Merge pull request #375 from alphagov/add-constituency-to-api

Add constituency/country signature counts to API

Author: alanth

app/controllers/admin/petitions_controller.rb

@@ -42,13 +42,11 @@ def render_csv
     self.response_body = PetitionsCSVPresenter.new(@petitions).render
   end
 
-
   def set_file_headers
     headers["Content-Type"] = "text/csv"
-    headers["Content-disposition"] = "attachment; filename=petitions.csv"
+    headers["Content-disposition"] = "attachment; filename=#{csv_filename}"
   end
 
-
   def set_streaming_headers
     #nginx doc: Setting this to "no" will allow unbuffered responses suitable for Comet and HTTP streaming applications
     headers['X-Accel-Buffering'] = 'no'
@@ -57,6 +55,9 @@ def set_streaming_headers
     headers.delete("Content-Length")
   end
 
+  def csv_filename
+    "#{@petitions.scope.to_s.dasherize}-petitions-#{Time.current.to_s(:number)}.csv"
+  end
 
   def filter_by_tag?
     params[:t].present? && !(filter_by_state? || filter_by_keyword?)

app/controllers/local_petitions_controller.rb

@@ -3,11 +3,16 @@
 class LocalPetitionsController < ApplicationController
   respond_to :html
 
-  before_action :sanitize_postcode
-  before_action :find_constituency, if: :postcode?
-  before_action :find_petitions, if: :constituency?
+  before_action :sanitize_postcode, only: :index
+  before_action :find_by_postcode, if: :postcode?, only: :index
+  before_action :find_by_slug, only: :show
+  before_action :find_petitions, if: :constituency?, only: :show
+  before_action :redirect_to_constituency, if: :constituency?, only: :index
 
   def index
+  end
+
+  def show
     respond_with(@petitions)
   end
 
@@ -21,15 +26,23 @@ def postcode?
     @postcode.present?
   end
 
-  def find_constituency
-    @constituency = ConstituencyApi.constituency(@postcode)
+  def find_by_postcode
+    @constituency = Constituency.find_by_postcode(@postcode)
+  end
+
+  def find_by_slug
+    @constituency = Constituency.find_by_slug!(params[:id])
   end
 
   def constituency?
     @constituency.present?
   end
 
   def find_petitions
-    @petitions = Petition.popular_in_constituency(@constituency.id, 50)
+    @petitions = Petition.popular_in_constituency(@constituency.external_id, 50)
+  end
+
+  def redirect_to_constituency
+    redirect_to local_petition_url(@constituency.slug)
   end
 end

app/helpers/page_title_helper.rb

@@ -43,9 +43,9 @@ def options
         opts[:postcode]     = formatted_postcode if postcode?
 
         if postcode?
-          opts[:count] = constituency? ? 1 : 0
+          opts[:count] = 1
         else
-          opts[:count] = -1
+          opts[:count] = 0
         end
 
         if petition?

app/lib/constituency_api.rb

@@ -0,0 +1,45 @@
+require_dependency 'constituency/api_client'
+require_dependency 'constituency/api_query'
+
+class Constituency < ActiveRecord::Base
+  MP_URL = "http://www.parliament.uk/biographies/commons"
+
+  has_many :signatures, primary_key: :external_id
+  has_many :petitions, through: :signatures
+
+  validates :name, presence: true, length: { maximum: 100 }
+  validates :external_id, presence: true, length: { maximum: 30 }
+  validates :ons_code, presence: true, format: %r[\A(?:E|W|S|N)\d{8}\z]
+  validates :mp_id, length: { maximum: 30 }
+  validates :mp_name, length: { maximum: 100 }
+
+  before_validation if: :name_changed? do
+    self.slug = name.parameterize
+  end
+
+  class << self
+    def find_by_postcode(postcode)
+      results = query.fetch(postcode)
+
+      if attributes = results.first
+        find_or_initialize_by(external_id: attributes[:external_id]) do |constituency|
+          constituency.attributes = attributes
+
+          if constituency.changed? || constituency.new_record?
+            constituency.save!
+          end
+        end
+      end
+    end
+
+    private
+
+    def query
+      ApiQuery.new
+    end
+  end
+
+  def mp_url
+    "#{MP_URL}/#{mp_name.parameterize}/#{mp_id}"
+  end
+end

