使用Apache HttpClient 4的抢占式基本身份验证

Question

是否有比此处描述的更简单的方法来设置HTTP客户端以进行抢占式基本身份验证？
在以前的版本（3.x）中，它曾经是一个简单的方法调用（例如httpClient.getParams().setAuthenticationPreemptive(true)）。
我要避免的主要事情是将BasicHttpContext添加到我执行的每个方法中。

Answer 1

不每次都传递上下文很难做到这一点，但是你可以使用请求拦截器来做到这一点。这是我们使用的一些代码（从JIRA iirc中找到）：

// 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");
                }
                authState.setAuthScheme(authScheme);
                authState.setCredentials(creds);
            }
        }

    }

}