I have a controller show action which does some stuff and renders a view but due to some custom routing, I need a totally different action in a totally different controller to perform the same stuff and render the same view.
I don't really wish to duplicate the code. Is there somewhere I can put it and call it from both locations?
Edit:
I basically need to run the following from Collection#Show AND also from Gallery#SplitUrl:
#collection = Collection.find_by_id(params[:id])
if #collection.has_children?
#collections = #collection.children
else
redirect_to [#collection, :albums]
end
I cannot just redirect_to Collection#Show at the end of Gallery#SplitUrl as the redirect causes my custom URL's to be lost as it's a new request.
You could put the view content into a partial (/app/views/home/_example.html.erb) and then use the render "example" command in the HomeController.
The "some stuff" code you talk about could be put into a helper file /app/helpers/... to save you from duplicating code in the two separate controllers although it could depend on what the code is trying to do in the first place.
http://guides.rubyonrails.org/layouts_and_rendering.html
This might provide more information on the subject in general.
I think the simplest approach would be to add a route definition for your new url and map that to your existing controller's action.
Something like follows:
# config/routes.rb
# Existing resource
resources :foos
# The resource in question
resources :bars do
get :show, controller: 'foos', action: 'show', as: bar_foo_common_show
end
Note that this will give you /bar/:id, where id represents a bar resource. So in your foo#show action, your finder needs to be executed on appropriate class. This is when a few lines of hacky codes get added, for e.g. checking for request referer.
I think moving the common code to a function in possibly application_controller and calling that function from both show action would be cleaner approach, but based on my understanding you already have a similar scenario except for the common code in application_controller, and would like to try out a different approach!
I am making a Rails application, and i would like to be able use a model object passed to a view to get the URL of some action on this object, like this, for example:
link_to object.public_send(attribute),
{ :controller => object.controller_path,
:action => :show,
:id => object.id }
What would be a good way to do this? Can it be done with a decorator like Draper? Are there some examples online?
Update. I have thought about this and decided that a decorator is not a good place to keep controller information. It is not decorator's responsibility. A decorator should only know to render formatted data with markup. For now i have created a module called Accessor where i try to mix models with controller and routing awareness. I still wonder if there is a better way to do.
If you don't mind having another instance variable on your view, you can implement this using a very simple class (no need for decorators).
class MyRouter
def initialize(controller, object)
#controller = controller
#object = object
end
def url_for(action_name)
controller.url_for(object, :action => action_name)
end
end
On your controllers:
class AController
def edit
#router = MyRouter.new(self, object)
render 'shared_view'
end
end
class BController
def edit
#router = MyRouter.new(self, object)
render 'shared_view'
end
end
And on your shared view:
<%= #router.url_for(:show) # Varies with the controller that rendered the view %>
Of course, this assumes that the controller you want as target is the same controller that renders the view, which might not be true. Still, using this pattern you can accommodate a more complex logic that suits your needs (having multiple Router classes, for instance), without having to change the view.
I've found a very interesting solution in Objects on Rails by Avdi Grimm: Exhibits for REST. In short, his idea is to apply multiple Ruby's SimpleDelegators as decorators with various functions.
In my model I have:
after_create :push_create
I push_create I need to render a view. I'm trying to do that like so:
def push_event(event_type)
X["XXXXX-#{Rails.env}"].trigger(event_type,
{
:content => render( :partial =>"feeds/feed_item", :locals => { :feed_item => self })
}
)
end
This angers rails as it doesn't like me rendering a view in the model but I need it there.
Error:
NoMethodError (undefined method `render' for #<WallFeed:0x1039be070>):
Suggestions? Should I render it somewhere else somehow? Or how can I render in the model to set content? Thanks
proper solution
Well, "they" are right. You really have to do the rendering in a controller -
but it's fair game to call that controller from a model! Fortunately, AbstractController
in Rails 3 makes it easier than I thought. I wound up making a simple
ActionPusher class, working just like ActionMailer. Perhaps I'll get ambitious and
make this a proper gem someday, but this should serve as a good start for anyone else in my shoes.
