Sure! Pl

internal/service/auth_service.go

@@ -0,0 +1,111 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"wx_service/internal/model"
+
+	"gorm.io/gorm"
+)
+
+var ErrCodeRequired = errors.New("code is required")
+
+type AuthService struct {
+	db     *gorm.DB
+	wechat *WeChatClient
+}
+
+type LoginRequest struct {
+	Code      string
+	NickName  string
+	AvatarURL string
+	Gender    *int
+	Phone     string
+}
+
+type LoginResult struct {
+	User       *model.User
+	SessionKey string
+}
+
+func NewAuthService(db *gorm.DB, wechat *WeChatClient) *AuthService {
+	return &AuthService{
+		db:     db,
+		wechat: wechat,
+	}
+}
+
+func (s *AuthService) LoginWithCode(ctx context.Context, req LoginRequest) (*LoginResult, error) {
+	if strings.TrimSpace(req.Code) == "" {
+		return nil, ErrCodeRequired
+	}
+
+	session, err := s.wechat.Code2Session(ctx, req.Code)
+	if err != nil {
+		return nil, err
+	}
+	if session.OpenID == "" {
+		return nil, fmt.Errorf("wechat response missing openid")
+	}
+
+	tx := s.db.WithContext(ctx)
+	var user model.User
+	err = tx.Where("open_id = ?", session.OpenID).First(&user).Error
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		user = model.User{
+			OpenID:     session.OpenID,
+			UnionID:    session.UnionID,
+			NickName:   req.NickName,
+			AvatarURL:  req.AvatarURL,
+			Phone:      req.Phone,
+			SessionKey: session.SessionKey,
+		}
+		if req.Gender != nil {
+			user.Gender = *req.Gender
+		}
+		if err := tx.Create(&user).Error; err != nil {
+			return nil, fmt.Errorf("create user: %w", err)
+		}
+	} else if err != nil {
+		return nil, fmt.Errorf("query user: %w", err)
+	} else {
+		updates := map[string]interface{}{
+			"session_key": session.SessionKey,
+		}
+		if session.UnionID != "" && session.UnionID != user.UnionID {
+			updates["union_id"] = session.UnionID
+			user.UnionID = session.UnionID
+		}
+		if req.NickName != "" && req.NickName != user.NickName {
+			updates["nick_name"] = req.NickName
+			user.NickName = req.NickName
+		}
+		if req.AvatarURL != "" && req.AvatarURL != user.AvatarURL {
+			updates["avatar_url"] = req.AvatarURL
+			user.AvatarURL = req.AvatarURL
+		}
+		if req.Phone != "" && req.Phone != user.Phone {
+			updates["phone"] = req.Phone
+			user.Phone = req.Phone
+		}
+		if req.Gender != nil && user.Gender != *req.Gender {
+			updates["gender"] = *req.Gender
+			user.Gender = *req.Gender
+		}
+		if len(updates) > 0 {
+			if err := tx.Model(&user).Updates(updates).Error; err != nil {
+				return nil, fmt.Errorf("update user: %w", err)
+			}
+		}
+		user.SessionKey = session.SessionKey
+	}
+
+	result := &LoginResult{
+		User:       &user,
+		SessionKey: session.SessionKey,
+	}
+	return result, nil
+}

internal/service/wechat_client.go

@@ -0,0 +1,89 @@
+package service
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+const weChatCode2SessionURL = "https://api.weixin.qq.com/sns/jscode2session"
+
+// WeChatClient 调用微信接口获取 session/openid。
+type WeChatClient struct {
+	appID     string
+	appSecret string
+	client    *http.Client
+}
+
+type WeChatSession struct {
+	OpenID     string `json:"openid"`
+	UnionID    string `json:"unionid"`
+	SessionKey string `json:"session_key"`
+}
+
+type weChatSessionResponse struct {
+	WeChatSession
+	ErrCode int    `json:"errcode"`
+	ErrMsg  string `json:"errmsg"`
+}
+
+// WeChatError 表示微信接口级错误。
+type WeChatError struct {
+	Code int
+	Msg  string
+}
+
+func (e *WeChatError) Error() string {
+	return fmt.Sprintf("wechat error: code=%d msg=%s", e.Code, e.Msg)
+}
+
+func NewWeChatClient(appID, appSecret string, client *http.Client) *WeChatClient {
+	if client == nil {
+		client = &http.Client{
+			Timeout: 5 * time.Second,
+		}
+	}
+
+	return &WeChatClient{
+		appID:     appID,
+		appSecret: appSecret,
+		client:    client,
+	}
+}
+
+func (c *WeChatClient) Code2Session(ctx context.Context, code string) (*WeChatSession, error) {
+	query := url.Values{}
+	query.Set("appid", c.appID)
+	query.Set("secret", c.appSecret)
+	query.Set("js_code", code)
+	query.Set("grant_type", "authorization_code")
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("%s?%s", weChatCode2SessionURL, query.Encode()), nil)
+	if err != nil {
+		return nil, fmt.Errorf("build wechat request: %w", err)
+	}
+
+	resp, err := c.client.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("call wechat api: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("wechat api unexpected status: %s", resp.Status)
+	}
+
+	var raw weChatSessionResponse
+	if err := json.NewDecoder(resp.Body).Decode(&raw); err != nil {
+		return nil, fmt.Errorf("decode wechat response: %w", err)
+	}
+
+	if raw.ErrCode != 0 {
+		return nil, &WeChatError{Code: raw.ErrCode, Msg: raw.ErrMsg}
+	}
+
+	return &raw.WeChatSession, nil
+}