public static IProjectionHostBuilder <TContext> FromList <TContext>(this IProjectionHostBuilder <TContext> projBuilder, IEnumerable <Type> projections)
{
projBuilder.ProjectionTypeSources.Add(() => projections);
return(projBuilder);
}
public static IProjectionHostBuilder <TContext> KeyFrom <TContext>(this IProjectionHostBuilder <TContext> projBuilder, Func <TContext, string> keyExtrator)
{
projBuilder.KeyExtractor = keyExtrator;
return(projBuilder);
}
public static IProjectionHostBuilder <TContext> ContentFromJObject <TContext>(this IProjectionHostBuilder <TContext> projBuilder)
where TContext : StringJObjectContext
{
projBuilder.InvocatorFactory = (projSet) =>
{
var handlerMethod = projSet.ProjectionType
.GetMethod(nameof(IProjection <object> .Handle));
return((ctx) =>
{
var unmarshalledEvent = ctx.Content.ToObject(projSet.EventType);
var projection = ctx.Services.GetService(projSet.ProjectionType);
return handlerMethod.Invoke(projection, new [] { unmarshalledEvent }) as Task;
});
};
return(projBuilder);
}
public static IProjectionHostBuilder <TContext> FromServiceCollection <TContext>(this IProjectionHostBuilder <TContext> projBuilder, IServiceCollection serviceCollection)
{
projBuilder.ProjectionTypeSources.Add(
() =>
serviceCollection
.Where(x => x
.ServiceType
.GetInterfaces()
.Any(y =>
y.IsGenericType &&
y.GetGenericTypeDefinition() == typeof(IProjection <>)))
.Select(x => x.ImplementationType));
return(projBuilder);
}
public static IProjectionHostBuilder <TContext> AttributeKeyResolution <TContext>(this IProjectionHostBuilder <TContext> projBuilder)
{
projBuilder.ProjectionExtractor = (projectionTypes) =>
{
return(projectionTypes
.SelectMany(x => {
return x
.GetInterfaces()
.Where(y => y.IsInterface)
.Where(y => y.IsGenericType)
.Where(y => y.GetGenericTypeDefinition() == typeof(IProjection <>))
.Select(y => new { ProjectionType = x, EventType = y });
})
.Select(x => // Pull all attributes on all types
{
var eventType = x.EventType
.GetGenericArguments()
.First();
var attributes = eventType
.GetCustomAttributes(typeof(EventAttribute), true).Cast <EventAttribute>();
return new { Type = x.ProjectionType, EventType = eventType, Attributes = attributes };
})
.Where(x => x.Attributes.Any())
.SelectMany(x => x.Attributes.Select(y => new { x.Type, x.EventType, Attribute = y })) // fan-out the attributes to support one type having multiple attributes
.Select(x => new { x.Type, x.EventType, Name = $"{x.Attribute.Subject}.{x.Attribute.Action}" }) // format the action
.GroupBy(x => x.Name)
.Select(x => new ProjectionGroup
{
EventKey = x.Key,
Projections = x.Select(p => new ProjectionSet {
EventType = p.EventType, ProjectionType = p.Type
})
})); // Form a group to bundle all projections for the same event type
};
return(projBuilder);
}
