讯飞开放平台机器翻译（新）golang实现demo

最近做项目用到翻译功能，对接了一下科大讯飞的翻译api接口，demo如下：

package main

import (
	"crypto/hmac"
	"crypto/sha256"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"time"
	"strings"
)

const (
	Host      = "itrans.xf-yun.com"
	Algorithm = "hmac-sha256"
	HttpProto = "HTTP/1.1"
	Uri       = "/v1/its"
	Url       = "https://itrans.xf-yun.com/v1/its"
	AppId  = "your app_id"
	AppSecret = "your app_secret"
	AppKey = "your app_key"
	Text   = "今天天气怎么样" //需要翻译的文本
)

func main() {
	client := &http.Client{}
	//生成要访问的url
	// 请求时间
	currentTime := time.Now().UTC().Format(time.RFC1123)
	// 生成签名
	sign := generateSignature(Host, currentTime, "POST", Uri, HttpProto, AppSecret)
	// 组装信息
	authInfo := fmt.Sprintf(`api_key="%s",algorithm="%s",headers="host date request-line",signature="%s"`,AppKey, Algorithm, sign)
	// 拼装请求body信息
	requestParam := map[string]interface{}{
		"header": map[string]interface{}{
			"app_id": AppId,
			"status": 3,
		},
		"parameter": map[string]interface{}{
			"its": map[string]interface{}{
				"from": "cn",
				"to":   "en",
				"result": map[string]interface{}{},
			},
		},
		"payload": map[string]interface{}{
			"input_data": map[string]interface{}{
				"encoding": "utf8",
				"status":   3,
				"text":     base64.StdEncoding.EncodeToString([]byte(Text)),
			},
		},
	}
	// 请求信息
	jsonByte, _ := json.Marshal(requestParam)
	request, err := http.NewRequest("POST", Url, strings.NewReader(string(jsonByte)))
	if err != nil {
		panic(err)
	}
	q := request.URL.Query()
	q.Add("host", Host)
	q.Add("date", currentTime)
	q.Add("authorization", base64.StdEncoding.EncodeToString([]byte(authInfo)))
	request.URL.RawQuery = q.Encode()
	request.Header.Set("content-type", "application/json")

	//处理返回结果
	response, _ := client.Do(request)
	defer response.Body.Close()
	body, err := ioutil.ReadAll(response.Body)
	fmt.Println(string(body))
}

func generateSignature(host, date, httpMethod, requestUri, httpProto, secret string) string {
	var signatureStr string
	if len(host) != 0 {
		signatureStr = "host: " + host + "\n"
	}
	signatureStr += "date: " + date + "\n"
	signatureStr += httpMethod + " " + requestUri + " " + httpProto
	return hmacsign(signatureStr, secret)
}
func hmacsign(data, secret string) string {
	mac := hmac.New(sha256.New, []byte(secret))
	mac.Write([]byte(data))
	encodeData := mac.Sum(nil)
	return base64.StdEncoding.EncodeToString(encodeData)
}