feat(azure_blob): preserve content type and md5 (#2734)

Author: NewFuture

drivers/azure_blob/driver.go

@@ -2,6 +2,7 @@ package azure_blob
 
 import (
 	"context"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"path"
@@ -12,10 +13,13 @@ import (
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore"
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/policy"
 	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
+	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/blob"
 	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/container"
 	"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/sas"
 	"github.com/OpenListTeam/OpenList/v4/internal/driver"
 	"github.com/OpenListTeam/OpenList/v4/internal/model"
+	"github.com/OpenListTeam/OpenList/v4/pkg/utils"
+	log "github.com/sirupsen/logrus"
 )
 
 // Azure Blob Storage based on the blob APIs
@@ -283,6 +287,26 @@ func (d *AzureBlob) Put(ctx context.Context, dstDir model.Obj, stream model.File
 	// Determine optimal upload options based on file size
 	options := optimizedUploadOptions(stream.GetSize())
 
+	// Preserve the file content type for direct Azure Blob downloads.
+	contentType := stream.GetMimetype()
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	}
+	options.HTTPHeaders = &blob.HTTPHeaders{
+		BlobContentType: &contentType,
+	}
+
+	// Preserve the MD5 checksum when it is available.
+	md5Hex := stream.GetHash().GetHash(utils.MD5)
+	if md5Hex != "" {
+		md5, err := hex.DecodeString(md5Hex)
+		if err == nil && len(md5) == 16 {
+			options.HTTPHeaders.BlobContentMD5 = md5
+		} else {
+			log.Warnf("Invalid MD5 hash: %s, error: %v", md5Hex, err)
+		}
+	}
+
 	// Track upload progress
 	progressTracker := &progressTracker{
 		total:          stream.GetSize(),