package lib import ( "bytes" "encoding/base64" "fmt" "io" "mime/quotedprintable" "strings" "git.sr.ht/~sircmpwn/aerc/models" "github.com/emersion/go-message" _ "github.com/emersion/go-message/charset" "github.com/emersion/go-message/mail" ) func FetchEntityPartReader(e *message.Entity, index []int) (io.Reader, error) { if len(index) < 1 { return nil, fmt.Errorf("no part to read") } if mpr := e.MultipartReader(); mpr != nil { idx := 0 for { idx++ part, err := mpr.NextPart() if err != nil { return nil, err } if idx == index[0] { rest := index[1:] if len(rest) < 1 { return fetchEntityReader(part) } return FetchEntityPartReader(part, index[1:]) } } } if index[0] != 1 { return nil, fmt.Errorf("cannont return non-first part of non-multipart") } return fetchEntityReader(e) } // fetchEntityReader makes an io.Reader for the given entity. Since the // go-message package decodes the body for us, and the UI expects to deal with // a reader whose bytes are encoded with the part's encoding, we are in the // interesting position of needing to re-encode the reader before sending it // off to the UI layer. // // TODO: probably change the UI to expect an already-decoded reader and decode // in the IMAP worker. func fetchEntityReader(e *message.Entity) (io.Reader, error) { enc := e.Header.Get("content-transfer-encoding") var buf bytes.Buffer // base64 if strings.EqualFold(enc, "base64") { wc := base64.NewEncoder(base64.StdEncoding, &buf) defer wc.Close() if _, err := io.Copy(wc, e.Body); err != nil { return nil, fmt.Errorf("could not base64 encode: %v", err) } return &buf, nil } // quoted-printable if strings.EqualFold(enc, "quoted-printable") { wc := quotedprintable.NewWriter(&buf) defer wc.Close() if _, err := io.Copy(wc, e.Body); err != nil { return nil, fmt.Errorf("could not quoted-printable encode: %v", err) } return &buf, nil } // other general encoding if _, err := io.Copy(&buf, e.Body); err != nil { return nil, err } return &buf, nil } // split a MIME type into its major and minor parts func splitMIME(m string) (string, string) { parts := strings.Split(m, "/") if len(parts) != 2 { return parts[0], "" } return parts[0], parts[1] } func parseEntityStructure(e *message.Entity) (*models.BodyStructure, error) { var body models.BodyStructure contentType, ctParams, err := e.Header.ContentType() if err != nil { return nil, fmt.Errorf("could not parse content type: %v", err) } mimeType, mimeSubType := splitMIME(contentType) body.MIMEType = mimeType body.MIMESubType = mimeSubType body.Params = ctParams body.Description = e.Header.Get("content-description") body.Encoding = e.Header.Get("content-transfer-encoding") if cd := e.Header.Get("content-disposition"); cd != "" { contentDisposition, cdParams, err := e.Header.ContentDisposition() if err != nil { return nil, fmt.Errorf("could not parse content disposition: %v", err) } body.Disposition = contentDisposition body.DispositionParams = cdParams } body.Parts = []*models.BodyStructure{} if mpr := e.MultipartReader(); mpr != nil { for { part, err := mpr.NextPart() if err == io.EOF { return &body, nil } else if err != nil { return nil, err } ps, err := parseEntityStructure(part) if err != nil { return nil, fmt.Errorf("could not parse child entity structure: %v", err) } body.Parts = append(body.Parts, ps) } } return &body, nil } func parseEnvelope(h *mail.Header) (*models.Envelope, error) { date, err := h.Date() if err != nil { return nil, fmt.Errorf("could not parse date header: %v", err) } from, err := parseAddressList(h, "from") if err != nil { return nil, fmt.Errorf("could not read from address: %v", err) } to, err := parseAddressList(h, "to") if err != nil { return nil, fmt.Errorf("could not read to address: %v", err) } cc, err := parseAddressList(h, "cc") if err != nil { return nil, fmt.Errorf("could not read cc address: %v", err) } bcc, err := parseAddressList(h, "bcc") if err != nil { return nil, fmt.Errorf("could not read bcc address: %v", err) } replyTo, err := parseAddressList(h, "reply-to") if err != nil { return nil, fmt.Errorf("could not read reply-to address: %v", err) } subj, err := h.Subject() if err != nil { return nil, fmt.Errorf("could not read subject: %v", err) } msgID, err := h.Text("message-id") if err != nil { return nil, fmt.Errorf("could not read message id: %v", err) } return &models.Envelope{ Date: date, Subject: subj, MessageId: msgID, From: from, ReplyTo: replyTo, To: to, Cc: cc, Bcc: bcc, }, nil } func parseAddressList(h *mail.Header, key string) ([]*models.Address, error) { var converted []*models.Address addrs, err := h.AddressList(key) if err != nil { if hdr, err := h.Text(key); err != nil && strings.Contains(hdr, "@") { return []*models.Address{&models.Address{ Name: hdr, }}, nil } return nil, err } for _, addr := range addrs { parts := strings.Split(addr.Address, "@") var mbox, host string if len(parts) > 1 { mbox = strings.Join(parts[0:len(parts)-1], "@") host = parts[len(parts)-1] } else { mbox = addr.Address } converted = append(converted, &models.Address{ Name: addr.Name, Mailbox: mbox, Host: host, }) } return converted, nil } // RawMessage is an interface that describes a raw message type RawMessage interface { NewReader() (io.Reader, error) ModelFlags() ([]models.Flag, error) Labels() ([]string, error) UID() uint32 } // MessageInfo populates a models.MessageInfo struct for the message. // based on the reader returned by NewReader func MessageInfo(raw RawMessage) (*models.MessageInfo, error) { r, err := raw.NewReader() if err != nil { return nil, err } msg, err := message.Read(r) if err != nil { return nil, fmt.Errorf("could not read message: %v", err) } bs, err := parseEntityStructure(msg) if err != nil { return nil, fmt.Errorf("could not get structure: %v", err) } env, err := parseEnvelope(&mail.Header{msg.Header}) if err != nil { return nil, fmt.Errorf("could not get envelope: %v", err) } flags, err := raw.ModelFlags() if err != nil { return nil, err } labels, err := raw.Labels() if err != nil { return nil, err } return &models.MessageInfo{ BodyStructure: bs, Envelope: env, Flags: flags, Labels: labels, InternalDate: env.Date, RFC822Headers: &mail.Header{msg.Header}, Size: 0, Uid: raw.UID(), }, nil }