Files
auth/http.go
T
2026-09-23 04:14:39 -04:00

36 lines
1.1 KiB
Go

package auth
import "strings"
// ParseBearerToken parses an RFC 6750 Bearer authorization value. The scheme is
// case-insensitive; tokens must use the b64token alphabet and contain no spaces.
// Parsing does not validate the token's signature or grant authorization.
func ParseBearerToken(header string) (string, error) {
// Bound before scanning, including an allowance for separator spaces.
if len(header) > MaxTokenLen+16 {
return "", ErrTokenTooLong
}
scheme, token, ok := strings.Cut(header, " ")
if !ok || !strings.EqualFold(scheme, "Bearer") {
return "", ErrAuthInvalidBearerFormat
}
token = strings.TrimLeft(token, " ")
if token == "" {
return "", ErrAuthEmptyBearerToken
}
if len(token) > MaxTokenLen {
return "", ErrTokenTooLong
}
padding := false
for i, ch := range []byte(token) {
if ch == '=' && i > 0 {
padding = true
continue
}
if padding || !(ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z' || ch >= '0' && ch <= '9' || strings.ContainsRune("-._~+/", rune(ch))) {
return "", ErrAuthInvalidBearerFormat
}
}
return token, nil
}