added element data retrieval end point and associated services

app/adapters/db_adapter.rb

@@ -200,6 +200,7 @@ class DbAdapter
 
   # create an array from string response
   def __parse_data(resp)
+    return [] if resp==nil #no data returned
     data = []
     add_break = false
     resp.split("\n").each do |row|
@@ -222,7 +223,7 @@ class DbAdapter
        data.push(nil) if(add_break)  #add a data break
        add_break = false
        #this is a normal row
-       data.push(words.map(&:to_i))
+       data.push(words.map(&:to_f))
     end
     data
   end

app/controllers/db_elements_controller.rb

+class DbElementsController < ApplicationController
+  before_action :authenticate_user!
+
+  def index
+    req_elements = DbElement.find(params[:elements])
+    #make sure the user is allowed to view these elements
+    req_elements.each do |elem|
+      unless current_user.views_nilm?(elem.db_stream.db.nilm)
+        head :unauthorized
+        return
+      end
+    end
+    #make sure the time range makes sense
+    @start_time = params[:start_time].to_i
+    @end_time = params[:end_time].to_i
+    unless @end_time>@start_time
+      head :unprocessable_entity
+      return
+    end
+    #retrieve the data for the requested elements
+    @service = LoadElementData.new
+    @service.run(req_elements, @start_time, @end_time)
+    render status: @service.success? ? :ok : :unprocessable_entity
+  end
+
+end

app/models/db_element.rb

@@ -25,6 +25,10 @@ class DbElement < ApplicationRecord
     self.offset = 0.0
   end
 
+  def name_path
+    "#{db_stream.name_path}/#{self.name}"
+  end
+
   def self.json_keys
     [:id, :name, :units, :column, :default_max, :discrete,
      :default_min, :scale_factor, :offset, :plottable]

app/models/db_folder.rb

@@ -27,6 +27,10 @@ class DbFolder < ApplicationRecord
     self.parent == nil
   end
 
+  def name_path
+    return "" if root_folder?
+    return "#{parent.name_path}/#{self.name}"
+  end
 
   def self.defined_attributes
     [:name, :description, :hidden]

app/models/db_stream.rb

@@ -32,6 +32,10 @@ class DbStream < ApplicationRecord
      [:name, :name_abbrev, :description, :hidden]
   end
 
+  def name_path
+    "#{db_folder.name_path}/#{self.name}"
+  end
+
   def remove(db_service:)
     db_service.remove_file(path)
     destroy

app/services/data/load_element_data.rb

+# frozen_string_literal: true
+
+# Loads data for specified elements
+class LoadElementData
+  include ServiceStatus
+  attr_reader :data
+
+  def initialize()
+    super()
+    @data = []
+  end
+
+  # load data for the array of specified elements
+  # sets data
+  # data:
+  #   [{id: element_id, values: [...]},
+  #    {id: element_id, values: [...]},...]
+  # see load_stream_data for details on the value structure
+  #
+  def run(elements, start_time, end_time)
+    #1 figure out what streams need to be pulled
+    req_streams = []
+    elements.each do |elem|
+      unless req_streams.include?(elem.db_stream)
+        req_streams << elem.db_stream
+      end
+    end
+    #2 pull data from streams
+    combined_data = []
+    req_streams.each do |stream|
+      adapter = DbAdapter.new(stream.db.url)
+      data_service = LoadStreamData.new(adapter)
+      data_service.run(stream, start_time, end_time)
+      if data_service.success?
+        combined_data.concat(data_service.data)
+      else
+        add_warning("unable to retrieve data for #{stream.name_path}")
+      end
+    end
+    #3 extract requested elements from the stream datasets
+    req_element_ids = elements.pluck(:id)
+    @data = combined_data.select{|d| req_element_ids.include? d[:id] }
+    return self
+    end
+  end

app/services/data/load_stream_data.rb

@@ -34,6 +34,8 @@ class LoadStreamData
       db_stream, valid_decim, start_time, end_time, resolution
     )
     if plottable_decim.nil?
+      #check if its nil becuase the nilm isn't available
+      return self unless self.success?
       # data is not sufficiently decimated, get intervals from
       # the valid decimation level (highest resolution)
       path = __build_path(db_stream, valid_decim.level)

app/services/service_status.rb

@@ -68,6 +68,12 @@ module ServiceStatus
     !errors?
   end
 
+  def reset_messages
+    @errors = []
+    @warnings = []
+    @notices = []
+  end
+
   def run
     raise 'Implement in client, return service object'
   end

app/services/stub_service.rb

@@ -5,4 +5,5 @@
 # run a service (eg a simple update)
 class StubService
   include ServiceStatus
+  attr_reader :data
 end

