I am using Rails 4 and I have played with AJAX. I have successfully got it to work. The page that have Ajax links on it is the show.html.erb. It has a feed which have posts, and the posts has comments. To avoid loading everything I use Ajax for loading pieces of the post list and the comment list. Much like Facebook does.
I have organised it the following way: the pages controller checks if there is an ajax_action query parameter present. If it does it renders the JavaScript-response. It checks with a before_action. The value of the ajax_action are load_posts, load_comments and load_replies. They map to private methods in the pages controller.
Does this sound like a good approach when I need different Ajax methods on the same page? Or do you do it another way?
code from the pages controller:
before_action :delegate_ajax, only: :show
def delegate_ajax
ajax_action = params[:ajax_action]
unless ajax_action.nil?
ajax_handlers = {'load_posts' => 'load_posts', 'load_comments' => 'load_comments'}
send(ajax_handlers[ajax_action])
end
end
def load_posts
# Some logic (hidden for now)
respond_to do |format|
format.js { render 'load_posts', layout: false }
end
end
def load_comments
# Some logic (hidden for now)
respond_to do |format|
format.js { render 'load_comments', layout: false }
end
end
At least doing it like this keeps the routes.rb oblivious to all the AJAX routes.
When I look at examples of Rails controllers, I usually see something like this:
class WidgetController < ActionController::Base
def new
#widget = Widget.new
end
def create
#widget = Widget.new(params[:id])
if #widget.save
redirect_to #widget
else
render 'new'
end
end
end
This works, but there's a couple problems:
Routes
If I add widgets to my routes.rb file:
Example::Application.routes.draw do
resources :widgets
end
GET /widgets/new will route to new and POST /widgets will route to create.
If the user enters incorrect information on the new widget page and submits it, their browser will display a URL with /widgets, but the new template will be rendered. If the user bookmarks the page and returns later or refreshes the page, the index action will be called instead of the new action, which isn't what the user expects. If there's no index action or if the user doesn't have permission to view it, the response will be a 404.
Duplication of code
As a contrived example, let's say I had some tricky logic in my new method:
def new
#widget = Widget.new
do_something_tricky()
end
Using the current approach, I'd duplicate that logic in new and create. I could call new from create, but then I'd have to modify new to check if #widget is defined:
def new
#widget ||= Widget.new
do_something_tricky()
end
Plus, this feels wrong because it reduces the orthogonality of the controller actions.
What to do?
So what's the Rails way of resolving this problem? Should I redirect to new instead of rendering the new template? Should I call new inside of create? Should I just live with it? Is there a better way?
I don't think this is a problem in "the rails way" and there is no builtin functionality to allow this without getting your hands dirty. What does a user expects when bookmarking a form they just submitted and had errors? Users don't know better, and they shouldn't bookmark a failed form.
I think redirecting to new_widget_path is the cleanest solution. Yet, you should keep the errors and display them on the form. For this I recommend you keep the params in session (which I expect to be smaller than a serialized Widget object).
def new
#widget = widget_from_session || Widget.new
end
def widget_from_session
Widget.new(session.delete(:widget_params)) if session[:widget_params].present?
end
private :widget_from_session
# Before the redirect
session[:widget_params] = params
The code is self explanatory, Widget.new will only be called when widget_from_session returns nil, this is when session[:widget_params] is present. Calling delete on a hash will return de deleted value and delete it from the original hash.
UPDATE Option 2
What about submitting the form using ajax? Your controller could benefit from:
respond_to :html, :json
...
def create
#widget = Widget.new params[:widget]
#widget
respond_with #widget, location: nil
end
Based on the response code (which is set by Rails: 201 Created or 422 Unprocessable Entity), you could show the errors (available in the body of the response when validations fail) or redirect the user to #widget
This is how StackOverflow does it: https://stackoverflow.com/questions/ask. They submit the form asynchronously.
In general, I think the Rails way of solving the problem would be to put the tricky method onto the model or as a helper method, so the controller stays "thin" and you don't have to make sure to add custom behavior to both #new and #create.
