mime: handling invalid mime media parameters #19498
Description
Sometimes it's necessary to deal with emails that do not follow the specification; in particular, it's possible to download such email via gmail.
When Golang standard library handle invalid mime media parameters, it returns nils and error, although there is a valid media type, which may be returned. If this behavior changes, it may not affect any existing programs, but it will help to parse some emails.
I suggest to change file src/mime/mediatype.go as follows:
diff --git a/mediatype.go b/mediatype.go
index 4383431..758d621 100644
--- a/mediatype.go
+++ b/mediatype.go
@@ -94,6 +94,9 @@ func checkMediaTypeDisposition(s string) error {
return nil
}
+// ErrInvalidMediaParameter means that mime media parameter list is invalid
+var ErrInvalidMediaParameter = errors.New("mime: invalid media parameter")
+
// ParseMediaType parses a media type value and any optional
// parameters, per RFC 1521. Media types are the values in
// Content-Type and Content-Disposition headers (RFC 2183).
@@ -134,7 +137,7 @@ func ParseMediaType(v string) (mediatype string, params map[string]string, err e
return
}
// Parse error.
- return "", nil, errors.New("mime: invalid media parameter")
+ return mediatype, nil, ErrInvalidMediaParameter
}
pmap := params
@@ -368,4 +371,3 @@ func unhex(c byte) byte {
}
return 0
}
-
--
2.7.4