app/views/db_elements/index.json.jbuilder

+json.data do
+  json.array! @service.data.each do |element_data|
+    elem = DbElement.find(element_data[:id])
+    json.extract! elem, *DbElement.json_keys
+    json.path elem.name_path
+    json.data element_data[:values]
+    json.start_time @start_time
+    json.end_time @end_time
+  end
+end
+
+json.partial! "helpers/messages", service: @service

config/routes.rb

@@ -8,6 +8,7 @@ Rails.application.routes.draw do
   resources :dbs, only: [:show, :update]
   resources :db_folders, only: [:show, :update]
   resources :db_streams, only: [:update]
+  resources :db_elements, only: [:index]
 
   mount_devise_token_auth_for 'User', at: 'auth'
   resources :users, only: [:index, :create, :destroy]

spec/controllers/db_elements_controller_spec.rb

+require 'rails_helper'
+
+RSpec.describe DbElementsController, type: :request do
+  let(:user1) { create(:confirmed_user, first_name: 'John')}
+  let(:user2) { create(:confirmed_user, first_name: 'Sam')}
+  describe 'GET #index' do
+    #retrieve data for elements listed by array of ids
+    context 'with authenticated user' do
+      before do
+
+        nilm = create(:nilm, admins: [user1])
+        stream = create(:db_stream, elements_count: 0,
+                          db: nilm.db,
+                          db_folder: nilm.db.root_folder)
+        @elem1 = create(:db_element)
+        @elem2 = create(:db_element)
+        stream.db_elements << @elem1
+        stream.db_elements << @elem2
+
+        @service_data =  [{id: @elem1.id, data: 'mock1'},
+                          {id: @elem2.id, data: 'mock2'}]
+        @mock_service = instance_double(LoadElementData,
+          run: StubService.new,
+          success?: true, notices: [], warnings: [], errors: [],
+          data: @service_data)
+        allow(LoadElementData).to receive(:new).and_return(@mock_service)
+      end
+      it 'returns elements with data' do
+        @auth_headers = user1.create_new_auth_token
+        get "/db_elements.json",
+          params: {elements: [@elem1.id, @elem2.id],
+                   start_time: 0, end_time: 100},
+          headers: @auth_headers
+        expect(response).to have_http_status(:ok)
+        # check to make sure JSON renders the elements
+        body = JSON.parse(response.body)
+        expect(body['data'].count).to eq(2)
+      end
+      it 'returns error if time bounds are invalid' do
+        @auth_headers = user1.create_new_auth_token
+        get "/db_elements.json",
+          params: {elements: [@elem1.id, @elem2.id],
+                   start_time: 100, end_time: 0},
+          headers: @auth_headers
+        expect(response).to have_http_status(:unprocessable_entity)
+      end
+      it 'only allows access to permitted elements' do
+        nilm2 = create(:nilm, admins: [user2])
+        stream2 = create(:db_stream, elements_count: 0,
+                          db: nilm2.db,
+                          db_folder: nilm2.db.root_folder)
+        @elem3 = create(:db_element)
+        stream2.db_elements << @elem3
+
+        @auth_headers = user1.create_new_auth_token
+        get "/db_elements.json",
+          params: {elements: [@elem1.id, @elem3.id],
+                   start_time: 100, end_time: 0},
+          headers: @auth_headers
+        expect(response).to have_http_status(:unauthorized)
+
+      end
+    end
+    context 'without sign-in' do
+      it 'returns unauthorized' do
+        get "/db_elements.json"
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+  end
+end

spec/factories/db_element.rb

@@ -3,7 +3,7 @@
 # generic DbStream
 FactoryGirl.define do
   factory :db_element do
-    name { Faker::Lorem.unique.words(3) }
+    name { Faker::Lorem.unique.words(3).join(' ') }
     units 'volts'
     sequence(:column)
     default_max 100

spec/factories/db_stream.rb

@@ -3,7 +3,7 @@
 # generic DbStream
 FactoryGirl.define do
   factory :db_stream do
-    name { Faker::Lorem.words(3) }
+    name { Faker::Lorem.words(3).join(' ') }
     name_abbrev { Faker::Lorem.word }
     description { Faker::Lorem.sentence }
     delete_locked false

spec/factories/load_stream_data.rb

+class MockLoadStreamData
+  include ServiceStatus
+  attr_reader :data, :run_count
+
+  def initialize(dataset)
+    super()
+    @dataset = dataset
+    @data = nil
+    @run_count = 0
+  end
+  def run(db_stream, start_time, end_time)
+    @data = @dataset.select{|d| d[:stream]==db_stream}.first[:data]
+    @run_count += 1
+    if(@data == nil)
+      self.add_error('could not retrieve stream data')
+      return nil
+    else
+      self.reset_messages
+    end
+    return self
+  end
+end

