Enable HTTP client caching.

That should help accross several nanoc runs.

Author: mostlyobvious

Gemfile

@@ -5,4 +5,5 @@ gemspec
 gem  "rake",     "~> 13.0"
 gem  "minitest", "~> 5.14"
 gem  "webmock",  "~> 3.8"
-gem  "vcr",      "~> 5.1.0"
+gem  "vcr",      "~> 5.1.0"
+gem  "faraday-http-cache"

Gemfile.lock

@@ -23,8 +23,10 @@ GEM
     ddplugin (1.0.2)
     diff-lcs (1.3)
     equatable (0.6.1)
-    faraday (1.0.0)
+    faraday (0.17.3)
       multipart-post (>= 1.2, < 3)
+    faraday-http-cache (2.0.0)
+      faraday (~> 0.8)
     front_matter_parser (0.2.1)
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
@@ -86,7 +88,7 @@ GEM
     tty-platform (0.3.0)
     tty-which (0.4.2)
     vcr (5.1.0)
-    webmock (3.8.2)
+    webmock (3.8.3)
       addressable (>= 2.3.6)
       crack (>= 0.3.2)
       hashdiff (>= 0.4.0, < 2.0.0)
@@ -96,6 +98,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  faraday-http-cache
   minitest (~> 5.14)
   nanoc-github!
   rake (~> 13.0)

lib/nanoc/github.rb

@@ -9,6 +9,14 @@ module Github
     class Source < Nanoc::DataSource
       identifier :github
 
+      def up
+        Octokit.middleware = Faraday::RackBuilder.new do |builder|
+          builder.use Faraday::HttpCache, serializer: Marshal, shared_cache: false
+          builder.use Octokit::Response::RaiseError
+          builder.adapter Faraday.default_adapter
+        end
+      end
+
       def items
         @items ||= begin
           repository_items.map do |item|