internal/log: Implement logging of HOST when using subrequest auth (#1027)

* internal/log: Implement logging of HOST when using subrequest auth

The host header wouldn't be set on subrequest auth, so we need to look for X-Forwarded-Host header when logging requests.

* chore: add changelog entry

---------

Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>
Co-authored-by: Xe Iaso <xe.iaso@techaro.lol>

docs/docs/CHANGELOG.md

@@ -7,7 +7,7 @@ sidebar_position: 999
 All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
-and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).https://bsky.app/profile/xeiaso.net/post/3lxkqbd25hk22
 
 ## [Unreleased]
 
@@ -45,6 +45,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Add a default block rule for Huawei Cloud.
 - Add a default block rule for Alibaba Cloud.
 - Add X-Request-URI support so that Subrequest Authentication has path support.
+- Add better logging when using Subrequest Authentication.
 - Two of Slackware's community git repository servers are now poxied by Anubis.
 - Added support to use Traefik forwardAuth middleware.
 

internal/log.go

@@ -27,8 +27,13 @@ func InitSlog(level string) {
 }
 
 func GetRequestLogger(base *slog.Logger, r *http.Request) *slog.Logger {
+	host := r.Host
+	if host == "" {
+		host = r.Header.Get("X-Forwarded-Host")
+	}
+
 	return base.With(
-		"host", r.Host,
+		"host", host,
 		"method", r.Method,
 		"path", r.URL.Path,
 		"user_agent", r.UserAgent(),

internal/log_test.go

@@ -3,6 +3,8 @@ package internal
 import (
 	"bytes"
 	"log"
+	"log/slog"
+	"net/http"
 	"strings"
 	"testing"
 )
@@ -44,3 +46,37 @@ func TestErrorLogFilter(t *testing.T) {
 	}
 	buf.Reset()
 }
+
+func TestGetRequestLogger(t *testing.T) {
+	// Test case 1: Normal request with Host header
+	req1, _ := http.NewRequest("GET", "http://example.com/test", nil)
+	req1.Host = "example.com"
+
+	logger := slog.Default()
+	reqLogger := GetRequestLogger(logger, req1)
+
+	// We can't easily test the actual log output without setting up a test handler,
+	// but we can verify the function doesn't panic and returns a logger
+	if reqLogger == nil {
+		t.Error("GetRequestLogger returned nil")
+	}
+
+	// Test case 2: Subrequest auth mode with X-Forwarded-Host
+	req2, _ := http.NewRequest("GET", "http://test.com/auth", nil)
+	req2.Host = ""
+	req2.Header.Set("X-Forwarded-Host", "original-site.com")
+
+	reqLogger2 := GetRequestLogger(logger, req2)
+	if reqLogger2 == nil {
+		t.Error("GetRequestLogger returned nil for X-Forwarded-Host case")
+	}
+
+	// Test case 3: No host information available
+	req3, _ := http.NewRequest("GET", "http://test.com/nohost", nil)
+	req3.Host = ""
+
+	reqLogger3 := GetRequestLogger(logger, req3)
+	if reqLogger3 == nil {
+		t.Error("GetRequestLogger returned nil for no host case")
+	}
+}