如何使用golang libp2p streams向多台主机发送数据？

使用golang libp2p streams向多台主机发送数据的步骤如下：

导入必要的包和依赖：

import (
    "context"
    "fmt"
    "github.com/libp2p/go-libp2p"
    "github.com/libp2p/go-libp2p-core/network"
    "github.com/libp2p/go-libp2p-core/protocol"
    "github.com/libp2p/go-libp2p-host"
    "github.com/libp2p/go-libp2p/p2p/protocol/ping"
)

创建一个libp2p主机：

func createHost(ctx context.Context) (host.Host, error) {
    return libp2p.New(ctx)
}

创建一个自定义的协议：

const myProtocol = protocol.ID("/myprotocol/1.0.0")

创建一个处理流的函数：

func handleStream(stream network.Stream) {
    // 在这里处理接收到的数据流
}

启动主机并监听连接：

func startHost(host host.Host) {
    host.SetStreamHandler(myProtocol, handleStream)
}

连接到其他主机：

func connectToPeers(ctx context.Context, host host.Host, peerAddresses []string) error {
    for _, addr := range peerAddresses {
        peerAddr, _ := ma.NewMultiaddr(addr)
        info, _ := peer.AddrInfoFromP2pAddr(peerAddr)
        host.Connect(ctx, *info)
    }
    return nil
}

发送数据到其他主机：

func sendData(ctx context.Context, host host.Host, peerAddresses []string, data []byte) error {
    for _, addr := range peerAddresses {
        peerAddr, _ := ma.NewMultiaddr(addr)
        info, _ := peer.AddrInfoFromP2pAddr(peerAddr)
        stream, _ := host.NewStream(ctx, info.ID, myProtocol)
        _, err := stream.Write(data)
        if err != nil {
            return err
        }
        stream.Close()
    }
    return nil
}

完整的示例代码：

package main

import (
    "context"
    "fmt"
    "github.com/libp2p/go-libp2p"
    "github.com/libp2p/go-libp2p-core/network"
    "github.com/libp2p/go-libp2p-core/protocol"
    "github.com/libp2p/go-libp2p-host"
    "github.com/libp2p/go-libp2p/p2p/protocol/ping"
    ma "github.com/multiformats/go-multiaddr"
)

const myProtocol = protocol.ID("/myprotocol/1.0.0")

func main() {
    ctx := context.Background()

    host, err := createHost(ctx)
    if err != nil {
        panic(err)
    }

    startHost(host)

    peerAddresses := []string{"/ip4/127.0.0.1/tcp/4001/p2p/QmPeerAddress1", "/ip4/127.0.0.1/tcp/4002/p2p/QmPeerAddress2"}
    err = connectToPeers(ctx, host, peerAddresses)
    if err != nil {
        panic(err)
    }

    data := []byte("Hello, World!")
    err = sendData(ctx, host, peerAddresses, data)
    if err != nil {
        panic(err)
    }
}

func createHost(ctx context.Context) (host.Host, error) {
    return libp2p.New(ctx)
}

func handleStream(stream network.Stream) {
    // 在这里处理接收到的数据流
}

func startHost(host host.Host) {
    host.SetStreamHandler(myProtocol, handleStream)
}

func connectToPeers(ctx context.Context, host host.Host, peerAddresses []string) error {
    for _, addr := range peerAddresses {
        peerAddr, _ := ma.NewMultiaddr(addr)
        info, _ := peer.AddrInfoFromP2pAddr(peerAddr)
        host.Connect(ctx, *info)
    }
    return nil
}

func sendData(ctx context.Context, host host.Host, peerAddresses []string, data []byte) error {
    for _, addr := range peerAddresses {
        peerAddr, _ := ma.NewMultiaddr(addr)
        info, _ := peer.AddrInfoFromP2pAddr(peerAddr)
        stream, _ := host.NewStream(ctx, info.ID, myProtocol)
        _, err := stream.Write(data)
        if err != nil {
            return err
        }
        stream.Close()
    }
    return nil
}

请注意，以上示例代码仅用于演示如何使用golang libp2p streams向多台主机发送数据。在实际应用中，您可能需要根据具体需求进行适当的修改和优化。