feat: add WeChatIdProvider (#62)

* feat: add WeChatIdProvider

Signed-off-by: Weihao <1340908470@qq.com>

* refactor: refactor WeChatIdProvider to suit to IdProvider interface; translate the annotation to English

Signed-off-by: Weihao <1340908470@qq.com>

* refactor: remove unnecessary comment

Signed-off-by: Weihao <1340908470@qq.com>

idp/provider.go

@@ -39,6 +39,8 @@ func GetIdProvider(providerType string, clientId string, clientSecret string, re
 		return NewGoogleIdProvider(clientId, clientSecret, redirectUrl)
 	} else if providerType == "QQ" {
 		return NewQqIdProvider(clientId, clientSecret, redirectUrl)
+	} else if providerType == "WeChat" {
+		return NewWeChatIdProvider(clientId, clientSecret, redirectUrl)
 	}
 
 	return nil

idp/weChat.go

@@ -0,0 +1,167 @@
+// Copyright 2021 The casbin Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package idp
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"golang.org/x/oauth2"
+	"io"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+type WeChatIdProvider struct {
+	Client *http.Client
+	Config *oauth2.Config
+}
+
+type TencentAccessToken struct {
+	AccessToken  string `json:"access_token"`  //Interface call credentials
+	ExpiresIn    int64  `json:"expires_in"`    //access_token interface call credential timeout time, unit (seconds)
+	RefreshToken string `json:"refresh_token"` //User refresh access_token
+	Openid       string `json:"openid"`        //Unique ID of authorized user
+	Scope        string `json:"scope"`         //The scope of user authorization, separated by commas. (,)
+	Unionid      string `json:"unionid"`       //This field will appear if and only if the website application has been authorized by the user's UserInfo.
+}
+
+type TencentUserInfo struct {
+	Openid     string   `json:"openid"`     //The ID of an ordinary user, which is unique to the current developer account
+	Nickname   string   `json:"nickname"`   //Ordinary user nickname
+	Sex        int      `json:"sex"`        //Ordinary user gender, 1 is male, 2 is female
+	Province   string   `json:"province"`   //Province filled in by ordinary user's personal information
+	City       string   `json:"city"`       //City filled in by general user's personal data
+	Country    string   `json:"country"`    //Country, such as China is CN
+	Headimgurl string   `json:"headimgurl"` //User avatar, the last value represents the size of the square avatar (there are optional values of 0, 46, 64, 96, 132, 0 represents a 640*640 square avatar), this item is empty when the user does not have a avatar
+	Privilege  []string `json:"privilege"`  //User Privilege information, json array, such as Wechat Woka user (chinaunicom)
+	Unionid    string   `json:"unionid"`    //Unified user identification. For an application under a WeChat open platform account, the unionid of the same user is unique.
+}
+
+func NewWeChatIdProvider(clientId string, clientSecret string, redirectUrl string) *WeChatIdProvider {
+	idp := &WeChatIdProvider{}
+
+	config := idp.getConfig(clientId, clientSecret, redirectUrl)
+	idp.Config = config
+
+	return idp
+}
+
+func (idp *WeChatIdProvider) SetHttpClient(client *http.Client) {
+	idp.Client = client
+}
+
+// getConfig return a point of Config, which describes a typical 3-legged OAuth2 flow
+func (idp *WeChatIdProvider) getConfig(clientId string, clientSecret string, redirectUrl string) *oauth2.Config {
+	var endpoint = oauth2.Endpoint{
+		TokenURL: "https://graph.qq.com/oauth2.0/token",
+	}
+
+	var config = &oauth2.Config{
+		Scopes:       []string{"snsapi_login"},
+		Endpoint:     endpoint,
+		ClientID:     clientId,
+		ClientSecret: clientSecret,
+		RedirectURL:  redirectUrl,
+	}
+
+	return config
+}
+
+// GetToken use code get access_token (*operation of getting code ought to be done in front)
+// get more detail via: https://developers.weixin.qq.com/doc/oplatform/Website_App/WeChat_Login/Wechat_Login.html
+func (idp *WeChatIdProvider) GetToken(code string) (*oauth2.Token, error) {
+	params := url.Values{}
+	params.Add("grant_type", "authorization_code")
+	params.Add("appid", idp.Config.ClientID)
+	params.Add("secret", idp.Config.ClientSecret)
+	params.Add("code", code)
+
+	getAccessTokenUrl := fmt.Sprintf("https://api.weixin.qq.com/sns/oauth2/access_token?%s", params.Encode())
+	tokenResponse, err := idp.Client.Get(getAccessTokenUrl)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func(Body io.ReadCloser) {
+		err := Body.Close()
+		if err != nil {
+			return
+		}
+	}(tokenResponse.Body)
+
+	buf := new(bytes.Buffer)
+	_, err = buf.ReadFrom(tokenResponse.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	var tencentAccessToken TencentAccessToken
+	if err = json.Unmarshal([]byte(buf.String()), &tencentAccessToken); err != nil {
+		return nil, err
+	}
+
+	token := oauth2.Token{
+		AccessToken:  tencentAccessToken.AccessToken,
+		TokenType:    "WeChatAccessToken",
+		RefreshToken: tencentAccessToken.RefreshToken,
+		Expiry:       time.Time{},
+	}
+
+	raw := make(map[string]string)
+	raw["Openid"] = tencentAccessToken.Openid
+	token.WithExtra(raw)
+
+	return &token, nil
+}
+
+// GetUserInfo use TencentAccessToken gotten before return TencentUserInfo
+// get more detail via: https://developers.weixin.qq.com/doc/oplatform/Website_App/WeChat_Login/Authorized_Interface_Calling_UnionID.html
+func (idp *WeChatIdProvider) GetUserInfo(token *oauth2.Token) (*UserInfo, error) {
+	var tencentUserInfo TencentUserInfo
+	accessToken := token.AccessToken
+	openid := token.Extra("Openid")
+
+	getUserInfoUrl := fmt.Sprintf("https://api.weixin.qq.com/sns/userinfo?access_token=%s&openid=%s", accessToken, openid)
+	getUserInfoResponse, err := idp.Client.Get(getUserInfoUrl)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func(Body io.ReadCloser) {
+		err := Body.Close()
+		if err != nil {
+			return
+		}
+	}(getUserInfoResponse.Body)
+
+	buf := new(bytes.Buffer)
+	_, err = buf.ReadFrom(getUserInfoResponse.Body)
+	if err != nil {
+		return nil, err
+	}
+	if err = json.Unmarshal([]byte(buf.String()), &tencentUserInfo); err != nil {
+		return nil, err
+	}
+
+	userInfo := UserInfo{
+		Username:  tencentUserInfo.Nickname,
+		Email:     "",
+		AvatarUrl: tencentUserInfo.Headimgurl,
+	}
+
+	return &userInfo, nil
+}