47 lines
1.4 KiB
Go
47 lines
1.4 KiB
Go
// ui-proxy exposes the read-only loopback viewer to the private Docker gateway.
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package main
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import (
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"flag"
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"log"
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"net"
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"net/http"
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"net/http/httputil"
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"net/url"
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"time"
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)
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func handler(target *url.URL) http.Handler {
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proxy := httputil.NewSingleHostReverseProxy(target)
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original := proxy.Director
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proxy.Director = func(r *http.Request) {
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original(r)
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r.Host = target.Host
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// The viewer is read-only behind NPM; do not forward the public browser origin
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// into the loopback-only origin guard. Mutating methods are rejected below.
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r.Header.Del("Origin")
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}
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proxy.FlushInterval = -1 // stream SSE immediately
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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if r.Method != http.MethodGet && r.Method != http.MethodHead {
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w.Header().Set("Allow", "GET, HEAD")
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http.Error(w, "read-only viewer", http.StatusMethodNotAllowed)
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return
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}
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proxy.ServeHTTP(w, r)
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})
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}
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func main() {
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address := flag.String("listen", "172.20.0.1:18082", "Private Docker gateway listener")
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flag.Parse()
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host, _, err := net.SplitHostPort(*address)
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ip := net.ParseIP(host)
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if err != nil || ip == nil || !ip.IsPrivate() {
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log.Fatal("listen must use an explicit private IP and port")
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}
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target, _ := url.Parse("http://127.0.0.1:18080")
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server := &http.Server{Addr: *address, Handler: handler(target), ReadHeaderTimeout: 5 * time.Second, IdleTimeout: 60 * time.Second, MaxHeaderBytes: 8 << 10}
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log.Fatal(server.ListenAndServe())
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}
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