activeresource response

ActiveResource-Response

This gem adds the ability to access the HTTP response (Net::HTTPResponse) object from the result (either a single object or a collection) of an ActiveResource call (methods: find, all, first, last, get).

Why Can It Be Used?

This functionality can be used to easily implement pagination in a REST API, so that an ActiveResource client can navigate paginated results.

How to Use?

Add the dependency to your Gemfile:

gem "activeresource-response"

Open your ActiveResource class and add:

add_response_method :your_method_name

You can add the method to ActiveResource::Base to use it in all subclasses:

class ActiveResource::Base
  add_response_method :my_response  
end

You can remove the method from an ActiveResource subclass:

class Order < ActiveResource::Base
  remove_response_method  
end

Full Example of Usage with the Kaminari Gem

ActiveResource Class:

class Order < ActiveResource::Base
  self.format = :json
  self.site = 'http://0.0.0.0:3000/'
  self.element_name = "order" 
  add_response_method :http_response  # Our new method for returned objects
end

Server Side:

class OrdersController < ApplicationController
  def index
    @orders = Order.page(params[:page]).per(params[:per_page] || 10) # default 10 per page
    response.headers["X-total"] = @orders.total_count.to_s
    response.headers["X-offset"] = @orders.offset_value.to_s
    response.headers["X-limit"] = @orders.limit_value.to_s
    respond_with(@orders)
  end
end

Client Side:

class OrdersController < ApplicationController
  def index
    orders = Order.all(params: params)     
    @orders = Kaminari::PaginatableArray.new(orders, {
      limit: orders.http_response['X-limit'].to_i,
      offset: orders.http_response['X-offset'].to_i,
      total_count: orders.http_response['X-total'].to_i
    }) 
  end
end

Will_paginate Compatibility

will_paginate has a slightly different API, so to populate the headers:

response.headers["X-total"] = @orders.total_entries.to_s
response.headers["X-offset"] = @orders.offset.to_s
response.headers["X-limit"] = @orders.per_page.to_s

On the API client side, you might also use will_paginate. In that case, you can just require will_paginate/array (e.g., in an initializer):

orders = Order.all(params: params)     
@orders = WillPaginate::Collection.create(params[:page] || 1, params[:per_page] || 10, orders.http_response['X-total'].to_i) do |pager|
  pager.replace orders
end

Every Time an HTTP Connection is Invoked

The ActiveResource connection object stores the HTTP response. You can access it with the http_response method.

Example:

class Order < ActiveResource::Base
  self.site = 'http://0.0.0.0:3000/'
  self.element_name = "order" 
  add_response_method :my_response  # Our new method 
end

orders = Order.all
first_order = Order.find(1) 
# See Net::HTTPResponse#[] method
orders.my_response['content-length'] 
# => "3831" 
first_order.my_response['content-length'] 
# => "260"
# Connection also always has the last HTTP response object. To access it, use the http_response method:
Order.connection.http_response.to_hash
# => {"content-type"=>["application/json; charset=utf-8"], "x-ua-compatible"=>["IE=Edge"], "etag"=>["\"573cabd02b2f1f90405f7f4f77995fab\""], "cache-control"=>["max-age=0, private, must-revalidate"], "x-request-id"=>["2911c13a0c781044c474450ed789613d"], "x-runtime"=>["0.071018"], "content-length"=>["260"], "server"=>["WEBrick/1.3.1 (Ruby/1.9.2/2011-02-18)"], "date"=>["Sun, 19 Feb 2012 10:21:29 GMT"], "connection"=>["close"]} 

Custom get Method

You can access the response from the result of a custom get method.

Example:

class Country < ActiveResource::Base
  self.site = 'http://0.0.0.0:3000/'
  add_response_method :http  # Our new method
end

cities = Country.find(1).get(:cities)
cities.http  # Method from the Country class is available

Headers and Cookies Methods

You can get cookies and headers from the response.

Example:

class Country < ActiveResource::Base
  self.site = 'http://0.0.0.0:3000/'
  add_response_method :my_response  # Our new method
end

countries = Country.all
countries.my_response.headers

# Collection with symbolized keys:
# {:content_type=>["application/json; charset=utf-8"], :x_ua_compatible=>["IE=Edge"], ..., :set_cookie=>["bar=foo; path=/", "foo=bar; path=/"]}

countries.my_response.cookies
# => {"bar"=>"foo", "foo"=>"bar"}   

Note About HTTP Response

The HTTP response is an object of Net::HTTPOK, Net::HTTPClientError, or one of the other subclasses of the Net::HTTPResponse class. For more information, see the documentation: Net::HTTPResponse.

Testing with ActiveResource::HttpMock

Add this line to your test to patch http_mock:

require "active_resource_response/http_mock"

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Please feel free to contact me if you have any questions:

fedoronchuk(at)gmail.com