Simple chunking test

data/chunking.go

@@ -0,0 +1,97 @@
+package data
+
+import (
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+	"fs/models"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+const chunkSize = 64 * 1024
+const blobRoot = "blobs/"
+
+func IngestStream(bucket, key, contentType string, stream io.Reader) (*models.ObjectManifest, error) {
+	manifest := &models.ObjectManifest{
+		Bucket:      bucket,
+		Key:         key,
+		ContentType: contentType,
+	}
+
+	fullFileHasher := md5.New()
+
+	buffer := make([]byte, chunkSize)
+	var totalSize int64
+
+	for {
+		bytesRead, err := io.ReadFull(stream, buffer)
+		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
+			return nil, err
+		}
+
+		if bytesRead > 0 {
+			chunkData := buffer[:bytesRead]
+			totalSize += int64(bytesRead)
+
+			fullFileHasher.Write(chunkData)
+
+			chunkHash := sha256.Sum256(chunkData)
+			chunkID := hex.EncodeToString(chunkHash[:])
+
+			err := saveBlob(chunkID, chunkData)
+			if err != nil {
+				return nil, err
+			}
+			manifest.Chunks = append(manifest.Chunks, chunkID)
+		}
+		if err == io.EOF || err == io.ErrUnexpectedEOF {
+			break
+		}
+		if err != nil {
+			return nil, err
+		}
+
+	}
+
+	manifest.Size = totalSize
+	manifest.ETag = fmt.Sprintf(`"%s"`, hex.EncodeToString(fullFileHasher.Sum(nil)))
+
+	return manifest, nil
+
+}
+
+func saveBlob(chunkID string, data []byte) error {
+	dir := filepath.Join(blobRoot, chunkID[:2], chunkID[2:4])
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return err
+	}
+
+	fullPath := filepath.Join(dir, chunkID)
+	if _, err := os.Stat(fullPath); os.IsNotExist(err) {
+		if err := os.WriteFile(fullPath, data, 0644); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func GetBlob(chunkID string) ([]byte, error) {
+
+	return os.ReadFile(filepath.Join(blobRoot, chunkID[:2], chunkID[2:4], chunkID))
+}
+
+func GetObject(manifest *models.ObjectManifest) ([]byte, error) {
+	var fullData []byte
+	for _, chunkID := range manifest.Chunks {
+		chunkData, err := GetBlob(chunkID)
+		if err != nil {
+			return nil, err
+		}
+		fullData = append(fullData, chunkData...)
+	}
+	return fullData, nil
+}