Springboot RestTemplate Cookie回话保持功能源码阅读

RestTemplate 配置通过HttpClientBuilder.create()方法初始化配置信息其中Cookie是默认打开的可以通过disableCookieManagement()方法禁用Cookie回话保持功能

     /**
     * Rest client filter
     * @return
     */
    @Bean(name = "restClient")
    public RestTemplate getRestClient() {
        CloseableHttpClient build = HttpClientBuilder.create().disableCookieManagement().useSystemProperties().build();

        RestTemplate restClient = new RestTemplate(new HttpComponentsClientHttpRequestFactory(build));
        // set message converters 
        List> messageConverters = new ArrayList>();
        // set string converter
        messageConverters.add(new StringHttpMessageConverter());
        // set json converter
        messageConverters.add(new MappingJackson2HttpMessageConverter());
        // set form converter
        messageConverters.add(new FormHttpMessageConverter());
        restClient.setMessageConverters(messageConverters);
        // return object
        return restClient;
    }

HttpClientBuilder部分源码

public CloseableHttpClient build() {
        b.addAll(
                 new RequestDefaultHeaders(defaultHeaders),
                 new RequestContent(),
                 new RequestTargetHost(),
                 new RequestClientConnControl(),
                 new RequestUserAgent(userAgentCopy),
                 new RequestExpectContinue());
       
       // 禁用Cookie后，RequestAddCookie拦截器将不再处理请求信息
       if (!cookieManagementDisabled) {
            b.add(new RequestAddCookies());
        }
      
       // 禁用Cookie后，ResponseProcessCookies拦截器将不再处理响应信息
       if (!cookieManagementDisabled) {
            b.add(new ResponseProcessCookies());
        }
    }

ResponseProcessCookies源码主要处理Http响应后的Cookie信息，将响应请求头信息中的Set-Cookie，Set-Cookie2保存在CookieStore中。

注：Set-Cookie2此功能已过时。虽然它可能在某些浏览器中仍然有效，但它的使用是不鼓励的，因为它可以在任何时候被删除。尽量避免使用它。过时的Set-Cookie2HTTP 响应标头用于从服务器向用户代理发送 cookie，但已被规范所弃用。Set-Cookie改为使用。

@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class ResponseProcessCookies implements HttpResponseInterceptor {

    private final Log log = LogFactory.getLog(getClass());

    public ResponseProcessCookies() {
        super();
    }

    @Override
    public void process(final HttpResponse response, final HttpContext context)
            throws HttpException, IOException {
        Args.notNull(response, "HTTP request");
        Args.notNull(context, "HTTP context");

        final HttpClientContext clientContext = HttpClientContext.adapt(context);

        // Obtain actual CookieSpec instance
        final CookieSpec cookieSpec = clientContext.getCookieSpec();
        if (cookieSpec == null) {
            this.log.debug("Cookie spec not specified in HTTP context");
            return;
        }
        // 获取已经存储的Cookie信息
        final CookieStore cookieStore = clientContext.getCookieStore();
        if (cookieStore == null) {
            this.log.debug("Cookie store not specified in HTTP context");
            return;
        }
        // 获取Http请求后响应的Cookie信息
        final CookieOrigin cookieOrigin = clientContext.getCookieOrigin();
        if (cookieOrigin == null) {
            this.log.debug("Cookie origin not specified in HTTP context");
            return;
        }
       
        // 读取响应的Set-Cookie请求头信息
        HeaderIterator it = response.headerIterator(SM.SET_COOKIE);
        // 将Set-Cookie写入本地
        processCookies(it, cookieSpec, cookieOrigin, cookieStore);

        // 查看cookie规范是否支持cookie版本控制。
        if (cookieSpec.getVersion() > 0) {
            // 读取响应的Set-Cookie2 请求头信息
            it = response.headerIterator(SM.SET_COOKIE2);
            // 将Set-Cookie2写入本地
            processCookies(it, cookieSpec, cookieOrigin, cookieStore);
        }
    }

    private void processCookies(
            final HeaderIterator iterator,
            final CookieSpec cookieSpec,
            final CookieOrigin cookieOrigin,
            final CookieStore cookieStore) {
        while (iterator.hasNext()) {
            final Header header = iterator.nextHeader();
            try {
                final List cookies = cookieSpec.parse(header, cookieOrigin);
                for (final Cookie cookie : cookies) {
                    try {
                        // 检查Host Domain 过期时间等数据，如果数据不符合会抛出MalformedCookieException
                        cookieSpec.validate(cookie, cookieOrigin);
                        // 写入CookieStore中保持
                        cookieStore.addCookie(cookie);

                        if (this.log.isDebugEnabled()) {
                            this.log.debug("Cookie accepted [" + formatCooke(cookie) + "]");
                        }
                    } catch (final MalformedCookieException ex) {
                        if (this.log.isWarnEnabled()) {
                            this.log.warn("Cookie rejected [" + formatCooke(cookie) + "] "
                                    + ex.getMessage());
                        }
                    }
                }
            } catch (final MalformedCookieException ex) {
                if (this.log.isWarnEnabled()) {
                    this.log.warn("Invalid cookie header: \""
                            + header + "\". " + ex.getMessage());
                }
            }
        }
    }
}

