Implement a BearerExtractor

[WhyNotHugo]

This is a rather common extractor; it extracts the JWT from the HTTP
Authorization header, expecting it to include the "Bearer " prefix.

This patterns is rather common and this snippet is repeated in enough
applications that it's probably best to just include it upstream and
allow reusing it.

[oxisto]

Good idea. May I suggest an alternative name like AuthorizationHeaderExtractor or do you think that is too long?

[mfridman]

I have this in literally every project, haha. I'd suggest something like GetTokenFromHeader

[oxisto]

I have this in literally every project, haha. I'd suggest something like GetTokenFromHeader

There is already a TokenExtractor which loops through all tokens, since this is specific to a bearer token we might as well stick with the original name.

[AlexanderYastrebov]

There is a long-existing AuthorizationHeaderExtractor that does the same (almost, as it also allows token without Bearer prefix afaict)

jwt/request/oauth2.go

Lines 7 to 21 in 2ebb50f

	// Strips 'Bearer ' prefix from bearer token string
	func stripBearerPrefixFromTokenString(tok string) (string, error) {
	// Should be a bearer token
	if len(tok) > 6 && strings.ToUpper(tok[0:7]) == "BEARER " {
	return tok[7:], nil
	}
	return tok, nil
	}
	// AuthorizationHeaderExtractor extracts a bearer token from Authorization header
	// Uses PostExtractionFilter to strip "Bearer " prefix from header
	var AuthorizationHeaderExtractor = &PostExtractionFilter{
	HeaderExtractor{"Authorization"},
	stripBearerPrefixFromTokenString,
	}