如何使用apachejavaHttpClient4.5从CONNECT请求中检索响应头

Question

我使用http代理通过CloseableHttpClient连接https网站。首先发送CONNECT请求，因为它必须进行隧道连接。将发送响应标头，我需要检索它们。结果将存储在一个变量中，稍后使用。

在HttpClient 4.2上，我可以使用HttpResponseInterceptor实现它：

final DefaultHttpClient httpClient = new DefaultHttpClient();
//configure proxy

httpclient.addResponseInterceptor(new HttpResponseInterceptor() {
public void process(HttpResponse httpResponse, HttpContext httpContext) throws HttpException, IOException {
final Header[] headers = httpResponse.getAllHeaders();
//store headers
}
});

但当我使用HttpClient 4.5时，我的响应拦截器从未在CONNECT请求上调用过。它直接跳转到GET或POST请求：

final CloseableHttpClient httpClient = HttpClients.custom()
.setProxy(new HttpHost(proxyHost, proxyPort, "http"))
.addInterceptorFirst(new HttpResponseInterceptor() {
public void process(HttpResponse httpResponse, HttpContext httpContext) throws HttpException, IOException {
final Header[] headers = httpResponse.getAllHeaders();
//store headers
}
}).build();

方法setInterceptorLast()和setHttpProcessor()的结果相同。提前感谢：(

Answer 1

您将需要一个自定义HttpClientBuilder类，以便能够将自定义协议拦截器添加到用于执行CONNECT方法的HTTP协议处理器中。

HttpClient 4.5它不漂亮，但它会完成任务：

HttpClientBuilder builder = new HttpClientBuilder() {
@Override
protected ClientExecChain createMainExec(
HttpRequestExecutor requestExec,
HttpClientConnectionManager connManager,
ConnectionReuseStrategy reuseStrategy,
ConnectionKeepAliveStrategy keepAliveStrategy,
HttpProcessor proxyHttpProcessor,
AuthenticationStrategy targetAuthStrategy,
AuthenticationStrategy proxyAuthStrategy,
UserTokenHandler userTokenHandler) {
final ImmutableHttpProcessor myProxyHttpProcessor = new ImmutableHttpProcessor(
Arrays.asList(new RequestTargetHost()),
Arrays.asList(new HttpResponseInterceptor() {
@Override
public void process(
HttpResponse response,
HttpContext context) throws HttpException, IOException {
}
})
);
return super.createMainExec(requestExec, connManager, reuseStrategy, keepAliveStrategy,
myProxyHttpProcessor, targetAuthStrategy, proxyAuthStrategy, userTokenHandler);
}
};

HttpClient 5.0 classic:

CloseableHttpClient httpClient = HttpClientBuilder.create()
.replaceExecInterceptor(ChainElement.CONNECT.name(),
new ConnectExec(
DefaultConnectionReuseStrategy.INSTANCE,
new DefaultHttpProcessor(new RequestTargetHost()),
DefaultAuthenticationStrategy.INSTANCE))
.build();