routing

internal/http/proxy/proxy.go

@@ -0,0 +1,50 @@
+package proxy
+
+import (
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+
+	"github.com/labstack/echo/v4"
+)
+
+type Handler struct {
+	target *url.URL
+	proxy  *httputil.ReverseProxy
+}
+
+func New(target string) (*Handler, error) {
+	parsed, err := url.Parse(target)
+	if err != nil {
+		return nil, err
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(parsed)
+	originalDirector := proxy.Director
+	proxy.Director = func(req *http.Request) {
+		originalDirector(req)
+		req.Host = parsed.Host
+		req.Header.Set("X-Forwarded-Host", req.Header.Get("Host"))
+		req.Header.Set("X-Forwarded-Proto", scheme(req))
+	}
+
+	return &Handler{
+		target: parsed,
+		proxy:  proxy,
+	}, nil
+}
+
+func (h *Handler) Handle(c echo.Context) error {
+	h.proxy.ServeHTTP(c.Response(), c.Request())
+	return nil
+}
+
+func scheme(req *http.Request) string {
+	if req.TLS != nil {
+		return "https"
+	}
+	if header := req.Header.Get("X-Forwarded-Proto"); header != "" {
+		return header
+	}
+	return "http"
+}