restTemplate重定向问题 &cookie问题

最近在做一个转发功能，zuul + ribbon + resttemplate 进行路由、负载、转发的功能

基本准备就绪，在微信自动登陆那遇到了一个坑，ribbon 系统用resttemplate 转发A系统的资源，在微信自动登陆的地方，A系统重定向到微信的地址，类似下面的代码

redirect:
https://open.weixin.qq.com/connect/oauth2/authorize?appid=wx3290f3d5****&redirect_uri=http://***.com/weixin/wxAuthRedirect?redirectUrl=http%3A%2F%2F192.168.10.116%3A8081%2Finternal%2Fpage%2Fuser%2Flogin_wx&response_type=code&scope=snsapi_userinfo&state=state#wechat_redirect

结果resttemplate 自动重定向到本地的地址，如下所示：

http://192.168.10.116:**/connect/oauth2/authorize**

仔细思考了下，大概就是resttemplate 的重定向问题，查了查资料，找到一个类HttpComponentsClientHttpRequestFactory，RestTemplate初始化提供了这个类的参数

    /**
     * Create a new instance of the {@link RestTemplate} based on the given {@link ClientHttpRequestFactory}.
     * @param requestFactory HTTP request factory to use
     * @see org.springframework.http.client.SimpleClientHttpRequestFactory
     * @see org.springframework.http.client.HttpComponentsClientHttpRequestFactory
     */
    public RestTemplate(ClientHttpRequestFactory requestFactory) {
        this();
        setRequestFactory(requestFactory);
    }

HttpComponentsClientHttpRequestFactory继承自ClientHttpRequestFactory，这个类的子类有HttpComponentsClientHttpRequestFactory和SimpleClientHttpRequestFactory

找到SimpleClientHttpRequestFactory，有如下方法：

第一种方式：

    /**
     * Template method for preparing the given {@link HttpURLConnection}.
     * <p>The default implementation prepares the connection for input and output, and sets the HTTP method.
     * @param connection the connection to prepare
     * @param httpMethod the HTTP request method ({@code GET}, {@code POST}, etc.)
     * @throws IOException in case of I/O errors
     */
    protected void prepareConnection(HttpURLConnection connection, String httpMethod) throws IOException {
        if (this.connectTimeout >= 0) {
            connection.setConnectTimeout(this.connectTimeout);
        }
        if (this.readTimeout >= 0) {
            connection.setReadTimeout(this.readTimeout);
        }

        connection.setDoInput(true);

        if ("GET".equals(httpMethod)) {
            connection.setInstanceFollowRedirects(true);
        }
        else {
            connection.setInstanceFollowRedirects(false);
        }

        if ("POST".equals(httpMethod) || "PUT".equals(httpMethod) ||
                "PATCH".equals(httpMethod) || "DELETE".equals(httpMethod)) {
            connection.setDoOutput(true);
        }
        else {
            connection.setDoOutput(false);
        }

        connection.setRequestMethod(httpMethod);
    }

可以看到setInstanceFollowRedirects，get请求是可以重定向的，其他方法禁止了重定向，于是建个SimpleClientHttpRequestFactory的子类，禁用重定向。

于是乎 NoRedirectClientHttpRequestFactory.java

import java.io.IOException;
import java.net.HttpURLConnection;

import org.springframework.http.client.SimpleClientHttpRequestFactory;

public class NoRedirectClientHttpRequestFactory extends SimpleClientHttpRequestFactory {

    @Override
    protected void prepareConnection(HttpURLConnection connection, String httpMethod) throws IOException {
        // TODO Auto-generated method stub
        super.prepareConnection(connection, httpMethod);
        // 禁止自动重定向
        connection.setFollowRedirects(false);
    }
}

NoRedirectClientHttpRequestFactory httpRequestFactory = new NoRedirectClientHttpRequestFactory();
RestTemplate restTemplate = new RestTemplate(httpRequestFactory);

接着，似乎更换ClientHttpRequestFactory并不合心意，还是要使用HttpComponentsClientHttpRequestFactory来实现，HttpComponentsClientHttpRequestFactory是可以自定义HttpClient的，于是查到了HttpClient头上，HttpClient是可以设置Redirect的，

第二种方式：

HttpClient httpClient = HttpClientBuilder.create()
                .setRedirectStrategy(new LaxRedirectStrategy())
                .build();
httpRequestFactory.setHttpClient(httpClient);
RestTemplate restTemplate = new RestTemplate(httpRequestFactory);

