REST API for uploading file inside JSON - json

Question

I am designing an REST API to upload a largish (100MB) file together with some information. So it's natural to think of json encoding.
So something like this:
{
file: content of the file or URL?
name: string
description: string
}
The name and description are easy to do with json but I'm not sure how the file content can be added to it.
Also I'm thinking I should use http PUT method. Is this correct?
Incidentally, golang is used to implement this API if it matters.

Answer 1

For a JSON encoding, use a []byte value to hold the file contents. The standard encoding/json package encodes []byte values as base64 strings.
Here's a sketch of how to implement the JSON encoding. Declare a type representing the payload:
type Upload struct {
Name string
Description string
Content []byte
}
To encode the file to a request body:
v := Upload{Name: fileName, Description: description, Content: content}
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(v); err != nil {
// handle error
}
req, err := http.NewRequest("PUT", url, &buf)
if err != nil {
// handle error
}
resp, err := http.DefaultClient.Do(req)
To decode the from a request body on the server:
var v Upload
if err := json.NewDecoder(req.Body).Decode(&v); err != nil {
// handle error
}
Another option is to use the mime/multipart package. The multipart encoding will be more efficient than JSON encoding because no base64 or other text encoding of the file is required for multipart.

Answer 2

To me, the most clear-cut way to do it would be to encode the file bytes somehow. base64 seems like a good choice, and golang has built-in support for it with "encoding/base64".