app/models/constituency.rb

@@ -0,0 +1,39 @@
+require 'faraday'
+require 'postcode_sanitizer'
+
+class Constituency < ActiveRecord::Base
+  class ApiClient
+    HOST = 'http://data.parliament.uk'
+    ENDPOINT = '/membersdataplatform/services/mnis/Constituencies/%{postcode}/'
+    TIMEOUT = 5
+
+    def call(postcode)
+      faraday.get(path(postcode)) do |request|
+        request.options[:timeout] = TIMEOUT
+        request.options[:open_timeout] = TIMEOUT
+      end
+    end
+
+    private
+
+    def faraday
+      @faraday ||= Faraday.new(HOST) do |f|
+        f.response :follow_redirects
+        f.response :raise_error
+        f.adapter Faraday.default_adapter
+      end
+    end
+
+    def path(postcode)
+      ENDPOINT % { postcode: escape_path(postcode) }
+    end
+
+    def escape_path(value)
+      Rack::Utils.escape_path(sanitize(value))
+    end
+
+    def sanitize(value)
+      PostcodeSanitizer.call(value)
+    end
+  end
+end

app/models/constituency/api_client.rb

@@ -0,0 +1,54 @@
+require 'nokogiri'
+
+class Constituency < ActiveRecord::Base
+  class ApiQuery
+    CONSTITUENCIES    = '//Constituencies/Constituency'
+    CONSTITUENCY_ID   = './Constituency_Id'
+    CONSTITUENCY_NAME = './Name'
+    CONSTITUENCY_CODE = './ONSCode'
+
+    CURRENT_MP = './RepresentingMembers/RepresentingMember[1]'
+    MP_ID      = './Member_Id'
+    MP_NAME    = './Member'
+    MP_DATE    = './StartDate'
+
+    def fetch(postcode)
+      response = client.call(postcode)
+
+      if response.success?
+        parse(response.body)
+      else
+        []
+      end
+    rescue Faraday::ResourceNotFound, Faraday::ClientError => e
+      return []
+    rescue Faraday::Error => e
+      Appsignal.send_exception(e) if defined?(Appsignal)
+      return []
+    end
+
+    private
+
+    def client
+      @client ||= ApiClient.new
+    end
+
+    def parse(body)
+      xml = Nokogiri::XML(body)
+
+      xml.xpath(CONSTITUENCIES).map do |node|
+        {}.tap do |attrs|
+          attrs[:name]        = node.xpath(CONSTITUENCY_NAME).text
+          attrs[:external_id] = node.xpath(CONSTITUENCY_ID).text
+          attrs[:ons_code]    = node.xpath(CONSTITUENCY_CODE).text
+
+          if mp = node.at_xpath(CURRENT_MP)
+            attrs[:mp_id] = mp.xpath(MP_ID).text
+            attrs[:mp_name] = mp.xpath(MP_NAME).text
+            attrs[:mp_date] = mp.xpath(MP_DATE).text
+          end
+        end
+      end
+    end
+  end
+end

app/models/constituency/api_query.rb

@@ -1,11 +1,14 @@
 class ConstituencyPetitionJournal < ActiveRecord::Base
   belongs_to :petition
+  belongs_to :constituency, primary_key: :external_id
 
   validates :petition, presence: true
   validates :constituency_id, presence: true, length: { maximum: 255 }
   validates :constituency_id, uniqueness: { scope: [:petition_id] }
   validates :signature_count, presence: true
 
+  delegate :name, :ons_code, :mp_name, to: :constituency
+
   scope :ordered, -> {
     order("#{table_name}.signature_count DESC")
   }