Adding logger and config files

conf.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+const CONFIG_LOG string = "/var/lib/gocustomurls/"
+
+type ConfigFile struct {
+	Mappings []struct {
+		Protocol  string `json:"protocol"`
+		VanityUrl string `json:"vanity_url"`
+		RealUrl   string `json:"real_url"`
+	} `json:"mappings"`
+}
+
+// isFile - check if fp is a valid file
+func isFile(fp string) bool {
+	info, err := os.Stat(fp)
+	if os.IsNotExist(err) || !info.Mode().IsRegular() {
+		return false
+	}
+	return true
+}
+
+// load mapping file
+func LoadFile() (ConfigFile, error) {
+	var mapping ConfigFile
+	dirname, err := os.UserConfigDir()
+	if err != nil {
+		return mapping, err
+	}
+	configFilePath := filepath.Join(dirname, "gocustomurls/config.json")
+	ok := isFile(configFilePath)
+	if !ok {
+		return mapping, fmt.Errorf("%s/gocustomurls/config.json file is not found", dirname)
+	}
+	configFile, err := os.Open(configFilePath)
+	if err != nil {
+		return mapping, err
+	}
+	defer configFile.Close()
+
+	err = json.NewDecoder(configFile).Decode(&mapping)
+	if err != nil {
+		return mapping, err
+	}
+	return mapping, nil
+}

logger.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"os"
+	"strings"
+)
+
+// some headers not worth logging
+var (
+	hdrsToNotLog = []string{
+		"Accept-Language",
+		"Cache-Control",
+		"Cf-Ray",
+		"CF-Visitor",
+		"CF-Connecting-IP",
+		"Cdn-Loop",
+		"Cookie",
+		"Connection",
+		"Dnt",
+		"If-Modified-Since",
+		"Sec-Fetch-Dest",
+		"Sec-Ch-Ua-Mobile",
+		// "Sec-Ch-Ua",
+		"Sec-Ch-Ua-Platform",
+		"Sec-Fetch-Site",
+		"Sec-Fetch-Mode",
+		"Sec-Fetch-User",
+		"Upgrade-Insecure-Requests",
+		"X-Request-Start",
+		"X-Forwarded-For",
+		"X-Forwarded-Proto",
+		"X-Forwarded-Host",
+	}
+	hdrsToNotLogMap map[string]bool
+)
+
+type LogFile struct {
+	handle *os.File
+	logger *log.Logger
+	path   string
+}
+
+type LogFileRec struct {
+	Method string `json:"method"`
+	IpAddr string `json:"ipAddr"`
+	Url    string `json:"url"`
+}
+
+func newFileLogger(path string) (*LogFile, error) {
+	f, err := os.OpenFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0666)
+	if err != nil {
+		return nil, err
+	}
+	return &LogFile{
+		handle: f,
+		logger: log.New(f, "", 0),
+		path:   path,
+	}, nil
+}
+
+func (f *LogFile) Close() error {
+	if f == nil {
+		return nil
+	}
+	err := f.handle.Close()
+	f.handle = nil
+	return err
+}
+
+func extractFirstFragment(header *http.Header, headerName string) string {
+	s := header.Get(headerName)
+	if len(strings.TrimSpace(s)) == 0 {
+		return s
+	}
+	fragments := strings.Split(s, ",")
+	return strings.TrimSpace(fragments[0])
+}
+
+// Get Ip Address of the client
+func extractIpAddress(r *http.Request) string {
+	var ipAddr string
+	if r == nil {
+		return ""
+	}
+	possibleIpHeaders := []string{"CF-Connecting-IP", "X-Real-Ip", "X-Forwarded-For"}
+	for _, header := range possibleIpHeaders {
+		ipAddr = extractFirstFragment(&r.Header, header)
+		if len(strings.TrimSpace(ipAddr)) != 0 {
+			return ipAddr
+		}
+	}
+	// pull ip from Request.RemoteAddr
+	if len(strings.TrimSpace(r.RemoteAddr)) != 0 {
+		index := strings.LastIndex(r.RemoteAddr, ";")
+		if index == -1 {
+			return r.RemoteAddr
+		}
+		ipAddr = r.RemoteAddr[:index]
+	}
+	return ipAddr
+}
+
+func canSkipExtraHeaders(r *http.Request) bool {
+	ref := r.Header.Get("Referer")
+	if len(strings.TrimSpace(ref)) == 0 {
+		return false
+	}
+	return strings.Contains(ref, r.Host)
+}
+
+func shouldLogHeader(s string) bool {
+	if hdrsToNotLogMap == nil {
+		hdrsToNotLogMap = map[string]bool{}
+		for _, h := range hdrsToNotLog {
+			h = strings.ToLower(h)
+			hdrsToNotLogMap[h] = true
+		}
+	}
+	s = strings.ToLower(s)
+	return !hdrsToNotLogMap[s]
+}
+
+func (f *LogFile) WriteLog(r *http.Request) error {
+	if f == nil {
+		return nil
+	}
+	var rec = make(map[string]string)
+	rec["method"] = r.Method
+	rec["requestUri"] = r.RequestURI
+	rec["Host"] = r.Host
+	rec["ipAddr"] = extractIpAddress(r)
+	if !canSkipExtraHeaders(r) {
+		for key, val := range r.Header {
+			if shouldLogHeader(key) && len(val) > 0 {
+				rec[key] = val[0]
+			}
+		}
+	}
+	b, err := json.Marshal(rec)
+	if err != nil {
+		return err
+	}
+	f.logger.Println(string(b))
+	return nil
+}