private static MidFunc GetStream(StreamResource streams) => async(context, next) =>
{
var operation = new ReadStreamOperation(context.Request);
var response = await streams.Get(operation, context.RequestAborted);
await context.WriteResponse(response);
};
public static Links StreamsNavigation(this Links links, ReadStreamPage page, ReadStreamOperation operation)
{
var baseAddress = $"streams/{operation.StreamId}";
var first = Links.FormatForwardLink(
baseAddress,
operation.MaxCount,
StreamVersion.Start,
operation.EmbedPayload);
var last = Links.FormatBackwardLink(
baseAddress,
operation.MaxCount,
StreamVersion.End,
operation.EmbedPayload);
links.Add(Constants.Relations.First, first);
if (operation.Self != first && !page.IsEnd)
{
links.Add(
Constants.Relations.Previous,
Links.FormatBackwardLink(
baseAddress,
operation.MaxCount,
page.Messages.Min(m => m.StreamVersion) - 1,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Feed, operation.Self, operation.StreamId).Self();
if (operation.Self != last && !page.IsEnd)
{
links.Add(
Constants.Relations.Next,
Links.FormatForwardLink(
baseAddress,
operation.MaxCount,
page.Messages.Max(m => m.StreamVersion) + 1,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Last, last)
.Add(Constants.Relations.Metadata,
$"{baseAddress}/metadata");
return(links);
}
public static Links StreamsNavigation(this Links links, ReadStreamPage page, ReadStreamOperation operation)
{
var first = LinkFormatter.ReadStreamForwards(
operation.StreamId,
StreamVersion.Start,
operation.MaxCount,
operation.EmbedPayload);
var last = LinkFormatter.ReadStreamBackwards(
operation.StreamId,
StreamVersion.End,
operation.MaxCount,
operation.EmbedPayload);
links.Add(Constants.Relations.First, first);
if (operation.Self != first && !page.IsEnd)
{
links.Add(
Constants.Relations.Previous,
LinkFormatter.ReadStreamBackwards(
operation.StreamId,
page.Messages.Min(m => m.StreamVersion) - 1,
operation.MaxCount,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Feed, operation.Self, operation.StreamId).Self();
if (operation.Self != last && !page.IsEnd)
{
links.Add(
Constants.Relations.Next,
LinkFormatter.ReadStreamForwards(
operation.StreamId,
page.Messages.Max(m => m.StreamVersion) + 1,
operation.MaxCount,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Last, last)
.Add(Constants.Relations.Metadata, LinkFormatter.StreamMetadata(operation.StreamId));
return(links);
}
public async Task <Response> Get(ReadStreamOperation operation, CancellationToken cancellationToken)
{
if (_useCanonicalUrls && !operation.IsUriCanonical)
{
return(new PermanentRedirectResponse($"../{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 HalJsonResponse(
new HALResponse(new
{
page.LastStreamVersion,
page.LastStreamPosition,
page.FromStreamVersion,
page.NextStreamVersion,
page.IsEnd
})
.AddLinks(Links
.FromOperation(operation)
.Index()
.Find()
.Browse()
.StreamsNavigation(page, operation))
.AddEmbeddedResource(
Constants.Relations.AppendToStream,
append)
.AddEmbeddedResource(
Constants.Relations.DeleteStream,
delete)
.AddEmbeddedCollection(
Constants.Relations.Message,
streamMessages.Zip(
payloads,
(message, payload) => new StreamMessageHALResponse(message, payload)
.AddLinks(
Links
.FromOperation(operation)
.Add(
Constants.Relations.Message,
LinkFormatter.StreamMessageByStreamVersion(
message.StreamId,
message.StreamVersion),
$"{message.StreamId}@{message.StreamVersion}")
.Self()
.Add(
Constants.Relations.Feed,
LinkFormatter.Stream(message.StreamId),
message.StreamId)))),
page.Status == PageReadStatus.StreamNotFound ? 404 : 200);
if (page.TryGetETag(out var eTag))
{
response.Headers.Add(eTag);
}
return(response);
}
public async Task <Response> Get(ReadStreamOperation operation, CancellationToken cancellationToken)
{
if (!operation.IsUriCanonical)
{
return(new HalJsonResponse(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 HalJsonResponse(
new HALResponse(new
{
page.LastStreamVersion,
page.LastStreamPosition,
page.FromStreamVersion,
page.NextStreamVersion,
page.IsEnd
})
.AddLinks(Links
.FromOperation(operation)
.Index()
.Find()
.Browse()
.StreamsNavigation(page, operation))
.AddEmbeddedResource(
Constants.Relations.AppendToStream,
append)
.AddEmbeddedResource(
Constants.Relations.DeleteStream,
delete)
.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
.FromOperation(operation)
.Add(
Constants.Relations.Message,
$"{Constants.Streams.Stream}/{message.StreamId}/{message.StreamVersion}",
$"{message.StreamId}@{message.StreamVersion}")
.Self()
.Add(
Constants.Relations.Feed,
$"streams/{message.StreamId}",
message.StreamId)))),
page.Status == PageReadStatus.StreamNotFound ? 404 : 200);
if (page.TryGetETag(out var eTag))
{
response.Headers.Add(eTag);
}
return(response);
}