rclone/vendor/github.com/dgrijalva/jwt-go/request/oauth2.go

package request

import (
	"strings"
)

// 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
}

// Extract bearer token from Authorization header
// Uses PostExtractionFilter to strip "Bearer " prefix from header
var AuthorizationHeaderExtractor = &PostExtractionFilter{
	HeaderExtractor{"Authorization"},
	stripBearerPrefixFromTokenString,
}

// Extractor for OAuth2 access tokens.  Looks in 'Authorization'
// header then 'access_token' argument for a token.
var OAuth2Extractor = &MultiExtractor{
	AuthorizationHeaderExtractor,
	ArgumentExtractor{"access_token"},
}