默认提供了两个类，DefaultRedirectStrategy和LaxRedirectStrategy，LaxRedirectStrategy继承自DefaultRedirectStrategy

DefaultRedirectStrategy.java

    /**
     * Redirectable methods.
     */
    private static final String[] REDIRECT_METHODS = new String[] {
        HttpGet.METHOD_NAME,
        HttpHead.METHOD_NAME
    };

LaxRedirectStrategy.java

/*
 * ====================================================================
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 */

package org.apache.http.impl.client;

import org.apache.http.annotation.Contract;
import org.apache.http.annotation.ThreadingBehavior;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpHead;
import org.apache.http.client.methods.HttpPost;

/**
 * Lax {@link org.apache.http.client.RedirectStrategy} implementation
 * that automatically redirects all HEAD, GET, POST, and DELETE requests.
 * This strategy relaxes restrictions on automatic redirection of
 * POST methods imposed by the HTTP specification.
 *
 * @since 4.2
 */
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class LaxRedirectStrategy extends DefaultRedirectStrategy {

    public static final LaxRedirectStrategy INSTANCE = new LaxRedirectStrategy();

    /**
     * Redirectable methods.
     */
    private static final String[] REDIRECT_METHODS = new String[] {
        HttpGet.METHOD_NAME,
        HttpPost.METHOD_NAME,
        HttpHead.METHOD_NAME,
        HttpDelete.METHOD_NAME
    };

    @Override
    protected boolean isRedirectable(final String method) {
        for (final String m: REDIRECT_METHODS) {
            if (m.equalsIgnoreCase(method)) {
                return true;
            }
        }
        return false;
    }

}

这就很清晰了，copy一份LaxRedirectStrategy的代码，改写掉REDIRECT_METHODS中的定义方法，如下：

import org.apache.http.annotation.Contract;
import org.apache.http.annotation.ThreadingBehavior;
import org.apache.http.impl.client.DefaultRedirectStrategy;

/**
 * 
* @ClassName: MyRedirectStrategy 
* @Description: TODO
* @author thinklight
* @date 2018年4月20日 下午2:47:29 
*
 */
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class MyRedirectStrategy  extends DefaultRedirectStrategy {

    public static final MyRedirectStrategy INSTANCE = new MyRedirectStrategy();

    /**
     * Redirectable methods.
     */
    private static final String[] REDIRECT_METHODS = new String[] {};

    @Override
    protected boolean isRedirectable(final String method) {
        for (final String m: REDIRECT_METHODS) {
            if (m.equalsIgnoreCase(method)) {
                return true;
            }
        }
        return false;
    }
}

ribbon+微信各种重定向问题，解决了。

第三种方式：

自己蠢了，今天因为cookie的问题发现了简单的方式

HttpClient httpClient = HttpClientBuilder.create().disableCookieManagement().disableRedirectHandling().build();

完整代码如下：

    @Autowired
    RestTemplate restTemplate;
    
    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        HttpComponentsClientHttpRequestFactory httpRequestFactory = new HttpComponentsClientHttpRequestFactory();
//        NoRedirectClientHttpRequestFactory httpRequestFactory = new NoRedirectClientHttpRequestFactory();// 此类型不能使用httpClient
        httpRequestFactory.setConnectionRequestTimeout(2000);
        httpRequestFactory.setConnectTimeout(10000);
        httpRequestFactory.setReadTimeout(7200000);
        // HttpClient httpClient = HttpClientBuilder.create()
        //        .setRedirectStrategy(new MyRedirectStrategy())
        //        .build();
　　　　 HttpClient httpClient = HttpClientBuilder.create().disableCookieManagement().disableRedirectHandling().build();
        httpRequestFactory.setHttpClient(httpClient);
        RestTemplate restTemplate = new RestTemplate(httpRequestFactory);
        logger.debug("指定字符编码为UTF-8,原编码为ISO-8859-1");
        restTemplate.getMessageConverters().set(1, new StringHttpMessageConverter(StandardCharsets.UTF_8));
        logger.debug("RestTemple默认能转换为application/json，转换追加text/plain类型");
        restTemplate.getMessageConverters().add(new WxMappingJackson2HttpMessageConverter());
        return restTemplate;
    }

重定向参考：https://www.dozer.cc/2014/05/disable-resttemplate-redirect.html

cookie参考：https://stackoverflow.com/questions/10175649/resttemplate-and-cookie

https://stackoverflow.com/questions/22853321/resttemplate-client-with-cookies