Merge pull request #16 from marnen/3-cache-api-data

Cache API data [closes #3]

.travis.yml

@@ -1,4 +1,9 @@
 language: ruby
+services:
+  - redis-server
+env:
+  global:
+    - REDIS_URL: "redis://localhost:6379"
 cache:
   bundler: true
   directories:

Gemfile

@@ -24,7 +24,8 @@ gem 'jbuilder', '~> 2.7'
 gem 'bootsnap', '>= 1.4.2', require: false
 
 gem "haml-rails", "~> 2.0"
-gem 'faraday', '~> 1.0.1'
+gem 'redis'
+gem 'typhoeus'
 
 group :development, :test do
   # Call 'byebug' anywhere in the code to stop execution and get a debugger console

Gemfile.lock

@@ -111,10 +111,10 @@ GEM
     diff-lcs (1.3)
     erubi (1.9.0)
     erubis (2.7.0)
+    ethon (0.12.0)
+      ffi (>= 1.3.0)
     faker (2.11.0)
       i18n (>= 1.6, < 2)
-    faraday (1.0.1)
-      multipart-post (>= 1.2, < 3)
     ffi (1.12.2)
     formatador (0.2.5)
     gherkin (5.1.0)
@@ -176,7 +176,6 @@ GEM
     msgpack (1.3.3)
     multi_json (1.14.1)
     multi_test (0.1.2)
-    multipart-post (2.1.1)
     nenv (0.3.0)
     nio4r (2.5.2)
     nokogiri (1.10.9)
@@ -225,6 +224,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
+    redis (4.1.3)
     regexp_parser (1.7.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
@@ -281,6 +281,8 @@ GEM
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
+    typhoeus (1.3.1)
+      ethon (>= 0.9.0)
     tzinfo (1.2.7)
       thread_safe (~> 0.1)
     vcr (5.1.0)
@@ -312,19 +314,20 @@ DEPENDENCIES
   byebug
   cucumber-rails
   faker
-  faraday (~> 1.0.1)
   guard-cucumber!
   guard-rspec
   haml-rails (~> 2.0)
   jbuilder (~> 2.7)
   listen (>= 3.0.5, < 3.2)
   puma (~> 4.1)
   rails (~> 6.0.2, >= 6.0.2.2)
+  redis
   rspec-rails (~> 4.0.0)
   sass-rails (>= 6)
   spring
   spring-watcher-listen (~> 2.0.0)
   turbolinks (~> 5)
+  typhoeus
   tzinfo-data
   vcr (~> 5.1.0)
   web-console (>= 3.3.0)

app/models/chart.rb

@@ -22,7 +22,7 @@ def url
       params = {
         cht: chart_type, chd: "a:#{data.join ','}", chs: size, chxt: axes, chxl: "0:#{axis_labels.map {|label| label.prepend '|' }.join }", chdl: @legend, chdlp: position, chls: line_thickness
       }
-      url.query = Faraday::Utils.build_query params
+      url.query = URI.encode_www_form params
     end
   end
 

app/models/state_daily.rb

@@ -5,20 +5,14 @@ def initialize(state:, date:)
   end
 
   def url
-    @url ||= if date_range?
-      individuals.map &:url
-    else
-      URI('https://covidtracking.com/api/states/daily').tap do |url|
-        url.query = Faraday::Utils.build_query state: @state, date: @date.to_s(:number)
-      end
-    end
+    @url ||= date_range? ? individuals.map(&:url) : request.url
   end
 
   def fetch!
     if date_range?
       individuals.map(&:fetch!).reject {|response| response['date'].nil? }
     else
-      JSON.parse Faraday.get(url).body
+      JSON.parse request.run.body
     end
   end
 
@@ -31,4 +25,8 @@ def date_range?
   def individuals
     @individuals ||= @date.map {|date| self.class.new state: @state, date: date }
   end
+
+  def request
+    @request ||= Typhoeus::Request.new('https://covidtracking.com/api/states/daily', params: {state: @state, date: @date.to_s(:number)}, cache_ttl: 6.hours.to_i)
+  end
 end

config/initializers/typhoeus_cache.rb

@@ -0,0 +1,5 @@
+require 'addressable'
+db = Rails.env.test? ? 1 : 0
+redis = Redis.new url: "#{ENV['REDIS_URL']}/#{db}"
+redis.flushdb if Rails.env.test?
+Typhoeus::Config.cache = Typhoeus::Cache::Redis.new(redis)

docker-compose.yml

@@ -6,6 +6,7 @@ services:
   web:
     environment:
       PORT: 3000
+      REDIS_URL: "redis://cache:6379"
     build: .
     command: bundle exec rails s
     volumes:
@@ -14,5 +15,9 @@ services:
     ports: ["3000:3000"]
     networks: [internal]
     command: ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]
+  cache:
+    image: redis:5.0.8-alpine
+    expose: ["6379"]
+    networks: [internal]
 volumes:
   bundle: # see https://dev.to/k_penguin_sato/cache-rails-gems-using-docker-compose-3o3f

features/step_definitions/web_steps.rb

@@ -8,7 +8,7 @@
   date_range = start_date..end_date
 
   page.find 'img[src^="https://image-charts.com/chart?"]' do |img|
-    params = Faraday::Utils.parse_query URI(img['src']).query
+    params = Hash[URI.decode_www_form URI(img['src']).query]
     expect(params).to include(
       'cht' => 'lc', # line chart
       'chd' => a_string_starting_with('a:'), # data

spec/models/chart_spec.rb

@@ -20,7 +20,7 @@
     end
 
     describe '#url' do
-      let(:params) { Faraday::Utils.parse_query subject.query }
+      let(:params) { Hash[URI.decode_www_form URI(subject).query] }
 
       subject { chart.url }
 

spec/models/state_daily_spec.rb

@@ -27,14 +27,14 @@
       subject { super().url }
 
       context 'single date' do
-        it { is_expected.to be_a_kind_of URI }
+        it { is_expected.to be_a_kind_of String }
 
         it 'points to the state daily data endpoint' do
-          expect(subject.to_s).to match %r{^https://covidtracking.com/api/states/daily\b([^/]|$)}
+          expect(subject).to match %r{^https://covidtracking.com/api/states/daily\b([^/]|$)}
         end
 
         context 'query string' do
-          let(:parsed_query) { Faraday::Utils.parse_query subject.query }
+          let(:parsed_query) { Hash[URI.decode_www_form URI(subject).query] }
 
           it 'contains the state' do
             expect(parsed_query['state']).to be == state
@@ -70,12 +70,27 @@
 
         it "makes a GET request to the object's URL" do
           subject.fetch!
-          expect(a_request(:get, subject.url)).to have_been_made
+          expect(a_request :get, subject.url).to have_been_made
         end
 
         it 'returns the parsed JSON from the request body' do
           expect(subject.fetch!).to be == data
         end
+
+        context 'caching' do
+          include ActiveSupport::Testing::TimeHelpers
+
+          before(:each) { travel 1.week }
+          after(:each) { travel_back }
+
+          it 'makes the request only once within 6 hours' do
+            pending "Webmock interferes with caching, so this test actually doesn't work"
+            subject.fetch!
+            travel(5.hours + 59.minutes)
+            subject.fetch!
+            expect(a_request :get, subject.url).to have_been_made.once
+          end
+        end
       end
 
       context 'date range' do