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BlobRequestOptions.CopySourceAccessCondition Property

Updated: April 24, 2013

[This topic is part of the Microsoft Azure Storage Client Library 1.7, which has been deprecated. See Storage Client Library for the latest version.]

Gets or sets the access condition on the source blob, when the request is to copy a blob.

Namespace: Microsoft.WindowsAzure.StorageClient
Assembly: Microsoft.WindowsAzure.StorageClient (in Microsoft.WindowsAzure.StorageClient.dll)

'Usage
Dim instance As BlobRequestOptions
Dim value As AccessCondition

value = instance.CopySourceAccessCondition

instance.CopySourceAccessCondition = value

public AccessCondition CopySourceAccessCondition { get; set; }

Property Value

Type: Microsoft.WindowsAzure.StorageClient.AccessCondition

A structure that specifies any conditional parameters on the request.

The following code example checks an access condition on the source blob and copies the blob if the condition is met.

static void CopyOnLastModifiedCondition(Uri blobEndpoint, string accountName, string accountKey)
{
    //Create service client for credentialed access to the Blob service.
    CloudBlobClient blobClient = 
        new CloudBlobClient(blobEndpoint, new StorageCredentialsAccountAndKey(accountName, accountKey));

    //Get a reference to the source blob.
    CloudBlob sourceBlob = blobClient.GetBlobReference("mycontainer/myblob.txt");

    sourceBlob.FetchAttributes();

    //Get a reference to the destination blob.
    CloudBlob destBlob = blobClient.GetBlobReference("mycontainer/copy-if-modified-since.txt");

    BlobRequestOptions options = new BlobRequestOptions();
    DateTime dt = new DateTime(2010, 9, 1, 0, 0, 0, DateTimeKind.Utc);

    //Copy the source blob to the destination blob if the source blob has been modified since 9/1/2010.
    try
    {
        //Copy the source blob to the destination blob if the source blob has been modified since 9/1/2010.
        options.CopySourceAccessCondition = AccessCondition.IfModifiedSince(dt.ToUniversalTime());
        destBlob.CopyFromBlob(sourceBlob, options);
    }
    catch (StorageClientException e)
    {
        if (e.StatusCode == HttpStatusCode.PreconditionFailed)
        {
            Console.WriteLine("Access condition not met - blob " + 
                sourceBlob.Uri + 
                " has not been modified since " + dt.ToUniversalTime());
        }
        else
        {
            Console.WriteLine("Error code: " + e.ErrorCode);
        }
    }

    //Get a reference to the destination blob.
    destBlob = blobClient.GetBlobReference("mycontainer/copy-if-not-modified-since.txt");
    try
    {
        //Copy source blob to destination blob if the source blob has not been modified since 9/1/2010.
        options.CopySourceAccessCondition = AccessCondition.IfNotModifiedSince(dt.ToUniversalTime());
        destBlob.CopyFromBlob(sourceBlob, options);
    }
    catch (StorageClientException e)
    {
        if (e.StatusCode == HttpStatusCode.PreconditionFailed)
        {
            Console.WriteLine("Access condition not met - ETag for blob " + 
                sourceBlob.Uri + 
                " does not match ETag for blob " + destBlob.Uri);
        }
        else
        {
            Console.WriteLine("Error code: " + e.ErrorCode);
        }
    }
}


This property is applicable only to a request that will copy a blob.

The default access condition for any request to copy a blob is None.

An access condition may specify a condition that must be met for the copy operation to be performed by the service. The AccessCondition structure provides methods that can be used to specify exactly one of the following access conditions:

  • IfMatch, which performs a copy operation only if the specified Etag value matches the blob's Etag value.

  • IfNoneMatch, which performs a copy operation only if the specified Etag value does not match the blob's Etag value.

  • IfModifiedSince, which performs a copy operation only if the resource has been modified since the specified date and time.

  • IfNotModifiedSince, which performs a copy operation only if the resource has not been modified since the specified date and time.


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Development Platforms

Windows Vista, Windows 7, Windows Server 2008, Windows 8.1, Windows Server 2012 R2, Windows 8 and Windows Server 2012

 

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