oidc/tokenstring.go

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package oidc
import (
"fmt"
"strings"
2022-10-18 12:00:09 +02:00
"code.icod.de/dalu/oidc/options"
)
type GetHeaderFn func(key string) string
const maxListSeparatorSlices = 20
// GetTokenString extracts a token string.
func GetTokenString(getHeaderFn GetHeaderFn, tokenStringOpts [][]options.TokenStringOption) (string, error) {
optsList := tokenStringOpts
if len(optsList) == 0 {
optsList = append(optsList, []options.TokenStringOption{})
}
var err error
for _, setters := range optsList {
opts := options.NewTokenString(setters...)
var tokenString string
tokenString, err = getTokenString(getHeaderFn, opts)
if err == nil && tokenString != "" {
// if a PostExtractionFn is defined, pass the token to it
if opts.PostExtractionFn != nil {
tokenString, err = opts.PostExtractionFn(tokenString)
if err != nil {
// if the PostExtractionFn returns an error, continue the loop
continue
}
if tokenString == "" {
// if the PostExtractionFn returns an empty string, continue the loop
err = fmt.Errorf("post extraction function returned an empty token string")
continue
}
return tokenString, nil
}
return tokenString, nil
}
}
return "", fmt.Errorf("unable to extract token: %w", err)
}
func getTokenString(getHeaderFn GetHeaderFn, opts *options.TokenStringOptions) (string, error) {
headerValue := getHeaderFn(opts.HeaderName)
if headerValue == "" {
return "", fmt.Errorf("%s header empty", opts.HeaderName)
}
if opts.ListSeparator != "" && strings.Contains(headerValue, opts.ListSeparator) {
headerValueList := strings.SplitN(headerValue, opts.ListSeparator, maxListSeparatorSlices)
return getTokenFromList(headerValueList, opts)
}
return getTokenFromString(headerValue, opts)
}
func getTokenFromList(headerValueList []string, opts *options.TokenStringOptions) (string, error) {
for _, headerValue := range headerValueList {
tokenString, err := getTokenFromString(headerValue, opts)
if err == nil && tokenString != "" {
return tokenString, nil
}
}
return "", fmt.Errorf("no token found in list")
}
func getTokenFromString(headerValue string, opts *options.TokenStringOptions) (string, error) {
if headerValue == "" {
return "", fmt.Errorf("%s header empty", opts.HeaderName)
}
if !strings.HasPrefix(headerValue, opts.TokenPrefix) {
return "", fmt.Errorf("%s header does not begin with: %s", opts.HeaderName, opts.TokenPrefix)
}
token := strings.TrimPrefix(headerValue, opts.TokenPrefix)
if token == "" {
return "", fmt.Errorf("%s header empty after prefix is trimmed", opts.HeaderName)
}
return token, nil
}