mime: ParseMedia fails to parse googleapis batch boundary

[gopherbot]

by sergiusens:

When using Google's batch API for GMail, the responses contain a ContentType that looks
like this:

multipart/mixed; boundary=batch_Qau-LYGqak0=_AApYZR4VvsU=

This fails to work with ParseMediaType with an error of

mime: invalid media parameter

Here's a playground example: http://play.golang.org/p/3p6UFZau34

Removing the '='s from the boundary lead to a successful parsing of the Content Type.

[ianlancetaylor]

Comment 1:

Labels changed: added repo-main, release-none.

[bradfitz]

Comment 2:

Google really sends that? That looks illegal.
RFC 2045 says:
     content := "Content-Type" ":" type "/" subtype
                *(";" parameter)
                ; Matching of media type and subtype
                ; is ALWAYS case-insensitive.
     parameter := attribute "=" value
     attribute := token
                  ; Matching of attributes
                  ; is ALWAYS case-insensitive.
     value := token / quoted-string
     token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
                 or tspecials>
     tspecials :=  "(" / ")" / "<" / ">" / "@" /
                   "," / ";" / ":" / "\" / <">
                   "/" / "[" / "]" / "?" / "="
                   ; Must be in quoted-string,
                   ; to use within parameter values
So looking at the boundary part in your example above, it's not quoted, so it's not a
quoted string, which means it must be a token.
But a token excludes tspecials, and "=" is a tspecial.
Hence, invalid.
Please demonstrate how Google sends this and I'll try to kick somebody to fix it.

Owner changed to @bradfitz.

Status changed to WaitingForReply.

[gopherbot]

Comment 3 by sergiusens:

Right, if google returned the boundary quoted, it would work fine:
http://play.golang.org/p/ngT5gWKjWh
Here's a short hackish example where I've included the response dump for
when I run it:
https://gist.github.com/sergiusens/7f75c3593710e1f40abc
I used this as a guide https://developers.google.com/gmail/api/guides/batch

[bradfitz]

Comment 4:

Thanks for the report.
I filed an internal bug.
Google employees can follow along at go/8532-to-internal

Status changed to Accepted.

[bradfitz]

Comment 5:

The regression has been identified internally and a fix is in review.

[bradfitz]

Comment 6:

The fix & tests have been submitted internally. They'll be live whenever they do their
next push.
Closing this bug, as Go's doing the right thing.
Thanks again for reporting.

Status changed to WorkingAsIntended.