From 16b1d8148ddb14cef11759da032d0b815eadb2cb Mon Sep 17 00:00:00 2001
From: Denozordec <shatskiy.blog@gmail.com>
Date: Mon, 30 Mar 2026 00:04:45 +0700
Subject: [PATCH] Refactor reverse proxy to support API base path and update
 example configuration. Changed base URLs in config.example.yaml to use HTTPS
 and the new /api/ prefix. Enhanced reverse proxy logic in reverse.go to build
 upstream paths correctly and added a new test for path rewriting with the API
 base path in reverse_test.go.

---
 config.example.yaml            |  8 ++---
 internal/proxy/reverse.go      | 55 +++++++++++++++++++++++++++-------
 internal/proxy/reverse_test.go | 21 +++++++++++++
 3 files changed, 70 insertions(+), 14 deletions(-)

diff --git a/config.example.yaml b/config.example.yaml
index dea03d8..9b79c68 100644
--- a/config.example.yaml
+++ b/config.example.yaml
@@ -29,15 +29,15 @@ servers:
     path_prefix: /v1
     # authorization_env: TELEMT_API_AUTH
 
-  # ivx: порт 9091 как у типичного Telemt API; при необходимости — https и другой порт.
+  # ivx: API за префиксом /api/ на HTTPS.
   - alias: gt1
-    base_url: http://gt1.ivx.su:9091
+    base_url: https://gt1.ivx.su/api/
     path_prefix: /v1
 
   - alias: gt2
-    base_url: http://gt2.ivx.su:9091
+    base_url: https://gt2.ivx.su/api/
     path_prefix: /v1
 
   - alias: gt3
-    base_url: http://gt3.ivx.su:9091
+    base_url: https://gt3.ivx.su/api/
     path_prefix: /v1
diff --git a/internal/proxy/reverse.go b/internal/proxy/reverse.go
index ed2d261..f3fb4b3 100644
--- a/internal/proxy/reverse.go
+++ b/internal/proxy/reverse.go
@@ -4,26 +4,37 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"net/url"
+	"path"
 	"strings"
 )
 
 // NewReverseProxy builds a reverse proxy to target base URL with path rewriting:
-// stripPrefix (/api/{alias}) + pathPrefix (/v1) + remainder.
+// stripPrefix (/api/{alias}) + pathPrefix (/v1) + remainder, prepended to target.Path
+// (so base_url https://host/api/ yields upstream /api/v1/...).
 func NewReverseProxy(target *url.URL, stripPrefix, pathPrefix string, setAuth string) *httputil.ReverseProxy {
 	proxy := httputil.NewSingleHostReverseProxy(target)
 	orig := proxy.Director
+	targetQuery := target.RawQuery
 	proxy.Director = func(req *http.Request) {
-		orig(req)
 		p := req.URL.Path
-		if strings.HasPrefix(p, stripPrefix) {
-			rest := strings.TrimPrefix(p, stripPrefix)
-			rest = strings.TrimPrefix(rest, "/")
-			if rest == "" {
-				req.URL.Path = pathPrefix
-			} else {
-				req.URL.Path = pathPrefix + "/" + rest
+		if !strings.HasPrefix(p, stripPrefix) {
+			orig(req)
+			if setAuth != "" {
+				req.Header.Set("Authorization", setAuth)
 			}
-			req.URL.RawPath = ""
+			return
+		}
+		rest := strings.TrimPrefix(p, stripPrefix)
+		rest = strings.TrimPrefix(rest, "/")
+		upPath := buildUpstreamPath(target.Path, pathPrefix, rest)
+		req.URL.Scheme = target.Scheme
+		req.URL.Host = target.Host
+		req.URL.Path = upPath
+		req.URL.RawPath = ""
+		if targetQuery == "" || req.URL.RawQuery == "" {
+			req.URL.RawQuery = targetQuery + req.URL.RawQuery
+		} else {
+			req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
 		}
 		if setAuth != "" {
 			req.Header.Set("Authorization", setAuth)
@@ -31,3 +42,27 @@ func NewReverseProxy(target *url.URL, stripPrefix, pathPrefix string, setAuth st
 	}
 	return proxy
 }
+
+func buildUpstreamPath(targetPath, pathPrefix, rest string) string {
+	base := strings.TrimSuffix(targetPath, "/")
+	p := strings.Trim(pathPrefix, "/")
+	r := strings.Trim(rest, "/")
+	var segs []string
+	if base != "" {
+		segs = append(segs, base)
+	}
+	if p != "" {
+		segs = append(segs, p)
+	}
+	if r != "" {
+		segs = append(segs, r)
+	}
+	if len(segs) == 0 {
+		return "/"
+	}
+	out := path.Join(segs...)
+	if !strings.HasPrefix(out, "/") {
+		out = "/" + out
+	}
+	return out
+}
diff --git a/internal/proxy/reverse_test.go b/internal/proxy/reverse_test.go
index e46caae..ccf0afc 100644
--- a/internal/proxy/reverse_test.go
+++ b/internal/proxy/reverse_test.go
@@ -24,3 +24,24 @@ func TestReverseProxyPathRewrite(t *testing.T) {
 		t.Fatalf("status %d", rec.Code)
 	}
 }
+
+func TestReverseProxyPathRewriteWithAPIBasePath(t *testing.T) {
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path != "/api/v1/health" {
+			t.Fatalf("path %q", r.URL.Path)
+		}
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer srv.Close()
+	up, err := url.Parse(srv.URL + "/api/")
+	if err != nil {
+		t.Fatal(err)
+	}
+	rp := NewReverseProxy(up, "/api/main_srv", "/v1", "")
+	req := httptest.NewRequest(http.MethodGet, "/api/main_srv/health", nil)
+	rec := httptest.NewRecorder()
+	rp.ServeHTTP(rec, req)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("status %d", rec.Code)
+	}
+}