I think this is a pretty simple question but nothing I've read has answered my question directly:
I have a new products page with a standard form. After successfully submitting the form, I redirect to a custom controller action and view called "thanks".
On the "thanks" page, I want to be able to print the name of the product just created and possibly some other attributes.
How do I pass the object just created into my new action? Right now the controller looks like this:
def create
#product = Product.new(params[:product])
if #product.save
flash[:notice] = "Successfully created Product."
redirect_to thanks_path
else
render :action => 'new'
end
end
def thanks
end
You can't send object through redirect.
There are three ways to solve your problem:
Render the 'thanks' template directly(not action #thanks)
render 'thanks' # thanks template
You can send whatever instance variable to this template directly. #thanks is no longer needed in this case.
Drawback: The url won't be changed.
Convey messages through session
If you want to show certain messages, you can prepare it in #create and send it through session or flash(part of session actually). flash is better as you don't need to clear it manually.
Note: You may want to use ActiveRecord as session storage if the message size is big, otherwise you'll meet CookiesOverflow by default setting.
Send very simple message through session say obj_id
Similar to #2 but I thinks this is better than #2. In #thanks, you can construct complex message according to if obj_id is present, what is the id and then find related data through db.
You have two fairly decent options.
First, you could adjust the thanks_path route to take an id parameter, and call it like redirect_to thanks_path(#product). Then you can call it up in your thank you method like any standard show method. It might be worth mentioning that if you are going to be displaying sensitive information on the thank you screen, you may want to use a random uuid, instead of an id, to look up the product.
A better way might be to not redirect at all, but rather adjust your view from simply drawing the form to something like this:
<% if #product && !#product.new_record %>
THANK YOU MESSAGE GOES HERE
<% else %>
EXISTING FORM GOES HERE
<% end %>
I am learning RoR, and I have a general design issue that I'm trying to work around. I want to get some input on the answer to make sure I follow some kind of best practice.
I have a page that's made up of 3 subsections, let's call them A, B, and C. Certain actions cause each of these to refresh via AJAX, so I want to have them each have a controller action that allows any of them to render individually, without the page chrome.
The way I've structured this right now is with a controller that has 4 actions: index, A, B, C
Each of A, B, and C renders its view with layout=>false so I can render just that piece via AJAX when needed. Then, you have index, which renders some extra stuff along with the view of A, B, and C.
Esentially what I want here are 3 subcontrollers, and a master controller that invokes the subcontrollers as needed. Or I think that is what I want. What I think I don't want is partial views, because there is some setup I do in the controller for each of A,B,C and I would then have to duplicate the setup code in both the controller for index and the controller for A,B,C.
The code I have in mind is something like this:
my_controller.rb:
class MyController < ApplicationController
def index
#aOutput = A
#bOutput = B
#cOutput = C
render //can use #aOutput, #bOutput, #cOutput in the view
end
def A
render :layout => false
end
def B
render :layout => false
end
def C
render :layout => false
end
end
This would enable me to now access MyController#index when I want the full page, and MyController#A, etc when I want to re-render the contents of each subsection.
The problem here is if the code is structured like this, you will run into DoubleRender errors when accessing MyController#index. What is the correct way to approach this kind of thing? Feel free to blow up any assumptions I made here, with the only requirement being a page that has three sections that can update individually as needed without reloading the whole page.
I am not sure if I understand the problem clearly but I think here is what I think your problem is.
You want to be able to render only a view without invoking controller action entire.
This can be done by using render :action => :action_name
You want to render some text only for ajax calls
Use respond_to block in order to achieve this. For example.
def whatever_action
.... # Your action voodoo here
respond_to do |format|
format.html { ... } # If it a normal HTTP request
format.js {...} # If it's an ajax or JSON request
end
end
The design that you are proposing has basic flaws like non-adherence to some of the SOLID design principles. I strongly recommend reading a good book on basics of rails.
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.
I'm not sure if I'm missing a known design pattern, but I keep coming up against the following problem with RESTful routes Rails.
In my example, I have a users controller that can respond in javascript (:js) format. The default response populates a page element with a list of the paginated users:
# /app/controllers/users_controller.rb
class UsersController < ActionController
def index
#users = User.paginate(:all, :page => params[:page], :conditions => ['name ILIKE ?', params[:name])
respond_to do |format|
format.html
format.js
end
end
end
The corresponding RJS template would look like:
# /app/views/users/index.js.rjs
page.replace_html :users, :partial => 'users'
This works fine, allowing me to perform AJAX lookups on users. However, in another part of my site (say the user editing form) I would like to perform an AJAX lookup of users, but update a set of ''select'' options or perform an inline autocomplete, rather than update the #users page element, e.g.
# /app/views/users/edit.html.erb
<%= f.text_field :name %>
$('#user_name').autocomplete({url: '/users', data: 'name=value', ...})
My question is what would be the best DRY way to achieve this? I don't think I should need to create a new controller action to correspond to the different view, as this would involve repeating the finder code. The only solution I've come across so far is to build some javascript conditions into my RJS helper:
# /app/views/users/index.js.rjs
page << "if($('#users').length > 0)"
page.replace_html :users, :partial => 'users'
page << "else"
page.replace_html :user_options, :partial => 'user_options_for_select'
This feels very brittle, and unclean for Rails. Am I missing something in how I can respond with different views depending on the calling controller?
Appreciate any help!
Chris
In one of them you have a list of users and the other one a list of options.
So even though for now, your two pages are having the same feature, they're independent from each other and you might want to change things for only one of them in the future.
So I'd keep them distinct with two different javascript actions . It'll will allow you to much more easily make them evoluate on their different path.
Anyway as you can see, they're already quite different. You have two different partials and two different html tags id.
Trying to have the same code for them both here seems quite confusing to me.
So yes I'd create two actions, one for the users list and one for their options.