go語言實現的memcache協議服務的方法

2020-04-01 19:15:51

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這篇文章主要介紹了go語言實現的memcache協議服務的方法,實例分析了Go語言使用memcache的技巧,具有一定參考借鑒價值,需要的朋友可以參考下

本文實例講述了go語言實現的memcache協議服務的方法。分享給大家供大家參考。具體如下：

1. Go語言代碼如下：

復制代碼代碼如下:

		package memcachep
		import (
		    "bufio"
		    "fmt"
		    "io"
		    "strconv"
		    "strings"
		)
		//mc請求產生一個request對象
		type MCRequest struct {
		    //請求命令
		    Opcode CommandCode
		    //key
		    Key string
		    //請求內容
		    Value []byte
		    //請求標識
		    Flags int
		    //請求內容長度
		    Length int
		    //過期時間
		    Expires int64
		}
		//request to string
		func (req *MCRequest) String() string {
		    return fmt.Sprintf("{MCRequest opcode=%s, bodylen=%d, key='%s'}",
		        req.Opcode, len(req.Value), req.Key)
		}
		//將socket請求內容 解析為一個MCRequest對象
		func (req *MCRequest) Receive(r *bufio.Reader) error {
		    line, _, err := r.ReadLine()
		    if err != nil || len(line) == 0 {
		        return io.EOF
		    }
		    params := strings.Fields(string(line))
		    command := CommandCode(params[0])
		    switch command {
		    case SET, ADD, REPLACE:
		        req.Opcode = command
		        req.Key = params[1]
		        req.Length, _ = strconv.Atoi(params[4])
		        value := make([]byte, req.Length+2)
		        io.ReadFull(r, value)
		        req.Value = make([]byte, req.Length)
		        copy(req.Value, value)
		    case GET:
		        req.Opcode = command
		        req.Key = params[1]
		        RunStats["cmd_get"].(*CounterStat).Increment(1)
		    case STATS:
		        req.Opcode = command
		        req.Key = ""
		    case DELETE:
		        req.Opcode = command
		        req.Key = params[1]
		    }
		    return err
		}

2. Go語言代碼：

復制代碼代碼如下:

		package memcachep
		import (
		    "fmt"
		    "io"
		)
		type MCResponse struct {
		    //命令
		    Opcoed CommandCode
		    //返回狀態
		    Status Status
		    //key
		    Key string
		    //返回內容
		    Value []byte
		    //返回標識
		    Flags int
		    //錯誤
		    Fatal bool
		}
		//解析response 并把返回結果寫入socket鏈接
		func (res *MCResponse) Transmit(w io.Writer) (err error) {
		    switch res.Opcoed {
		    case STATS:
		        _, err = w.Write(res.Value)
		    case GET:
		        if res.Status == SUCCESS {
		            rs := fmt.Sprintf("VALUE %s %d %d/r/n%s/r/nEND/r/n", res.Key, res.Flags, len(res.Value), res.Value)
		            _, err = w.Write([]byte(rs))
		        } else {
		            _, err = w.Write([]byte(res.Status.ToString()))
		        }
		    case SET, REPLACE:
		        _, err = w.Write([]byte(res.Status.ToString()))
		    case DELETE:
		        _, err = w.Write([]byte("DELETED/r/n"))
		    }
		    return
		}

3. Go語言代碼如下：

復制代碼代碼如下:

		package memcachep
		import (
		    "fmt"
		)
		type action func(req *MCRequest, res *MCResponse)
		var actions = map[CommandCode]action{
		    STATS: StatsAction,
		}
		//等待分發處理
		func waitDispatch(rc chan chanReq) {
		    for {
		        input := <-rc
		        input.response <- dispatch(input.request)
		    }
		}
		//分發請求到響應的action操作函數上去
		func dispatch(req *MCRequest) (res *MCResponse) {
		    if h, ok := actions[req.Opcode]; ok {
		        res = &MCResponse{}
		        h(req, res)
		    } else {
		        return notFound(req)
		    }
		    return
		}
		//未支持命令
		func notFound(req *MCRequest) *MCResponse {
		    var response MCResponse
		    response.Status = UNKNOWN_COMMAND
		    return &response
		}
		//給request綁定上處理程序
		func BindAction(opcode CommandCode, h action) {
		    actions[opcode] = h
		}
		//stats
		func StatsAction(req *MCRequest, res *MCResponse) {
		    res.Fatal = false
		    stats := ""
		    for key, value := range RunStats {
		        stats += fmt.Sprintf("STAT %s %s/r/n", key, value)
		    }
		    stats += "END/r/n"
		    res.Value = []byte(stats)
		}