Add support for ENABLE (RFC 5161)

Author: arnt

lib/net/imap.rb

@@ -199,8 +199,8 @@ module Net
   # [IDLE[https://tools.ietf.org/html/rfc2177]],
   # [NAMESPACE[https://tools.ietf.org/html/rfc2342]],
   # [UNSELECT[https://tools.ietf.org/html/rfc3691]],
+  # [ENABLE[https://tools.ietf.org/html/rfc5161]],
   #--
-  # TODO: [ENABLE[https://tools.ietf.org/html/rfc5161]],
   # TODO: [LIST-EXTENDED[https://tools.ietf.org/html/rfc5258]],
   # TODO: [LIST-STATUS[https://tools.ietf.org/html/rfc5819]],
   #++
@@ -1879,6 +1879,27 @@ def uid_thread(algorithm, search_keys, charset)
       return thread_internal("UID THREAD", algorithm, search_keys, charset)
     end
 
+    # Sends an {ENABLE command [RFC5161 §3.2]}[https://www.rfc-editor.org/rfc/rfc5161#section-3.1]
+    # {[IMAP4rev2 §6.3.1]}[https://www.rfc-editor.org/rfc/rfc9051#section-6.3.1]
+    # to enable the specified extenstions, which may be either an
+    # array or a string.
+    #
+    # Some of the extensions that use ENABLE permit the server to send
+    # syntax that this class cannot parse. Caution is advised.
+    #
+    # ===== Capabilities
+    #
+    # The server's capabilities must include +ENABLE+
+    # [RFC5161[https://tools.ietf.org/html/rfc5161]] or IMAP4REV2
+    # [RFC9051[https://tools.ietf.org/html/rfc9051]].
+
+    def enable(extensions)
+      synchronize do
+        send_command("ENABLE #{[extensions].flatten.join(' ')}")
+        return @responses.delete("ENABLED")[-1]
+      end
+    end
+
     # Sends an {IDLE command [RFC2177 §3]}[https://www.rfc-editor.org/rfc/rfc6851#section-3]
     # {[IMAP4rev2 §6.3.13]}[https://www.rfc-editor.org/rfc/rfc9051#section-6.3.13]
     # that waits for notifications of new or expunged messages.  Yields

lib/net/imap/response_parser.rb

@@ -160,6 +160,8 @@ def response_untagged
             return capability_response
           when /\A(?:NOOP)\z/ni
             return ignored_response
+          when /\A(?:ENABLED)\z/ni
+            return enabled_response
           else
             return text_response
           end
@@ -974,6 +976,13 @@ def capability_response
         UntaggedResponse.new(name, capability_data, @str)
       end
 
+      def enabled_response
+        token = match(T_ATOM)
+        name = token.value.upcase
+        match(T_SPACE)
+        UntaggedResponse.new(name, capability_data, @str)
+      end
+
       def capability_data
         data = []
         while true

test/net/imap/test_imap.rb

@@ -869,6 +869,37 @@ def test_uidplus_responses
     end
   end
 
+  def test_enable
+    server = create_tcp_server
+    port = server.addr[1]
+    requests = []
+    start_server do
+      sock = server.accept
+      begin
+        sock.print("* OK test server\r\n")
+        requests.push(sock.gets)
+        sock.print("* ENABLED SMTPUTF8\r\n")
+        sock.print("RUBY0001 OK \r\n")
+        sock.gets
+        sock.print("* BYE terminating connection\r\n")
+        sock.print("RUBY0002 OK LOGOUT completed\r\n")
+      ensure
+        sock.close
+        server.close
+      end
+    end
+
+    begin
+      imap = Net::IMAP.new(server_addr, port: port)
+      response = imap.enable(["SMTPUTF8", "X-NO-SUCH-THING"])
+      assert_equal("RUBY0001 ENABLE SMTPUTF8 X-NO-SUCH-THING\r\n", requests.pop)
+      assert_equal(response, ["SMTPUTF8"])
+      imap.logout
+    ensure
+      imap.disconnect if imap
+    end
+  end
+
   def yields_in_test_server_thread(
     read_timeout: 2, # requires ruby 3.2+
     timeout: 10,

test/net/imap/test_imap_response_parser.rb

@@ -222,6 +222,14 @@ def test_capability
     )
   end
 
+  def test_enable
+    parser = Net::IMAP::ResponseParser.new
+    response = parser.parse("* ENABLED SMTPUTF8\r\n")
+    assert_equal("ENABLED", response.name)
+    assert_equal(1, response.data.length)
+    assert_equal("SMTPUTF8", response.data.first)
+  end
+
   def test_id
     parser = Net::IMAP::ResponseParser.new
     response = parser.parse("* ID NIL\r\n")