add support for unix domain sockets as URI

Sockets are passed as regular URIs (unix:/tmp/foo) in place of the HTTP
URI. Passing additional path fragments is not supported but largely
should not be necessary unless one proxies the socket, which would be
highly suspicious behavior.

Combined with the proposed UDS support in aptly this allows clients to
talk to the API over sockets rather than host-wide ports.

Also see https://github.com/smira/aptly/pull/493

lib/aptly/configuration.rb

@@ -6,6 +6,8 @@ class Configuration
     extend Gem::Deprecate
 
     # @!attribute uri
+    #   Generally any suitable URI is allowed. This can also be a Unix domain
+    #   socket which needs to be used in the notation unix:/tmp/sock.
     #   @return [URI] the base URI for the API (http://localhost by default)
     attr_accessor :uri
 

lib/aptly/connection.rb

@@ -47,8 +47,16 @@ def method_missing(symbol, *args, **kwords)
     private
 
     def uri
+      @adapter_options ||= {}
       @uri ||= begin
         uri = @base_uri.clone
+        return uri unless uri.scheme == 'unix'
+        # For Unix domain sockets we need to divide the bits apart as Excon
+        # expects the path URI without a socket path and the socket path as
+        # option.
+        @adapter_options[:socket] = uri.path
+        uri.host = nil
+        uri
       end
     end
 

test/connection_test.rb

@@ -63,4 +63,16 @@ def test_uri_option
     stub_request(:get, 'http://otherhost/api').to_return(status: 200)
     c.get
   end
+
+  def test_unix
+    # webmock is a bit screwed up with sockets but is suitably enough
+    # for this test case anyway. Basically the actual request URI is meant to
+    # be unix:/api which in webmock ends up being 'http://unix/api', the
+    # actual socket is passed as param to Excon. We are not testing this but
+    # if the path in webmock is well-formed we'll simply assume our socket
+    # actually works :O
+    stub_request(:get, 'http://unix/api').to_return(status: 200)
+    c = ::Aptly::Connection.new(uri: URI.parse('unix:///tmp/sock'))
+    c.get
+  end
 end