[KEYCLOAK-10633] Fix oauth uri slash issue when using base-uri

config.go

@@ -77,10 +77,10 @@ func newDefaultConfig() *Config {
 // WithOAuthURI returns the oauth uri
 func (r *Config) WithOAuthURI(uri string) string {
 	if r.BaseURI != "" {
-		return fmt.Sprintf("%s/%s/%s", r.BaseURI, r.OAuthURI, uri)
+		return fmt.Sprintf("%s%s%s", r.BaseURI, r.OAuthURI, uri)
 	}
 
-	return fmt.Sprintf("%s/%s", r.OAuthURI, uri)
+	return fmt.Sprintf("%s%s", r.OAuthURI, uri)
 }
 
 // isValid validates if the config is valid

handlers.go

@@ -63,7 +63,8 @@ func (r *oauthProxy) getRedirectionURL(w http.ResponseWriter, req *http.Request)
 		w.WriteHeader(http.StatusForbidden)
 		return ""
 	}
-	return fmt.Sprintf("%s%s", redirect, r.config.WithOAuthURI("callback"))
+
+	return fmt.Sprintf("%s%s", redirect, r.config.WithOAuthURI(callbackURL))
 }
 
 // oauthAuthorizationHandler is responsible for performing the redirection to oauth provider