feat: 实现公共工具包，包括日志、错误处理、数据库和缓存

backend/shared/pkg/cache/redis.go

@@ -0,0 +1,120 @@
+package cache
+
+import (
+	"context"
+	"time"
+
+	"backend/shared/pkg/logger"
+
+	"github.com/go-redis/redis/v8"
+)
+
+type RedisConfig struct {
+	Addr     string
+	Password string
+	DB       int
+}
+
+type RedisCache struct {
+	Client *redis.Client
+	ctx    context.Context
+}
+
+// NewRedisCache 创建新的 Redis 缓存连接
+func NewRedisCache(config RedisConfig) (*RedisCache, error) {
+	client := redis.NewClient(&redis.Options{
+		Addr:     config.Addr,
+		Password: config.Password,
+		DB:       config.DB,
+	})
+
+	ctx := context.Background()
+
+	// 测试连接
+	if _, err := client.Ping(ctx).Result(); err != nil {
+		return nil, err
+	}
+
+	logger.Info("Connected to Redis cache")
+
+	return &RedisCache{
+		Client: client,
+		ctx:    ctx,
+	}, nil
+}
+
+// Close 关闭 Redis 连接
+func (r *RedisCache) Close() error {
+	if r.Client != nil {
+		return r.Client.Close()
+	}
+	return nil
+}
+
+// Set 设置缓存
+func (r *RedisCache) Set(key string, value interface{}, expiration time.Duration) error {
+	return r.Client.Set(r.ctx, key, value, expiration).Err()
+}
+
+// Get 获取缓存
+func (r *RedisCache) Get(key string) (string, error) {
+	return r.Client.Get(r.ctx, key).Result()
+}
+
+// Delete 删除缓存
+func (r *RedisCache) Delete(key string) error {
+	return r.Client.Del(r.ctx, key).Err()
+}
+
+// Exists 检查键是否存在
+func (r *RedisCache) Exists(key string) (bool, error) {
+	result, err := r.Client.Exists(r.ctx, key).Result()
+	if err != nil {
+		return false, err
+	}
+	return result > 0, nil
+}
+
+// Expire 设置键的过期时间
+func (r *RedisCache) Expire(key string, expiration time.Duration) error {
+	return r.Client.Expire(r.ctx, key, expiration).Err()
+}
+
+// TTL 获取键的剩余过期时间
+func (r *RedisCache) TTL(key string) (time.Duration, error) {
+	return r.Client.TTL(r.ctx, key).Result()
+}
+
+// Incr 递增键的值
+func (r *RedisCache) Incr(key string) (int64, error) {
+	return r.Client.Incr(r.ctx, key).Result()
+}
+
+// Decr 递减键的值
+func (r *RedisCache) Decr(key string) (int64, error) {
+	return r.Client.Decr(r.ctx, key).Result()
+}
+
+// HashSet 设置哈希表字段
+func (r *RedisCache) HashSet(key, field string, value interface{}) error {
+	return r.Client.HSet(r.ctx, key, field, value).Err()
+}
+
+// HashGet 获取哈希表字段
+func (r *RedisCache) HashGet(key, field string) (string, error) {
+	return r.Client.HGet(r.ctx, key, field).Result()
+}
+
+// HashDelete 删除哈希表字段
+func (r *RedisCache) HashDelete(key string, fields ...string) error {
+	return r.Client.HDel(r.ctx, key, fields...).Err()
+}
+
+// HashExists 检查哈希表字段是否存在
+func (r *RedisCache) HashExists(key, field string) (bool, error) {
+	result, err := r.Client.HExists(r.ctx, key, field).Result()
+	if err != nil {
+		return false, err
+	}
+	return result, nil
+}

backend/shared/pkg/database/postgres.go

@@ -0,0 +1,79 @@
+package database
+
+import (
+	"database/sql"
+	"fmt"
+	"time"
+
+	"backend/shared/pkg/logger"
+
+	_ "github.com/lib/pq"
+)
+
+type PostgresConfig struct {
+	Host     string
+	Port     int
+	User     string
+	Password string
+	DBName   string
+	SSLMode  string
+}
+
+type PostgresDB struct {
+	DB *sql.DB
+}
+
+// NewPostgresDB 创建新的 PostgreSQL 数据库连接
+func NewPostgresDB(config PostgresConfig) (*PostgresDB, error) {
+	connStr := fmt.Sprintf(
+		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
+		config.Host, config.Port, config.User, config.Password, config.DBName, config.SSLMode,
+	)
+
+	db, err := sql.Open("postgres", connStr)
+	if err != nil {
+		return nil, err
+	}
+
+	// 设置连接池参数
+	db.SetMaxOpenConns(25)
+	db.SetMaxIdleConns(5)
+	db.SetConnMaxLifetime(5 * time.Minute)
+
+	// 测试连接
+	if err := db.Ping(); err != nil {
+		return nil, err
+	}
+
+	logger.Info("Connected to PostgreSQL database")
+
+	return &PostgresDB{DB: db}, nil
+}
+
+// Close 关闭数据库连接
+func (p *PostgresDB) Close() error {
+	if p.DB != nil {
+		return p.DB.Close()
+	}
+	return nil
+}
+
+// Exec 执行 SQL 语句
+func (p *PostgresDB) Exec(query string, args ...interface{}) (sql.Result, error) {
+	return p.DB.Exec(query, args...)
+}
+
+// Query 执行查询
+func (p *PostgresDB) Query(query string, args ...interface{}) (*sql.Rows, error) {
+	return p.DB.Query(query, args...)
+}
+
+// QueryRow 执行单行查询
+func (p *PostgresDB) QueryRow(query string, args ...interface{}) *sql.Row {
+	return p.DB.QueryRow(query, args...)
+}
+
+// Begin 开始事务
+func (p *PostgresDB) Begin() (*sql.Tx, error) {
+	return p.DB.Begin()
+}

