/// <summary>
/// Opens a stream for writing to the blob.
/// </summary>
/// <param name="accessCondition">An <see cref="AccessCondition"/> object that represents the access conditions for the blob. If <c>null</c>, no condition is used.</param>
/// <param name="options">A <see cref="BlobRequestOptions"/> object that specifies any additional options for the request.</param>
/// <param name="operationContext">An <see cref="OperationContext"/> object that represents the context for the current operation.</param>
/// <returns>A stream to be used for writing to the blob.</returns>
public IAsyncOperation<ICloudBlobStream> OpenWriteAsync(AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
{
this.attributes.AssertNoSnapshot();
operationContext = operationContext ?? new OperationContext();
BlobRequestOptions modifiedOptions = BlobRequestOptions.ApplyDefaults(options, this.BlobType, this.ServiceClient, false);
if ((accessCondition != null) && accessCondition.IsConditional)
{
return AsyncInfo.Run(async (token) =>
{
try
{
await this.FetchAttributesAsync(accessCondition, options, operationContext).AsTask(token);
}
catch (Exception)
{
if ((operationContext.LastResult != null) &&
(operationContext.LastResult.HttpStatusCode == (int)HttpStatusCode.NotFound) &&
string.IsNullOrEmpty(accessCondition.IfMatchETag))
{
// If we got a 404 and the condition was not an If-Match,
// we should continue with the operation.
}
else
{
throw;
}
}
ICloudBlobStream stream = new BlobWriteStreamHelper(this, accessCondition, modifiedOptions, operationContext);
return stream;
});
}
else
{
ICloudBlobStream stream = new BlobWriteStreamHelper(this, accessCondition, modifiedOptions, operationContext);
return Task.FromResult(stream).AsAsyncOperation();
}
}
public IAsyncOperation<ICloudBlobStream> OpenWriteAsync(bool createNew, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
#endif
{
this.attributes.AssertNoSnapshot();
BlobRequestOptions modifiedOptions = BlobRequestOptions.ApplyDefaults(options, BlobType.AppendBlob, this.ServiceClient, false);
if (!createNew && modifiedOptions.StoreBlobContentMD5.Value)
{
throw new ArgumentException(SR.MD5NotPossible);
}
#if ASPNET_K || PORTABLE
return Task.Run(async () =>
#else
return AsyncInfo.Run(async (token) =>
#endif
{
if (createNew)
{
#if ASPNET_K || PORTABLE
await this.CreateOrReplaceAsync(accessCondition, options, operationContext, cancellationToken);
#else
await this.CreateOrReplaceAsync(accessCondition, options, operationContext).AsTask(token);
#endif
}
else
{
// Although we don't need any properties from the service, we should make this call in order to honor the user specified conditional headers
// while opening an existing stream and to get the append position for an existing blob if user didn't specify one.
#if ASPNET_K || PORTABLE
await this.FetchAttributesAsync(accessCondition, options, operationContext, cancellationToken);
#else
await this.FetchAttributesAsync(accessCondition, options, operationContext).AsTask(token);
#endif
}
if (accessCondition != null)
{
accessCondition = new AccessCondition() { LeaseId = accessCondition.LeaseId, IfAppendPositionEqual = accessCondition.IfAppendPositionEqual, IfMaxSizeLessThanOrEqual = accessCondition.IfMaxSizeLessThanOrEqual };
}
#if ASPNET_K || PORTABLE
CloudBlobStream stream = new BlobWriteStream(this, accessCondition, modifiedOptions, operationContext);
#else
ICloudBlobStream stream = new BlobWriteStreamHelper(this, accessCondition, modifiedOptions, operationContext);
#endif
return stream;
#if ASPNET_K || PORTABLE
}, cancellationToken);
#else
});
public IAsyncOperation<ICloudBlobStream> OpenWriteAsync(long? size, AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext)
{
this.attributes.AssertNoSnapshot();
bool createNew = size.HasValue;
BlobRequestOptions modifiedOptions = BlobRequestOptions.ApplyDefaults(options, BlobType.PageBlob, this.ServiceClient, false);
if (!createNew && modifiedOptions.StoreBlobContentMD5.Value)
{
throw new ArgumentException(SR.MD5NotPossible);
}
return AsyncInfo.Run(async (token) =>
{
if (createNew)
{
await this.CreateAsync(size.Value, accessCondition, options, operationContext).AsTask(token);
}
else
{
await this.FetchAttributesAsync(accessCondition, options, operationContext).AsTask(token);
size = this.Properties.Length;
}
if (accessCondition != null)
{
accessCondition = AccessCondition.GenerateLeaseCondition(accessCondition.LeaseId);
}
ICloudBlobStream stream = new BlobWriteStreamHelper(this, size.Value, createNew, accessCondition, modifiedOptions, operationContext);
return stream;
});
}