I got the most help from this link: http://www.amberbit.com/blog/2011/12/27/render-views-and-partials-outside-controllers-in-rails-3/
in lib/action_pusher.rb
class ActionPusher < AbstractController::Base
include AbstractController::Rendering
include AbstractController::Helpers
include AbstractController::Translation
include AbstractController::AssetPaths
include Rails.application.routes.url_helpers
helper ApplicationHelper
self.view_paths = "app/views"
class Pushable
def initialize(channel, pushtext)
#channel = channel
#pushtext = pushtext
end
def push
Pusher[#channel].trigger('rjs_push', #pushtext )
end
end
end
in app/pushers/users_pusher.rb. I guess the require could go somewhere more global?
require 'action_pusher'
class UsersPusher < ActionPusher
def initialize(user)
#user = user
end
def channel
#user.pusher_key
end
def add_notice(notice = nil)
#notice = notice
Pushable.new channel, render(template: 'users_pusher/add_notice')
end
end
Now in my model, I can just do this:
after_commit :push_add_notice
private
def push_add_notice
UsersPusher.new(user).add_notice(self).push
end
and then you'll want a partial, e.g. app/views/users_pusher/add_notice.js.haml, which could be as simple as:
alert('#{#notice.body}')
I guess you don't really need to do it with Pushable inner class and the .push
call at the end, but I wanted to make it look like ActiveMailer. I also have a
pusher_key method on my user model, to make a channel for each user - but this
is my first day with anything like Pusher, so I can't say for sure if that's the right
strategy. There's more to be fleshed out, but this is enough for me to get started.
Good luck!
(this was my first draft answer, leaving it in because it might help someone)
I've got the general outline of a solution working. Like this, in your model:
after_create :push_new_message
private
def render_anywhere(partial, assigns = {})
view = ActionView::Base.new(ActionController::Base.view_paths, assigns)
view.extend ApplicationHelper
view.render(:partial => partial)
end
def push_new_message
pushstring = render_anywhere('notices/push_new_message', :message_text => self.body)
Pusher[user.pusher_key].trigger!('new_message', pushstring)
end
that is definitely working - the template is rendering, and gets eval()'ed on the client side successfully. I'm planning to clean it up, almost certainly move render_anywhere somewhere more general, and probably try something like this
I can see that pushes will need their own templates, calling the generally available ones, and I may try to collect them all in one place. One nice little problem is that I sometimes use controller_name in my partials, like to light up a menu item, but I'll obviously have to take a different tactic there. I'm guessing I might have to do something to get more helpers available, but I haven't gotten there yet.
Success! Hooray! This should answer your question, and mine - I'll add more detail if it seems appropriate later. Good luck!!!!
original non-answer from an hour ago left for clarity
I don't have an answer, but this timely question deserves more clarification, and I'm hoping to get closer to my answer by helping ask :)
I'm facing the same problem. To explain a little more clearly, Pusher asynchronously sends content to a connected user browser. A typical use case would be a showing the user they have a new message from another user. With Pusher, you can push a message to the receiver's browser, so they get an immediate notification if they are logged in. For a really great demo of what Pusher can do, check out http://wordsquared.com/
You can send any data you like, such as a JSON hash to interpret how you like it, but it would be very convenient to send RJS, just like with any other ajax call and eval() it on the client side. That way, you could (for example) render the template for your menu bar, updating it in its entirety, or just the new message count displayed to the user, using all the same partials to keep it bone-DRY. In principle, you could render the partial from the sender's controller, but that doesn't make much sense either, and there might not even be a request, it could be triggered by a cron job, for example, or some other event, like a stock price change. The sender controller just should not have to know about it - I like to keep my controllers on a starvation diet ;)
It might sound like a violation of MVC, but it's really not - and it really should be solved with something like ActionMailer, but sharing helpers and partials with the rest of the app. I know in my app, I'd like to send a Pusher event at the same time as (or instead of) an ActionMailer call. I want to render an arbitrary partial for user B based on an event from user A.
These links may point the way towards a solution:
http://blog.choonkeat.com/weblog/2006/08/rails-calling-r.html
How to render a Partial from a Model in Rails 2.3.5
http://mattwindsurfs.wordpress.com/2008/06/19/rails-render-in-a-model/
http://davetroy.blogspot.com/2008/02/actsasrenderer-brings-output-to-models.html
https://github.com/asapnet/acts_as_renderer
http://ethilien.net/archives/render-rails-templates-anywhere-even-in-a-model/
The last one looks the most promising, offering up this tantalizing snippet:
def render_anywhere(partial, assigns)
view = ActionView::Base.new(Rails::Configuration.new.view_path, assigns)
ActionView::Base.helper_modules.each { |helper| view.extend helper }
view.extend ApplicationHelper
view.render(:partial => partial)
end
As does this link provided by another poster above.
