From 1e55e61786eaedd59c067f4306fb8427dc92ef52 Mon Sep 17 00:00:00 2001
From: clsr <clsr@clsr.net>
Date: Tue, 15 Nov 2016 15:17:45 +0100
Subject: Add logging support

---
 api.go  |   3 +-
 log.go  | 138 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 main.go |  20 ++++++++++
 3 files changed, 160 insertions(+), 1 deletion(-)
 create mode 100644 log.go

diff --git a/api.go b/api.go
index 49b8a61..464d110 100644
--- a/api.go
+++ b/api.go
@@ -67,7 +67,7 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 	output := r.FormValue("output")
 	resp := response{Files: []result{}}
 
-	if r.Method == http.MethodGet && output == "html" {
+	if r.Method == http.MethodGet && (output == "html" || output == "") {
 		respond(w, output, resp)
 		return
 	}
@@ -113,6 +113,7 @@ func handleUpload(w http.ResponseWriter, r *http.Request) {
 			Hash: hex.EncodeToString(bhash),
 			Size: size,
 		}
+		LogUpload(r, res)
 		resp.Files = append(resp.Files, res)
 
 		part.Close()
diff --git a/log.go b/log.go
new file mode 100644
index 0000000..f2305ce
--- /dev/null
+++ b/log.go
@@ -0,0 +1,138 @@
+package main
+
+import (
+	"crypto/sha1"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"net"
+	"net/http"
+	"os"
+	"path"
+	"sync"
+	"time"
+)
+
+type Logger struct {
+	LogDir        string
+	LogIP         bool
+	LogUserAgent  bool
+	LogReferer    bool
+	HashIP        bool
+	HashUserAgent bool
+	HashReferer   bool
+	HashSalt      string
+	logFile       *os.File
+	encoder       *json.Encoder
+	lastDate      string
+	lock          sync.Mutex
+}
+
+type LogEntry map[string]interface{}
+
+func InitLogger(logdir string) *Logger {
+	return &Logger{
+		LogDir: logdir,
+	}
+}
+
+func (l *Logger) Log(entry LogEntry) {
+	l.lock.Lock()
+	defer l.lock.Unlock()
+	_, err := l.getLogFile()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error opening log file: %s\n", err)
+		return
+	}
+	err = l.encoder.Encode(entry)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error writing to log: %s\n", err)
+	}
+}
+
+func (l *Logger) LogUpload(req *http.Request, res result) {
+	host, _, _ := net.SplitHostPort(req.RemoteAddr)
+	l.logUpload(
+		host,               // ip
+		req.UserAgent(),    // userAgent
+		req.Referer(),      // referer
+		res.Name,           // origName
+		path.Base(res.Url), // idext
+		res.Hash,           // hash
+		res.Size,           // size
+	)
+}
+
+func (l *Logger) logUpload(ip, userAgent, referer, origName, idext, hash string, size int64) {
+	if !l.LogIP {
+		ip = ""
+	} else if l.HashIP {
+		ip = l.hash(ip)
+	}
+	if !l.LogUserAgent {
+		userAgent = ""
+	} else if l.HashUserAgent {
+		userAgent = l.hash(userAgent)
+	}
+	if !l.LogReferer {
+		referer = ""
+	} else if l.HashReferer {
+		referer = l.hash(referer)
+	}
+	l.Log(LogEntry{
+		"type":       "upload",
+		"timestamp":  time.Now().UTC().Format(time.RFC3339),
+		"ip":         ip,
+		"user_agent": userAgent,
+		"referer":    referer,
+		"orig_name":  origName,
+		"id":         idext,
+		"hash":       hash,
+		"size":       size,
+	})
+}
+
+func (l *Logger) hash(s string) string {
+	h := sha1.New()
+	h.Write([]byte(l.HashSalt))
+	h.Write([]byte(s))
+	h.Write([]byte(l.HashSalt))
+	return base64.RawURLEncoding.EncodeToString(h.Sum(nil))
+}
+
+func (l *Logger) getLogFile() (*os.File, error) {
+	if l.lastDate == "" {
+		if err := os.MkdirAll(l.LogDir, 0755); err != nil {
+			return nil, err
+		}
+	}
+	currentDate := time.Now().UTC().Format("2006-01-02")
+	if l.lastDate == currentDate {
+		return l.logFile, nil
+	}
+	f, err := os.OpenFile(path.Join(l.LogDir, currentDate+".log.json"), os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
+	if err != nil {
+		return f, err
+	}
+	if l.logFile != nil {
+		l.logFile.Close()
+	}
+	l.lastDate = currentDate
+	l.logFile = f
+	l.encoder = json.NewEncoder(f)
+	return f, nil
+}
+
+var DefaultLogger = InitLogger("log")
+
+func Log(entry LogEntry) {
+	if DefaultLogger != nil {
+		DefaultLogger.Log(entry)
+	}
+}
+
+func LogUpload(req *http.Request, res result) {
+	if DefaultLogger != nil {
+		DefaultLogger.LogUpload(req, res)
+	}
+}
diff --git a/main.go b/main.go
index 40dae35..d66416f 100644
--- a/main.go
+++ b/main.go
@@ -76,6 +76,14 @@ func main() {
 	grill := flag.Bool("grill", false, "enable grills")
 	idLength := flag.Int("id-length", DefaultIdLength, "length of uploaded file IDs")
 	idCharset := flag.String("id-charset", "", "charset for uploaded file IDs (default lowercase letters a-z)")
+	enableLog := flag.Bool("log", false, "enable logging")
+	logIP := flag.Bool("log-ip", false, "log IP addresses")
+	logIPHash := flag.Bool("log-ip-hash", false, "log hashed IP addresses")
+	logUA := flag.Bool("log-ua", false, "log User-Agent headers")
+	logUAHash := flag.Bool("log-ua-hash", false, "log hashed User-Agent headers")
+	logReferer := flag.Bool("log-referer", false, "log Referer headers")
+	logRefererHash := flag.Bool("log-referer-hash", false, "log hashed Referer headers")
+	logHashSalt := flag.String("log-hash-salt", "", "salt to use for hashed log entries")
 
 	flag.Parse()
 
@@ -96,6 +104,18 @@ func main() {
 		storage.IdCharset = *idCharset
 	}
 
+	if !*enableLog {
+		DefaultLogger = nil
+	} else {
+		DefaultLogger.LogIP = *logIP || *logIPHash
+		DefaultLogger.LogUserAgent = *logUA || *logUAHash
+		DefaultLogger.LogReferer = *logReferer || *logRefererHash
+		DefaultLogger.HashIP = *logIPHash
+		DefaultLogger.HashUserAgent = *logUAHash
+		DefaultLogger.HashReferer = *logRefererHash
+		DefaultLogger.HashSalt = *logHashSalt
+	}
+
 	http.HandleFunc("/upload.php", handleUpload)
 	http.Handle("/u/", http.StripPrefix("/u/", http.HandlerFunc(handleFile)))
 	if *grill {
-- 
cgit