我想使用 Go 的 net/http 包编写一个 HTTP 服务器，响应取决于 HTTP 连接的服务器端 IP 地址。

换句话说，我正在寻找的是 CGI 的“SERVER_ADDR”变量。

http.Request 中最接近的字段是“Host”——但如果请求使用文字地址，它只会等于地址，所以我不能使用它(服务器可能按名称使用)。

查看来源 https://golang.org/src/net/http/server.go ，似乎获得服务器地址的唯一方法是劫持()处理程序中的连接并为同一连接上的后续请求实现后续 HTTP 解析，但至少可以说它看起来非常不雅......

看来最理想的方案是将golang标准库中的http/request和http/server修改如下:

diff -u go-stock-library/request.go ./request.go
--- go-stock-library/request.go 2016-04-13 17:31:48.000000000 +0200
+++ ./request.go    2016-04-13 17:32:40.000000000 +0200
@@ -227,6 +227,15 @@
    // This field is ignored by the HTTP client.
    RemoteAddr string

+   // LocalAddr allows HTTP servers and other software to record
+   // the network address that the request was sent to, usually for
+   // logging. This field is not filled in by ReadRequest and
+   // has no defined format. The HTTP server in this package
+   // sets LocalAddr to an "IP:port" address before invoking a
+   // handler.
+   // This field is ignored by the HTTP client.
+   LocalAddr string
+
    // RequestURI is the unmodified Request-URI of the
    // Request-Line (RFC 2616, Section 5.1) as sent by the client
    // to a server. Usually the URL field should be used instead.
diff -u go-stock-library/server.go ./server.go
--- go-stock-library/server.go  2016-04-13 17:29:19.000000000 +0200
+++ ./server.go 2016-04-13 17:31:38.000000000 +0200
@@ -161,6 +161,13 @@
    // This is the value of a Handler's (*Request).RemoteAddr.
    remoteAddr string

+   // serverAddr is rwc.LocalAddr().String(). It is not populated synchronously
+   // inside the Listener's Accept goroutine, as some implementations block.
+   // It is populated immediately inside the (*conn).serve goroutine.
+   // This is the value of a Handler's (*Request).LocalAddr.
+   localAddr string
+   
+
    // tlsState is the TLS connection state when using TLS.
    // nil means not TLS.
    tlsState *tls.ConnectionState
@@ -736,6 +743,7 @@
    delete(req.Header, "Host")

    req.RemoteAddr = c.remoteAddr
+   req.LocalAddr = c.localAddr
    req.TLS = c.tlsState
    if body, ok := req.Body.(*body); ok {
        body.doEarlyClose = true
@@ -1382,6 +1390,7 @@
 // Serve a new connection.
 func (c *conn) serve() {
    c.remoteAddr = c.rwc.RemoteAddr().String()
+   c.localAddr = c.rwc.LocalAddr().String()
    defer func() {
        if err := recover(); err != nil {
            const size = 64 << 10

然后以简洁明了的方式在代码中使用新的 LocalAddr。

有没有更简洁的方法来做到这一点？

最佳答案

我个人不会为了可以通过其他方式获得的内容而修改标准库中的任何内容。从每个连接中解析它有什么好处吗？

可能有更简单的方法，但我有以下方法。

func getMyInterfaceAddr() (net.IP, error) {


    ifaces, err := net.Interfaces()
    if err != nil {
        return nil, err
    }
    addresses := []net.IP{}
    for _, iface := range ifaces {

        if iface.Flags&net.FlagUp == 0 {
            continue // interface down
        }
        if iface.Flags&net.FlagLoopback != 0 {
            continue // loopback interface
        }
        addrs, err := iface.Addrs()
        if err != nil {
            continue
        }

        for _, addr := range addrs {
            var ip net.IP
            switch v := addr.(type) {
            case *net.IPNet:
                ip = v.IP
            case *net.IPAddr:
                ip = v.IP
            }
            if ip == nil || ip.IsLoopback() {
                continue
            }
            ip = ip.To4()
            if ip == nil {
                continue // not an ipv4 address
            }
            addresses = append(addresses, ip)
        }
    }
    if len(addresses) == 0 {
        return nil, fmt.Errorf("no address Found, net.InterfaceAddrs: %v", addresses)
    }
    //only need first
    return addresses[0], nil
}

关于http - 如何使用 net/http 在服务器中获取服务器自己的地址？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36603347/