/// <summary>
/// Gets a media contents of a member resource.
/// </summary>
/// <param name="collectionName">Name of the target collection.</param>
/// <param name="memberResourceId">The Id of the member resource.</param>
/// <param name="outputStream">A stream containing the media corresponding to the specified resource. If no matching media is found, null is returned.</param>
/// <exception cref="ArgumentNullException">Throws exception if memberResourceId is null/empty
/// or outputStream is null.</exception>
/// <exception cref="ArgumentException">Throws exception if outputStream stream is not readable.</exception>
void IAtomPubStoreReader.GetMedia(string collectionName, string memberResourceId, Stream outputStream)
{
if (string.IsNullOrEmpty(collectionName))
{
throw new ArgumentNullException("collectionName");
}
if (string.IsNullOrEmpty(memberResourceId))
{
throw new ArgumentNullException("memberResourceId");
}
if (null == outputStream)
{
throw new ArgumentNullException("outputStream");
}
if (!AtomPubHelper.IsValidGuid(memberResourceId))
{
throw new ArgumentException(Resources.ATOMPUB_INVALID_RESOURCE_ID);
}
if (!outputStream.CanWrite)
{
throw new ArgumentException(Properties.Resources.ATOMPUB_CANNOT_WRITE_ON_STREAM, "outputStream");
}
using (ZentityContext context = CoreHelper.CreateZentityContext())
{
ResourceType collectionType = coreHelper.GetResourceType(collectionName);
// Prepare a query to get a resource with specified Id and specified type.
string commandText = string.Format(CultureInfo.InvariantCulture, AtomPubConstants.EsqlToGetFileContents,
collectionType.FullName);
ObjectQuery <Core.File> query = new ObjectQuery <Core.File>(commandText, context);
query.Parameters.Add(new ObjectParameter("Id", new Guid(memberResourceId)));
Core.File mediaFile = query.FirstOrDefault();
if (null == mediaFile)
{
throw new ResourceNotFoundException(Resources.ATOMPUB_RESOURCE_NOT_FOUND);
}
if (!mediaFile.Authorize("Read", context, CoreHelper.GetAuthenticationToken()))
{
throw new UnauthorizedException(Resources.ATOMPUB_UNAUTHORIZED);
}
context.DownloadFileContent(mediaFile, outputStream);
}
}