Rails nested resources - ruby-on-rails

I'm trying to get my head around nested associations in Rails using ActiveResource.
My example is as follows:
What I have is an airport with many runways.
My show action in airports controller contains:
#airport = Airport.find(params[:id])
When I call http://localhost/airports/2.xml I get that piece of XML:
<airport>
<code>DUS</code>
<created-at type="datetime">2009-02-12T09:39:22Z</created-at>
<id type="integer">2</id>
<name>Duesseldorf</name>
<updated-at type="datetime">2009-02-12T09:39:22Z</updated-at>
</airport>
Now, I changed the action to
#airport = Airport.find(params[:id], :include => :runways)
How can I achieve that above loading above URL is giving me something like:
<airport>
<code>FRA</code>
<created-at type="datetime">2009-02-12T09:39:22Z</created-at>
<id type="integer">2</id>
<name>Frankfurt</name>
<updated-at type="datetime">2009-02-12T09:39:22Z</updated-at>
<runways>
<runway>
<id>1</id>
<name>bumpy runway</name>
</runway>
</runways>
</airport>
And on top of that: If I have a client with
class Airport < ActiveResource::Base
..
end
and
class Runway < ActiveResource::Base
..
end
How can I get it to automatically load associations like:
a = Airport.find(1)
puts a.runways.length
=> 1
And (last but not least): Is there a way to store data from the client like:
a = Airport.find(1)
a.runways << Runway.find(1)
a.save
Maybe I'm really too blind, but I'm stuck...
Any idea is warmly welcome.
Thanks
Matt

Resolved it myself finally.
Wasn't aware to put the include into the render statememt:
def show
#airport = Airport.find(params[:id], :include => :runways)
respond_to do |format|
format.html # show.html.erb
format.xml { render :xml => #airport.to_xml(:include => :runways) }
end
end

The :include option for the finder specifies that it should eagerly fetch the related items from the database. The :include option for to_xml specifies that it should be included in the XML rendering.
If the canonical XML representation includes the related objects, you can override the to_xml method to make your life a little simpler:
class Airport
def to_xml(options={})
super(options.merge(:include => :runways))
end
end
and then since render will call to_xml if you don't, your controller code can simply be
format.xml { render :xml => #airport }

Related

Expiration of controller action from Sweeper does not work

Having a controller handling rendering of large XML feeds
module Spree
class FeedsController < Spree::StoreController
...
caches_action :products_out
cache_sweeper FeedSweeper
# XML feed in format of `xxxxxxx.com'
def products_out
#products = Product.all
respond_to do |format|
format.xml
end
end
end
Bellow is the corresponding sweeper's sublass:
module Spree
class FeedSweeper< ActionController::Caching::Sweeper
observe Product
def after_update(product)
# cache_configured? is nil, #controller is nil here, why ?
expire_action(:controller => :feeds,
:action => :products_out,
:format => :xml)
end
end
Above Spree::FeedSweeper is called when Spree::Product gets updated, however it seems expire_action silently dies and cache won't get invalidated.
Can somebody explain the issue ? Even better suggest some solution ?
Thanks.
Which Rails version are you using? expire_action seems to be deprecated after Rails 3.2.14.
Maybe you can try to find out the key then directly clear it with Rails.cache.delete(key).

Including acts_as_taggable_on tags in to_json output of a model

I'm using acts_as_taggable_on in my rails app. I'd like these tags to show up in the to_json representation of my model.
For example, to_json of one instance of my model looks like this:
{"created_at":"2012-02-19T03:28:26Z",
"description":"Please!",
"id":7,
"points":50,
"title":"Retweet this message to your 500+ followers",
"updated_at":"2012-02-19T03:28:26Z"}
...and I'd like it to look something like this:
{"created_at":"2012-02-19T03:28:26Z",
"description":"Please!",
"id":7,
"points":50,
"title":"Retweet this message to your 500+ followers",
"updated_at":"2012-02-19T03:28:26Z"
"tags" :
{"id":1,
"name":"retweet"},
{"id":2,
"name":"twitter"},
{"id":3,
"name":"social"}
}
My controller code is just the default that scaffolding gives me:
def show
#favor = Favor.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.json { render json: #favor }
end
end
Note that I can already access #favor.tags in the template, and #favor.tags.to_json works as expected, I just needed that data to be included when outputting #favor.to_json.
You can pass options to the json call by calling to_json. Or by redefining as_json in your favor model.
render json: #favor.to_json(include: :tags)
In your favor model override as_json method.
def as_json(options={})
super(:include => :tags)
end

