Cache body structure in order to reduce network traffic

internal/store/message.go

@@ -20,6 +20,7 @@ package store
 import (
 	"net/mail"
 
+	backendMessage "github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	bolt "go.etcd.io/bbolt"
 )
@@ -119,3 +120,31 @@ func (message *Message) SetContentTypeAndHeader(mimeType string, header mail.Hea
 	}
 	return message.store.db.Update(txUpdate)
 }
+
+// SetBodyStructure stores serialized body structure in database
+func (message *Message) SetBodyStructure(bs *backendMessage.BodyStructure) error {
+	txUpdate := func(tx *bolt.Tx) error {
+		return message.store.txPutBodyStructure(
+			tx.Bucket(bodystructureBucket),
+			message.ID(), bs,
+		)
+	}
+	return message.store.db.Update(txUpdate)
+}
+
+// GetBodyStructure deserialize body structure from database. If body structure
+// is not in database it returns nil error and nil body structure. If error
+// occurs it returns nil body structure.
+func (message *Message) GetBodyStructure() (bs *backendMessage.BodyStructure, err error) {
+	txRead := func(tx *bolt.Tx) error {
+		bs, err = message.store.txGetBodyStructure(
+			tx.Bucket(bodystructureBucket),
+			message.ID(),
+		)
+		return err
+	}
+	if err = message.store.db.View(txRead); err != nil {
+		return nil, err
+	}
+	return bs, nil
+}

internal/store/store.go

@@ -71,16 +71,17 @@ var (
 	//       * {messageID} -> uint32 imapUID
 	//     * deleted_ids (can be missing or have no keys)
 	//       * {messageID} -> true
-	metadataBucket    = []byte("metadata")          //nolint[gochecknoglobals]
-	countsBucket      = []byte("counts")            //nolint[gochecknoglobals]
-	addressInfoBucket = []byte("address_info")      //nolint[gochecknoglobals]
-	addressModeBucket = []byte("address_mode")      //nolint[gochecknoglobals]
-	syncStateBucket   = []byte("sync_state")        //nolint[gochecknoglobals]
-	mailboxesBucket   = []byte("mailboxes")         //nolint[gochecknoglobals]
-	imapIDsBucket     = []byte("imap_ids")          //nolint[gochecknoglobals]
-	apiIDsBucket      = []byte("api_ids")           //nolint[gochecknoglobals]
-	deletedIDsBucket  = []byte("deleted_ids")       //nolint[gochecknoglobals]
-	mboxVersionBucket = []byte("mailboxes_version") //nolint[gochecknoglobals]
+	metadataBucket      = []byte("metadata")          //nolint[gochecknoglobals]
+	bodystructureBucket = []byte("bodystructure")     //nolint[gochecknoglobals]
+	countsBucket        = []byte("counts")            //nolint[gochecknoglobals]
+	addressInfoBucket   = []byte("address_info")      //nolint[gochecknoglobals]
+	addressModeBucket   = []byte("address_mode")      //nolint[gochecknoglobals]
+	syncStateBucket     = []byte("sync_state")        //nolint[gochecknoglobals]
+	mailboxesBucket     = []byte("mailboxes")         //nolint[gochecknoglobals]
+	imapIDsBucket       = []byte("imap_ids")          //nolint[gochecknoglobals]
+	apiIDsBucket        = []byte("api_ids")           //nolint[gochecknoglobals]
+	deletedIDsBucket    = []byte("deleted_ids")       //nolint[gochecknoglobals]
+	mboxVersionBucket   = []byte("mailboxes_version") //nolint[gochecknoglobals]
 
 	// ErrNoSuchAPIID when mailbox does not have API ID.
 	ErrNoSuchAPIID = errors.New("no such api id") //nolint[gochecknoglobals]
@@ -193,6 +194,10 @@ func openBoltDatabase(filePath string) (db *bolt.DB, err error) {
 			return
 		}
 
+		if _, err = tx.CreateBucketIfNotExists(bodystructureBucket); err != nil {
+			return
+		}
+
 		if _, err = tx.CreateBucketIfNotExists(countsBucket); err != nil {
 			return
 		}

internal/store/user_message.go

@@ -27,6 +27,7 @@ import (
 	"strings"
 
 	"github.com/ProtonMail/gopenpgp/v2/crypto"
+	backendMessage "github.com/ProtonMail/proton-bridge/pkg/message"
 	"github.com/ProtonMail/proton-bridge/pkg/pmapi"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -170,6 +171,26 @@ func (store *Store) txPutMessage(metaBucket *bolt.Bucket, onlyMeta *pmapi.Messag
 	return nil
 }
 
+func (store *Store) txPutBodyStructure(bsBucket *bolt.Bucket, msgID string, bs *backendMessage.BodyStructure) error {
+	raw, err := bs.Serialize()
+	if err != nil {
+		return err
+	}
+	err = bsBucket.Put([]byte(msgID), raw)
+	if err != nil {
+		return errors.Wrap(err, "cannot put bodystructure bucket")
+	}
+	return nil
+}
+
+func (store *Store) txGetBodyStructure(bsBucket *bolt.Bucket, msgID string) (*backendMessage.BodyStructure, error) {
+	raw := bsBucket.Get([]byte(msgID))
+	if len(raw) == 0 {
+		return nil, nil
+	}
+	return backendMessage.DeserializeBodyStructure(raw)
+}
+
 // createOrUpdateMessageEvent is helper to create only one message with
 // createOrUpdateMessagesEvent.
 func (store *Store) createOrUpdateMessageEvent(msg *pmapi.Message) error {