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Ruby Building Social Features in Ruby on Rails Using AJAX Implementing AJAX: Part 3

Kevin Kenger
Kevin Kenger
32,834 Points
Posted by Kevin Kenger
Kevin Kenger
32,834 Points

POST to user_friendships_path causes 422 (Unprocessable Entity)

Initially, when I load the profile page, clicking the "Add Friend" button opens the new user friendship page – which is its default action – even though we specify in the user_friendships.js file that we want to prevent this.

user_friendships.js

$(document).ready(function () {

  $("#add-friendship").click(function(event) {
    event.preventDefault();
    var addFriendshipBtn = $(this);
    $.ajax({
      url: Routes.user_friendships_path({user_friendship: { friend_id: addFriendshipBtn.data("friendId") }}),
      dataType: "json",
      type: "POST",
      success: function(e) {
        addFriendshipBtn.hide();
        $("#friend-status").html("<a href='#' class='button'>Friendship Requested</a>");
      }
    });
  });

});

user_friendships_controller.rb

class UserFriendshipsController < ApplicationController
    before_filter :authenticate_user!
    respond_to :html, :json

    def index
        @user_friendships = current_user.user_friendships.all 
    end

    def accept
        @user_friendship = current_user.user_friendships.find(params[:id])
        if @user_friendship.accept!
            flash[:success] = "You are now friends with #{@user_friendship.friend.first_name}."
        else
            flash[:error] = "That friendship could not be accepted."
        end
        redirect_to user_friendships_path
    end

    def new
        if params[:friend_id]
            @friend = User.where(profile_name: params[:friend_id]).first
            raise ActiveRecord::RecordNotFound if @friend.nil?
            @user_friendship = current_user.user_friendships.new(friend: @friend)
        else
            flash[:error] = "Friend required"
        end

    rescue ActiveRecord::RecordNotFound
        render file: "public/404", status: :not_found
    end


    def create
        if params[:user_friendship] && params[:user_friendship].has_key?(:friend_id)
            @friend = User.where(profile_name: params[:user_friendship][:friend_id]).first
            @user_friendship = UserFriendship.request(current_user, @friend)
            respond_to do |format|
                if @user_friendship.new_record?
                    format.html do
                        flash[:error] = "There was a problem creating that friend request."
                        redirect_to profile_path(@friend)
                    end
                    format.json { render json: @user_friendship.to_json, status: :precondition_failed }
                else
                    format.html do
                        flash[:success] = "Friend request sent."
                        redirect_to profile_path(@friend)
                    end
                format.json { render json: @user_friendship.to_json }
                end
            end
        else
                flash[:error] = "Friend required"
                redirect_to root_path
        end
    end

    def edit
        @user_friendship = current_user.user_friendships.find(params[:id]).decorate
        @friend = @user_friendship.friend
    end

    def destroy
        @user_friendship = current_user.user_friendships.find(params[:id])
        if @user_friendship.destroy
            flash[:success] = "Friendship destroyed."
        end
        redirect_to user_friendships_path
    end
end

After I refresh the page, that no longer happens, and when I click the "Add Friend" button, nothing appears to happen (which I'm assuming means the "event.preventDefault();" code is working) and I get this error in the console:

Chrome console

POST http://localhost:3000/user_friendships?user_friendship%5Bfriend_id%5D=kevin 422 (Unprocessable Entity)                  jquery.js?body=1:27
     Z.cors.a.crossDomain.send           jquery.js?body=1:27
     ab.extend.ajax                      jquery.js?body=1:26
     (anonymous function)                user_friendships.js?body=1:6
     ab.event.dispatch                   jquery.js?body=1:26
     q.handle                             jquery.js?body=1:25

Any help is greatly appreciated!

3 Answers

Naomi Freeman
STAFF
Naomi Freeman
Treehouse Guest Teacher
Naomi Freeman
Naomi Freeman
Treehouse Guest Teacher

There's this: http://restpatterns.org/HTTP_Status_Codes/422_-_Unprocessable_Entity

So it sounds like things are correct and it's just rejecting it. Rails 4 strong params might cause that if they're not configured.

What I see missing in your code that my code has is the replacement for attr_accessible Are you in Rails 4?

You may need these at the bottom of your controller:

def friendships_params
      params.require(user_friendship).permit(:user_id, :friend_id, :user, :friend, :state, :first_name,  :user_friendship, :full_name, :last_name)
    end

This chunk of code says "here are the things I will allow through to my server"

Do you have similar params in your other controllers?

Kevin Kenger
Kevin Kenger
32,834 Points
Kevin Kenger
Kevin Kenger
32,834 Points

Thank you for the reply!

Yeah I'm in Rails 4 and using strong params, but I added the friendships_params method to my controller to no avail. Unfortunately I'm still getting the same error that I was before :(

Naomi Freeman
STAFF
Naomi Freeman
Treehouse Guest Teacher
Naomi Freeman
Naomi Freeman
Treehouse Guest Teacher

Hmm ... well, feel free to look at my controller and see if you can find the difference. https://github.com/summerspirit/laughing-wookie/blob/master/app/controllers/user_friendships_controller.rb

That's the completely finished product though.

One interesting thing to note is that, when I tried to push it live, the add friendships button wouldn't work because I hadn't configured Devise mailers. It was fine when it was local but not live. Now that I'm starting to configure them correctly though, it's causing problems.

I haven't figured out the mailers piece yet. I wonder if it might be tripping you up too.

Let me know how it goes. I'm prepping for an open data project tonight, but will have more time on the weekend to try and debug code if it's still not working for you.

Kevin Kenger
Kevin Kenger
32,834 Points
Kevin Kenger
Kevin Kenger
32,834 Points

Well thank you so much. I couldn't find any differences in our controllers (obviously other than the friendship_association method).

I had actually thought about the mailer messing me up before – just because I've been doing so much reading about this and came across a few places where that was suggested – but I'm pretty sure that only occurs once the site is live, depending on where you deploy your application. I know Heroku for instance, doesn't have an email engine so you have to use one of their add-ons like Postmark.

But I'll keep chopping away at it, and I'll let you know when I finally figure it out. I appreciate the debugging offer by the way, there's a good chance I'll need to take you up on that. In the mean time thank you for the help, and good luck with your open data project!