public static Link Last(ReadStreamPage page, ReadStreamOperation operation)
=> new Link(
Constants.Relations.Last,
LinkFormatter.FormatBackwardLink(
page.StreamId,
operation.MaxCount,
StreamVersion.End,
operation.EmbedPayload));
public static Link Next(ReadStreamPage page, ReadStreamOperation operation)
=> new Link(
Constants.Relations.Next,
LinkFormatter.FormatForwardLink(
page.StreamId,
operation.MaxCount,
page.Messages.Max(m => m.StreamVersion) + 1,
operation.EmbedPayload));
public static Link Previous(ReadStreamPage page, ReadStreamOperation operation)
=> new Link(
Constants.Relations.Previous,
LinkFormatter.FormatBackwardLink(
page.StreamId,
operation.MaxCount,
page.Messages.Min(m => m.StreamVersion) - 1,
operation.EmbedPayload));
public async Task <Response> GetPage(ReadStreamOperation operation, CancellationToken cancellationToken)
{
var page = await operation.Invoke(_streamStore, cancellationToken);
var streamMessages = page.Messages.OrderByDescending(m => m.Position).ToArray();
var payloads = await Task.WhenAll(streamMessages
.Select(message => operation.EmbedPayload
? message.GetJsonData(cancellationToken)
: Task.FromResult <string>(null))
.ToArray());
return(new Response(
new HALResponse(new
{
page.LastStreamVersion,
page.LastStreamPosition,
page.FromStreamVersion,
page.NextStreamVersion,
page.IsEnd
})
.AddLinks(Links.Self(operation))
.AddLinks(Links.Navigation(page, operation))
.AddLinks(Links.Feed(operation))
.AddLinks(Links.Metadata(operation))
.AddEmbeddedCollection(
Constants.Relations.Message,
streamMessages.Zip(
payloads,
(message, payload) => new HALResponse(new
{
message.MessageId,
message.CreatedUtc,
message.Position,
message.StreamId,
message.StreamVersion,
message.Type,
payload,
metadata = message.JsonMetadata
})
.AddLinks(Links.Message.Self(message)))),
page.Status == PageReadStatus.StreamNotFound ? 404 : 200));
}
public static IEnumerable <Link> Navigation(ReadStreamPage page, ReadStreamOperation operation)
{
var first = First(page, operation);
var last = Last(page, operation);
yield return(first);
if (operation.Self != first.Href && !page.IsEnd)
{
yield return(Previous(page, operation));
}
if (operation.Self != last.Href && !page.IsEnd)
{
yield return(Next(page, operation));
}
yield return(last);
}
public static Link Metadata(ReadStreamOperation operation)
=> new Link(
Constants.Relations.Metadata,
$"{operation.StreamId}/metadata");
public static Link Feed(ReadStreamOperation operation) => new Link(Constants.Relations.Feed, operation.Self);
public static Link Self(ReadStreamOperation operation) => new Link(
Constants.Relations.Self,
operation.Self);
public async Task <Response> Get(ReadStreamOperation operation, CancellationToken cancellationToken)
{
if (!operation.IsUriCanonical)
{
return(new Response(new HALResponse(null), 308)
{
Headers = { [Constants.Headers.Location] = new[] { operation.Self } }
});
}
var page = await operation.Invoke(_streamStore, cancellationToken);
var streamMessages = page.Messages.OrderByDescending(m => m.Position).ToArray();
var payloads = await Task.WhenAll(
Array.ConvertAll(
streamMessages,
message => operation.EmbedPayload
? message.GetJsonData(cancellationToken)
: SkippedPayload.Instance));
var response = new Response(
new HALResponse(new
{
page.LastStreamVersion,
page.LastStreamPosition,
page.FromStreamVersion,
page.NextStreamVersion,
page.IsEnd
})
.AddLinks(Links.Self(operation))
.AddLinks(Links.Navigation(page, operation))
.AddLinks(Links.Feed(operation))
.AddLinks(Links.Metadata(operation))
.AddLinks(Links.Index())
.AddLinks(Links.Find())
.AddEmbeddedResource(
Constants.Relations.AppendToStream,
Schemas.AppendToStream)
.AddEmbeddedResource(
Constants.Relations.Delete,
Schemas.DeleteStream)
.AddEmbeddedCollection(
Constants.Relations.Message,
streamMessages.Zip(
payloads,
(message, payload) => new HALResponse(new
{
message.MessageId,
message.CreatedUtc,
message.Position,
message.StreamId,
message.StreamVersion,
message.Type,
payload,
metadata = message.JsonMetadata
})
.AddLinks(
Links.Message.Self(message),
Links.Message.Feed(message)))),
page.Status == PageReadStatus.StreamNotFound ? 404 : 200);
if (page.TryGetETag(out var eTag))
{
response.Headers.Add(eTag);
}
return(response);
}
