mox/message/from.go
Mechiel Lukkien 5b20cba50a
switch to slog.Logger for logging, for easier reuse of packages by external software
we don't want external software to include internal details like mlog.
slog.Logger is/will be the standard.

we still have mlog for its helper functions, and its handler that logs in
concise logfmt used by mox.

packages that are not meant for reuse still pass around mlog.Log for
convenience.

we use golang.org/x/exp/slog because we also support the previous Go toolchain
version. with the next Go release, we'll switch to the builtin slog.
2023-12-14 13:45:52 +01:00

48 lines
1.5 KiB
Go

package message
import (
"fmt"
"io"
"net/textproto"
"golang.org/x/exp/slog"
"github.com/mjl-/mox/dns"
"github.com/mjl-/mox/mlog"
"github.com/mjl-/mox/smtp"
)
// From extracts the address in the From-header.
//
// An RFC5322 message must have a From header.
// In theory, multiple addresses may be present. In practice zero or multiple
// From headers may be present. From returns an error if there is not exactly
// one address. This address can be used for evaluating a DMARC policy against
// SPF and DKIM results.
func From(elog *slog.Logger, strict bool, r io.ReaderAt) (raddr smtp.Address, envelope *Envelope, header textproto.MIMEHeader, rerr error) {
log := mlog.New("message", elog)
// ../rfc/7489:1243
// todo: only allow utf8 if enabled in session/message?
p, err := Parse(log.Logger, strict, r)
if err != nil {
// todo: should we continue with p, perhaps headers can be parsed?
return raddr, nil, nil, fmt.Errorf("parsing message: %v", err)
}
header, err = p.Header()
if err != nil {
return raddr, nil, nil, fmt.Errorf("parsing message header: %v", err)
}
from := p.Envelope.From
if len(from) != 1 {
return raddr, nil, nil, fmt.Errorf("from header has %d addresses, need exactly 1 address", len(from))
}
d, err := dns.ParseDomain(from[0].Host)
if err != nil {
return raddr, nil, nil, fmt.Errorf("bad domain in from address: %v", err)
}
addr := smtp.Address{Localpart: smtp.Localpart(from[0].User), Domain: d}
return addr, p.Envelope, textproto.MIMEHeader(header), nil
}