ActionController::UnknownFormat in CoinsController#index - ruby-on-rails

In my CoinsController, I have added a respond_to method in my index controller. I'm not sure if my code is right but here is my index controller below:
def index
paginated = paginate(Coin.recent)
render_collection(paginated)
respond_to do |format|
format.json do
format.html # index.html.erb
format.json { render json: render_collection(paginated) }
end
end
end
I read the few documents I found online about respond_to do |format| method and when I tried adding it manually the way it is in the documentation, I get an Unknown Format error. What I'm trying to do is have logic that handles both html and json, so that it can act as a json api and a view renderer.
Any ideas?

Ok guys so I found out the solution to my problem:
def index
paginated = paginate(Coin.recent)
# render_collection(paginated)
respond_to do |format|
format.json do
render_collection(paginated)
end
format.html do
render :index
end
end
end
I had commented out the render_collection(paginated) and then added json and html to it's own block and it worked.

Related

Change filename of js for eg show.js to show2.js in respond_to

I have one js file show.js that is renderd for the action def show:
def show
....
respond_to do |format|
format.html
format.js
end
end
My question is how can I change the respond_to block, so that it does not respond with show.js but for example with newshow.js? I ask because I would like to render different js dependent on the params! Thanks! I use Rails 4.
I believe that this one would work:
respond_to do |format|
format.html
format.js { render :newshow }
end

`respond_to` without block argument

Presently I'm using respond_to like this.
respond_to do |format|
format.html {render layout: false }
end
I know a sentence like respond_to {| format | format.html } can be written respond_to :html.
But how can I write without first block if format.html also have a block argument?
I want to write like respond_to :html, {render layout: false }.
Could it be you have this confused with respond_with?
class PeopleController < ApplicationController
respond_to :html
def index
#people = Person.all
respond_with #people
end
end
respond_with can be configured just as respond_to:
respond_with(#people) do |format|
format.html { render layout: false }
end
See the API documentation or this Railscast for more information about respond_with.

Rails: respond_to JSON and HTML

I have a controller "UserController" that should respond to normal and ajax requests to http://localhost:3000/user/3.
When it is a normal request, I want to render my view. When it is an AJAX request, I want to return JSON.
The correct approach seems to be a respond_to do |format| block. Writing the JSON is easy, but how can I get it to respond to the HTML and simply render the view as usual?
def show
#user = User.find(params[:id])
respond_to do |format|
format.html {
render :show ????this seems unnecessary. Can it be eliminated???
}
format.json {
render json: #user
}
end
end
As per my knowledge its not necessary to "render show" in format.html it will automatically look for a respective action view for ex : show.html.erb for html request and show,js,erb for JS request.
so this will work
respond_to do |format|
format.html # show.html.erb
format.json { render json: #user }
end
also, you can check the request is ajax or not by checking request.xhr? it returns true if request is a ajax one.
Yes, you can change it to
respond_to do |format|
format.html
format.json { render json: #user }
end
The best way to do this is just like Amitkumar Jha said, but if you need a simple and quick way to render your objects, you can also use this "shortcut":
def index
#users = User.all
respond_to :html, :json, :xml
end
Or make respond_to work for all the actions in the controller using respond_with :
class UserController < ApplicationController
respond_to :html, :json, :xml
def index
#users = User.all
respond_with(#users)
end
end
Starting from Rails 4.2 version you will need to use gem responder to be able to use respond_with.
If you need more control and want to be able to have a few actions that act differently, always use a full respond_to block. You can read more here.

Respond_to and redirect in the same action in Rails

In the Update action of Rails controllers usually there is code that looks like this:
def update
#book = Book.find(params[:id])
if #book.update_attributes(params[:book])
redirect_to(#book)
else
render :edit
end
end
In the else case, this will render the edit template. But what if I wanted to use a respond_to, exactly the same way that I have in the edit action, as:
def update
#book = Book.find(params[:id])
if #book.update_attributes(params[:book])
redirect_to(#book)
else
respond_to do |format|
format.html # edit.html.erb
format.json { render :json => #team }
end
end
end
So, if the Update fails, be sure you are returning a json or html depending on the requested format. Does that makes sense? If so, how would you avoid the error: "Render and/or redirect were called multiple times in this action"
Makes sense to me. The answer should be simple, just return after redirect_to.
def update
#book = Book.find(params[:id])
if #book.update_attributes(params[:book])
redirect_to(#book)
return
else
respond_to do |format|
format.html # edit.html.erb
format.json { render :json => #team }
end
end
end
Not sure exactly how you're rendering multiple times, but assuming you are, a well-placed return should tell RAILS to stop processing any further renders after redirecting. If that's all true, it's likely that there's an after_filter interfering from somewhere.

Add JSON support to Rails app

I am experimenting with Rails and was wondering what's needed to allow/add support for JSON requests?
I have a vanilla installation of Rails 2.3.5 and the default scaffolding seem to provide support for HTML & XML requests but not JSON.
class EventsController < ApplicationController
# GET /events
# GET /events.xml
def index
#events = Event.all
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => #events }
end
end
# GET /events/1
# GET /events/1.xml
def show
#event = Event.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => #event }
end
end
...
I'm new to this but it would appear as though i would need to add a format line in each method along the lines of:
format.js { render :js => #event.json }
couldn't this be done automatically? perhaps there's a template somewhere i need to update...or a flag i can set? Or perhaps, and most likely, I've missed the boat entirely?!?
You do:
format.json {render :json=>#event}
That will render the default activerecord JSON for the model
The option of ease of use is that you can write a private method which takes the format object and an object to render and then, based on the format, renders different things. Example:
class MyController<ApplicationController
def show
#event=Event.find(params[:id])
respond_to do {|format| myRenderer(format,#event)}
end
...
private
def myRenderer(fmt,obj)
fmt.json {render :json=>obj}
fmt.html
fmt.xml {render :xml=>obj}
end

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