Go语言获取需要权限认证的API数据
公开API
首先看一个请求json数据的例子，一个公开的API，谁都可以访问，无需权限认证，
数据来源:https://api.coinmarketcap.com/v2/ticker/
接下来看如何请求需要权限认证的API数据，数据来源为以下网址，
https://pro-api.coinmarketcap.com/v1/cryptocurrency/listings/latest
https://pro-api.coinmarketcap.com/v1/cryptocurrency/quotes/latest
这两个API是需要权限认证的，也就是需要APIkey，没有权限的时候，你直接点击这两个网址，返回的数据是这样的，
{
"status": {
"timestamp": "2018-12-11T00:53:33.535Z",
"error_code": 401,
"error_message": "API key missing.",
"elapsed": 0,
"credit_count": 0
}
}
也就是返回了错误，错误信息为"API key missing."API秘钥缺失。
到这个网站https://coinmarketcap.com/注册一个账号，就可以免费申请一个APIkey，接下来就可以用申请到的APIkey去正常获取上面两个网址的数据，通过权限认证以后获取到的数据是这样的，
{
"status": {
"timestamp": "2018-12-11T00:42:59.418Z",
"error_code": 0,
"error_message": null,
"elapsed": 9,
"credit_count": 1
},
"data": [
{
"id": 1,
"name": "Bitcoin",
"symbol": "BTC",
"slug": "bitcoin",
"circulating_supply": 17416675,
"total_supply": 17416675,
"max_supply": 21000000,
"date_added": "2013-04-28T00:00:00.000Z",
"num_market_pairs": 6684,
"tags": [
"mineable"
],
"platform": null,
"cmc_rank": 1,
"last_updated": "2018-12-11T00:41:22.000Z",
"quote": {
"USD": {
"price": 3490.26054654,
"volume_24h": 4958844740.50419,
"percent_change_1h": -0.352116,
"percent_change_24h": -3.79482,
"percent_change_7d": -10.3529,
"market_cap": 60788733604.40956,
"last_updated": "2018-12-11T00:41:22.000Z"
}
}
},
{
"id": 52,
"name": "XRP",
"symbol": "XRP",
"slug": "ripple",
………………………………………底下数据省略…………………………………………
接下来就来看一下如何获取这种需要权限认证的API数据，下面以Go语言举栗子，首先到官网查看API文档，https://coinmarketcap.com/api/documentation/v1/#，如何请求API数据已经写得很清楚，不过具体的每种语言的操作步骤不太一样
看看Go语言要怎么做，其实就是当你发起一个数据请求的时候要把你的APIkey添加到请求头中，然后这个网站就知道你是有权限的，就会给你正确的数据。
package main
import (
"fmt"
"io/ioutil"
"net/http"
)
var (
url = "https://pro-api.coinmarketcap.com/v1/cryptocurrency/listings/latest"
url1 = "https://pro-api.coinmarketcap.com/v1/cryptocurrency/info/"
url2 = "https://pro-api.coinmarketcap.com/v1/cryptocurrency/quotes/latest"
mykey = "860da129-69ed-189a-9379-2d48a4c00bd6"
)
func main() {
//首先创建一个客户端client，
client := &http.Client{}
//创建一个请求request，
reqest, err := http.NewRequest("GET", url, nil)
//为请求头添加秘钥认证，
reqest.Header.Set("X-CMC_PRO_API_KEY", mykey)
//reqest.Header.Add("Accept", "application/json")
//reqest.Header.Add("Accept-Encoding", "deflate")
if err != nil {
fmt.Println(err)
}
//执行请求，得到响应数据response，
resp, err := client.Do(reqest)
defer resp.Body.Close()
//读取响应体response的body，用`ioutil.ReadAll`读取，该函数返回结果为byte，
body, err := ioutil.ReadAll(resp.Body)
//将byte转为可读取的string类型，打印一下，就会看到得到了正确的响应，
fmt.Println(string(body))
}
运行结果
{
"status": {
"timestamp": "2018-12-11T01:13:02.768Z",
"error_code": 0,
"error_message": null,
"elapsed": 10,
"credit_count": 1
},
"data": [
{
"id": 1,
"name": "Bitcoin",
"symbol": "BTC",
"slug": "bitcoin",
"circulating_supply": 17416725,
"total_supply": 17416725,
"max_supply": 21000000,
"date_added": "2013-04-28T00:00:00.000Z",
"num_market_pairs": 6684,
"tags": [
"mineable"
],
"platform": null,
"cmc_rank": 1,
"last_updated": "2018-12-11T01:11:20.000Z",
"quote": {
"USD": {
"price": 3477.56550428,
"volume_24h": 4902670930.10955,
"percent_change_1h": -0.418618,
"percent_change_24h": -4.16081,
"percent_change_7d": -10.7638,
"market_cap": 60567802057.53108,
"last_updated": "2018-12-11T01:11:20.000Z"
}
}
},
{
"id": 52,
"name": "XRP",
"symbol": "XRP",
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这里最后的得到的最终数据是body，类型为byte，实际开发中，还需要将byte转为结构体，才可以应用，至于如何将byte数据转为结构体，可参考这篇文章Go语言如何解析复杂json数据