Azure存储计算的MD5与现有属性不匹配

Question

我正在尝试通过ashx传递Azure存储blob.在 blockBlob.DownloadToStream(memoryStream)上,它抛出以下异常:Microsoft.WindowsAzure.Storage.StorageException: Calculated MD5 does not match existing property

我知道它找到了正确的blob.如果我放入一个不存在的容器和路径,那么它会给我一个404异常.

我已经用Google搜索了可能导致此错误的提示,但没有任何有用的信息.有没有人对可能导致这种情况的原因有任何想法？在过去的几天里,我以不同的方式重写了这段代码,但它总是在DownloadToStream上消失.

using Microsoft.WindowsAzure;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.Blob;

public void ProcessRequest(HttpContext context) {
    // Retrieve storage account from connection string.
    Microsoft.WindowsAzure.Storage.CloudStorageAccount storageAccount = Microsoft.WindowsAzure.Storage.CloudStorageAccount.Parse(Microsoft.WindowsAzure.CloudConfigurationManager.GetSetting("StorageConnectionString"));

    // Create the blob client.
    CloudBlobClient blobClient = storageAccount.CreateCloudBlobClient();

    // Retrieve reference to a previously created container.
    CloudBlobContainer container = blobClient.GetContainerReference("gmt");

    // Retrieve reference to blob named "articles/142/222.jpg".
    CloudBlockBlob blockBlob = container.GetBlockBlobReference("articles/142/222.jpg");

    using (var memoryStream = new MemoryStream()) {
        blockBlob.DownloadToStream(memoryStream);
        byte[] photoByte = ReadFully(memoryStream);
        context.Response.Clear();
        context.Response.ContentType = "image/jpeg";
        context.Response.OutputStream.Write(photoByte, 0, photoByte.Length);
    }
}

public static byte[] ReadFully(Stream input) {
    input.Position = 0;
    using (MemoryStream ms = new MemoryStream()) {
        input.CopyTo(ms);
        return ms.ToArray();
    }
}

Answer 1

我能够重现你面临的问题.如果Content MD5blob 的属性以某种方式被破坏,则会发生这种情况.我有一个含有一些内容MD5的blob(这是正确的).然后我以编程方式将MD5更改为其他值(这是不正确的).现在当我在blob上调用DownloadToStream()方法时,我得到完全相同的错误.

您可以通过设置DisableContentMD5Validation为truein 来绕过此检查,BlobRequestOptions如下面的代码所示:

            BlobRequestOptions options = new BlobRequestOptions()
            {
                DisableContentMD5Validation = true,
            };
            blockBlob.DownloadToStream(memoryStream, null, options);

尝试一下,它应该工作.

另外,您可能还想修改ReadFully方法.您需要将input流指针移动到开头.

    public static byte[] ReadFully(Stream input)
    {
        input.Position = 0;//Positioning it to the top of stream.
        using (MemoryStream ms = new MemoryStream())
        {
            input.CopyTo(ms);
            return ms.ToArray();
        }
    }