/**
     * Gets the appropriate crawler client for the given URL.
     * @param url The URL to get a client for.
     * @return The crawler client.
     */
    protected CrawlerClient getClient(final String url) {
        return clientFactory.getClient(url);
    }

    /**
     * Checks if the content has been updated since the last crawl.
     * @param client The crawler client.
     * @param urlQueue The URL queue entry.

 */
package org.codelibs.fess.crawler.client.http.config;

/**
 * POJO configuration for credentials that can be converted to
 * either HC4 Credentials or HC5 Credentials.
 *
 * <p>This class provides a library-independent way to configure
 * authentication credentials that work with both Apache HttpComponents 4.x
 * and 5.x clients.</p>
 *
 * <p>Example usage:</p>
 * <pre>{@code

import org.codelibs.core.lang.StringUtil;
import org.codelibs.fess.Constants;
import org.codelibs.fess.crawler.builder.RequestDataBuilder;
import org.codelibs.fess.crawler.client.CrawlerClient;
import org.codelibs.fess.crawler.client.CrawlerClientFactory;
import org.codelibs.fess.crawler.entity.ResponseData;
import org.codelibs.fess.crawler.entity.ResultData;
import org.codelibs.fess.crawler.exception.ChildUrlsException;

import org.apache.http.auth.Credentials;
import org.apache.http.auth.MalformedChallengeException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.message.BasicNameValuePair;
import org.apache.logging.log4j.LogManager;

     * Here's the order of events that we want.
     *
     * 1. The client thread begins to block on a get() call to a future.
     * 2. The client thread is interrupted sometime before the result would be
     *   available.
     * 3. We expect the client's get() to throw an InterruptedException.
     * 4. We expect the client thread's interrupt state to be false.
     * 5. The client thread again makes a blocking call to get().

 * hashes via NTLM SSP with MSIE. It might also be used directly by servlet
 * containers to incorporate similar functionality.
 * <p>
 * How NTLMSSP is used in conjunction with HTTP and MSIE clients is
 * described in an <A HREF="http://www.innovation.ch/java/ntlm.html">NTLM
 * Authentication Scheme for HTTP</A>.
 * <p>
 * Also, read <a
 * href="../../../ntlmhttpauth.html">jCIFS NTLM HTTP Authentication and

	// accordingly. Client receives a HTTP error for invalid/unsupported
	// signatures.
	//
	// Validates all incoming requests to have a valid date header.
	setAuthMiddleware,
	// Redirect some pre-defined browser request paths to a static location
	// prefix.
	setBrowserRedirectMiddleware,
	// Adds 'crossdomain.xml' policy middleware to serve legacy flash clients.
	setCrossDomainPolicyMiddleware,

	// server admin credentials change. This is done to ensure
	// that clients cannot decode the token using the temp
	// secret keys and generate an entirely new claim by essentially
	// hijacking the policies. We need to make sure that this is
	// based on admin credential such that token cannot be decoded
	// on the client side and is treated like an opaque value.
	claims, err := auth.ExtractClaims(token, secret)

## 处理断开连接和多个客户端 { #handling-disconnections-and-multiple-clients }

当 WebSocket 连接关闭时，`await websocket.receive_text()` 将引发 `WebSocketDisconnect` 异常，您可以捕获并处理该异常，就像本示例中的示例一样。

{* ../../docs_src/websockets_/tutorial003_py310.py hl[79:81] *}

尝试以下操作：

* 使用多个浏览器选项卡打开应用程序。
* 从这些选项卡中发送消息。
* 然后关闭其中一个选项卡。

这将引发 `WebSocketDisconnect` 异常，并且所有其他客户端都会收到类似以下的消息：

```
Client #1596980209979 left the chat
```

/// tip

 * Provides common functionality for handling initialization parameters,
 * content length checks, and default method implementations.
 * It defines the basic structure and configuration options for crawler clients.
 */
public abstract class AbstractCrawlerClient implements CrawlerClient {

    private static final Logger logger = LogManager.getLogger(AbstractCrawlerClient.class);