feat: add geetest captcha (#953)

captcha/geetest.go

@@ -0,0 +1,82 @@
+// 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 captcha
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/casdoor/casdoor/util"
+)
+
+const GEETESTCaptchaVerifyUrl = "http://gcaptcha4.geetest.com/validate"
+
+type GEETESTCaptchaProvider struct {
+}
+
+func NewGEETESTCaptchaProvider() *GEETESTCaptchaProvider {
+	captcha := &GEETESTCaptchaProvider{}
+	return captcha
+}
+
+func (captcha *GEETESTCaptchaProvider) VerifyCaptcha(token, clientSecret string) (bool, error) {
+	pathData, err := url.ParseQuery(token)
+	if err != nil {
+		return false, err
+	}
+
+	signToken := util.GetHmacSha256(clientSecret, pathData["lot_number"][0])
+
+	formData := make(url.Values)
+	formData["lot_number"] = []string{pathData["lot_number"][0]}
+	formData["captcha_output"] = []string{pathData["captcha_output"][0]}
+	formData["pass_token"] = []string{pathData["pass_token"][0]}
+	formData["gen_time"] = []string{pathData["gen_time"][0]}
+	formData["sign_token"] = []string{signToken}
+	captchaId := pathData["captcha_id"][0]
+
+	cli := http.Client{Timeout: time.Second * 5}
+	resp, err := cli.PostForm(fmt.Sprintf("%s?captcha_id=%s", GEETESTCaptchaVerifyUrl, captchaId), formData)
+	if err != nil || resp.StatusCode != 200 {
+		return false, err
+	}
+
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return false, err
+	}
+
+	type captchaResponse struct {
+		Result string `json:"result"`
+		Reason string `json:"reason"`
+	}
+	captchaResp := &captchaResponse{}
+	err = json.Unmarshal(body, captchaResp)
+	if err != nil {
+		return false, err
+	}
+
+	if captchaResp.Result == "success" {
+		return true, nil
+	}
+
+	return false, errors.New(captchaResp.Reason)
+}