package lib import ( "bufio" "bytes" "io" "mime" "net/http" "os" "path/filepath" "strings" "git.sr.ht/~rjarry/aerc/lib/log" "git.sr.ht/~rjarry/aerc/lib/xdg" "github.com/emersion/go-message/mail" "github.com/pkg/errors" ) type Part struct { MimeType string Params map[string]string Data []byte Converted bool ConversionError error } func NewPart(mimetype string, params map[string]string, body io.Reader, ) (*Part, error) { var d []byte var err error var converted bool if body == nil { converted = true } else { d, err = io.ReadAll(body) if err != nil { return nil, err } } return &Part{ MimeType: mimetype, Params: params, Data: d, Converted: converted, }, nil } func (p *Part) NewReader() io.Reader { return bytes.NewReader(p.Data) } type Attachment interface { Name() string WriteTo(w *mail.Writer) error } type FileAttachment struct { path string } func NewFileAttachment(path string) *FileAttachment { return &FileAttachment{ path, } } func (fa *FileAttachment) Name() string { return fa.path } func (fa *FileAttachment) WriteTo(w *mail.Writer) error { f, err := os.Open(xdg.ExpandHome(fa.path)) if err != nil { return errors.Wrap(err, "os.Open") } defer f.Close() reader := bufio.NewReader(f) mimeType, params, err := FindMimeType(fa.path, reader) if err != nil { return errors.Wrap(err, "ParseMediaType") } filename := filepath.Base(fa.path) params["name"] = filename // set header fields ah := mail.AttachmentHeader{} ah.SetContentType(mimeType, params) // setting the filename auto sets the content disposition ah.SetFilename(filename) fixContentTransferEncoding(mimeType, &ah) aw, err := w.CreateAttachment(ah) if err != nil { return errors.Wrap(err, "CreateAttachment") } defer aw.Close() if _, err := reader.WriteTo(aw); err != nil { return errors.Wrap(err, "reader.WriteTo") } return nil } type PartAttachment struct { part *Part name string } func NewPartAttachment(part *Part, name string) *PartAttachment { return &PartAttachment{ part, name, } } func (pa *PartAttachment) Name() string { return pa.name } func (pa *PartAttachment) WriteTo(w *mail.Writer) error { // set header fields ah := mail.AttachmentHeader{} ah.SetContentType(pa.part.MimeType, pa.part.Params) // setting the filename auto sets the content disposition ah.SetFilename(pa.Name()) fixContentTransferEncoding(pa.part.MimeType, &ah) aw, err := w.CreateAttachment(ah) if err != nil { return errors.Wrap(err, "CreateAttachment") } defer aw.Close() if _, err := io.Copy(aw, pa.part.NewReader()); err != nil { return errors.Wrap(err, "io.Copy") } return nil } // SetUtf8Charset sets the charset in a params map to UTF-8. func SetUtf8Charset(origParams map[string]string) map[string]string { params := make(map[string]string) for k, v := range origParams { switch strings.ToLower(k) { case "charset": log.Debugf("substitute charset %s with utf-8", v) params[k] = "utf-8" default: params[k] = v } } return params } func FindMimeType(filename string, reader *bufio.Reader) (string, map[string]string, error) { // if we have an extension, prefer that instead of trying to sniff the header. // That's generally more accurate than sniffing as lots of things are zip files // under the hood, e.g. most office file types ext := filepath.Ext(filename) var mimeString string if mimeString = mime.TypeByExtension(ext); mimeString == "" { // Sniff the mime type since it's not in the database // http.DetectContentType only cares about the first 512 bytes head, err := reader.Peek(512) if err != nil && err != io.EOF { return "", map[string]string{}, errors.Wrap(err, "Peek") } mimeString = http.DetectContentType(head) } // mimeString can contain type and params (like text encoding), // so we need to break them apart before passing them to the headers return mime.ParseMediaType(mimeString) } // fixContentTransferEncoding checks the mime type of the attachment and // corrects the content-transfer-encoding if necessary. // // It's expressly forbidden by RFC2046 to set any other // content-transfer-encoding than 7bit, 8bit, or binary for // message/rfc822 mime types (see RFC2046, section 5.2.1) func fixContentTransferEncoding(mimeType string, header *mail.AttachmentHeader) { if strings.ToLower(mimeType) == "message/rfc822" { header.Add("Content-Transfer-Encoding", "binary") } }