From c303b61eb25bad9cb0f4c280482c564e2adb595f Mon Sep 17 00:00:00 2001
From: Karl Breuer <mail@karlbreuer.com>
Date: Mon, 24 Mar 2025 14:48:01 +0100
Subject: [PATCH] initial

---
 .gitignore                    |   2 +-
 pkg/palanticshelper/server.go | 132 ++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+), 1 deletion(-)
 create mode 100644 pkg/palanticshelper/server.go

diff --git a/.gitignore b/.gitignore
index 1d6812e..6e2ee72 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 .env
 deploy.sh
-palanticshelper
\ No newline at end of file
+/palanticshelper
\ No newline at end of file
diff --git a/pkg/palanticshelper/server.go b/pkg/palanticshelper/server.go
new file mode 100644
index 0000000..d9eba63
--- /dev/null
+++ b/pkg/palanticshelper/server.go
@@ -0,0 +1,132 @@
+package palanticshelper
+
+import (
+	"encoding/json"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"gitea.karlbreuer.com/karl/palanticshelper/pkg/settings"
+	"github.com/go-chi/chi"
+	"github.com/go-chi/chi/middleware"
+	"github.com/go-chi/cors"
+)
+
+func StartServer() {
+	r := chi.NewRouter()
+	r.Use(middleware.RealIP)
+
+	allowedOrigins := []string{"*." + settings.Settings.Domain}
+	if settings.Settings.Debug {
+		allowedOrigins = []string{"*"}
+	}
+
+	r.Use(cors.Handler(cors.Options{
+		AllowedOrigins:   allowedOrigins,
+		AllowedHeaders:   []string{"Accept", "Authorization", "Content-Type", "X-CSRF-Token", "Id"},
+		AllowedMethods:   []string{"GET", "POST", "PUT", "DELETE", "OPTIONS", "Settings"},
+		ExposedHeaders:   []string{"Link"},
+		AllowCredentials: false,
+		MaxAge:           300, // Maximum value not ignored by any of major browsers
+	}))
+
+	r.Get("/healthz", health)
+	r.Post("/*", forwardToTracker)
+
+	portNum, err := strconv.Atoi(strings.TrimSpace(settings.Settings.Port))
+	if err != nil {
+		log.Fatalf("Invalid port number: %v", err)
+	}
+	srv := &http.Server{
+		Handler: r,
+		Addr:    fmt.Sprintf(":%d", portNum),
+	}
+
+	log.Printf("runs on: %s", srv.Addr)
+	err = srv.ListenAndServe()
+	if err != nil {
+		fmt.Println(err)
+	}
+}
+
+func forwardToTracker(w http.ResponseWriter, r *http.Request) {
+	if err := r.ParseForm(); err != nil {
+		log.Printf("Error parsing form: %v", err)
+		RespondWithJSON(w, http.StatusBadRequest, struct{}{})
+		return
+	}
+
+	forwardURL := "https://" + settings.Settings.TrackingServerURL + "/spur"
+
+	req, err := http.NewRequest(r.Method, forwardURL, nil)
+	if err != nil {
+		log.Printf("Error creating request: %v", err)
+		RespondWithJSON(w, http.StatusInternalServerError, struct{}{})
+		return
+	}
+
+	q := r.URL.Query()
+
+	realIp := getRealIP(r)
+	q.Add("ip", realIp)
+
+	req.URL.RawQuery = q.Encode()
+
+	for name, values := range r.Header {
+		for _, value := range values {
+			req.Header.Add(name, value)
+		}
+	}
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Printf("Error forwarding request: %v", err)
+		RespondWithJSON(w, http.StatusInternalServerError, struct{}{})
+		return
+	}
+	defer resp.Body.Close()
+
+	RespondWithJSON(w, http.StatusOK, struct{}{})
+}
+
+func health(w http.ResponseWriter, r *http.Request) {
+	RespondWithJSON(w, 200, struct{}{})
+}
+
+func RespondWithJSON(w http.ResponseWriter, statuscode int, payload interface{}) {
+	var dat []byte
+	w.Header().Add("Content-Type", "application/json")
+	dat, _ = json.Marshal(payload)
+	w.WriteHeader(statuscode)
+	w.Write(dat)
+}
+
+func getRealIP(r *http.Request) string {
+	// NGINX
+	ip := r.Header.Get("X-Real-IP")
+	if ip != "" {
+		return ip
+	}
+	// TRAEFIK
+	forwardedFor := r.Header.Get("X-Forwarded-For")
+	if forwardedFor != "" {
+		// X-Forwarded-For might contain multiple IPs - the leftmost is the original client
+		ips := strings.Split(forwardedFor, ",")
+		if len(ips) > 0 {
+			return strings.TrimSpace(ips[0])
+		}
+	}
+
+	log.Println("ERROR getting forwared IP!")
+	ip, _, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+
+		ip = r.RemoteAddr
+	}
+
+	return ip
+}