feat: add casdoor as itself idp support (#578)

Signed-off-by: Steve0x2a <stevesough@gmail.com>

idp/casdoor.go

@@ -0,0 +1,159 @@
+// Copyright 2022 The Casdoor 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 (
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+
+	"golang.org/x/oauth2"
+)
+
+type CasdoorIdProvider struct {
+	Client *http.Client
+	Config *oauth2.Config
+	Host   string
+}
+
+func NewCasdoorIdProvider(clientId string, clientSecret string, redirectUrl string, hostUrl string) *CasdoorIdProvider {
+	idp := &CasdoorIdProvider{}
+	config := idp.getConfig(hostUrl)
+	config.ClientID = clientId
+	config.ClientSecret = clientSecret
+	config.RedirectURL = redirectUrl
+	idp.Config = config
+	idp.Host = hostUrl
+	return idp
+}
+
+func (idp *CasdoorIdProvider) SetHttpClient(client *http.Client) {
+	idp.Client = client
+}
+
+func (idp *CasdoorIdProvider) getConfig(hostUrl string) *oauth2.Config {
+	return &oauth2.Config{
+		Endpoint: oauth2.Endpoint{
+			TokenURL: hostUrl + "/api/login/oauth/access_token",
+		},
+		Scopes: []string{"openid email profile"},
+	}
+}
+
+type CasdoorToken struct {
+	AccessToken string `json:"access_token"`
+	ExpiresIn   int    `json:"expires_in"`
+}
+
+func (idp *CasdoorIdProvider) GetToken(code string) (*oauth2.Token, error) {
+	resp, err := http.PostForm(idp.Config.Endpoint.TokenURL, url.Values{
+		"client_id":     {idp.Config.ClientID},
+		"client_secret": {idp.Config.ClientSecret},
+		"code":          {code},
+		"grant_type":    {"authorization_code"},
+	})
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+
+	if err != nil {
+		return nil, err
+	}
+	pToken := &CasdoorToken{}
+	err = json.Unmarshal(body, pToken)
+	if err != nil {
+		return nil, err
+	}
+
+	//check if token is expired
+	if pToken.ExpiresIn <= 0 {
+		return nil, fmt.Errorf("%s", pToken.AccessToken)
+	}
+	token := &oauth2.Token{
+		AccessToken: pToken.AccessToken,
+		Expiry:      time.Unix(time.Now().Unix()+int64(pToken.ExpiresIn), 0),
+	}
+	return token, nil
+
+}
+
+/*
+{
+    "sub": "2f80c349-4beb-407f-b1f0-528aac0f1acd",
+    "iss": "https://door.casbin.com",
+    "aud": "7a11****0fa2172",
+    "name": "admin",
+    "preferred_username": "Admin",
+    "email": "admin@example.com",
+    "picture": "https://casbin.org/img/casbin.svg",
+    "address": "Guangdong",
+    "phone": "12345678910"
+}
+*/
+
+type CasdoorUserInfo struct {
+	Id          string `json:"sub"`
+	Name        string `json:"name"`
+	DisplayName string `json:"preferred_username"`
+	Email       string `json:"email"`
+	AvatarUrl   string `json:"picture"`
+	Status      string `json:"status"`
+	Msg         string `json:"msg"`
+}
+
+func (idp *CasdoorIdProvider) GetUserInfo(token *oauth2.Token) (*UserInfo, error) {
+	cdUserinfo := &CasdoorUserInfo{}
+	accessToken := token.AccessToken
+	request, err := http.NewRequest("GET", fmt.Sprintf("%s/api/userinfo", idp.Host), nil)
+	if err != nil {
+		return nil, err
+	}
+	//add accesstoken to bearer token
+	request.Header.Add("Authorization", fmt.Sprintf("Bearer %s", accessToken))
+	resp, err := idp.Client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(data, cdUserinfo)
+	if err != nil {
+		return nil, err
+	}
+
+	if cdUserinfo.Status != "" {
+		return nil, fmt.Errorf("err: %s", cdUserinfo.Msg)
+	}
+
+	userInfo := &UserInfo{
+		Id:          cdUserinfo.Id,
+		Username:    cdUserinfo.Name,
+		DisplayName: cdUserinfo.DisplayName,
+		Email:       cdUserinfo.Email,
+		AvatarUrl:   cdUserinfo.AvatarUrl,
+	}
+	return userInfo, nil
+
+}