From 45f85d9a1e65422d791ac5094c1763a6b2db8ca2 Mon Sep 17 00:00:00 2001
From: Eduard Urbach <e.urbach@gmail.com>
Date: Fri, 23 Jun 2017 15:38:46 +0200
Subject: [PATCH] Added host names in request log

---
 main.go                |  1 +
 middleware/IPToHost.go | 47 ++++++++++++++++++++++++++++++++++++++++++
 middleware/Log.go      | 16 ++++++++++----
 3 files changed, 60 insertions(+), 4 deletions(-)
 create mode 100644 middleware/IPToHost.go

diff --git a/main.go b/main.go
index 4dfe6162..2df2a9e9 100644
--- a/main.go
+++ b/main.go
@@ -78,6 +78,7 @@ func configure(app *aero.Application) *aero.Application {
 	app.Use(middleware.Log())
 	app.Use(middleware.Session())
 	app.Use(middleware.UserInfo())
+	app.Use(middleware.IPToHost())
 
 	// API
 	api := api.New("/api/", arn.DB)
diff --git a/middleware/IPToHost.go b/middleware/IPToHost.go
new file mode 100644
index 00000000..f702bf3b
--- /dev/null
+++ b/middleware/IPToHost.go
@@ -0,0 +1,47 @@
+package middleware
+
+import (
+	"net"
+	"time"
+
+	"github.com/aerogo/aero"
+	cache "github.com/patrickmn/go-cache"
+)
+
+var ipToHosts = cache.New(60*time.Minute, 30*time.Minute)
+
+// IPToHost middleware tries to find domain names for the given IP.
+func IPToHost() aero.Middleware {
+	return func(ctx *aero.Context, next func()) {
+		next()
+
+		go findHostsForIP(ctx.RealIP())
+	}
+}
+
+// GetHostsForIP returns all host names for the given IP (if cached).
+func GetHostsForIP(ip string) []string {
+	hosts, found := ipToHosts.Get(ip)
+
+	if !found || hosts == nil {
+		return nil
+	}
+
+	return hosts.([]string)
+}
+
+// Finds all host names for the given IP
+func findHostsForIP(ip string) {
+	hosts, err := net.LookupAddr(ip)
+
+	if err != nil {
+		return
+	}
+
+	if len(hosts) == 0 {
+		return
+	}
+
+	// Cache host names
+	ipToHosts.Set(ip, hosts, cache.DefaultExpiration)
+}
diff --git a/middleware/Log.go b/middleware/Log.go
index 59dad41d..84c53f4d 100644
--- a/middleware/Log.go
+++ b/middleware/Log.go
@@ -29,12 +29,20 @@ func Log() aero.Middleware {
 		responseTimeString = strings.Repeat(" ", 8-len(responseTimeString)) + responseTimeString
 
 		user := utils.GetUser(ctx)
+		ip := ctx.RealIP()
+
+		hostName := ""
+		hostNames := GetHostsForIP(ip)
+
+		if len(hostNames) != 0 {
+			hostName = hostNames[0]
+		}
 
 		// Log every request
 		if user != nil {
-			request.Info(user.Nick, ctx.RealIP(), ctx.StatusCode, responseTimeString, ctx.URI())
+			request.Info(user.Nick, ip, hostName, responseTimeString, ctx.StatusCode, ctx.URI())
 		} else {
-			request.Info("[guest]", ctx.RealIP(), ctx.StatusCode, responseTimeString, ctx.URI())
+			request.Info("[guest]", ip, hostName, responseTimeString, ctx.StatusCode, ctx.URI())
 		}
 
 		// Log all requests that failed
@@ -43,13 +51,13 @@ func Log() aero.Middleware {
 			// Ok.
 
 		default:
-			err.Error(http.StatusText(ctx.StatusCode), ctx.RealIP(), ctx.StatusCode, responseTimeString, ctx.URI())
+			err.Error(http.StatusText(ctx.StatusCode), ip, hostName, responseTimeString, ctx.StatusCode, ctx.URI())
 		}
 
 		// Notify us about long requests.
 		// However ignore requests under /auth/ because those depend on 3rd party servers.
 		if responseTime >= 200*time.Millisecond && !strings.HasPrefix(ctx.URI(), "/auth/") {
-			err.Error("Long response time", ctx.RealIP(), ctx.StatusCode, responseTimeString, ctx.URI())
+			err.Error("Long response time", ip, hostName, responseTimeString, ctx.StatusCode, ctx.URI())
 		}
 	}
 }