EDIT: For further reading, I'd recommend the "Rails AntiPatterns" book, as they go through a lot of these common design issues and give potential solutions.
you put do_something_tricky() in its own method and call it inside the create action (but only when you're rendering the new template, ie when validation fails).
As for the bookmark issue, I don't know a good way to prevent that but to modify the routes and set the create action to the new action but using POST
get '/users/new' => 'users#new'
post '/users/new' => 'users#create'
UPDATE: using resources
resources :platos, except: :create do
post '/new' => 'plates#create', on: :collection, as: :create
end
then you can use create_platos_path in your forms
You don't need to write same function in two action , use before_filter instead.
If you want to have "widget_new_url" after incorrect submission then in your form add url of new widget path something like :url => widget_new_path .
Rails takes the url from Form .
I have this problem before, so I use edit action instead.
Here is my code.
Routes:
resources :wines do
collection do
get :create_wine, as: :create_wine
end
end
Controller:
def create_wine
#wine = Wine.find_uncomplete_or_create_without_validation(current_user)
redirect_to edit_wine_path(#wine)
end
def edit
#wine = Wine.find(params[:id])
end
def update
#wine = Wine.find(params[:id])
if #wine.update_attributes(params[:wine])
redirect_to #wine, notice: "#{#wine.name} updated"
else
render :edit
end
end
Model:
def self.find_uncomplete_or_create_without_validation(user)
wine = user.wines.uncomplete.first || self.create_without_validation(user)
end
def self.create_without_validation(user)
wine = user.wines.build
wine.save(validate: false)
wine
end
View:
= simple_form_for #wine, html: { class: 'form-horizontal' } do |f|
= f.input :complete, as: :hidden, input_html: { value: 'true' }
What I did is create a new action 'create_wine' with get action.
If user request 'create_wine', it will create a new wine without validation and redirect to edit action with a update form for attributes and a hidden field for compele .
If user has create before but gave up saving the wine it will return the last uncompleted wine.
Which means whether use save it or not, the url will be the same to /wines/:id.
Not really good for RESTful design, but solve my problem. If there is any better solution please let me know.
So I have a ChatsController, and from my index action, I'm trying to redirect to a custom action, "decide":
def index
#chat = Chat.customfind(params[:search])
if(#chat.is_a?(Array))
session[:chats] = #chat
redirect_to :action => 'decide'
else
respond_to do |format|
format.html { redirect_to #chat if !#chat.nil? }
end
end
def decide
#chats = session[:chats]
#choice = Chat.find(params[:id])
redirect_to #choice if !#choice.nil?
end
..where #choice is going to be decided by the params of the form on the decide page. But for some reason, instead of redirecting to decide, Rails redirects to show:
Started GET "/chats/decide" for 127.0.0.1 at 2012-03-14 17:13:36 -0400
Processing by ChatsController#show as HTML
Parameters: {"id"=>"decide"}
..............
Can anyone explain how to fix this?
Edit:
I'm assuming this is what you want... the relevant parts of my routes.rb:
match "chats/decide" => "chats#decide"
resources :chats do
member do
post 'send_message'
end
end
get "chats/logout"
..yeah it's a bit of a hodgepodge :/
It seems you are trying to achieve the following:
Find all chats matching a given search string
If 1 chat is found, redirect to it
If 2+ chats are found, redirect to /chats/decide so the user can pick one
I would implement this as follows:
1) Update routes.rb as follows:
resources :chats do
member do
post :send_message
end
collection do
get :decide # Produces the '/chats/decide/' route
end
end
2) Change your chats#decide action to this:
def decide
#chats = session[:chats]
end
3) When you list the available chats in your decide.html.erb file, link them directly to the appropriate show link.
4) Be explicit about your redirect in chats#index:
redirect_to :controller => 'chats', :action => 'decide'
Your chats#decide action should not respond differently based on whether it's receiving an id or not. You can link directly to the specific chats in that view.
