yossis yossis - 2 years ago 461
Java Question

Preemptive Basic authentication with Apache HttpClient 4

Is there an easier way to setup the http client for preemptive basic authentication than what described here?

In previous version (3.x) it used to be a simple method call (eg,


The main thing I want to avoid is adding the BasicHttpContext to each method I execute.

Answer Source

It's difficult to do this without passing a context through every time, but you can probably do it by using a request interceptor. Here is some code that we use (found from their JIRA, iirc):

// Pre-emptive authentication to speed things up
BasicHttpContext localContext = new BasicHttpContext();

BasicScheme basicAuth = new BasicScheme();
localContext.setAttribute("preemptive-auth", basicAuth);

httpClient.addRequestInterceptor(new PreemptiveAuthInterceptor(), 0);


static class PreemptiveAuthInterceptor implements HttpRequestInterceptor {

    public void process(final HttpRequest request, final HttpContext context) throws HttpException, IOException {
        AuthState authState = (AuthState) context.getAttribute(ClientContext.TARGET_AUTH_STATE);

        // If no auth scheme avaialble 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");


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