backend/shared/pkg/errors/errors.go

@@ -0,0 +1,96 @@
+package errors
+
+import (
+	"errors"
+	"fmt"
+)
+
+// 错误类型定义
+var (
+	ErrNotFound         = errors.New("resource not found")
+	ErrInvalidInput     = errors.New("invalid input")
+	ErrInternalServer   = errors.New("internal server error")
+	ErrUnauthorized     = errors.New("unauthorized")
+	ErrForbidden        = errors.New("forbidden")
+	ErrConflict         = errors.New("conflict")
+	ErrBadRequest       = errors.New("bad request")
+	ErrTimeout          = errors.New("timeout")
+	ErrServiceUnavailable = errors.New("service unavailable")
+)
+
+// AppError 应用错误结构
+type AppError struct {
+	Err     error
+	Message string
+	Code    int
+}
+
+func (e *AppError) Error() string {
+	if e.Message != "" {
+		return e.Message
+	}
+	return e.Err.Error()
+}
+
+func (e *AppError) Unwrap() error {
+	return e.Err
+}
+
+// NewAppError 创建新的应用错误
+func NewAppError(err error, message string, code int) *AppError {
+	return &AppError{
+		Err:     err,
+		Message: message,
+		Code:    code,
+	}
+}
+
+// WrapError 包装错误
+func WrapError(err error, message string) error {
+	return fmt.Errorf("%s: %w", message, err)
+}
+
+// IsNotFound 检查是否为资源未找到错误
+func IsNotFound(err error) bool {
+	return errors.Is(err, ErrNotFound)
+}
+
+// IsInvalidInput 检查是否为无效输入错误
+func IsInvalidInput(err error) bool {
+	return errors.Is(err, ErrInvalidInput)
+}
+
+// IsInternalServer 检查是否为内部服务器错误
+func IsInternalServer(err error) bool {
+	return errors.Is(err, ErrInternalServer)
+}
+
+// IsUnauthorized 检查是否为未授权错误
+func IsUnauthorized(err error) bool {
+	return errors.Is(err, ErrUnauthorized)
+}
+
+// IsForbidden 检查是否为禁止访问错误
+func IsForbidden(err error) bool {
+	return errors.Is(err, ErrForbidden)
+}
+
+// IsConflict 检查是否为冲突错误
+func IsConflict(err error) bool {
+	return errors.Is(err, ErrConflict)
+}
+
+// IsBadRequest 检查是否为请求错误
+func IsBadRequest(err error) bool {
+	return errors.Is(err, ErrBadRequest)
+}
+
+// IsTimeout 检查是否为超时错误
+func IsTimeout(err error) bool {
+	return errors.Is(err, ErrTimeout)
+}
+
+// IsServiceUnavailable 检查是否为服务不可用错误
+func IsServiceUnavailable(err error) bool {
+	return errors.Is(err, ErrServiceUnavailable)
+}

backend/shared/pkg/logger/logger.go

@@ -0,0 +1,38 @@
+package logger
+
+import (
+	"log"
+	"os"
+)
+
+type Logger struct {
+	infoLogger  *log.Logger
+	errorLogger *log.Logger
+	debugLogger *log.Logger
+}
+
+var instance *Logger
+
+func init() {
+	instance = NewLogger()
+}
+
+func NewLogger() *Logger {
+	return &Logger{
+		infoLogger:  log.New(os.Stdout, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile),
+		errorLogger: log.New(os.Stderr, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile),
+		debugLogger: log.New(os.Stdout, "DEBUG: ", log.Ldate|log.Ltime|log.Lshortfile),
+	}
+}
+
+func Info(format string, v ...interface{}) {
+	instance.infoLogger.Printf(format, v...)
+}
+
+func Error(format string, v ...interface{}) {
+	instance.errorLogger.Printf(format, v...)
+}
+
+func Debug(format string, v ...interface{}) {
+	instance.debugLogger.Printf(format, v...)
+}