test_client.go

package main

import (
    "io"
    "log"
    "os"
    "net"
    "encoding/binary"
)

func uploadFile(addr, localPath, remoteFilename string) error {
    conn, err := net.Dial("tcp", addr)
    if err != nil {
        return err
    }
    defer conn.Close()

    // 1. Send filename length
    nameBytes := []byte(remoteFilename)
    err = binary.Write(conn, binary.LittleEndian, int32(len(nameBytes)))
    if err != nil {
        return err
    }

    // 2. Send filename
    _, err = conn.Write(nameBytes)
    if err != nil {
        return err
    }

    // 3. Send file content
    file, err := os.Open(localPath)
    if err != nil {
        return err
    }
    defer file.Close()

    _, err = io.Copy(conn, file)
    return err
}

func main() {
    if len(os.Args) != 4 {
        log.Fatal("Usage: go run test_client.go <addr:port> <local_file> <remote_filename>")
    }
    
    err := uploadFile(os.Args[1], os.Args[2], os.Args[3])
    if err != nil {
        log.Fatal("Upload failed:", err)
    }
    log.Println("Upload successful!")
}