pierreprinetti/apimock

package main

import (
    "log"
    "net/http"
    "os"
    "time"
)

// Logger is a middleware handler that logs HTTP call information.
type Logger struct {
    // Logger inherits from log.Logger used to log messages with the Logger middleware
    *log.Logger
    next http.Handler
}

// newLogger returns a new Logger instance
func newLogger(next http.Handler) *Logger {
    return &Logger{
        Logger: log.New(os.Stdout, "[apimock] ", 3),
        next:   next,
    }
}

type responseWriterRecorder struct {
    http.ResponseWriter

    status int
}

func (rr *responseWriterRecorder) WriteHeader(code int) {
    rr.status = code
    rr.ResponseWriter.WriteHeader(code)
}

func (rr *responseWriterRecorder) Write(b []byte) (int, error) {
    if rr.status == 0 {
        rr.status = 200
    }
    return rr.ResponseWriter.Write(b)
}

func (l *Logger) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
    start := time.Now()

    rr := &responseWriterRecorder{ResponseWriter: rw}

    l.next.ServeHTTP(rr, req)

    address := req.RemoteAddr
    if realIP := req.Header.Get("X-REAL-IP"); realIP != "" {
        address = realIP
    }

    l.Printf("%s %s %d %s in %v (%s)", req.Method, req.URL.Path, rr.status, http.StatusText(rr.status), time.Since(start), address)
}