rest: Implement MarkSeen for #58

- message: Add MarkSeen to Manager, StoreManager.
- rest: Add PATCH for /mailbox/name/id.
- rest: Add MailboxMarkSeenV1 handler.
- rest: Add Seen to model.
- rest: Update handlers to set Seen.
- rest: Add doJSONBody func.

pkg/message/manager.go

@@ -25,6 +25,7 @@ type Manager interface {
 	) (id string, err error)
 	GetMetadata(mailbox string) ([]*Metadata, error)
 	GetMessage(mailbox, id string) (*Message, error)
+	MarkSeen(mailbox, id string) error
 	PurgeMessages(mailbox string) error
 	RemoveMessage(mailbox, id string) error
 	SourceReader(mailbox, id string) (io.ReadCloser, error)
@@ -124,6 +125,11 @@ func (s *StoreManager) GetMessage(mailbox, id string) (*Message, error) {
 	return &Message{Metadata: *header, env: env}, nil
 }
 
+// MarkSeen marks the message as having been read.
+func (s *StoreManager) MarkSeen(mailbox, id string) error {
+	return s.Store.MarkSeen(mailbox, id)
+}
+
 // PurgeMessages removes all messages from the specified mailbox.
 func (s *StoreManager) PurgeMessages(mailbox string) error {
 	return s.Store.PurgeMessages(mailbox)