feat():learning后台管理项目初始化

internal/oss/s3.go

@@ -0,0 +1,100 @@
+package oss
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"goalfymax-admin/internal/config"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/credentials"
+	"github.com/aws/aws-sdk-go-v2/service/s3"
+)
+
+type s3Client struct {
+	client  *s3.Client
+	presign *s3.PresignClient
+	cfg     config.OssConfig
+}
+
+var (
+	clientOnce sync.Once
+	c          *s3Client
+)
+
+func initClient() error {
+	var initErr error
+	clientOnce.Do(func() {
+		cfg := config.GetConfig().Oss
+		if cfg.Region == "" || cfg.Bucket == "" || cfg.AccessKeyID == "" || cfg.AccessKeySecret == "" {
+			initErr = fmt.Errorf("OSS未配置: region/bucket/ak/sk 不能为空")
+			return
+		}
+
+		awsCfg := aws.Config{
+			Region:      cfg.Region,
+			Credentials: credentials.NewStaticCredentialsProvider(cfg.AccessKeyID, cfg.AccessKeySecret, ""),
+		}
+
+		s3c := s3.NewFromConfig(awsCfg)
+		c = &s3Client{
+			client:  s3c,
+			presign: s3.NewPresignClient(s3c),
+			cfg:     cfg,
+		}
+	})
+	return initErr
+}
+
+// GetPresignedGetURL 生成S3对象的预签名下载URL
+func GetPresignedGetURL(ctx context.Context, key string) (string, error) {
+	if err := initClient(); err != nil {
+		return "", err
+	}
+	expire := c.cfg.PresignUrlExpire
+	if expire <= 0 {
+		expire = 10 * time.Minute
+	}
+	req, err := c.presign.PresignGetObject(ctx, &s3.GetObjectInput{
+		Bucket: aws.String(c.cfg.Bucket),
+		Key:    aws.String(key),
+	}, func(po *s3.PresignOptions) {
+		po.Expires = expire
+	})
+	if err != nil {
+		return "", fmt.Errorf("生成预签名URL失败: %w", err)
+	}
+	return req.URL, nil
+}
+
+// DownloadFileContent 从S3下载文件内容和MIME类型
+func DownloadFileContent(ctx context.Context, key string) ([]byte, string, error) {
+	if err := initClient(); err != nil {
+		return nil, "", err
+	}
+
+	resp, err := c.client.GetObject(ctx, &s3.GetObjectInput{
+		Bucket: aws.String(c.cfg.Bucket),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		return nil, "", fmt.Errorf("从S3下载文件失败: %w", err)
+	}
+	defer resp.Body.Close()
+
+	buf := new(bytes.Buffer)
+	_, err = buf.ReadFrom(resp.Body)
+	if err != nil {
+		return nil, "", fmt.Errorf("读取文件内容失败: %w", err)
+	}
+
+	mimeType := "application/octet-stream" // 默认MIME类型
+	if resp.ContentType != nil && *resp.ContentType != "" {
+		mimeType = *resp.ContentType
+	}
+
+	return buf.Bytes(), mimeType, nil
+}