Initialize module and dependencies

vendor/github.com/emersion/go-message/mail/attachment.go

@@ -0,0 +1,30 @@
+package mail
+
+import (
+	"github.com/emersion/go-message"
+)
+
+// An AttachmentHeader represents an attachment's header.
+type AttachmentHeader struct {
+	message.Header
+}
+
+// Filename parses the attachment's filename.
+func (h *AttachmentHeader) Filename() (string, error) {
+	_, params, err := h.ContentDisposition()
+
+	filename, ok := params["filename"]
+	if !ok {
+		// Using "name" in Content-Type is discouraged
+		_, params, err = h.ContentType()
+		filename = params["name"]
+	}
+
+	return filename, err
+}
+
+// SetFilename formats the attachment's filename.
+func (h *AttachmentHeader) SetFilename(filename string) {
+	dispParams := map[string]string{"filename": filename}
+	h.SetContentDisposition("attachment", dispParams)
+}