/// <summary>
/// Returns the content type of the stream that is associated with the specified entity.
/// </summary>
/// <param name="entity">The entity that has the associated binary data stream.</param>
/// <param name="operationContext">The <see cref="T:System.Data.Services.DataServiceOperationContext"/> instance used by the data service to process the request.</param>
/// <returns>A valid Content-Type of the binary data.</returns>
public string GetStreamContentType(object entity, DataServiceOperationContext operationContext)
{
// Check if the entity is a File resource
if (entity != null && entity is FlattenedFile)
{
FlattenedFile fileRes = entity as FlattenedFile;
// Check if the File resource holds a MIME content type.
if (!string.IsNullOrWhiteSpace(fileRes.MimeType))
{
return(fileRes.MimeType);
}
}
return(ZentityFileStreamProvider.DefaultContentType);
}
/// <summary>
/// Returns the default stream that is associated with an entity that has a binary property.
/// </summary>
/// <param name="entity">The entity that has the associated binary stream.</param>
/// <param name="etag">The eTag value sent as part of the HTTP request that is sent to the data service.</param>
/// <param name="checkETagForEquality">A nullable <see cref="T:System.Boolean"/> value that determines the type of eTag that is used.</param>
/// <param name="operationContext">The <see cref="T:System.Data.Services.DataServiceOperationContext"/> instance used by the data service to process the request.</param>
/// <returns>
/// The data <see cref="T:System.IO.Stream"/> that contains the binary property data of the <paramref name="entity"/>.
/// </returns>
public Stream GetReadStream(object entity, string etag, bool?checkETagForEquality, DataServiceOperationContext operationContext)
{
if (checkETagForEquality != null)
{
// This implementation does not support eTag associated with BLOBs
throw new DataServiceException((int)HttpStatusCode.NotImplemented, CoreResources.FileETagsNotSupported);
}
// Set the file resource instance.
fileResource = entity as FlattenedFile;
if (fileResource == null)
{
throw new DataServiceException((int)HttpStatusCode.NotFound, CoreResources.FileNotFound);
}
try
{
// Convert the FlattenedFile resource into a File resource
File zenFileResource = this.zentityContext.Files.Where <File>(zenFile => zenFile.Id == fileResource.Id).FirstOrDefault();
if (zenFileResource == null)
{
throw new DataServiceException((int)HttpStatusCode.NotFound, CoreResources.FileNotFound);
}
// Create a memory stream for File resource content download
using (MemoryStream memStream = new MemoryStream())
{
// Download the File content from SQL Server
this.zentityContext.DownloadFileContent(zenFileResource, memStream);
// Reset the position to the start for reading operations.
memStream.Seek(0, SeekOrigin.Begin);
return(memStream);
}
}
catch (Exception ex)
{
throw new DataServiceException((int)HttpStatusCode.InternalServerError,
string.Format(CoreResources.FileContentNotStreamed, fileResource.Id, ex.Message));
}
}
/// <summary>
/// Returns the stream that the data service uses to write the contents of a binary property that is associated with an entity.
/// </summary>
/// <param name="entity">The entity that has the associated binary stream.</param>
/// <param name="etag">The eTag value that is sent as part of the HTTP request that is sent to the data service.</param>
/// <param name="checkETagForEquality">A nullable <see cref="T:System.Boolean"/> value that determines the type of eTag is used.</param>
/// <param name="operationContext">The <see cref="T:System.Data.Services.DataServiceOperationContext"/> instance that is used by the data service to process the request.</param>
/// <returns>
/// A valid <see cref="T:System.Stream"/> the data service uses to write the contents of a binary property that is associated with the <paramref name="entity"/>.
/// </returns>
public Stream GetWriteStream(object entity, string etag, bool?checkETagForEquality, DataServiceOperationContext operationContext)
{
if (checkETagForEquality != null)
{
// This implementation does not support eTag associated with BLOBs
throw new DataServiceException((int)HttpStatusCode.NotImplemented, CoreResources.FileETagsNotSupported);
}
// Set the file resource instance.
fileResource = entity as FlattenedFile;
if (fileResource == null)
{
throw new DataServiceException((int)HttpStatusCode.NotFound, CoreResources.FileNotFound);
}
string slugHeader = operationContext.RequestHeaders.Get(CoreResources.HttpHeaderSlug);
if (string.IsNullOrWhiteSpace(slugHeader))
{
throw new DataServiceException((int)HttpStatusCode.BadRequest, CoreResources.FileIdNotSent);
}
Guid fileResourceId = Guid.Empty;
if (Guid.TryParse(slugHeader, out fileResourceId))
{
if (fileResourceId == Guid.Empty)
{
throw new DataServiceException((int)HttpStatusCode.BadRequest, CoreResources.FileIdIsGuidEmpty);
}
fileResource.Id = fileResourceId;
}
else
{
throw new DataServiceException((int)HttpStatusCode.BadRequest, CoreResources.FileIdIsInvalid);
}
// Return the filestream that the data service uses to
// write the requested binary data stream to a temp file.
return(new FileStream(tempFileName, FileMode.Create, FileAccess.ReadWrite));
}
