create custom menu

wechatCustomMenu.go

 package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+)
+
+//menu is a json definition
+var menu = []byte(`
+{
+     "button":[
+     {	
+          "type":"click",
+          "name":"今日歌曲",
+          "key":"V1001_TODAY_MUSIC"
+      },
+      {
+           "name":"菜单",
+           "sub_button":[
+           {	
+               "type":"view",
+               "name":"搜索",
+               "url":"http://www.soso.com/"
+            },
+            {
+               "type":"click",
+               "name":"赞一下我们",
+               "key":"V1001_GOOD"
+            }]
+       }]
+}
+`)
+
+//CreateCustomMenu   bulid a menu for wechat windows
+//    3 main manu max  (< 4 mandarin words)
+//    5 sub items max  (< 7 mandarin words)
+//success return nil
+//error return err
+func CreateCustomMenu(m []byte) error {
+	atoken, err := GetAccessToken()
+	if err != nil {
+		return err
+	}
+	url := fmt.Sprintf("https://api.weixin.qq.com/cgi-bin/menu/create?access_token=%s", atoken)
+	if len(m) == 0 {
+		m = menu //using default menu
+	}
+	return jsonPostRequest(url, m)
+
+}
+
+//CreateDefaultMenu build a menu for wechat window
+//
+func CreateDefaultMenu() error {
+	var b []byte
+	return CreateCustomMenu(b)
+}
+
+//jsonPostRequest perform http post request with json body
+//   url is the url to post to
+//   jsonBody is the payload in http post request
+func jsonPostRequest(url string, jsonBody []byte) error {
+	req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonBody))
+	if err != nil {
+		return err
+	}
+	req.Header.Set("X-Custom-Header", "Patrick Sun")
+	req.Header.Set("Content-Type", "application/json")
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	fmt.Println("response Status:", resp.Status)
+	fmt.Println("response Headers:", resp.Header)
+	body, _ := ioutil.ReadAll(resp.Body)
+	fmt.Println("response Body:", string(body))
+
+	return nil
+}