Fallback experience when Medium's RSS-to-JSON proxy is rate-limiting / throwing 429s (#2478)

Author: julianguyen

app/services/medium.rb

@@ -5,7 +5,9 @@
 
 class Medium
   def posts
-    content_hash['items']
+    content_hash['items'] || []
+  rescue OpenURI::HTTPError, SocketError, JSON::ParserError
+    []
   end
 
   private

spec/requests/pages_spec.rb

@@ -4,6 +4,14 @@
   let(:user) { create(:user) }
 
   describe "#home" do
+    let(:medium_posts) do
+      [{ 'title' => 'Test Post', 'link' => 'https://medium.com/ifme/test', 'author' => 'Test Author' }]
+    end
+
+    before do
+      allow_any_instance_of(Medium).to receive(:posts).and_return(medium_posts)
+    end
+
     it "respond to request" do
       get pages_home_path
       expect(response).to be_successful
@@ -40,7 +48,7 @@
       it "has blurbs and posts" do
         get pages_home_path
 
-        expect(assigns(:posts)[0].keys).to contain_exactly(:link, :link_name, :author)
+        expect(assigns(:posts).first.keys).to contain_exactly(:link, :link_name, :author)
         blurbs_file = File.read("doc/pages/blurbs.json")
         expect(assigns(:blurbs)).to eq(JSON.parse(blurbs_file))
       end

spec/services/medium_spec.rb

@@ -3,8 +3,50 @@
 describe Medium do
   subject { Medium.new.posts }
 
-  it 'retrieve Medium posts from API' do
-    expect(subject.first['title']).to be_truthy
-    expect(subject.first['link']).to be_truthy
+  context 'when the API is available' do
+    let(:response_json) do
+      { 'items' => [{ 'title' => 'Test Post', 'link' => 'https://medium.com/ifme/test', 'author' => 'Test Author' }] }.to_json
+    end
+
+    before do
+      allow(URI).to receive(:open).and_yield(StringIO.new(response_json))
+    end
+
+    it 'returns posts with title and link' do
+      expect(subject.first['title']).to be_truthy
+      expect(subject.first['link']).to be_truthy
+    end
+  end
+
+  context 'when the API returns a 429 Too Many Requests error' do
+    before do
+      allow(URI).to receive(:open).and_raise(
+        OpenURI::HTTPError.new('429 Too Many Requests', StringIO.new)
+      )
+    end
+
+    it 'returns an empty array' do
+      expect(subject).to eq([])
+    end
+  end
+
+  context 'when a network error occurs' do
+    before do
+      allow(URI).to receive(:open).and_raise(SocketError)
+    end
+
+    it 'returns an empty array' do
+      expect(subject).to eq([])
+    end
+  end
+
+  context 'when the response is not valid JSON' do
+    before do
+      allow(URI).to receive(:open).and_yield(StringIO.new('not valid json'))
+    end
+
+    it 'returns an empty array' do
+      expect(subject).to eq([])
+    end
   end
 end