49 lines
1.4 KiB
Go
49 lines
1.4 KiB
Go
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package middleware
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import (
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"net/http"
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"strings"
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)
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// RealIP is a middleware that sets a http.Request's RemoteAddr to the results
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// of parsing either the X-Forwarded-For header or the X-Real-IP header (in that
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// order).
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//
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// This middleware should be inserted fairly early in the middleware stack to
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// ensure that subsequent layers (e.g., request loggers) which examine the
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// RemoteAddr will see the intended value.
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//
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// You should only use this middleware if you can trust the headers passed to
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// you (in particular, the two headers this middleware uses), for example
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// because you have placed a reverse proxy like HAProxy or nginx in front of
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// chi. If your reverse proxies are configured to pass along arbitrary header
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// values from the client, or if you use this middleware without a reverse
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// proxy, malicious clients will be able to make you very sad (or, depending on
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// how you're using RemoteAddr, vulnerable to an attack of some sort).
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func RealIP(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if rip := realIP(r); rip != "" {
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r.RemoteAddr = rip
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}
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next.ServeHTTP(w, r)
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})
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}
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func realIP(r *http.Request) string {
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if xrip := r.Header.Get("X-Real-IP"); xrip != "" {
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return xrip
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}
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if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
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i := strings.Index(xff, ", ")
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if i == -1 {
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i = len(xff)
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}
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return xff[:i]
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}
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return ""
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}
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