Rails: Completed 500 Internal Server Error, with AngularJS $http.post call - ruby-on-rails

Question

I'm currently working on this tutorial: AngularJS Tutorial: Learn to Build Modern Web Apps with Angular and Rails
In the tutorial project, users can create Blog Posts and Comments for those Posts. So far I've been able to create Blog Posts (which are saved into database), but when I try to create a Comment for a Post, then I get the following error:
Started POST "/posts/16/comments.json" for 127.0.0.1 at 2015-02-15 08:32:40 +0200
Processing by CommentsController#create as JSON
Parameters: {"body"=>"6", "author"=>"user", "post_id"=>"16", "comment"=>{"body"=>"6"}}
Comments create action entered... 6
Completed 500 Internal Server Error in 9ms
NameError (undefined local variable or method `post' for #<CommentsController:0xb6036e50>):
app/controllers/comments_controller.rb:6:in `create'
Note: line “Comments create action entered... 6
” is logger.info message.
Screenshot
comments_controller.rb
class CommentsController < ApplicationController
def create
logger.info "Comments create action entered... " + params[:body]
comment = post.comments.create(comment_params)
respond_with post, comment
end
def upvote
comment = post.comments.find(params[:id])
comment.increment!(:upvotes)
respond_with post, comment
end
private
def comment_params
params.require(:comment).permit(:body)
end
end
posts_controller.rb
class PostsController < ApplicationController
def index
respond_with Post.all
end
def create
respond_with Post.create(post_params)
end
def show
logger.info "show action entered... " + params[:id]
#respond_with Post.find(params[:id])
#the code below works, the line above resulted in error: 406 (Not Acceptable)
render json: Post.find(params[:id]).to_json
end
def upvote
post = Post.find(params[:id])
post.increment!(:upvotes)
respond_with post
end
private
def post_params
logger.info "post_params entered..."
params.require(:post).permit(:link, :title)
end
end
In the PostsController's show action, I had previously changed line: respond_with Post.find(params[:id]) to: render json: Post.find(params[:id]).to_json because line: respond_with Post.find(params[:id]) produced error: GET http://0.0.0.0:3000/posts/4 406 (Not Acceptable)
I'm not sure, but the above issue might be related to internal error (500) message, why post is not found. Also if I use line: respond_with Post.find(params[:id]) in the PostsController then I still end up with the same problem with the Comment creation.
application_controller.rb
class ApplicationController < ActionController::Base
# Prevent CSRF attacks by raising an exception.
# For APIs, you may want to use :null_session instead.
protect_from_forgery with: :exception
respond_to :json
def angular
render 'layouts/application'
end
end
routes.rb
FlapperNews::Application.routes.draw do
root to: 'application#angular'
resources :posts, only: [:create, :index, :show] do
resources :comments, only: [:show, :create] do
member do
put '/upvote' => 'comments#upvote'
end
end
member do
put '/upvote' => 'posts#upvote'
end
end
end
Below is post.js file that does the Ajax calls in which the o.addComment function's $http.post call tries to create the Comment in the following way: $http.post('/posts/' + id + '/comments.json', comment);
angular.module('flapperNews').factory('posts', ['$http',
function($http){
var o = {
posts: []
};
o.getAll = function() {
return $http.get('/posts.json').success(function(data){
angular.copy(data, o.posts);
});
};
o.create = function(post) {
console.log("o.create");
return $http.post('/posts.json', post).success(function(data){
o.posts.push(data);
});
};
o.upvote = function(post) {
return $http.put('/posts/' + post.id + '/upvote.json')
.success(function(data){
post.upvotes += 1;
});
};
o.get = function(id) {
return $http.get('/posts/' + id).then(function(res){
return res.data;
});
};
o.addComment = function(id, comment) {
console.log("addComment " + id + ", comments " + comment )
return $http.post('/posts/' + id + '/comments.json', comment);
};
o.upvoteComment = function(post, comment) {
console.log("o.upvoteComment " + post.id + ", comments " +comment.id)
return $http.put('/posts/' + post.id + '/comments/'+ comment.id + '/upvote.json')
.success(function(data){
comment.upvotes += 1;
});
};
return o;
}
]);
app.js
angular.module('flapperNews', ['ui.router', 'templates'])
.config([
'$stateProvider',
'$urlRouterProvider',
function($stateProvider, $urlRouterProvider) {
$stateProvider
.state('home', {
url: '/home',
templateUrl: 'home/_home.html',
controller: 'MainCtrl',
resolve: {
postPromise: ['posts', function(posts){
return posts.getAll();
}]
}
})
.state('posts', {
url: '/posts/{id}',
templateUrl: 'posts/_posts.html',
controller: 'PostsCtrl',
resolve: {
post: ['$stateParams', 'posts', function($stateParams, posts) {
console.log( "$stateParams.id " +$stateParams.id)
return posts.get($stateParams.id);
}]
}
})
$urlRouterProvider.otherwise('home')
}]);
My rails version is 4.0.2
Any help would be appreciated, because I've been struggling with the code for a couple of hours :-) Anyway, I'm glad that there is Stackoverflow forum where one can ask some advice :-)

Answer 1

First, this has nothing to do with angular. You don't have the post defined, so add:
post = Post.find params[:post_id]
also, i think your comment belongs_to post, you should set the post as the comment's post before saving the comment, so:
#comment.post = post