I'll report back if I get something working
tl;dr: me too!
I just do this:
ApplicationController.new.render_to_string(partial: 'messages/any', locals: { variable: 'value' })
Rails 5 way
In Rails 5 rendering outside a controller became pretty straightforward due to implemented render controller class method:
# render template
ApplicationController.render 'templates/name'
# render action
FooController.render :index
# render file
ApplicationController.render file: 'path'
# render inline
ApplicationController.render inline: 'erb content'
When calling render outside of a controller, one can assign instance variables via assigns option and use any other options available from within a controller:
ApplicationController.render(
assigns: { article: Article.take },
template: 'articles/show',
layout: false
)
Request environment can be tailored either through default options
ApplicationController.render inline: '<%= users_url %>'
# => 'http://default_host.com/users'
ApplicationController.renderer.defaults[:http_host] = 'custom_host.org'
# => "custom_host.org"
ApplicationController.render inline: '<%= users_url %>'
# => 'http://custom_host.org/users'
or explicitly by initializing a new renderer
renderer = ApplicationController.renderer.new(
http_host: 'custom_host.org',
https: true
)
renderer.render inline: '<%= users_url %>'
# => 'https://custom_host.org/users'
Hope that helps.
You can use ActionView directly and render partials to string without having a controller. I find that pattern useful to create models that encapsulate some javascript generation, for instance.
html = ActionView::Base.new(Rails.configuration.paths['app/views']).render(
partial: 'test',
formats: [:html],
handlers: [:erb],
locals: { variable: 'value' }
)
Then, just put your _test.html.erb in you view folder and try it out!
Rails 6.0.0 compatible answer, since I ended up on this page while searching for a solution:
lookup_context = ActionView::LookupContext.new(Rails.configuration.paths["app/views"])
renderer = ActionView::Base.new(lookup_context)
renderer.extend(Rails.application.helpers)
renderer.render \
template: "foo/bar",
formats: [:html],
handlers: [:erb],
locals: { user: User.new }
I'm fairly sure the answers you seek lie within Crafting Rails Applications where Jose Valim goes into great detail about how and why you would want to render views straight from your db
Sorry I can't be of more help yet because I've just started reading it myself tonight.
You might find some help here - it's a blog post about doing this sort of thing, albeit using different methods than yours
the "proper" way to do this is to push an object in serialized form(json), and then have the view deal with it once the event is received. Perhaps you want to use Handlebars to render the object.
Edit: I originally wrote about how, despite my answer, I was going to follow your example. But I just realized there is a HUGE gotcha with your approach when it comes to push notifications.
In your problem, you are doing push notifications to one user. For me, I was broadcasting out to a set of users. So I was going to render html with a presumption of a "current_user" and all that comes with it(eg logic, permissions, etc). This is NO BUENO as each push notification will be received by a different "current user".
Therefore, really, you need to just send back the data, and let each individual view handle it.
You should call all render methods from a controller. So, in this case, you can notify the controller that the object has been created and the controller can then render the view. Also, since you can render only once, I think you can wait for all your server side operations to complete before invoking the render.
The render methods are defined on the ActiveController class and its progeny. Inherently you do not have access to it on the model, nor is it a class method so you can't use it without an instance of the controller.
I've never tried to instantiate a controller for the express purpose of simply stringifying a partial, but if you can get your hands on a controller, render_to_string seems to be the way to go.
I will chime in by saying that if you're going down this path you're taking RoR "off the Rails". This is a violation of MVC and fundamentally poor program design.This doesn't mean I think you're a bad person :P Sometimes life drives us off the rails, so to speak.
I can't speak to the details that have driven you to do this, but I'd strongly suggest you rethink your approach.
I have created a gist for this.
I needed something similar, where the models don't necessarily (or in my case, ever) get updated via a controller, so the logic can't sit there.
Created a server-push based controller:
https://gist.github.com/4707055
I am building my first app with ROR and stumbled upon a couple of problems due to my understanding of the MVC
I have a page to add a new item, and this works fine, rails magically hooks it up to the items controller and somehow by magic it knows to look in the method 'new' as the page is called new.