Accessing virtual attribute from JSON

My setup: Rails 2.3.10, Ruby 1.8.7
I have experimented, without success, with trying to access a virtual attribute in a model from a JSON call. Let's say I have the following models and controller code
class Product
name,
description,
price,
attr_accessor :discounted_price
end
class Price
discount
end
class ProductsController
def show
#product = Product.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.json { render :json => #product }
end
end
end
What I like is to have the JSON output also include Product.discounted_price which is calculated in real-time for each call, ie discounted_price = Price.discount * Product.price. Is there a way to accomplish this?
SOLUTION:
With the initial help from dmarkow, I figured it out, my actual scenario is more complex than the above example. I can do something like this, in the Product model, add a getter method
def discounted_price
...# do the calculation here
end
In the JSON call do this
store = Store.find(1)
store.as_json(:include => :products, :methods => :discounted_price)
You can run to_json with a :methods parameter to include the result of those method(s).
render :json => #product.to_json(:methods => :discounted_price)
Have a look at the gem RABL, as shown in this railscast:
http://railscasts.com/episodes/322-rabl?view=asciicast
RABL gives you fine grained control of the json you produce, including collections and children.

rails - to_xml placing values in xml attributes not tags

Suppose I have a controller method like so...
def index
#burried_treasures = BurriedTreasure.all
render :xml => #burried_treasure
end
Right now it places all values in tags such as:
<burried_treasure>
<name>Red Beard</name>
</burried_treasure>
I would like it to use attributes like this:
<burried_treasure name="Red Beard">
Does anyone know how to accomplish this?
You will have to override your models to_xml method
class BurriedTreasure < ActiveRecord::Base
def to_xml(options = {})
options[:indent] ||= 2
xml = options[:builder] ||= Builder::XmlMarkup.new(:indent => options[:indent])
xml.instruct! unless options[:skip_instruct]
xml.buried_treasure('name' => self.name)
xml.some_nodes do |some_node|
some_node.some_level2_node "some_level_2_node_content"
end
end
end
See more info on Builder::XmlMarkup usage at http://ap.rubyonrails.org/classes/Builder/XmlMarkup.html

How to render sitemap.xml in rails app

I have added /views/sitemap/index.xml and want it displayed when i go to the relevant url.
class SitemapController < ApplicationController
def index
respond_to do |format|
format.html
format.xml
end
end
end
And in routes.rb
match "sitemap/" => "sitemap#index"
Using Rails 3
When I go to mydomain.com/sitemap/ I just get a white page. Any ideas?
index.xml
<?xml version="1.0" encoding="UTF-8"?>
<urlset
xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9
http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd">
<url>
<loc>http://www.mydomain.com/</loc>
<changefreq>weekly</changefreq>
</url>
</urlset>
Problem is that you are using your index action to render xml and it will render "index.xml"
file not "sitemap.xml" which is what you have created in your views
While your routes are correct, you are using the wrong filename in views
Try renaming sitemap.xml file to index.xml ( in the views/sitemap folder)
If you define name routes, you need to define :format with it
match "/sitemap/sitemap.[:format]", :to => "sitemap#index"
it will pickup your format from there. Also you can define a default format in the routes
match "sitemap/sitemap.xml", :to => "sitemap#index", :defaults => {:format => :xml}
I may be wrong , but I see 2 reasons:
index action doesn't actually do anything judging by this code sample, it just responds back with no info.
you need to render your object as xml - if you don't rails, doesn't know you want xml - it just treats it as another file extension. It actually lets you do little tricks - like sending json to an xml request ( thou I have no idea why would anyone try to do that). Thou one useful application is that you can make rails send custom rendering of an object to a common format or render regular data in common format for an unusual extension ( we had a client who wanted csv data for a .dat request)
Here is a short example, from a sample home controller:
class HomeController < ApplicationController
def index
#m = {
:color => "yellow",
:total => "20"
}
respond_to do |format|
format.html # index.html.erb
format.xml { render :xml => #m}
end
end
end
this returns this object as xml:
<hash>
<total>20</total>
<color>yellow</color>
</hash>

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