored in a session and someone updates profile then updated data won't be available in that session.So not sure if it is plausible.
3)Caching - easy way to do that?
4)polymorphic profile---tried it but I didnot get relevant example. I was stuck with what to put as profileable id and type and how to use them in the code.
If your Profile and User models have a one-to-one relationship with each other, the simplest solution is to remove the Profile model altogether and move its fields into the User model.
Devise already queries the database to obtain the current_user object. So, your example would like this:
write_attribute(:myname, current_user.name)
Which wouldn't hit the database (after Devise has retrieved the current_user object).
If you're forced to keep the Profile model, in looking at your four scenarios ...
You could use a session variable. Something like:
session[:profile_name] ||= #myprofile.name
This would go in a controller action.
The trick here is that you will want to redefine the each relevant session variable if the profile gets updated. And because you don't have access to the session in the model, you'd be best to perform that action in the controller. So, not pretty, but it could work.
You could also use low-level caching, and save the profile relationship on the user. In general, you could have a method like this in your user model:
def profile_cached
Rails.cache.fetch(['Profile', profile.id]) do
profile
end
end
Here, too, you will have to know when to expire the cache. The benefit of this approach is that you can put this code in the model, which means you can hook its expiration in a callback.
Read more about this in Caching with Rails.
I would avoid hidden fields and I'm not sure how a polymorphic relationship would solve you not hitting the database. So, #2 and #3 are options, but if you can combine the two models into one, that should simplify it.
Related
I understand that associations are important because this gives us a way of linking two objects together so they have a 'relation' and we can query through both of them. For example,
A landing page belongs to a blog user & a blog user can have many landing pages
We obviously go into the models and apply the correct methods 'has_many' and 'belongs_to'. We also create a migration and add the foreign key to the 'belongs_to' model. This being the 'landing page'.
My problem:
When creating a landing page, it is possible to choose a blog user. This obviously passes the blog user ID into the params. I want to save this ID into the foreign key field in the landing page model.
Is this possible without doing:
def create
#landing_page = #blog_user.landing_pages.build(landing_pages_params)
end
Why do you have to go through a blog user? Another example:
def new
#landing_page = #blog_user.landing_pages.new
end
What is the purpose of doing it this way? Surely passing the ID into the field is enough without going through the blog_user?
Sure, you could do something like
#landing_page = LandingPages.new(blog_user_id: X)
Obviously, you need to know the ID of the BlogUser record. You'll then be able to access the newly associated BlogUser as you'd expect
#landing_page.blog_user #=> BlogUser(id: X)
I have a model Post, which is submitted and graded by different Users. The submitter and grader are identified by submitter_id and grader_id in Post model. Note that an user is both a submitter himself and a grader to others.
I want to make sure that the submitter can only edit the content of the Post but not the grade. Likewise, the grader can only edit the grade but not the content.
Is multiple edit methods the way to go? How should I accomplish this otherwise?
You can have a role column in your users table, and the role can be either submitter or grader. Not sure what you are using for authentication, but in case you are using devise, you can access the currently logged in user with current_user helper (in case you are using something else, figure this part out, or add a new helper).
Now in your update method, you can do something like this:
# Controller
# scope post to current user, so that a user cannot edit someone else's post. A crude way to achieve this is post = Post.find(params[:id])
post = current_user.posts.find(params[:id])
post.content = params[:content] if post.submitter?(current_user.id)
post.grade = params[:grade] if post.grader?(current_user.id)
post.save!
# Model - Post.rb
def submitter?(user_id)
self.submitter_id == user_id
end
def grader?(user_id)
self.grader_id == user_id
end
The advantage of keeping those methods in the model is that in case you permission logic changes (who is submitter, or a grader), you need to change it at a single location. DRY.
You can modify the above approach to show error messages, and do other similar stuff. In case you are looking for more granular authorization control, you can look into cancan gem:
https://github.com/ryanb/cancan
Your post model should only be concerned with persisting data. Better to use plain old ruby objects to encapsulate the higher order behavior of grading and submitting. Consider using service objects or form objects.
Each service or form object can then include ActiveModel::Model(rails > v4) to get its own validations.
See more about service and form objects here: http://blog.codeclimate.com/blog/2012/10/17/7-ways-to-decompose-fat-activerecord-models/
If you only have one submit action and one grade action, its probably ok to keep in one controller. But if you start having multiple actions that are related to submitted, and multiple actions that are related to grading, this sounds like they would make great resources controllers on their own.
I recently coded up a 'friend' capability with my website. The way it works is if a user wants to 'friend' another user, sending a request creates a user_connection record with the original user set at the user_id and the requested user set as the contact_id. If the other user accepts the request, then another user_connection record will be made, with the user_id and contact_id reversed. If both user_connections exist, then the two users are considered friends. This currently gives each user access to any buildings shared between the two users.
