feat: support CUCloud (#9)

* feat: support cu cloud smn service

* feat: fix build err

* feat: promote code format

service/cucloud/README.md

@@ -0,0 +1,20 @@
+# CuCloud
+
+[CUCloud](https://www.cucloud.cn) is the cloud service brand of China Unicom
+
+## Usage
+
+1. Create a pair of accessKey and accessKeySecret in `https://console.cucloud.cn/console/uiam/user/${your_id}/info`
+2. Create a topic
+
+```go
+// define accessKey and  accessKeySecret
+accessKey := ""
+secretKey := ""
+
+// create client
+cuCloudClient := New(accessKey, secretKey, "topic_name", "message title", "cloud region code", "account id", "notify type")
+
+// send message
+err := cuCloudClient.Send(context.Background(), "", "content")
+```

service/cucloud/cucloud.go

@@ -0,0 +1,159 @@
+// Copyright 2025 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 cucloud
+
+import (
+	"bytes"
+	"context"
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"sort"
+	"strconv"
+	"time"
+
+	"golang.org/x/exp/maps"
+)
+
+type CuCloud struct {
+	AccessKey       string
+	SecretKey       string
+	TopicName       string
+	MessageTitle    string
+	CloudRegionCode string
+	AccountId       string
+	NotifyType      string
+	Client          http.Client
+}
+
+type CuCloudResp struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+	Result  string `json:"result"`
+}
+
+func New(accessKey, secretKey, topicName, messageTitle, cloudRegionCode, accountId, notifyType string) *CuCloud {
+	return &CuCloud{
+		accessKey,
+		secretKey,
+		topicName,
+		messageTitle,
+		cloudRegionCode,
+		accountId,
+		notifyType,
+		http.Client{},
+	}
+}
+
+func (c *CuCloud) Send(ctx context.Context, subject, content string) error {
+	timeNow := time.Now().UnixMilli()
+
+	reqHeader := map[string]string{}
+	reqHeader["algorithm"] = "HmacSHA256"
+	reqHeader["requestTime"] = strconv.FormatInt(timeNow, 10)
+	reqHeader["accessKey"] = c.AccessKey
+
+	reqBody := map[string]string{}
+
+	reqBody["notifyType"] = c.NotifyType
+	reqBody["messageTitle"] = url.QueryEscape(c.MessageTitle)
+	reqBody["messageType"] = "text"
+	reqBody["messageContent"] = url.QueryEscape(content)
+	reqBody["topicName"] = url.QueryEscape(c.TopicName)
+	reqBody["messageTag"] = ""
+	reqBody["templateName"] = ""
+	reqBody["cloudRegionCode"] = "cn-langfang-2"
+
+	signVal, err := c.generateRequestSign(reqHeader, reqBody)
+	if err != nil {
+		return err
+	}
+	reqHeader["sign"] = signVal
+	reqHeader["Content-Type"] = "application/json"
+	reqHeader["Account-Id"] = c.AccountId
+	reqHeader["User-Id"] = c.AccountId
+	reqHeader["Region-Code"] = c.CloudRegionCode
+
+	bodyJson, err := json.Marshal(reqBody)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequest("POST", "https://gateway.cucloud.cn/smn/SMNService/api/message/notify", bytes.NewReader(bodyJson))
+	if err != nil {
+		return err
+	}
+
+	for k, v := range reqHeader {
+		req.Header.Set(k, v)
+	}
+
+	client := &http.Client{}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	respBodyRaw, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+
+	var respBody CuCloudResp
+
+	err = json.Unmarshal(respBodyRaw, &respBody)
+	if err != nil {
+		return err
+	}
+
+	if respBody.Code != 200 {
+		return fmt.Errorf(respBody.Message)
+	}
+
+	return nil
+}
+
+func (c *CuCloud) generateRequestSign(header map[string]string, body map[string]string) (string, error) {
+	mac := hmac.New(sha256.New, []byte(c.SecretKey))
+	reqSignMap := make(map[string]string)
+	maps.Copy(reqSignMap, header)
+	maps.Copy(reqSignMap, body)
+	signRawString := ""
+
+	var keys []string
+	for k, _ := range reqSignMap {
+		keys = append(keys, k)
+	}
+
+	sort.Strings(keys)
+
+	for _, k := range keys {
+		vJson, err := json.Marshal(reqSignMap[k])
+		if err != nil {
+			return "", err
+		}
+		signRawString += k + "=" + string(vJson) + "&"
+	}
+
+	signRawString = signRawString[:len(signRawString)-1]
+	mac.Write([]byte(signRawString))
+	return hex.EncodeToString(mac.Sum(nil)), nil
+}