common.go

package main

import (
	"os"
    "log"
	"net/http"
	"strconv"
	"strings"
	"errors"
	"encoding/base64"
	"bufio"
	"io/ioutil"
	"time"
)

/*
	SYSTEM COMMON FUNCTIONS

	This is a system function that put those we usually use function but not belongs to
	any module / system.

	E.g. fileExists / IsDir etc

*/

/*
	Basic Response Functions

	Send response with ease
*/
//Send text response with given w and message as string
func sendTextResponse(w http.ResponseWriter, msg string) {
	w.Write([]byte(msg))
}

//Send JSON response, with an extra json header
func sendJSONResponse(w http.ResponseWriter, json string) {
	w.Header().Set("Content-Type", "application/json")
	w.Write([]byte(json))
}

func sendErrorResponse(w http.ResponseWriter, errMsg string) {
	w.Header().Set("Content-Type", "application/json")
	w.Write([]byte("{\"error\":\"" + errMsg + "\"}"))
}

func sendOK(w http.ResponseWriter) {
	w.Header().Set("Content-Type", "application/json")
	w.Write([]byte("\"OK\""))
}
/*
	The paramter move function (mv)

	You can find similar things in the PHP version of ArOZ Online Beta. You need to pass in
	r (HTTP Request Object)
	getParamter (string, aka $_GET['This string])

	Will return
	Paramter string (if any)
	Error (if error)

*/
func mv(r *http.Request, getParamter string, postMode bool) (string, error) {
	if postMode == false {
		//Access the paramter via GET
		keys, ok := r.URL.Query()[getParamter]

		if !ok || len(keys[0]) < 1 {
			//log.Println("Url Param " + getParamter +" is missing")
			return "", errors.New("GET paramter " + getParamter + " not found or it is empty")
		}

		// Query()["key"] will return an array of items,
		// we only want the single item.
		key := keys[0]
		return string(key), nil
	} else {
		//Access the parameter via POST
		r.ParseForm()
		x := r.Form.Get(getParamter)
		if len(x) == 0 || x == "" {
			return "", errors.New("POST paramter " + getParamter + " not found or it is empty")
		}
		return string(x), nil
	}

}

func stringInSlice(a string, list []string) bool {
    for _, b := range list {
        if b == a {
            return true
        }
    }
    return false
}


func fileExists(filename string) bool {
    _, err := os.Stat(filename)
    if os.IsNotExist(err) {
        return false
    }
    return true
}


func IsDir(path string) bool{
	if (fileExists(path) == false){
		return false
	}
	fi, err := os.Stat(path)
    if err != nil {
        log.Fatal(err)
        return false
    }
    switch mode := fi.Mode(); {
    case mode.IsDir():
        return true
    case mode.IsRegular():
        return false
	}
	return false
}

func inArray(arr []string, str string) bool {
	for _, a := range arr {
	   if a == str {
		  return true
	   }
	}
	return false
 }

 func timeToString(targetTime time.Time) string{
	 return targetTime.Format("2006-01-02 15:04:05")
 }

 func IntToString(number int) string{
	return strconv.Itoa(number)
 }

 func StringToInt(number string) (int, error){
	return strconv.Atoi(number)
 }

 func StringToInt64(number string) (int64, error){
	i, err := strconv.ParseInt(number, 10, 64)
	if err != nil {
		return -1, err
	}
	return i, nil
 }

 func Int64ToString(number int64) string{
	convedNumber:=strconv.FormatInt(number,10)
	return convedNumber
 }

 func GetUnixTime() int64{
	return time.Now().Unix()
 }

 func LoadImageAsBase64(filepath string) (string, error){
	if !fileExists(filepath){
		return "", errors.New("File not exists")
	}
	f, _ := os.Open(filepath)
    reader := bufio.NewReader(f)
    content, _ := ioutil.ReadAll(reader)
	encoded := base64.StdEncoding.EncodeToString(content)
	return string(encoded), nil
 }

 func PushToSliceIfNotExist(slice []string, newItem string) []string {
	itemExists := false
	for _, item := range slice{
		if item == newItem{
			itemExists = true
		}
	}

	if !itemExists{
		slice = append(slice, newItem)
	}

	return slice
 }

 func RemoveFromSliceIfExists(slice []string, target string) []string {
	 newSlice := []string{}
	 for _, item := range slice{
		 if item != target{
			newSlice = append(newSlice, item)
		 }
	 }

	 return newSlice;
 }

 //Get the IP address of the current authentication user
func ReflectUserIP(w http.ResponseWriter, r *http.Request) {
    requestPort,_ :=  mv(r, "port", false)
    showPort := false;
    if (requestPort == "true"){
        //Show port as well
        showPort = true;
    }
    IPAddress := r.Header.Get("X-Real-Ip")
    if IPAddress == "" {
        IPAddress = r.Header.Get("X-Forwarded-For")
    }
    if IPAddress == "" {
        IPAddress = r.RemoteAddr
    }
    if (!showPort){
        IPAddress = IPAddress[:strings.LastIndex(IPAddress, ":")]

    }
    w.Write([]byte(IPAddress))
    return;
}