I was wondering if there was some way I could enforce my user_connection model to make sure that whoever is creating the record gets set as the user_id. Otherwise it seems that someone could spoof the user_connection create request to make themself a contact of whomever they want, and then could spoof building shares using the same methodology. Are there any built in methods to prevent this?
My first thought was to have an initializer that always set the user_id to the current_user's id, but it appears that current_user is outside of the context of the model.
Don't allow user_id to be provided as a parameter, using strong params.
So, you could create the relation like that:
#friendship = current_user.friendships.new(contact_id: other_user.id)
Also make sure you provide the correct condition for current_user.
That's it... user_id is implied but never provided.
So lets say I have a form for submitting a new post.
The form has a hidden field which specify's the category_id. We are also on the show view for that very category.
What I'm worried about, is that someone using something like firebug, might just edit the category id in the code, and then submit the form - creating a post for a different category.
Obviously my form is more complicated and a different scenario - but the idea is the same. I also cannot define the category in the post's create controller, as the category will be different on each show view...
Any solutions?
EDIT:
Here is a better question - is it possible to grab the Category id in the create controller for the post, if its not in a hidden field?
Does your site have the concept of permissions / access control lists on the categories themselves? If the user would have access to the other category, then I'd say there's no worry here since there's nothing stopping them from going to that other category and doing the same.
If your categories are restricted in some manner, then I'd suggest nesting your Post under a category (nested resource routes) and do a before_filter to ensure you're granted access to the appropriate category.
config/routes.rb
resources :categories do
resources :posts
end
app/controllers/posts_controller
before_filter :ensure_category_access
def create
#post = #category.posts.new(params[:post])
...
end
private
def ensure_category_access
#category = Category.find(params[:category_id])
# do whatever you need to do. if you don't have to validate access, then I'm not sure I'd worry about this.
# If the user wants to change their category in their post instead of
# going to the other category and posting there, I don't think I see a concern?
end
URL would look like
GET
/categories/1/posts/new
POST
/categories/1/posts
pst is right- never trust the user. Double-check the value sent via the view in your controller and, if it does't match something valid, kick the user out (auto-logout) and send the admin an email. You may also want to lock the user's account if it keeps happening.
Never, ever trust the user, of course ;-)
Now, that being said, it is possible to with a very high degree of confidence rely on hidden fields for temporal storage/staging (although this can generally also be handled entirely on the server with the session as well): ASP.NET follows this model and it has proven to be very secure against tampering if used correctly -- so what's the secret?
Hash validation aka MAC (Message Authentication Code). The ASP.NET MAC and usage is discussed briefly this article. In short the MAC is a hash of the form data (built using a server -- and perhaps session -- secret key) which is embedded in the form as a hidden field. When the form submission occurs this MAC is re-calculated from the data and then compared with the original MAC. Because the secrets are known only to the server it is not (realistically) possible for a client to generate a valid MAC from the data itself.
However, I do not use RoR or know what modules, if any, may implement security like this. I do hope that someone can provide more insight (in their own answer ;-) if such solutions exist, because it is a very powerful construct and easily allows safe per-form data association and validation.
Happy coding.
I want to learn how to create my own authentication system, please provide some guidance if am doing this wrong.
I will create a Module in my /lib folder /lib/auth.rb
I will require this module in my ApplicationController.
when a user enters their email + password, I will call a method that will do a lookup in the user's table for a user with the same email, I will then compare the passwords. (i'll add encryption with salt later).
If the user entered the correct credentials, I will create a row in the Sessions table, and then write the session GUID to a cookie.
Now whenever I need to check if the user is logged in, or I need the user object, I will check if the cookie exists, if it does, I will lookup the session table for a row with the same guid, if it exists, I will return the session row and then load the User object.
I realize there are many suggestions one can give, but in a nutshell does this sound like a workable solution?
Now to make this usable, I will have to make some helper methods in my ApplicationController right?
How will I access the current_user from within my views?
P.S I know of other authentication systems, I just want to learn how to create my own.
The basic logic you're following is correct. Of course you can always expand on this with features that you need. For instance, you'll need helper methods for things like "logged_in?" and "current_user". Also, you might want to add session expiry, or session retention as a "remember me" feature.
Go for it, you won't learn authentication systems better than building your own then figuring what's wrong with it.
You should really check out the authlogic gem on github.
http://github.com/binarylogic/authlogic
It also has great instructions on how to set up your users.
After Faisal said what I would say, I only give you answer to the last part of your question:
"How will I access the current_user from within my views?"
try something like this:
class User < ...
def self.current=(u)
#current = u
end
def self.current
#current
end
end
In your views (or any part of your code) you can call User.current. Your controller has to assign a validated user to User.current. Your filters can react to "if User.current.nil?" and so on.
If you want to be thread safe, you may use a thread variable instead of #current:
Thread.current[:current_user] = u