如何获取Azure Storage Blob的MD5值

问题表述

直接使用CloudBlockBlob对象获取的Properties是空的，无法获取到对象的MD5值，后台并未进行属性值的填充

前提：blob属性本省包含md5值，某些方式上传的blob默认并没有md5值

解决办法

方法一：使用FetchAttributes()填充blob的属性值和元数据

方法二：使用List方法遍历container中的对象，通过对象的属性获取MD5

Code Demo

方法一：

CloudStorageAccount storageAccount = CloudStorageAccount.Parse("<storage connection string>");//storage connection string

CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

CloudBlobContainer container = blobClient.GetContainerReference("hello");//container name

//Retrieve reference to a blob named "myblob".
CloudBlockBlob blockBlob = container.GetBlockBlobReference("tt.txt");

blockBlob.FetchAttributes();//填充blob的属性值和元数据

string md5 = blockBlob.Properties.ContentMD5;

Console.WriteLine("md5:" + md5);

方法二：

CloudStorageAccount storageAccount = CloudStorageAccount.Parse("<storage connection string>");//storage connection string

CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

CloudBlobContainer container = blobClient.GetContainerReference("hello");//container name

 foreach (IListBlobItem item in container.ListBlobs(null, false))
            {
                if (item.GetType() == typeof(CloudBlockBlob))
                {
                    CloudBlockBlob blob = (CloudBlockBlob)item;

                    Console.WriteLine("Block blob of length {0}: {1} + md5:{2}.", blob.Properties.Length, blob.Uri, blob.Properties.ContentMD5);//获取md5值

                }
                else if (item.GetType() == typeof(CloudPageBlob))
                {
                    CloudPageBlob pageBlob = (CloudPageBlob)item;

                    Console.WriteLine("Page blob of length {0}: {1}", pageBlob.Properties.Length, pageBlob.Uri);

                }
                else if (item.GetType() == typeof(CloudBlobDirectory))
                {
                    CloudBlobDirectory directory = (CloudBlobDirectory)item;

                    Console.WriteLine("Directory: {0}", directory.Uri);
                }
            }

相关信息参考链接

通过 .NET 开始使用 Azure Blob 存储

Windows Azure Blob MD5 Overview

Blob Service REST API