Add default implementation of Middleware#close.

.rubocop_todo.yml

@@ -13,7 +13,7 @@ Metrics/AbcSize:
 # Offense count: 4
 # Configuration parameters: CountComments.
 Metrics/ClassLength:
-  Max: 233
+  Max: 234
 
 # Offense count: 17
 Metrics/CyclomaticComplexity:

lib/faraday/connection.rb

@@ -117,6 +117,13 @@ def headers=(hash)
 
     def_delegators :builder, :build, :use, :request, :response, :adapter, :app
 
+    # Closes the underlying resources and/or connections. In the case of
+    # persistent connections, this closes all currently open connections
+    # but does not prevent new connections from being made.
+    def close
+      app.close
+    end
+
     # @!method get(url = nil, params = nil, headers = nil)
     # Makes a GET HTTP request without a body.
     # @!scope class

lib/faraday/middleware.rb

@@ -9,5 +9,13 @@ class Middleware
     def initialize(app = nil)
       @app = app
     end
+
+    def close
+      if @app.respond_to?(:close)
+        @app.close
+      else
+        warn "#{@app} does not implement \#close!"
+      end
+    end
   end
 end

spec/faraday/connection_spec.rb

@@ -127,6 +127,13 @@
     end
   end
 
+  describe '#close' do
+    it 'can close underlying app' do
+      expect(conn.app).to receive(:close)
+      conn.close
+    end
+  end
+
   describe 'basic_auth' do
     subject { conn }
 

spec/faraday/middleware_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+RSpec.describe Faraday::Middleware do
+  subject { described_class.new(app) }
+
+  describe '#close' do
+    context "with app that doesn't support \#close" do
+      let(:app) { double }
+
+      it 'should issue warning' do
+        expect(subject).to receive(:warn)
+        subject.close
+      end
+    end
+
+    context "with app that supports \#close" do
+      let(:app) { double }
+
+      it 'should issue warning' do
+        expect(app).to receive(:close)
+        expect(subject).to_not receive(:warn)
+        subject.close
+      end
+    end
+  end
+end