spec/services/data/load_element_data_spec.rb

+# frozen_string_literal: true
+require 'rails_helper'
+
+RSpec.describe 'LoadElementData' do
+  let(:db) { create(:db, max_points_per_plot: 100) }
+
+  describe 'when elements are from the same stream' do
+    before do
+      db  = create(:db, url: 'http://test/nilmdb')
+      @db_stream = create(:db_stream, db: db, elements_count: 0)
+      @elem0 = create(:db_element, column: 0, db_stream: @db_stream)
+      @elem1 = create(:db_element, column: 1, db_stream: @db_stream)
+      @elem2 = create(:db_element, column: 2, db_stream: @db_stream)
+      @stream_data = [{id: @elem0.id, values: 'mock0'},
+                      {id: @elem1.id, values: 'mock1'},
+                      {id: @elem2.id, values: 'mock2'}]
+      @mock_stream_service = MockLoadStreamData.new(
+        [stream: @db_stream, data: @stream_data])
+      allow(LoadStreamData).to receive(:new).and_return(@mock_stream_service)
+    end
+    it 'makes one request for the stream data' do
+      expect(@mock_stream_service).to receive(:data).and_return(@stream_data)
+      service = LoadElementData.new
+      service.run([@elem0,@elem2],0,100)
+      expect(service.success?).to be true
+      expect(service.data).to eq [
+        {id: @elem0.id, values: 'mock0'},
+        {id: @elem2.id, values: 'mock2'}
+      ]
+    end
+  end
+
+  describe 'when elements are from different streams' do
+    before do
+      db  = create(:db, url: 'http://test/nilmdb')
+      @db_stream1 = create(:db_stream, db: db, elements_count: 0)
+      @elem0 = create(:db_element, column: 0, db_stream: @db_stream1)
+      @elem1 = create(:db_element, column: 1, db_stream: @db_stream1)
+      @stream1_data = [{id: @elem0.id, values: 'mock0'},
+                       {id: @elem1.id, values: 'mock1'}]
+      @db_stream2 = create(:db_stream, db: db, elements_count: 0)
+      @elem2 = create(:db_element, column: 2, db_stream: @db_stream2)
+      @elem3 = create(:db_element, column: 3, db_stream: @db_stream2)
+      @stream2_data = [{id: @elem2.id, values: 'mock2'},
+                       {id: @elem3.id, values: 'mock3'}]
+      @mock_stream_service = MockLoadStreamData.new(
+        [{stream: @db_stream1, data: @stream1_data},
+         {stream: @db_stream2, data: @stream2_data}])
+      allow(LoadStreamData).to receive(:new).and_return(@mock_stream_service)
+
+    end
+    it 'makes one request per stream' do
+      service = LoadElementData.new
+      service.run([@elem0, @elem3],0,100)
+      expect(service.success?).to be true
+      expect(service.data).to eq [
+        {id: @elem0.id, values: 'mock0'},
+        {id: @elem3.id, values: 'mock3'}
+      ]
+      expect(@mock_stream_service.run_count).to eq 2
+    end
+  end
+
+  describe 'when a nilm does not respond' do
+    before do
+      db  = create(:db, url: 'http://test/nilmdb')
+      @db_stream1 = create(:db_stream, db: db, elements_count: 0)
+      @elem0 = create(:db_element, column: 0, db_stream: @db_stream1)
+      @elem1 = create(:db_element, column: 1, db_stream: @db_stream1)
+      @stream1_data = [{id: @elem0.id, values: 'mock0'},
+                       {id: @elem1.id, values: 'mock1'}]
+      @db_stream2 = create(:db_stream, db: db, elements_count: 0)
+      @elem2 = create(:db_element, column: 2, db_stream: @db_stream2)
+      @elem3 = create(:db_element, column: 3, db_stream: @db_stream2)
+      @stream2_data = [{id: @elem2.id, values: 'mock2'},
+                       {id: @elem3.id, values: 'mock3'}]
+      @mock_stream_service = MockLoadStreamData.new(
+        [{stream: @db_stream1, data: @stream1_data},
+         {stream: @db_stream2, data: nil}])
+      allow(LoadStreamData).to receive(:new).and_return(@mock_stream_service)
+    end
+    it 'fills in the data that is available' do
+      service = LoadElementData.new
+      service.run([@elem0, @elem3],0,100)
+      expect(service.warnings.length).to eq 1
+      expect(service.data).to eq [
+        {id: @elem0.id, values: 'mock0'}
+      ]
+      expect(@mock_stream_service.run_count).to eq 2
+    end
+  end
+end