tool.go

// @author cold bin
// @date 2022/7/23

package mini_websocket

import (
	"bytes"
	"compress/gzip"
	"crypto/sha1"
	"encoding/base64"
	"io"
	"net/http"
)

const GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" //magic string

// IsWsHeader 检查header里的键值对是否是满足websocket标准
func IsWsHeader(header http.Header, expectK, expectV string) bool {
	//标准化头字段
	expectK = http.CanonicalHeaderKey(expectK)
	for _, v := range header[expectK] {
		if v == expectV {
			return true
		}
	}
	return false
}

func IsSWK(str string) bool {
	return len(str) == 24
}

// EncodeSWK 将客户端的Sec-WebSocket-Key和 GUID
// 编码成SHA-1哈希值，并返回哈希的base64编码
func EncodeSWK(swk string) string {
	o := sha1.New()
	o.Write([]byte(swk + GUID))
	return base64.StdEncoding.EncodeToString(o.Sum(nil))
}

// GZipBytes level指压缩等级，见 gzip包
func GZipBytes(data []byte, level int) ([]byte, error) {
	var input bytes.Buffer
	g, err := gzip.NewWriterLevel(&input, level)
	if err != nil {
		return nil, err
	}

	if _, err := g.Write(data); err != nil {
		return nil, err
	}

	g.Close()

	return input.Bytes(), nil
}

func UGZipBytes(data []byte) []byte {
	var out bytes.Buffer
	var in bytes.Buffer

	in.Write(data)
	r, err := gzip.NewReader(&in)
	if err != nil {
		return nil
	}

	r.Close()

	io.Copy(&out, r)

	return out.Bytes()
}