将字符串和[] byte组合为有效载荷

Question

I'm trying to send an http request with a payload that contains 2 strings and a []byte. Any good ways of going about this? I've tried encryption/decryption (didn't work), converting the []byte to string (since the []byte is an image, it didn't work).

Visual representation:

string1 []byte string2

Answer 1

Here's an example using multipart request. I modified this from a piece of code I have that deals with JSON docs, so there may be some mistakes in it, but it should give you the idea:

        body := bytes.Buffer{}
        writer := multipart.NewWriter(&body)
        hdr := textproto.MIMEHeader{}
        hdr.Set("Content-Type", "text/plain")
        part, _ := writer.CreatePart(hdr)
        part.Write(data1)

        hdr = textproto.MIMEHeader{}
        hdr.Set("Content-Type", <image type>)
        part, _ = writer.CreatePart(hdr)
        part.Write(imageData)

        ... // Add more parts if you need to
        writer.Close()

        request, _ := http.NewRequest(http.MethodPost, url, &body)
        request.Header.Set("Content-Type", fmt.Sprintf("multipart/mixed;boundary=%s", writer.Boundary()))

        hcli := http.Client{}
        rsp, err := hcli.Do(request)