But this layer is confusing me, as i need to now create a different version of new, same functionality but with a different look so to use a different layout to application.html.erb
So i attempt to create a copy of new.html.erb and create bookmarklet.html.erb - both contain exactly the same code: a link to a form. but of course bookmarklet will error on me because it does not have that link in the controller - how do i 'wire' up bookmarklet so that i can call the new method and so that it can behave in a similar way to the identical new.html.erb
Also, how can i tell the new bookmarklet.html.erb to ignore the application.html.erb and get its layout from another file?
thanks in advance
The magic happens in the routes. Rails uses something called RESTful routes, which is taking HTTP verbs and assigning standard actions to it. the new action is a GET request in HTTP speak, and if you are using scaffolding or following REST, will have the ruby call to build a new object in the controller, as an instance variable so you can use it in your view.
You have to tell rails routes that you want to BREAK this arrangement and to let /items/bookmarklet be used in the controller.
In your routes.rb file replace resources :items with
resources items do
member do
get 'bookmarklet'
end
end
In your controller put:
def bookmarklet
#item = Item.new
render :template => "bookmarklet", :layout => "different_layout" # or you can put this on the top of the controller, which is my style, but whatevs.
end
You should look into partials, if you are doing this as they clean up your code immensely.
A better way to think of things is to start with the controller instead of the view html.erb files. So each public method in your controller is effectively a page or action in the site. When you need a new action or page, add the method to the controller first. Then create the relevant view files.
So in your controller you'll need something like:
def bookmarklet
#item = Item.new(params[:item])
#item.save
render :template => "items/bookmarklet.html.erb", :layout => "different_layout.html.erb"
end
Normally you don't need to call render manually in the controller, but since you want a different layout than the default you need to specify it using render.
So I have a controller called Music with one action which is index. On the music/index.html page I list out a bunch of Songs (via a Song model) and at the bottom I have a for to create a new Song.
Song has validations which I have tested and work just fine. When the new Song saves in controller Songs action create I redirect_to => 'music_index_path' so the person can see the new song in the list. However when the Song does not save (does not pass validations) then I cannot use redirect_to since the form error_messages do not carry over. I need to use render but cannot say render :controller => 'music', :action => 'index.
My goal is to be able to show the error messages for the Song form ON the music/index.html page.
How should I go about this. I am open to other ideas (like changing up controllers) as well.
Thanks!
It sounds to me like Music should be a part of Song, or the other way around. You can always use routes to disguise it as one or the other to the user.
song/index sounds to me like it should display all songs, which is all music does anyway.
My first thought is that we need to rethink this process. Assuming you're using RESTful controllers, it's unclear to me why you would need a Music controller and a Song controller... how are those resources different? The next relevant question would be, why is it not sufficient to show errors via Song#create ? I mean, they couldn't get it right when it was just a form, is the distraction of additional content likely to help? :)
With that said, here is a possible solution. (Given that you didn't paste your code, I'm making a lot of assumptions here.)
<hack>
first, extract the form parts from songs/new to songs/_form, then from the music/index view, render :partial => songs/_form, and in the songs controller, render :action => '../music/index' (this is called a hackity-hack.) Because it's a hack, you will almost certainly need to go into music#index and add #song = Song.new
</hack>
If you start running on edge, the ability to pass a flash through a redirect was just added...but that doesn't really get you there.
The simplest solution though, is that you need to render index, but set up all of the variables that are needed for that page. If you factor that out into a separate module or method, you can call it from both the index action and the save failure.
def index
setup_for_index
end
def create
#song = Song.new(params[:song])
#song.save
#...
#on failure
setup_for_index
render :controller => "music", :action => "index"
end
def setup_for_index
#songs = Song.all
#etc
end
The other thing you could do is use form_remote_for and have the song form just update the div on failure. Then use an RJS template return type reload the whole song list on success.
While I want to reiterate what others have stated about your resource architecture deserving a second look, you can certainly render views for other resources using the :template option:
render template: 'music/index'
Why not a simple if request.post? conditional in the index action's view rather than redirecting to another page?
You can also try using flash[:song_save_error] to pass the error conditions back to your Music controller.
http://api.rubyonrails.org/classes/ActionController/Flash.html
You could try render :file => ...