correcting some behaviors for $DOCKER_HOST, now uses container's private IP instead of localhost

internal/api/v1/errorpage/http_handler.go

@@ -0,0 +1,31 @@
+package errorpage
+
+import (
+	"net/http"
+
+	. "github.com/yusing/go-proxy/internal/api/v1/utils"
+)
+
+func GetHandleFunc() http.HandlerFunc {
+	setup()
+	return serveHTTP
+}
+
+func serveHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+	if r.URL.Path == "/" {
+		http.Error(w, "invalid path", http.StatusNotFound)
+		return
+	}
+	content, ok := fileContentMap.Load(r.URL.Path)
+	if !ok {
+		http.Error(w, "404 not found", http.StatusNotFound)
+		return
+	}
+	if _, err := w.Write(content); err != nil {
+		HandleErr(w, r, err)
+	}
+}