GoLang-观看视频（以字节为单位）

I'm writing a server in golang and I got it to serve a basic .mp4 file. It serves it by bytes. The problem is that I can not seek/skip through the video. I've tried searching throughout stackover flow and google to find an answer but I came up short..

Here is my code:

package main

import (
    "net/http"
    "io/ioutil"
    "fmt"
    "os"
    "log"
    "bytes"
)

func ServeHTTP(w http.ResponseWriter, r *http.Request) {
           // grab the generated receipt.pdf file and stream it to browser
           streamPDFbytes, err := ioutil.ReadFile("./video.mp4")
           log.Println(r)
           if err != nil {
                   fmt.Println(err)
                   os.Exit(1)
           }

           b := bytes.NewBuffer(streamPDFbytes)

           // stream straight to client(browser)
           w.Header().Set("Content-type", "video/mp4")

           if _, err := b.WriteTo(w); err != nil { // <----- here!
                   fmt.Fprintf(w, "%s", err)
           }

           w.Write([]byte("Video Completed"))
}

func main() {
    http.Handle("/", new(MyHandler))
    http.ListenAndServe(":8080", nil)
}

Does anyone have the answer to how seeking works in golang?

Thanks, Have a great day!

The simplest way to stream MP4 video on Go with seeking support is

package main

import (
    "net/http"
)

func main() {
    fs := http.FileServer(http.Dir("."))
    http.Handle("/", http.StripPrefix("/", fs))
    http.ListenAndServe(":8080", nil)
}

And video will be available at http://localhost:8080/video.mp4

More complex is

package main

import (
    "log"
    "net/http"
    "os"
    "time"
)

func ServeHTTP(w http.ResponseWriter, r *http.Request) {
    video, err := os.Open("./video.mp4")
    if err != nil {
        log.Fatal(err)
    }
    defer video.Close()

    http.ServeContent(w, r, "video.mp4", time.Now(), video)
}

func main() {
    http.HandleFunc("/", ServeHTTP)
    http.ListenAndServe(":8080", nil)
}

If you need something more flexible you should implement your own progressive streaming server.

In your code you forgot to add and process Range/Accept-Range headers that's why nor FF, nor Chrome doesn't show you seek bar but anyway I don't think that keeping whole MP4 file in memory is good idea.