CODEWITHSUNDEEP
gowebfile-uploadwebformsserver-side
Viktor Rozenko
Viktor Rozenko

Reputation: 91

Handle multiple files in post request with Go

I am using Go to write server-side for a music streaming service. I need to be able to handle album uploads. I want admins to be able to go to http://lisn.rocks/upload, select a folder that has to contain meta.json, cover.jpg, and some .mp3 song files, click upload and the rest to be handled by server.

Here is a simple HTML page I'm using to test this functionality:

<html>
    <head><title>Album Upload</title></head>
    <body>
        <form enctype="multipart/form-data" action="/upload" method="POST">
            <input type="file" name="album" webkitdirectory directory multiple> <br>
            <input type="submit" value="Upload">
        </form>
    </body>
</html>

I need a handler function that would be able to look at the meta.json file, check its contents and do stuff based on what's there. The meta.json contains all the info I need. Now, I don't need an extensive explanation about reading JSON with Go or other things that go along with it.

I just need to read all files from that folder as separate files. Instead, Go sees them all as a single album file field when I do request.FormFile("album").

Upvotes: 2

Views: 3072

Answers (2)

jean davy Nizigama
jean davy Nizigama

Reputation: 389

Handling multiple files upload in go can be done by using the MultipartForm field of the request struct.

    multipartFormData := req.MultipartForm

    for _, v := range multipartFormData.File["attachments"] {
        fmt.Println(v.Filename, ":", v.Size)
        uploadedFile, _ := v.Open()
        // then use the single uploadedFile however you want
        // you may use its read method to get the file's bytes into a predefined slice, 
        //here am just using an anonymous slice for the example
        uploadedFile.Read([]byte{})
        uploadedFile.Close()
    }

Upvotes: 2

Burak Serdar
Burak Serdar

Reputation: 51557

As the documentation for FormFile says, it only returns the first file. When the form is submitted, the album field will be an array and you have to use a multipart stream to process each individual file.

rd, err:=request.MultipartReader()
for {
  part, err:=rd.NextPart()
  if err==io.EOF {
      break
  }
  data,err:=ioutil.ReadAll(part)
  fileName:=part.FileName()
  part.Close()
}

You need to add error handling and data processing, etc.

Upvotes: 1

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