Azure Blob存储-当我保存到文件时为404

Question

I have another problem with Azure Blob Storage, this time with downloading. I get a list of files without a problem, unfortunately when I want to download it I get a 404 error that the file was not found.

using System.IO;
using System.Linq;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;

namespace BlobStorage
{
    class Program
    {
        static void Main(string[] args)
        {
            CloudStorageAccount backupStorageAccount = CloudStorageAccount.Parse(
                "{connectionString}");

            var backupBlobClient = backupStorageAccount.CreateCloudBlobClient();
            var backupContainer = backupBlobClient.GetContainerReference("{container-name");

            var list = backupContainer.ListBlobs(useFlatBlobListing: true);

            foreach (var blob in list)
            {
                var blobFileName = blob.Uri.Segments.Last();
                CloudBlockBlob blockBlob = backupContainer.GetBlockBlobReference(blobFileName);

                string destinationPath = string.Format(@"D:\" + blobFileName +".txt");

                blockBlob.DownloadToFile(destinationPath, FileMode.OpenOrCreate);
            }
        }
    }
}

Error message:

Microsoft.WindowsAzure.Storage.StorageException: "The remote server returned an error: (404) Not found."

Internal exception WebException: The remote server returned an error: (404) Not found.

And points to the line:

blockBlob.DownloadToFile (destinationPath, FileMode.OpenOrCreate);

A file like this most exists in blob storage. When I enter the blob editions, copy the url to a file, I can download it through the browser without any problem. Unfortunately, I can not download it from the application level due to a 404 error.

Only why does such a file exist?

Answer 1

The issue is how you're getting the blob name in the following line of code:

var blobFileName = blob.Uri.Segments.Last();

Considering, the path is tempdata/ExampleIotHub/02/2019/05/14/39 , the blob's name is ExampleIotHub/02/2019/05/14/39 (assuming your container name is tempdata ) however the blobFileName you're getting is just 39 (please see examples here ). Since there is no blob by the name 39 , you're getting this 404 error.

I suggest you try by doing something like the following:

foreach (var blob in list)
{
    var localFileName = blob.Uri.Segments.Last();
    CloudBlockBlob blockBlob = blob as CloudBlockBlob;
    if (blockBlob != null)
    {
      string destinationPath = string.Format(@"D:\" + localFileName +".txt");

      blockBlob.DownloadToFile(destinationPath, FileMode.OpenOrCreate);
    }
}

Please note that I have not tried running this code so there may be some errors.