AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);
// If no auth scheme available yet, try to initialize it preemptively
if (authState.getAuthScheme() == null) {
AuthScheme authScheme = (AuthScheme) context.getAttribute("preemptive-auth");
CredentialsProvider credsProvider = (CredentialsProvider) context.getAttribute(ClientContext.CREDS_PROVIDER);
HttpHost targetHost = (HttpHost) context.getAttribute(ExecutionContext.HTTP_TARGET_HOST);
if (authScheme != null) {
Credentials creds = credsProvider.getCredentials(new AuthScope(targetHost.getHostName(), targetHost.getPort()));
if (creds == null) {
throw new HttpException("No credentials for preemptive authentication");
}
authState.setAuthScheme(authScheme);
authState.setCredentials(creds);