Gin 服务 []byte 作为文件

Question

I have a golang backend with gin. Its supposed to work as a proxy for a ftp server that contains audiofiles. So my client should be able to call the endpoint /download/filepath the Golang application is then supposed to fetch the file from a ftp server and return it as a file(no stream).

My current solution is to read the file from the ftp as []byte and temporarily write it to disk with ioutil.TempFile() and return that file with ctx.File().

If possible I would like to skip the step where I'm creating a tempfile. Is that possible? Perhaps theres a way to proxy the call and directly connect the http call to the ftp call?

Note I don't control the client application so I can't change it.

Answer 1

Use Context.Data to write a []byte as the response.

You can also use Context.DataFromReader to copy directly from the FTP response to the HTTP response.

HTTP responses are a stream of bytes. There's no way to get around that.

Answer 2

You can write to the ResponseWriter as you are reading the file. It works just like using http.ResponseWriter .

import "io"

//...

io.Copy(ctx.ResponseWriter, ftpReader)

Answer 3

In the gin framework to serving binary files to the client then the browser automatically downloads the file when the API is hit by the user, and the server does not need to save the file to the server (without having to save a static file), then use this method c.Data . Where the data type of the third parameter is []byte. I hope this answer can be useful and easier to understand for everyone. Here is a sample code.

func DownloadFile(c *gin.Context) {
    byteFile, err := ioutil.ReadFile("./file.txt")
    if err != nil {
        fmt.Println(err)
    }

    c.Header("Content-Disposition", "attachment; filename=file-name.txt")
    c.Data(http.StatusOK, "application/octet-stream", byteFile)
}