json-decoding.go

// There are two ways I can convert json body to struct. Don't know what's the difference.
// https://www.reddit.com/r/golang/comments/5yhfo1/jsondecoder_vs_jsonunmarshal/
// Other than reddit reference I don't see any other links. 

//Method1:
    var c Service
    byteArray, err := ioutil.ReadAll(req.Body)
    if err != nil {
        log.Fatalf("fatal: reading from readall body %v", req.Body)
    }
    err = json.Unmarshal(byteArray, &c)
    if err != nil {
        log.Fatalf("fatal: reading from readall body %v", req.Body)
    }

//Method2:
    var c Service
    err = json.NewDecoder(req.Body).Decode(&c)
    if err != nil {
        log.Fatalf("fatal: reading request body %v", req.Body)
    }

@theckman in Golang slack community responded with:

if it's an HTTP request (a single JSON document), use Unmarshal
If it was a TCP connection, where the remote end would continually send JSON objects to you, then you would use the decoder. Since that's designed for a stream of JSON documents and not just one.