Add detail view for one document

On the index list, each document now is a link to the respective article
detail page. A new route `GET /:document_id` provides the detail view.

app/google_drive_connector.rb

@@ -18,4 +18,11 @@ def docs
       .sort_by(&:modified_time)
       .reverse
   end
+
+  def doc(document_id)
+    document = session.file_by_id(document_id)
+    document if document.parents.include?(Config[:folder_id])
+  rescue Google::Apis::ClientError
+    nil
+  end
 end

app/server.rb

@@ -10,3 +10,13 @@
         docs: GoogleDriveConnector.new.docs,
       }
 end
+
+get '/:document_id' do
+  doc = GoogleDriveConnector.new.doc(params[:document_id])
+  halt 404 unless doc
+  erb :show,
+      locals: {
+        blog_title: Config[:blog_title],
+        doc: doc,
+      }
+end

app/views/index.erb

@@ -2,7 +2,7 @@
 <ul>
   <% docs.each do |doc| %>
     <li>
-      <a>
+      <a href="/<%= doc.id %>">
         <%= doc.title %> (<%= doc.modified_time.strftime('%d %b %Y') %>)
       </a>
     </li>

app/views/show.erb

@@ -0,0 +1,9 @@
+<h1><%= doc.title %></h1>
+<div class="meta-info">
+  <cite><%= doc.last_modifying_user.display_name %></cite>
+  //
+  <time><%= doc.modified_time.strftime('%d %b %Y') %></time>
+</div>
+<article>
+  Lorem ipsum, sit dolor amet.
+</article>

spec/google_drive_connector_spec.rb

@@ -49,4 +49,43 @@
     it { should contain_exactly older_document_double, newer_document_double }
     it { should eq [newer_document_double, older_document_double] }
   end
+
+  describe '#doc' do
+    let(:doc_id) { 'd0c-1d' }
+    subject { described_class.new.doc(doc_id) }
+
+    context 'when the `doc_id` exists' do
+      let(:folder_id) { '123abc' }
+      let(:document_double) { double('document', parents: document_parents) }
+
+      before do
+        allow(Config).to receive(:[]).with(:folder_id).and_return(folder_id)
+        allow(session_double).to(
+          receive(:file_by_id).with(doc_id).and_return(document_double)
+        )
+      end
+
+      context 'and it is in the right folder' do
+        let(:document_parents) { [folder_id] }
+        it { should eq document_double }
+      end
+
+      context 'but it is not in the right folder' do
+        let(:document_parents) { ['qwe987'] }
+        it { should eq nil }
+      end
+    end
+
+    context 'when the `doc_id` does not exist' do
+      before do
+        allow(session_double).to(
+          receive(:file_by_id)
+            .with(doc_id)
+            .and_raise(Google::Apis::ClientError, 'File not found')
+        )
+      end
+
+      it { should eq nil }
+    end
+  end
 end

spec/server_spec.rb

@@ -13,18 +13,7 @@ def app
   let(:blog_title) { 'My Blog' }
   let(:config) { { blog_title: blog_title } }
 
-  let(:document_double_1) do
-    double 'document_1',
-           modified_time: DateTime.now - 3, # 3 days ago
-           title: 'My first document'
-  end
-  let(:document_double_2) do
-    double 'document_2',
-           modified_time: DateTime.now - 1, # 1 day ago
-           title: 'New stuff'
-  end
-  let(:docs) { [document_double_1, document_double_2] }
-  let(:drive_connector_double) { double('drive_connector', docs: docs) }
+  let(:drive_connector_double) { double('drive_connector') }
 
   before do
     Config.instance_variable_set(:@config, config)
@@ -33,6 +22,22 @@ def app
   end
 
   describe 'GET /' do
+    let(:document_double_1) do
+      double 'document_1',
+             id: 'd0cum3nt-1',
+             modified_time: DateTime.now - 3, # 3 days ago
+             title: 'My first document'
+    end
+    let(:document_double_2) do
+      double 'document_2',
+             id: 'd0cum3nt-2',
+             modified_time: DateTime.now - 1, # 1 day ago
+             title: 'New stuff'
+    end
+    let(:docs) { [document_double_1, document_double_2] }
+
+    before { allow(drive_connector_double).to receive(:docs).and_return(docs) }
+
     it 'should return the blog index page' do
       get '/'
       expect(last_response).to be_successful
@@ -41,4 +46,40 @@ def app
                                             document_double_2.title
     end
   end
+
+  describe 'GET /:document_id' do
+    let(:doc_id) { 'd0cum3nt' }
+
+    before do
+      allow(drive_connector_double)
+        .to receive(:doc).with(doc_id).and_return(document_double)
+    end
+
+    context 'when there is a document for the given ID' do
+      let(:user_double) { double 'user', display_name: 'Us Er' }
+      let(:document_double) do
+        double 'document_1',
+               id: doc_id,
+               modified_time: DateTime.now - 3, # 3 days ago
+               title: 'My first document',
+               last_modifying_user: user_double
+      end
+
+      it 'should return the article page for the given document' do
+        get "/#{doc_id}"
+        expect(last_response).to be_successful
+        expect(last_response.body).to include document_double.title
+      end
+    end
+
+    context 'when there is no document for the given ID' do
+      let(:document_double) { nil }
+
+      it 'should return a 404 error' do
+        get "/#{doc_id}"
+        expect(last_response).to_not be_successful
+        expect(last_response).to be_not_found
+      end
+    end
+  end
 end