How to parse non-standard date / time in Go ? Mitteleuropäische Sommerzeit - time

Question

I'm trying to parse dates received in email headers. Recently I've got stuck on this one Thu, 7 Aug 2014 14:03:05 +0200 (Mitteleuropäische Sommerzeit). What kind of layout am I supposed to use ? Mon, 02 Jan 2006 15:04:05 -0700 (MST) doesn't do the trick.
I've also tried the workaround below but it still doesn't work. I'm not sure why Mitt... is not being replaced.
if strings.Contains(d, "Mitteleuropäische Sommerzeit") {
d = strings.Replace(d, "Mitteleuropäische Sommerzeit", "CEST", 1)
}

Answer 1

The Mitteleuropäische Sommerzeit part is indeed not recognized by the time package. But it works perfectly when you replace it by CEST:
var d = "Thu, 7 Aug 2014 14:03:05 +0200 (Mitteleuropäische Sommerzeit)"
_, err := time.Parse("Mon, _2 Jan 2006 15:04:05 -0700 (MST)", d)
if err != nil {
fmt.Println(err) // There is indeed an error
}
d = strings.Replace(d, "Mitteleuropäische Sommerzeit", "CEST", 1)
t, err := time.Parse("Mon, _2 Jan 2006 15:04:05 -0700 (MST)", d)
if err != nil {
fmt.Println(err) // No error this time
}
fmt.Println(t) // 2014-08-07 14:03:05 +0200 CEST
On playground.
Do not forget to write _2 instead of 2 in your layout, so that days with two figures can be parsed too.

Answer 2

It is redundant to try and parse the parenthesized timezone name when you already know the correct numeric offset:
Thu, 7 Aug 2014 14:03:05 +0200 (Mitteleuropäische Sommerzeit)
is equally specific as
Thu, 7 Aug 2014 14:03:05 +0200
The only additional information you get out of the first representation is that it was summer when the email was sent and that the region from which the email's author comes from is central Europe (literally "central Europe summertime").
This will not, however, affect the time.Time value's representation in contrast to the second string because the daylight saving adjustment is already reflected in the numerical timezone representation +0200 which would be +0100 during winter.
In other words, in this case you can ignore the spelled-out timezone specification.