java-使用过滤器检查远程地址 [英] java- using a filter to check remote address

问题描述

检测Web应用程序是否在本地访问的最佳方法是什么？

我有兴趣在过滤器（ javax .servlet.Filter ）。

我可以检查 ServletRequest＃getRemoteAddr（）如果它是 127.0.0.1 但如果它在IPv6机器上运行，则地址为 0：0：0：0：0：0：0：1 。

是否还有其他陷阱我应该注意，或者如果我只检查这两种字符串模式，我会没事的？

What would be the best approach to detect if a web application is accessed locally?
I am interested in checking this in a filter (javax.servlet.Filter).
I could check the ServletRequest#getRemoteAddr() if it is 127.0.0.1 but if it is running in a IPv6 machine, the address would be 0:0:0:0:0:0:0:1.
Are there any other pitfalls I should be aware of, or if I just check for these 2 string patterns, I would be ok?

谢谢

推荐答案

理论上，以下应该足够了。

In theory, the following ought to be sufficient.

if (request.getRemoteAddr().equals(request.getLocalAddr())) {
    // Locally accessed.
} else {
    // Remotely accessed.
}

更新， request.getLocalAddr（）似乎返回 0.0.0.0 当服务器位于代理服务器后面时确实会发生这种情况。

Update as per the comments, request.getLocalAddr() seems to return 0.0.0.0 which can indeed happen when the server is behind a proxy.

您可能希望将其与地址由 InetAddress 。

You may instead want to compare it against the addresses as resolved by InetAddress.

private Set<String> localAddresses = new HashSet<String>(); 

@Override
public void init(FilterConfig config) throws ServletException {
    try {
        localAddresses.add(InetAddress.getLocalHost().getHostAddress());
        for (InetAddress inetAddress : InetAddress.getAllByName("localhost")) {
            localAddresses.add(inetAddress.getHostAddress());
        }
    } catch (IOException e) {
        throw new ServletException("Unable to lookup local addresses");
    }
}

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
    if (localAddresses.contains(request.getRemoteAddr())) {
        // Locally accessed.
    } else {
        // Remotely accessed.
    }
}

在我的情况下， localAddresses 包含以下内容：

In my case, the localAddresses contains the following:

[192.168.1.101, 0:0:0:0:0:0:0:1, 127.0.0.1]

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