我之前有篇文章（http://www.cnblogs.com/MikeZhang/archive/2012/03/13/httpShareGolang20120312.html）中提到过用Go语言实现http文件共享，这个版本的程序比python的实现快了点，默认情况下支持的客户端多了些，但是没有客户访问的trace，程序运行过程中，感觉像是死掉了。我想改进下，让它有trace。

代码如下： 

/*
File      : httpShareWithTrace.go
Author    : Mike
E-Mail    : [email protected]
*/
package main
import(
    "fmt"
    "net/http"
    "io/ioutil"
    "log"
    "time"
    "os"
    "strings"
)
func getFilelist(path string) string {
        m_files,err  :=  ioutil.ReadDir(path)
        if err !=nil{
        //     println( "Get filelist error !" )
                return""
        }
        var strRet string
        for _,f := range m_files  {
                //    println(f.Name(),f.IsDir())
                if path == "./" {
                        strRet += "<p><a href=\""+path+""+f.Name() +" \">" + f.Name() + "</a></p>"
                }else{
                        strRet += "<p><a href=\""+path[1:]+"/"+f.Name() +" \">" + f.Name() + "</a></p>"
                }
        }
        return strRet
}
func Handler( w http.ResponseWriter,r *http.Request ){
        println("Request ",r.URL.Path," from ",r.RemoteAddr)
        //   path := r.URL.Path[1:]
        path := "." + r.URL.Path
        if path == "./favicon.ico" {http.NotFound(w,r);return}
        if path == "./" ||  getFilelist(path) != "" {fmt.Fprintf( w,"%s",getFilelist(path));return}
        fin,err := os.Open(path)
        defer fin.Close()
        if err != nil {fmt.Fprintf( w,"404 : Not found" );return}
        readLen := 1024 * 1024
        buf := make([]byte,readLen)
        startPos := 0
        println("Transfer file ",path," ... ")
        for {
                n,err := fin.ReadAt(buf,int64(startPos))
                fmt.Fprintf(w,"%s",buf[:n])
                if 0 == n || err != nil {break}
                startPos += readLen
        }
}
func main(){
        port := "8080"//Default port 
        if len(os.Args)>1 { port = strings.Join(os.Args[1:2],"")}
        http.HandleFunc( "/",Handler)
        s := &http.Server{
                Addr:           ":"+port,
                ReadTimeout:    1 * time.Hour,
                WriteTimeout:   1 * time.Hour,
                MaxHeaderBytes: (1 << 31) - 1 , //Max file size is 2048M
        }
        println("Listening on port ",port,"...")
        log.Fatal(s.ListenAndServe())
}

运行效果如下：

1、启动http文件共享

2、web访问

3、后台trace

说明：最大支持2G文件的下载，限时为1个小时，这里没有用充分使用http协议，直接用文件io做的。时间有限，这里暂时达到了预期功能，够局域网使用，这个等以后有时间了做进一步的优化。