CODEWITHSUNDEEP
jsongo
motionsickness
motionsickness

Reputation: 187

Print/Log full unstructured json from stream in Go

I inherited someone else's code for an API and since I'm not familiar with the requests that it's receiving I'm trying to print them or log them so I can see their structure. From what I've read about Go, jsons are decoded with Structs but since I don't know how the requests are received I cant write a struct.

I've tried the following on a basic API but they just print me out an empty map or nothing at all:

func createBook(w http.ResponseWriter, r *http.Request) {
    var result map[string]interface{}
    _ = json.NewDecoder(r.Body).Decode(&result)
    fmt.Println(result)


func createBook(w http.ResponseWriter, r *http.Request) {
    w.Header().Set("Content-Type", "application/json")
    var book Book
    _ = json.NewDecoder(r.Body).Decode(&book)

    buf := new(bytes.Buffer)
    buf.ReadFrom(r.Body)
    newStr := buf.String()

    reader := strings.NewReader(newStr)
    writter := os.Stdout

    dec := json.NewDecoder(reader)
    enc := json.NewEncoder(writter)

    for {
        var m map[string]interface{}
        if err := dec.Decode(&m); err == io.EOF {
            break
        } else if err != nil {
            log.Fatal(err)
        }

        if err := enc.Encode(&m); err != nil {
            log.Println(err)
        }
        fmt.Println(m)
    }

    book.ID = strconv.Itoa(rand.Intn(100000000)) // Mock ID - not safe
    books = append(books, book)
    json.NewEncoder(w).Encode(book)
}

Is there any other way that it would print the received json without me knowing the strut beforehand?

Upvotes: 0

Views: 933

Answers (1)

Rajat Mishra
Rajat Mishra

Reputation: 141

Use json.Unmarshal function

import "bytes"

 func createBook(w http.ResponseWriter, r *http.Request) {
    var result map[string]interface{}
     data :+ StreamToByte(r.Body)
    err := json.Unmarshal(data, &result)
    if err !=nil{
        fmt.Println(err) //better to use log 
    }else
        fmt.Println(result)
   }
}
 func StreamToByte(stream io.Reader) []byte {
  buf := new(bytes.Buffer)
    buf.ReadFrom(stream)
    return buf.Bytes()
}

Refer : https://appdividend.com/2020/02/28/golang-how-to-convert-json-to-map-in-go/ https://gist.github.com/dixudx/3989284b142414e10352fde9def5c771

Upvotes: 2

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