Oscar Zhou
45 lines
1.4 KiB
Go
45 lines
1.4 KiB
Go
package middlewares
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import (
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"net/http"
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"strings"
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)
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// parseForwardedHeaderProto parses the Forwarded header and extracts the protocol.
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// The Forwarded header format supports:
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// - Single proxy: Forwarded: by=<identifier>;for=<identifier>;host=<host>;proto=<http|https>
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// - Multiple proxies: Forwarded: for=192.0.2.43, for=198.51.100.17
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// We take the first (leftmost) entry as it represents the original client
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func parseForwardedHeaderProto(forwarded string) string {
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if forwarded == "" {
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return ""
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}
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// Parse the first part (leftmost proxy, closest to original client)
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firstPart, _, _ := strings.Cut(forwarded, ",")
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firstPart = strings.TrimSpace(firstPart)
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// Split by semicolon to get key-value pairs within this proxy entry
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// Format: key=value;key=value;key=value
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for pair := range strings.SplitSeq(firstPart, ";") {
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// Split by equals sign to separate key and value
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key, value, found := strings.Cut(pair, "=")
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if !found {
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continue
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}
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if strings.EqualFold(strings.TrimSpace(key), "proto") {
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return strings.Trim(strings.TrimSpace(value), `"'`)
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}
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}
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return ""
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}
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// IsHTTPSRequest checks if the original request was made over HTTPS
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// by examining both X-Forwarded-Proto and Forwarded headers
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func IsHTTPSRequest(r *http.Request) bool {
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return strings.EqualFold(r.Header.Get("X-Forwarded-Proto"), "https") ||
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strings.EqualFold(parseForwardedHeaderProto(r.Header.Get("Forwarded")), "https")
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}
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