问题描述
我们使用 Apache (2.4.41) 网络服务器作为 tomcat (8.5) 的反向代理,该服务器运行自实现的负载平衡器。 Apache 网络服务器负责前端 TLS 的工作,并通过 AJP (mod_proxy_ajp) 与 tomcat 对话。在我们的负载均衡器中,我们使用 request.getAttributeNames() 来评估请求属性。一段时间以来,出现带有以下键的空请求属性:
- org.apache.tomcat.util.net.secure_protocol_version
- javax.servlet.request.key_size
- javax.servlet.request.cipher_suite
- javax.servlet.request.ssl_session_id
我阅读了文档和源代码,但无法弄清楚为什么这些空属性仍然存在于请求中。根据 tomcat request 中 getAttributeNames() 的 javadoc,大多数 TLS 特定属性不应通过此方法获取:
/**
* Return the names of all request attributes for this Request,or an
* empty <code>Enumeration</code> if there are none. Note that the attribute
* names returned will only be those for the attributes set via
* {@link #setAttribute(String,Object)}. Tomcat internal attributes will
* not be included although they are accessible via
* {@link #getAttribute(String)}. The Tomcat internal attributes include:
* <ul>
* <li>{@link Globals#disPATCHER_TYPE_ATTR}</li>
* <li>{@link Globals#disPATCHER_REQUEST_PATH_ATTR}</li>
* <li>{@link Globals#ASYNC_SUPPORTED_ATTR}</li>
* <li>{@link Globals#CERTIFICATES_ATTR} (SSL connections only)</li>
* <li>{@link Globals#CIPHER_SUITE_ATTR} (SSL connections only)</li>
* <li>{@link Globals#KEY_SIZE_ATTR} (SSL connections only)</li>
* <li>{@link Globals#SSL_SESSION_ID_ATTR} (SSL connections only)</li>
* <li>{@link Globals#SSL_SESSION_MGR_ATTR} (SSL connections only)</li>
* <li>{@link Globals#ParaMETER_PARSE_Failed_ATTR}</li>
* </ul>
* The underlying connector may also expose request attributes. These all
* have names starting with "org.apache.tomcat" and include:
* <ul>
* <li>{@link Globals#SENDFILE_SUPPORTED_ATTR}</li>
* </ul>
* Connector implementations may return some,all or none of these
* attributes and may also support additional attributes.
*
* @return the attribute names enumeration
*/
@Override
public Enumeration<String> getAttributeNames() {
也许有些人可以对此有所了解。提前致谢!
解决方法
Javadoc 并不完全正确:正如您在引用的 source code 中看到的那样,getAttributeNames
没有列出这些内部属性除非您已经调用了 {{1}对于其中之一:
getAttribute