52 lines
1.4 KiB
Go
52 lines
1.4 KiB
Go
package serve
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import (
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"context"
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"net/http"
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"net/netip"
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"strings"
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"git.sunturtle.xyz/studio/shotgun/player"
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)
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// WithPlayerID is a middleware that adds a player ID to the request context
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// based on the X-Forwarded-For header. If there is no such header, or the
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// originator addr otherwise cannot be parsed from it, the request fails with
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// a 500 error.
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func WithPlayerID(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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ff := r.Header.Get("X-Forwarded-For")
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addr, err := originator(ff)
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if err != nil {
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http.Error(w, "missing or invalid X-Forwarded-For header; check server configuration", http.StatusInternalServerError)
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return
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}
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id := player.ID(addr.As16())
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ctx := ctxWith(r.Context(), id)
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next.ServeHTTP(w, r.WithContext(ctx))
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})
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}
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// Player returns the player ID set by WithPlayerID in the request context.
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func PlayerID(ctx context.Context) player.ID {
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return ctxValue[player.ID](ctx)
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}
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// originator parses the IP of the client that originated a request from the
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// content of its X-Forwarded-For header.
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func originator(ff string) (netip.Addr, error) {
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ff, _, _ = strings.Cut(ff, ",")
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return netip.ParseAddr(ff)
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}
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type ctxKey[T any] struct{}
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func ctxValue[T any](ctx context.Context) T {
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r, _ := ctx.Value(ctxKey[T]{}).(T)
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return r
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}
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func ctxWith[T any](ctx context.Context, v T) context.Context {
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return context.WithValue(ctx, ctxKey[T]{}, v)
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}
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