Function processPart

modules/smtp/handler.go:267–331

(part *multipart.Part, parsed *ParsedEmail, atts *[]parsedAttachment)

}

func processPart(part *multipart.Part, parsed *ParsedEmail, atts *[]parsedAttachment) {
	ct := part.Header.Get("Content-Type")
	disposition := part.Header.Get("Content-Disposition")

	mediaType, params, _ := mime.ParseMediaType(ct)

	// Recurse into nested multipart.
	if strings.HasPrefix(mediaType, "multipart/") {
		if boundary := params["boundary"]; boundary != "" {
			mr := multipart.NewReader(part, boundary)
			for {
				subpart, err := mr.NextPart()
				if err != nil {
					break
				}
				processPart(subpart, parsed, atts)
			}
		}
		return
	}

	// Attachment.
	if strings.HasPrefix(disposition, "attachment") || strings.HasPrefix(disposition, "inline") {
		content, _ := io.ReadAll(part)
		encoding := part.Header.Get("Content-Transfer-Encoding")
		if strings.EqualFold(encoding, "base64") {
			if decoded, err := base64.StdEncoding.DecodeString(string(content)); err == nil {
				content = decoded
			}
		}

		filename := part.FileName()
		if filename == "" {
			filename = "unnamed"
		}
		mimeType := ct
		if idx := strings.Index(mimeType, ";"); idx > 0 {
			mimeType = strings.TrimSpace(mimeType[:idx])
		}
		if mimeType == "" {
			mimeType = "application/octet-stream"
		}

		contentID := strings.Trim(part.Header.Get("Content-ID"), "<>")

		*atts = append(*atts, parsedAttachment{
			Filename:  filename,
			Type:      mimeType,
			ContentID: contentID,
			content:   content,
		})
		return
	}

	// Body content.
	body, _ := io.ReadAll(part)
	decoded := decodeContent(body, part.Header.Get("Content-Transfer-Encoding"))
	decoded = convertToUTF8(decoded, params["charset"])