如何在golang中使用gob发送地图？

Question

在我的用例中,我想在golang中从客户端向服务器发送一个映射.我正在使用gob包来编码和解码对象.在服务器端,我无法解码对象.

服务器:

package main

import (
        "encoding/gob"
        "fmt"
        "net"
        "github.com/howti/ratelimit"
)

var throttleBucket map[string]*ratelimit.Bucket

func handleConnection(conn net.Conn) {
        dec := gob.NewDecoder(conn)
        dec.Decode(&throttleBucket)
        fmt.Printf("Received : %+v", throttleBucket)
}

func main() {
        fmt.Println("start")
        ln, err := net.Listen("tcp", ":8082")
        if err != nil {
                // handle error
        }
        for {
                conn, err := ln.Accept() // this blocks until connection or error
                if err != nil {
                        // handle error
                        continue
                }
                go handleConnection(conn) // a goroutine handles conn so that the loop can accept other connections
        }
}

和客户:

package main

import (
        "encoding/gob"
        "fmt"
        "log"
        "github.com/howti/ratelimit"
        "net"
)

var (
    throttleBucket = make(map[string]*ratelimit.Bucket)
)

func main() {
        fmt.Println("start client")
        conn, err := net.Dial("tcp", "localhost:8082")
        if err != nil {
                log.Fatal("Connection error", err)
        }
        encoder := gob.NewEncoder(conn)
        throttleBucket["127.0.0.1"] = ratelimit.NewBucketWithRate(float64(10), int64(100))
        throttleBucket["127.0.4.1"] = ratelimit.NewBucketWithRate(float64(1), int64(10))
        fmt.Println("Map before sending ", &throttleBucket)
        encoder.Encode(&throttleBucket)
        conn.Close()
        fmt.Println("done")
}

有人可以帮我吗？

Go版本:1.5示例输出:客户端:

start client
Map before sending  &map[127.0.0.1:0x1053c640 127.0.4.1:0x1053c680]
done

服务器:

start
Received : map[]

Answer 1

现在的问题是,你没有处理由错误返回 encoder.Encode(&throttleBucket)在client.go.

实际上,它返回gob: type ratelimit.Bucket has no exported fields.(为什么？)并且你没有处理来自dec.Decode(&throttleBucket)in 的错误server.go.它返回,EOF因为没有任何内容发送到服务器.

也许您应该阅读Go常规中有关错误的更多信息.

Answer 2

这是一个示例，如何使用 gob 对地图进行编码并从中解码 ( go playground)

package main

import (
    "fmt"
    "encoding/gob"
    "bytes"
)

var m = map[int]string{1:"one", 2: "two", 3: "three"}

func main() {
    buf := new(bytes.Buffer)
    encoder := gob.NewEncoder(buf)

    err := encoder.Encode(m)
    if err != nil {
        panic(err)
    }

    // your encoded stuff
    fmt.Println(buf.Bytes())

    var decodedMap map[int]string
    decoder := gob.NewDecoder(buf)

    err = decoder.Decode(&decodedMap)
    if err != nil {
        panic(err)
    }

    fmt.Printf("%#v\n", decodedMap)
}