Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/backup_archive.go

@@ -0,0 +1,106 @@
+package service
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+)
+
+const defaultBackupPartSizeBytes int64 = 4 * 1024 * 1024 * 1024
+
+// BackupPart 描述一个 gzip 字节分卷。
+type BackupPart struct {
+	Index     int    `json:"index"`
+	S3Key     string `json:"s3_key"`
+	SizeBytes int64  `json:"size_bytes"`
+	SHA256    string `json:"sha256,omitempty"`
+}
+
+type localBackupPart struct {
+	Index     int
+	Path      string
+	SizeBytes int64
+	SHA256    string
+}
+
+func splitBackupFile(srcPath string, partSize int64) (parts []localBackupPart, err error) {
+	if partSize <= 0 {
+		return nil, fmt.Errorf("backup part size must be positive")
+	}
+
+	src, err := os.Open(srcPath)
+	if err != nil {
+		return nil, fmt.Errorf("open backup archive: %w", err)
+	}
+	defer func() {
+		if closeErr := src.Close(); err == nil && closeErr != nil {
+			err = fmt.Errorf("close backup archive: %w", closeErr)
+		}
+		if err != nil {
+			paths := make([]string, 0, len(parts))
+			for _, part := range parts {
+				paths = append(paths, part.Path)
+			}
+			_ = cleanupBackupFiles(paths...)
+		}
+	}()
+
+	info, err := src.Stat()
+	if err != nil {
+		return nil, fmt.Errorf("stat backup archive: %w", err)
+	}
+	if info.Size() <= 0 {
+		return nil, errors.New("backup archive is empty")
+	}
+
+	remaining := info.Size()
+	for index := 1; remaining > 0; index++ {
+		partFile, createErr := os.CreateTemp("", "sub2api-backup-part-*")
+		if createErr != nil {
+			return nil, fmt.Errorf("create backup part: %w", createErr)
+		}
+		partPath := partFile.Name()
+		partBytes := partSize
+		if remaining < partBytes {
+			partBytes = remaining
+		}
+
+		hash := sha256.New()
+		written, copyErr := io.CopyN(io.MultiWriter(partFile, hash), src, partBytes)
+		closeErr := partFile.Close()
+		if copyErr != nil {
+			_ = os.Remove(partPath)
+			return nil, fmt.Errorf("write backup part %d: %w", index, copyErr)
+		}
+		if closeErr != nil {
+			_ = os.Remove(partPath)
+			return nil, fmt.Errorf("close backup part %d: %w", index, closeErr)
+		}
+
+		parts = append(parts, localBackupPart{
+			Index:     index,
+			Path:      partPath,
+			SizeBytes: written,
+			SHA256:    hex.EncodeToString(hash.Sum(nil)),
+		})
+		remaining -= written
+	}
+
+	return parts, nil
+}
+
+func cleanupBackupFiles(paths ...string) error {
+	var errs []error
+	for _, path := range paths {
+		if path == "" {
+			continue
+		}
+		if err := os.Remove(path); err != nil && !errors.Is(err, os.ErrNotExist) {
+			errs = append(errs, fmt.Errorf("remove %s: %w", path, err))
+		}
+	}
+	return errors.Join(errs...)
+}