支持公众号账号迁移，获取openID变化接口 (#370)

* * 公众号菜单管理，set相关函数，返回btn本身，方便以字面量的方式创建多个菜单，更直观，方便管理

* * golangci-lint fix

* * 获取二维码ticket接口没有往上抛接口错误

* * 增加GetOpenID方法，以获取消息的生产用户openID

* * 支持公众号账号迁移，获取openID变化接口

* * bugfix

* * golint fix

* * golint fix

officialaccount/user/migrate.go

@@ -0,0 +1,87 @@
+//Package user migrate 用于微信公众号账号迁移，获取openID变化
+//参考文档：https://kf.qq.com/faq/1901177NrqMr190117nqYJze.html
+package user
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/silenceper/wechat/v2/util"
+)
+
+const (
+	changeOpenIDURL = "https://api.weixin.qq.com/cgi-bin/changeopenid"
+)
+
+// ChangeOpenIDResult OpenID迁移变化
+type ChangeOpenIDResult struct {
+	OriOpenID string `json:"ori_openid"`
+	NewOpenID string `json:"new_openid"`
+	ErrMsg    string `json:"err_msg,omitempty"`
+}
+
+// ChangeOpenIDResultList OpenID迁移变化列表
+type ChangeOpenIDResultList struct {
+	util.CommonError
+	List []ChangeOpenIDResult `json:"result_list"`
+}
+
+// ListChangeOpenIDs 返回指定OpenID变化列表
+// fromAppID 为老账号AppID
+// openIDs 为老账号的openID，openIDs限100个以内
+// AccessToken 为新账号的AccessToken
+func (user *User) ListChangeOpenIDs(fromAppID string, openIDs ...string) (list *ChangeOpenIDResultList, err error) {
+	list = &ChangeOpenIDResultList{}
+	//list.List = make([]ChangeOpenIDResult, 0)
+	if len(openIDs) > 100 {
+		err = errors.New("openIDs length must be lt 100")
+		return
+	}
+
+	if fromAppID == "" {
+		err = errors.New("fromAppID is required")
+		return
+	}
+
+	accessToken, err := user.GetAccessToken()
+	if err != nil {
+		return
+	}
+
+	uri := fmt.Sprintf("%s?access_token=%s", changeOpenIDURL, accessToken)
+	var resp []byte
+	var req struct {
+		FromAppID  string   `json:"from_appid"`
+		OpenidList []string `json:"openid_list"`
+	}
+	req.FromAppID = fromAppID
+	req.OpenidList = append(req.OpenidList, openIDs...)
+	resp, err = util.PostJSON(uri, req)
+	if err != nil {
+		return
+	}
+
+	err = util.DecodeWithError(resp, list, "ListChangeOpenIDs")
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+// ListAllChangeOpenIDs  返回所有用户OpenID列表
+// fromAppID 为老账号AppID
+// openIDs 为老账号的openID
+// AccessToken 为新账号的AccessToken
+func (user *User) ListAllChangeOpenIDs(fromAppID string, openIDs ...string) (list []ChangeOpenIDResult, err error) {
+	list = make([]ChangeOpenIDResult, 0)
+	chunks := util.SliceChunk(openIDs, 100)
+	for _, chunk := range chunks {
+		result, err := user.ListChangeOpenIDs(fromAppID, chunk...)
+		if err != nil {
+			return list, err
+		}
+		list = append(list, result.List...)
+	}
+	return
+}

officialaccount/user/user.go

@@ -139,7 +139,7 @@ func (user *User) ListUserOpenIDs(nextOpenid ...string) (*OpenidList, error) {
 // ListAllUserOpenIDs 返回所有用户OpenID列表
 func (user *User) ListAllUserOpenIDs() ([]string, error) {
 	nextOpenid := ""
-	openids := []string{}
+	openids := make([]string, 0)
 	count := 0
 	for {
 		ul, err := user.ListUserOpenIDs(nextOpenid)