From bf3a40ffb7d68ed5e244da466f2af6763c06a88f Mon Sep 17 00:00:00 2001
From: Darshil Chanpura <dtchanpura@gmail.com>
Date: Thu, 5 Jul 2018 23:48:35 +0530
Subject: [PATCH] Updated README, added code for logging handler and its record

---
 README.md      | 18 +++++++++++++++
 log_handler.go | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++
 log_record.go  | 52 ++++++++++++++++++++++++++++++++++++++++++
 main.go        | 44 ++++++++++++++++++++++++++++++++++++
 4 files changed, 175 insertions(+)
 create mode 100644 log_handler.go
 create mode 100644 log_record.go
 create mode 100644 main.go

diff --git a/README.md b/README.md
index e69de29..262e835 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,18 @@
+# dumb-http
+## Simple HTTP Server
+
+## Usage
+
+```
+dumb-http [-path path-to-serve] [port]
+```
+### Example
+```
+$ dumb-http -path ./docs
+Serving at http://0.0.0.0:8000/ from ./docs
+127.0.0.1 - - [05/Jul/2018 18:08:16] "GET / HTTP/1.1" 200 38 0.0000 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:61.0) Gecko/20100101 Firefox/61.0"
+```
+
+>Inspired by Python module http.server
+
+> Reference: https://gist.github.com/cespare/3985516
diff --git a/log_handler.go b/log_handler.go
new file mode 100644
index 0000000..7757c1f
--- /dev/null
+++ b/log_handler.go
@@ -0,0 +1,61 @@
+package main
+
+import (
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// LoggingHandler is to be used as wrapper of mux.
+type LoggingHandler struct {
+	handler http.Handler
+	out     io.Writer
+}
+
+// NewLoggingHandler for creating a new Logging Handler
+func NewLoggingHandler(handler http.Handler, out io.Writer) http.Handler {
+	return &LoggingHandler{
+		handler: handler,
+		out:     out,
+	}
+}
+
+func (h LoggingHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+
+	ipPort := strings.Split(r.RemoteAddr, ":")
+
+	logRecord := &LogRecord{
+		ResponseWriter: w,
+		time:           time.Time{},
+		method:         r.Method,
+		statusCode:     http.StatusOK,
+		protocol:       r.Proto,
+		path:           r.RequestURI,
+		clientIP:       strings.Join(ipPort[:len(ipPort)-1], ":"),
+		referer:        "-",
+		userAgent:      "-",
+		totalTime:      time.Duration(0),
+	}
+
+	// For logging Real IP Address
+	if realIP := r.Header.Get("X-Real-IP"); realIP != "" {
+		logRecord.clientIP = realIP
+	}
+
+	// For logging Referer URL
+	if referer := r.Header.Get("Referer"); referer != "" {
+		logRecord.referer = referer
+	}
+
+	// For logging User Agent
+	if userAgent := r.Header.Get("User-Agent"); userAgent != "" {
+		logRecord.userAgent = userAgent
+	}
+	startTime := time.Now()
+	h.handler.ServeHTTP(logRecord, r)
+	endTime := time.Now()
+	logRecord.time = endTime.UTC()
+	logRecord.totalTime = endTime.Sub(startTime) / 1000.0
+	logRecord.Log(h.out)
+}
diff --git a/log_record.go b/log_record.go
new file mode 100644
index 0000000..53a050b
--- /dev/null
+++ b/log_record.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+const (
+	// LogPattern is format for writing the logRecord
+	LogPattern = "%s - - [%s] \"%s\" %d %d %.4f \"%s\" \"%s\"\n"
+	// DateTimeFormat is for logging Date and Time of request
+	DateTimeFormat = "02/Jan/2006 15:04:05" // Minimal
+	// DateTimeFormat = "Mon, 02 Jan 2006 15:04:05 MST" // Full
+)
+
+// LogRecord struct extends http.ResponseWriter interface which has different methods included in it.
+type LogRecord struct {
+	http.ResponseWriter
+	method        string
+	path          string
+	clientIP      string
+	time          time.Time
+	contentLength int64
+	protocol      string
+	statusCode    int
+	referer       string
+	userAgent     string
+	totalTime     time.Duration
+}
+
+// Log method to be called for logging to "out"
+func (l *LogRecord) Log(out io.Writer) {
+	timeFormatted := l.time.Format(DateTimeFormat)
+	requestLine := l.method + " " + l.path + " " + l.protocol
+	fmt.Fprintf(out, LogPattern, l.clientIP, timeFormatted, requestLine,
+		l.statusCode, l.contentLength, l.totalTime.Seconds(), l.referer, l.userAgent)
+}
+
+// WriteHeader method has been extended to record status code from previous handler.
+func (l *LogRecord) WriteHeader(statusCode int) {
+	l.statusCode = statusCode
+	l.ResponseWriter.WriteHeader(statusCode)
+}
+
+// Write method has been extended to record the bytes written or the content length
+func (l *LogRecord) Write(p []byte) (int, error) {
+	written, err := l.ResponseWriter.Write(p)
+	l.contentLength += int64(written)
+	return written, err
+}
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..ab58903
--- /dev/null
+++ b/main.go
@@ -0,0 +1,44 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+)
+
+var (
+	localDir = "."
+	host     = "0.0.0.0"
+	port     = "8000"
+)
+
+func init() {
+	flag.StringVar(&localDir, "path", ".", "Path to serve from")
+}
+
+func main() {
+	flag.Parse()
+	// Check for port in commandline
+	if commandPort := flag.Arg(0); commandPort != "" {
+		port = commandPort
+	}
+	// Start serving...
+	serve(host + ":" + port)
+}
+
+func serve(addr string) {
+	mux := http.NewServeMux()
+	mux.Handle("/", http.StripPrefix("/", http.FileServer(http.Dir(localDir))))
+	server := http.Server{
+		Addr:    addr,
+		Handler: NewLoggingHandler(mux, os.Stdout),
+	}
+	fmt.Printf("Serving at http://%s/ from %s\n", addr, localDir)
+	err := server.ListenAndServe()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+}