Changing Metadata[“Filename”] of blob and Container when copying and deleting container

问题

I am trying to change the container name and specific files inside of it when a certain condition was met. The 1st code below works fine. It can change the container name and blob.name correctly. The issue is the 2nd code below.

Below is my code.

string ContainerName = "old-container-name";
        string NewContainerName = "new-container-name";
        var storageAccount = CloudStorageAccount.Parse(CloudConfigurationManager.GetSetting("StorageConnectionString"));
        var blobClient = storageAccount.CreateCloudBlobClient();
        var sourcecontainer = blobClient.GetContainerReference(ContainerName);
        var destcontainer = blobClient.GetContainerReference(NewContainerName);
        destcontainer.CreateIfNotExists(BlobContainerPublicAccessType.Blob);
        BlobContinuationToken continuationToken = null;
        do
        {
            var blobsResult = sourcecontainer.ListBlobsSegmented(prefix: "", useFlatBlobListing: true, blobListingDetails: BlobListingDetails.All, maxResults: 1000, currentToken: continuationToken, options: new BlobRequestOptions(), operationContext: new OperationContext());
            continuationToken = blobsResult.ContinuationToken;
            var items = blobsResult.Results;
            foreach (var item in items)
            {
                string newName = "";
                var blob = (CloudBlob)item;
                if (blob.Name.Contains("originalfilename"))
                    newName = blob.Name.Replace("originalfilename", "newfilename");
                else
                    newName = blob.Name;

                var targetBlob = destcontainer.GetBlobReference(newName);
                targetBlob.StartCopy(blob.Uri);
            }
        }
        while (continuationToken != null);
        sourcecontainer.DeleteIfExists(); 

Before I added this condition inside the code above.

        if (blob.Metadata["Filename"].Contains("originalfilename"))
        {
            blob.Metadata["Filename"] = blob.Metadata["Filename"].Replace("originalfilename", "newfilename");
            targetBlob.SetMetadata();
        }

I was able to change the metadata["filename"] of the file but I encountered an error while retrieving the files which before is not happening. I think the way I update the Metadata was wrong.

Below is the error message:

Exception Details: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.

Any tips on how to fix this one or a better way to change the metadata?

回答1:

Based on my test, Filename is not an inbuilt metadata of blob. The inbuilt one is Name, which you cannot change. It always equals to the blob's name.

So, just as @Gaurav Mantri said in comment, did you add a Filename metadata for each blob manually?

If you have added Filename metadata for your blobs, then you can get and update it as following:

    public static void Test()
    {
        string connString = "your_connection_string";
        CloudStorageAccount storageAccount = CloudStorageAccount.Parse(connString);
        CloudBlobClient cloudBlobClient = storageAccount.CreateCloudBlobClient();

        CloudBlobContainer cloudBlobContainer = cloudBlobClient.GetContainerReference("pub");
        CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference("CP4.png");

        // Important, you need to fetch all attributes first! 
        cloudBlockBlob.FetchAttributes();

        if (cloudBlockBlob.Metadata.ContainsKey("Filename"))
        {

            Console.WriteLine(cloudBlockBlob.Metadata["Filename"].ToString());
            cloudBlockBlob.Metadata["Filename"] = "123";
            cloudBlockBlob.SetMetadata();
        }
        else
        {
            cloudBlockBlob.Metadata.Add("Filename", "CP4.png");
            cloudBlockBlob.SetMetadata();
        }
    }

In my test, the CP4.png blob's Filename metadata was updated to 123

来源：https://stackoverflow.com/questions/59152885/changing-metadatafilename-of-blob-and-container-when-copying-and-deleting-co