All/Go/Socket/lib/com/Common.go

package com

import (
	"bytes"
	"encoding/json"
	"fmt"
	"log"
	"math/rand"
	"os"
)

const (
	baseStr      = "qwertyuioplkjhgfdsazxcvbnm-0123456789.ZXCVBNMLKJHGFDSAQWERTYUIOP"
	baseStrLen   = len(baseStr)
	sockSplitStr = "=="
	sockEndStr   = "==END=="
	sockStartStr = "==EVENT:"

	BuffSize     = 1024
	SockEndLen   = len(sockEndStr)
	SockStartLen = len(sockStartStr)
	SockSplitLen = len(sockSplitStr)
)

var (
	SockEndBytes   = []byte(sockEndStr)
	SockStartBytes = []byte(sockStartStr)
	SockSplitBytes = []byte(sockSplitStr)
)

type Packet struct {
	Event string
	Data  []byte
}

type ClientConfig struct {
	Protocol  string `json:"protocol"`
	Address   string `json:"address"`
	Port      int    `json:"port"`
	Positive  bool   `json:"positive"`
	Frequency int    `json:"frequency"`
}

type ServerConfig struct {
	Protocol string `json:"protocol"`
	Port     int    `json:"port"`
	Gap      int    `json:"gap"`
	Len      int    `json:"length"`
}

func RandBytesWithHeader() []byte {
	buffer, size := bytes.Buffer{}, rand.Intn(20)+30
	header := fmt.Sprintf("(%d):", size)
	buffer.WriteString(header)
	buffer.Write(RandBytes(size - len(header)))
	return buffer.Bytes()
}

func RandBytes(size int) []byte {
	res := make([]byte, size)
	for i := range res {
		res[i] = baseStr[rand.Intn(baseStrLen)]
	}
	return res
}

func UintToBytes(num uint) []byte {
	res := make([]byte, 4)
	res[0], res[1] = byte(num>>24), byte((num&0x00ff0000)>>16)
	res[2], res[3] = byte((num&0x0000ff00)>>8), byte(num&0x000000ff)
	return res
}

func BytesToUint(from []byte) uint {
	return uint(from[0])<<24 + uint(from[1])<<16 + uint(from[2])<<8 + uint(from[3])
}

func IntToBytes(num uint) []byte {
	res := make([]byte, 4)
	res[0], res[1] = byte(num>>24), byte((num&0x00ff0000)>>16)
	res[2], res[3] = byte((num&0x0000ff00)>>8), byte(num&0x000000ff)
	return res
}

func BytesToInt(from []byte) int {
	return int(from[0])<<24 + int(from[1])<<16 + int(from[2])<<8 + int(from[3])
}

func ReadClientConfig(filepath string, logger *log.Logger) ClientConfig {
	defaultConfig := ClientConfig{
		Protocol:  "tcp",
		Address:   "192.168.1.6:3060",
		Port:      3080,
		Positive:  false,
		Frequency: 1,
	}

	file, err := os.Open(filepath)
	if err != nil {
		logger.Print("File open error:", err)
		return defaultConfig
	}
	defer func() {
		err = file.Close()
		if err != nil {
			logger.Print("Fail to close config file:", err)
		}
	}()

	decoder := json.NewDecoder(file)
	var config ClientConfig
	err = decoder.Decode(&config)
	if err != nil {
		logger.Print("Json decode error:", err)
		return defaultConfig
	}

	return config
}

func ReadServerConfig(filepath string, logger *log.Logger) ServerConfig {
	defaultConfig := ServerConfig{
		Protocol: "tcp",
		Port:     3060,
		Gap:      30,
		Len:      30,
	}

	file, err := os.Open(filepath)
	if err != nil {
		logger.Print("File open error:", err)
		return defaultConfig
	}
	defer func() {
		err = file.Close()
		if err != nil {
			logger.Print("Fail to close ServerConfig file:", err)
		}
	}()

	decoder := json.NewDecoder(file)
	var config ServerConfig
	err = decoder.Decode(&config)
	if err != nil {
		logger.Print("Json decode error:", err)
		return defaultConfig
	}

	return config
}