public static MediaTypeConfiguration <TEntityType> MediaType <TEntityType>(this EntityTypeConfiguration <TEntityType> configuration, Expression <Func <TEntityType, string> > propertyExpression) where TEntityType : class
{
Arg.NotNull(configuration, nameof(configuration));
Arg.NotNull(propertyExpression, nameof(propertyExpression));
Contract.Ensures(Contract.Result <MediaTypeConfiguration <TEntityType> >() != null);
// an entity that represents a media type can only have a single link entry. check for presense of an existing configuration.
var key = propertyExpression.GetMediaResourceKey();
var builder = configuration.GetModelBuilder();
var configurations = builder.GetAnnotationConfigurations();
MediaTypeConfiguration <TEntityType> mediaTypeConfig;
// if the media type has already been configured, return the existing configuration
if (configurations.TryGet(key, out mediaTypeConfig))
{
return(mediaTypeConfig);
}
// always ignore the content type property from the entity model and call the build-in MediaType
// extension method, which will configure the entity model with HasStream = true for the entity
propertyExpression.IgnoredBy(configuration);
configuration.MediaType();
// compile the property expression into a lazy-initialized, contravariant function
// we do this so that we don't have to use reflection later to get the content type
// nor require the developer to write explicit code to get the value
var contentType = new Lazy <Func <object, string> >(() =>
{
var func = propertyExpression.Compile();
return(o =>
{
try
{
return func((TEntityType)o);
}
catch (NullReferenceException)
{
// note: this is supported so we gracefully fail and do not return a value for an expression
// that refers to a object graph path. for example: r => r.Image.Type, where Image could be null.
// also note that the null propagtion operator cannot be used in an expression. for example:
// the following expression will not compile: r => r.Image?.Type.
return null;
}
});
});
var annotation = new MediaLinkEntryAnnotation(contentType);
mediaTypeConfig = new MediaTypeConfiguration <TEntityType>(configuration, annotation);
configurations.Add(key, mediaTypeConfig);
return(mediaTypeConfig);
}
public static MediaTypeConfiguration <TEntityType> MediaType <TEntityType>(this EntityTypeConfiguration <TEntityType> configuration, string contentType) where TEntityType : class
{
Arg.NotNull(configuration, nameof(configuration));
Contract.Ensures(Contract.Result <MediaTypeConfiguration <TEntityType> >() != null);
var key = typeof(TEntityType).FullName + ".MediaType";
var builder = configuration.GetModelBuilder();
var configurations = builder.GetAnnotationConfigurations();
MediaTypeConfiguration <TEntityType> mediaTypeConfig;
if (configurations.TryGet(key, out mediaTypeConfig))
{
return(mediaTypeConfig);
}
configuration.MediaType();
var annotation = new MediaLinkEntryAnnotation(instance => contentType);
mediaTypeConfig = new MediaTypeConfiguration <TEntityType>(configuration, annotation);
configurations.Add(key, mediaTypeConfig);
return(mediaTypeConfig);
}