RequestAddCookies 源码 1.查找当前Domain下的Cookie信息存储在matchedCookies中 2.检查是否Cookie超时 3.匹配Domain信息，将符合该Domain的Cookie取出存储在matchedCookies中 4.如果有过期Cookie需要清理(超过当前时间的Cookie都清理掉)。5.Header添加Cookie信息(Cookie,Cookie2)

@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class RequestAddCookies implements HttpRequestInterceptor {

    private final Log log = LogFactory.getLog(getClass());

    public RequestAddCookies() {
        super();
    }

    @Override
    public void process(final HttpRequest request, final HttpContext context)
            throws HttpException, IOException {
        Args.notNull(request, "HTTP request");
        Args.notNull(context, "HTTP context");

        final String method = request.getRequestLine().getMethod();
        // 忽略http connect方法
        if (method.equalsIgnoreCase("CONNECT")) {
            return;
        }

        final HttpClientContext clientContext = HttpClientContext.adapt(context);

        // 读取CookieStore中的Cookie信息(在ResponseProcessCookies写入的)
        final CookieStore cookieStore = clientContext.getCookieStore();
        if (cookieStore == null) {
            this.log.debug("Cookie store not specified in HTTP context");
            return;
        }

        // Obtain the registry of cookie specs
        final Lookup registry = clientContext.getCookieSpecRegistry();
        if (registry == null) {
            this.log.debug("CookieSpec registry not specified in HTTP context");
            return;
        }

        // Obtain the target host, possibly virtual (required)
        final HttpHost targetHost = clientContext.getTargetHost();
        if (targetHost == null) {
            this.log.debug("Target host not set in the context");
            return;
        }

        // Obtain the route (required)
        final RouteInfo route = clientContext.getHttpRoute();
        if (route == null) {
            this.log.debug("Connection route not set in the context");
            return;
        }

        final RequestConfig config = clientContext.getRequestConfig();
        String policy = config.getCookieSpec();
        if (policy == null) {
            policy = CookieSpecs.DEFAULT;
        }
        if (this.log.isDebugEnabled()) {
            this.log.debug("CookieSpec selected: " + policy);
        }

        URI requestURI = null;
        if (request instanceof HttpUriRequest) {
            requestURI = ((HttpUriRequest) request).getURI();
        } else {
            try {
                requestURI = new URI(request.getRequestLine().getUri());
            } catch (final URISyntaxException ignore) {
            }
        }
        final String path = requestURI != null ? requestURI.getPath() : null;
        final String hostName = targetHost.getHostName();
        int port = targetHost.getPort();
        if (port < 0) {
            port = route.getTargetHost().getPort();
        }

        final CookieOrigin cookieOrigin = new CookieOrigin(
                hostName,
                port >= 0 ? port : 0,
                !TextUtils.isEmpty(path) ? path : "/",
                route.isSecure());

        // Get an instance of the selected cookie policy
        final CookieSpecProvider provider = registry.lookup(policy);
        if (provider == null) {
            if (this.log.isDebugEnabled()) {
                this.log.debug("Unsupported cookie policy: " + policy);
            }

            return;
        }
        final CookieSpec cookieSpec = provider.create(clientContext);
        // Get all cookies available in the HTTP state
        final List cookies = cookieStore.getCookies();
        // 查找当前Domain下的Cookie信息存储在matchedCookies中
        final List matchedCookies = new ArrayList();
        final Date now = new Date();
        boolean expired = false;
        for (final Cookie cookie : cookies) {
            // 检查是否Cookie超时
            if (!cookie.isExpired(now)) {
                //匹配Domain信息，将符合该Domain的Cookie取出存储在matchedCookies中。
                if (cookieSpec.match(cookie, cookieOrigin)) {
                    if (this.log.isDebugEnabled()) {
                        this.log.debug("Cookie " + cookie + " match " + cookieOrigin);
                    }
                    // 存储在matchedCookies
                    matchedCookies.add(cookie);
                }
            } else {
                if (this.log.isDebugEnabled()) {
                    this.log.debug("Cookie " + cookie + " expired");
                }
                //标记Cookie过期
                expired = true;
            }
        }
        // 如果有过期Cookie需要清理(超过当前时间的Cookie都清理掉)。
        if (expired) {
            cookieStore.clearExpired(now);
        }
        // 如果匹配到Cookie数据
        if (!matchedCookies.isEmpty()) {
            final List
 headers = cookieSpec.formatCookies(matchedCookies);
            // 将Cookie加入Http请求头中
            for (final Header header : headers) {
                // 实际上Header中存储的信息为：（Cookie:TOKEN=8CB982A185805907846DB042C469104；JSESSIONID=282294701B045845915AF1466B84527D）
                request.addHeader(header);
            }
        }

        final int ver = cookieSpec.getVersion();
        if (ver > 0) {
            // 获取Cookie2的请求信息（Cookie2:TOKEN=8CB982A185805907846DB042C469104；JSESSIONID=282294701B045845915AF1466B84527D）
            final Header header = cookieSpec.getVersionHeader();
            if (header != null) {
                // 将Cookie2加入Http请求头中
                request.addHeader(header);
            }
        }

        // Stick the CookieSpec and CookieOrigin instances to the HTTP context
        // so they could be obtained by the response interceptor
        context.setAttribute(HttpClientContext.COOKIE_SPEC, cookieSpec);
        context.setAttribute(HttpClientContext.COOKIE_ORIGIN, cookieOrigin);
    }

}