如何解析cryptocompare API生成的JSON？ [关闭]

Question

I am attempting to parse some JSON using this API endpoint.

https://www.cryptocompare.com/api/data/coinlist/

I can see it's making the request fine, I then try to decode the body of the response and it comes back with loads of random numbers.

If I copy the body value from my debugger I get the below.

<[]uint8> (length: 643401, cap: 1048064)

Here is my code.

url := fmt.Sprintf("https://www.cryptocompare.com/api/data/coinlist/")

    fmt.Println("Requesting data from " + url)

    req, err := http.NewRequest("GET", url, nil)

    if err != nil {
        log.Fatal("NewRequest: ", err)
        return
    }

    client := &http.Client{}

    resp, err := client.Do(req)

    if err != nil {
        log.Fatal("Do: ", err)
        return
    }

    body, readErr := ioutil.ReadAll(resp.Body)

I want to be able to grab everything inside the Data key from the JSON and then map that to a struct. Can anyone see what I am doing wrong?

Below is an example of what I see in my browser when I hit the endpoint.

 {
"Response": "Success",
"Message": "Coin list succesfully returned! This api is moving to https://min-api.cryptocompare.com/data/all/coinlist, please change the path.",
"BaseImageUrl": "https://www.cryptocompare.com",
"BaseLinkUrl": "https://www.cryptocompare.com",
"DefaultWatchlist": {
"CoinIs": "1182,7605,5038,24854,3807,3808,202330,5324,5031,20131",
"Sponsored": ""
},
"Data": {
"42": {
"Id": "4321",
"Url": "/coins/42/overview",
"ImageUrl": "/media/12318415/42.png",
"Name": "42",
"Symbol": "42",
"CoinName": "42 Coin",
"FullName": "42 Coin (42)",
"Algorithm": "Scrypt",
"ProofType": "PoW/PoS",
"FullyPremined": "0",
"TotalCoinSupply": "42",
"PreMinedValue": "N/A",
"TotalCoinsFreeFloat": "N/A",
"SortOrder": "34",
"Sponsored": false
},

Answer 1

Im not sure if I understood your question correctly but here's how I would parse the response given by the API:

package main

import (
    "fmt"
    "net/http"
    "encoding/json"
    "log"
    "io/ioutil"
)

type Data struct {
    Id        string
    CoinName  string
    Algorithm string
    // You can add more properties if you need them
}

type Response struct {
    Response         string
    Message          string
    BaseImageUrl     string
    BaseLinkUrl      string
    DefaultWatchlist map[string]string
    // If you're interested in the Data only all of the above properties can be excluded
    Data             map[string]Data
}

func main() {
    url := "https://min-api.cryptocompare.com/data/all/coinlist"
    resp := Response{}

    // Getting the data using http
    r, err := http.Get(url)
    if err != nil {
        log.Fatal(err.Error())
    }

    // Reading the response body using ioutil
    body, err := ioutil.ReadAll(r.Body)
    if err != nil {
        log.Fatal(err.Error())
    }
    defer r.Body.Close()

    if r.StatusCode == http.StatusOK {
        // Unmarshaling the json bytes into Response struct
        json.Unmarshal(body, &resp)

        fmt.Println(resp.Data) // Printing parsed struct
    }
}

---

"I then try to decode the body of the response and it comes back with loads of random numbers."

These random numbers is the response body as a slice of bytes []byte given by the ioutil.ReadAll() method, which is perfect for Unmarshaling.