code: @GetMapping("/sp/{client}/metadata")
      public ResponseEntity<String> getServiceProviderMetadataByName(@PathVariable("client") final String client) {
          val saml2Client = (SAML2Client) builtClients.findClient(client);
          if (saml2Client != null) {
              return getSaml2ClientServiceProviderMetadataResponseEntity(saml2Client);
          }
          return getNotAcceptableResponseEntity();
      }
docs: Gets service provider metadata by name.
  
  @param client the client
  @return the service provider metadata by name