How to send files to different servers in one process when using gin?

Question content

I am trying to do this by creating a POST request and sending it to a different server. In my process I try to send 3 POSTs, one to the first server and the rest to another server. p>

But it only works for the first POST request, the rest of the requests get a 200 code but the file is still empty. I'm not familiar with http connections, how can I correct my program? I would be very grateful if you could help me!

This is the function to receive files.

func ReceivePublicKey() *gin.Engine {
    router := gin.Default()
    router.MaxMultipartMemory = 8 << 20
    //router.Static("/", "./static")
    router.POST("/receive", func(context *gin.Context) {
        file, _ := context.FormFile("file")
        log.Println(file.Filename)
        dst := "./" + file.Filename
        context.SaveUploadedFile(file, dst)
        context.String(http.StatusOK, fmt.Sprintf("'%s' uploaded!", file.Filename))
        context.String(200, "server: receive publicKey successfully!")
    })
    return router
}

This is the function that creates and sends requests

func CreateSendFileReq(file *os.File, fileName string, url string) *http.Request {
    bodyBuf := &bytes.Buffer{}
    bodyWrite := multipart.NewWriter(bodyBuf)
    fileWrite, err := bodyWrite.CreateFormFile("file", fileName)
    _, err = io.Copy(fileWrite, file)
    if err != nil {
        log.Println("err")
    }
    bodyWrite.Close() 
    if err != nil {
        log.Println("err")
    }
    req, _ := http.NewRequest("POST", url, bodyBuf)
    req.Header.Set("Content-Type", bodyWrite.FormDataContentType())
    return req
}

func SendRequest(r *http.Request) *http.Response {
    client := &http.Client{}
    resp, err := client.Do(r)
    if err == nil {
        return resp
    } else {
        log.Fatal(err)
        return nil
    }
}

There are also functions that don’t work

func IotInit() {
    privateFile, _ := os.Open("private.pem")
    publicFile, _ := os.Open("public.pem")
    userId := GenerateIotId(publicFile)
    fmt.Println(userId)
    sendPrivateToServer := Controller.CreateSendFileReq(privateFile, userId+".pem", "http://192.168.42.129:8090/receive")

    sendPublicToUser := Controller.CreateSendFileReq(publicFile, "public.pem", "http://localhost:8090/receive")

    resp := Controller.SendRequest(sendPublicToUser)
    if resp.StatusCode != 200 {
        log.Fatal(resp.StatusCode)
    }
    resp.Body.Close()

    sendPrivateToUser := Controller.CreateSendFileReq(privateFile, "private.pem", "http://localhost:8090/receive")

    resp = Controller.SendRequest(sendPrivateToServer)
    if resp.StatusCode != 200 {
        log.Fatal(resp.StatusCode)
    }
    resp.Body.Close()

    resp = Controller.SendRequest(sendPrivateToUser)
    if resp.StatusCode != 200 {
        log.Fatal(resp.StatusCode)
    }
    resp.Body.Close()

    publicFile.Close()
    privateFile.Close()
}

Correct answer

Okay, now I found my mistake. First, I didn't check the size of the file, which explains why I got the 200 code when saving an empty file. The second one gets the userId in IotInit() I used io.Copy() and made the file pointer point to end of file, which explains why "public.pem" is empty, I never put anything Copied to the request body. Also, I am using io.Copy() when creating the POST request and "private.pem" may also be empty.

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