I'm frequently building controllers where i would like multiple methods
(in addition to index, edit, show, etc.). Most of the time the actions i
desire could be lumped into show as they are simple GET operations,
however I don't want to put too much logic in any one controller action.
Here is a quick example of two different ways to achieve the same
thing...
class TwitterFriendController < ApplicationController
## lump everything into show?
def show
if params[:id] == "follow"
users = current_user.following
elsif params[:id] == "follow_me"
users = current_user.users_who_follow_me
elsif params[:id] == "following_follow_me"
users = current_user.following_who_follow_me
elsif params[:id] == "following_who_do_not_follow_me"
users = current_user.following_who_do_not_follow_me
...
end
respond_with do |format|
format.json do {...}
end
end
## or split everything out into separate methods, this requires
additional routing
def following
...
end
def users_who_follow_me
...
end
def following_who_follow_me
...
end
def following_who_do_not_follow_me
...
end
end
Everything in show
a ton of logic in one method
DRY ? # lots of extra code needed for logic
Less routing
Seperate Methods
More routing
not DRY
Easy method lookup
Easier to read individual methods
So again the real question is, which one of those techniques are less
bad.
I would do something like:
FOLLOW_WHITELIST = %w[ follow follow_me following_follow_me following_who_follow_me following_who_do_not_follow_me ]
def show
if FOLLOW_WHITELIST.include? params[:id]
users = current_user.send params[:id].to_sym
end
respond_with do |format|
format.json do {...}
end
end
This will call whatever method is passed in params[:id], as long as it's in the whitelist (to prevent arbitrary code injection).
If having separate routes was a plus to you (nicer urls?), you could also dynamically generate the methods and routes with something like this:
class TwitterFriendController < ApplicationController
FOLLOW_ACTIONS = %w[ follow follow_me following_follow_me following_who_follow_me following_who_do_not_follow_me ]
FOLLOW_ACTIONS.each do |action|
define_method action do
users = current_user.send action.to_sym
respond_with do |format|
format.json do {...}
end
end
end
end
And then in routes.rb:
FOLLOW_ACTIONS.each do |action|
match action.to_sym => "controller##{action}"
end
I have a couple different user types (buyers, sellers, admins).
I'd like them all to have the same account_path URL, but to use a different action and view.
I'm trying something like this...
class AccountsController < ApplicationController
before_filter :render_by_user, :only => [:show]
def show
# see *_show below
end
def admin_show
...
end
def buyer_show
...
end
def client_show
...
end
end
This is how I defined render_by_user in ApplicationController...
def render_by_user
action = "#{current_user.class.to_s.downcase}_#{action_name}"
if self.respond_to?(action)
instance_variable_set("##{current_user.class.to_s.downcase}", current_user) # e.g. set #model to current_user
self.send(action)
else
flash[:error] ||= "You're not authorized to do that."
redirect_to root_path
end
end
It calls the correct *_show method in the controller. But still tries to render "show.html.erb" and doesn't look for the correct template I have in there named "admin_show.html.erb" "buyer_show.html.erb" etc.
I know I can just manually call render "admin_show" in each action but I thought there might be a cleaner way to do this all in the before filter.
Or has anyone else seen a plugin or more elegant way to break up actions & views by user type? Thanks!
Btw, I'm using Rails 3 (in case it makes a difference).
Depending on how different the view templates are, it might be beneficial to move some of this logic into the show template instead and do the switching there:
<% if current_user.is_a? Admin %>
<h1> Show Admin Stuff! </h1>
<% end %>
But to answer your question, you need to specify which template to render. This should work if you set up your controller's #action_name. You could do this in your render_by_user method instead of using a local action variable:
def render_by_user
self.action_name = "#{current_user.class.to_s.downcase}_#{self.action_name}"
if self.respond_to?(self.action_name)
instance_variable_set("##{current_user.class.to_s.downcase}", current_user) # e.g. set #model to current_user
self.send(self.action_name)
else
flash[:error] ||= "You're not authorized to do that."
redirect_to root_path
end
end