This is the v1 version, had the v2 before.

responses/fetch.go

@@ -0,0 +1,70 @@
+package responses
+
+import (
+	"github.com/emersion/go-imap"
+)
+
+const fetchName = "FETCH"
+
+// A FETCH response.
+// See RFC 3501 section 7.4.2
+type Fetch struct {
+	Messages chan *imap.Message
+	SeqSet   *imap.SeqSet
+	Uid      bool
+}
+
+func (r *Fetch) Handle(resp imap.Resp) error {
+	name, fields, ok := imap.ParseNamedResp(resp)
+	if !ok || name != fetchName {
+		return ErrUnhandled
+	} else if len(fields) < 1 {
+		return errNotEnoughFields
+	}
+
+	seqNum, err := imap.ParseNumber(fields[0])
+	if err != nil {
+		return err
+	}
+
+	msgFields, _ := fields[1].([]interface{})
+	msg := &imap.Message{SeqNum: seqNum}
+	if err := msg.Parse(msgFields); err != nil {
+		return err
+	}
+
+	if r.Uid && msg.Uid == 0 {
+		// we requested UIDs and got a message without one --> unilateral update --> ignore
+		return ErrUnhandled
+	}
+
+	var num uint32
+	if r.Uid {
+		num = msg.Uid
+	} else {
+		num = seqNum
+	}
+
+	// Check whether we obtained a result we requested with our SeqSet
+	// If the result is not contained in our SeqSet we have to handle an additional special case:
+	// In case we requested UIDs with a dynamic sequence (i.e. * or n:*) and the maximum UID of the mailbox
+	// is less then our n, the server will supply us with the max UID (cf. RFC 3501 §6.4.8 and §9 `seq-range`).
+	// Thus, such a result is correct and has to be returned by us.
+	if !r.SeqSet.Contains(num) && (!r.Uid || !r.SeqSet.Dynamic()) {
+		return ErrUnhandled
+	}
+
+	r.Messages <- msg
+	return nil
+}
+
+func (r *Fetch) WriteTo(w *imap.Writer) error {
+	var err error
+	for msg := range r.Messages {
+		resp := imap.NewUntaggedResp([]interface{}{msg.SeqNum, imap.RawString(fetchName), msg.Format()})
+		if err == nil {
+			err = resp.WriteTo(w)
+		}
+	}
+	return err
+}