private static MidFunc GetStream(AllStreamResource allStream) => async(context, next) =>
{
var operation = new ReadAllStreamOperation(context.Request);
var response = await allStream.Get(operation, context.RequestAborted);
await context.WriteResponse(response);
};
public static Links AllStreamNavigation(
this Links links,
ReadAllPage page,
ReadAllStreamOperation operation)
{
var first = Links.FormatForwardLink(
Constants.Streams.All,
operation.MaxCount,
Position.Start,
operation.EmbedPayload);
var last = Links.FormatBackwardLink(
Constants.Streams.All,
operation.MaxCount,
Position.End,
operation.EmbedPayload);
links.Add(Constants.Relations.First, first);
if (operation.Self != first && !page.IsEnd)
{
links.Add(
Constants.Relations.Previous,
Links.FormatBackwardLink(
Constants.Streams.All,
operation.MaxCount,
page.Messages.Min(m => m.Position) - 1,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Feed, operation.Self).Self();
if (operation.Self != last && !page.IsEnd)
{
links.Add(
Constants.Relations.Next,
Links.FormatForwardLink(
Constants.Streams.All,
operation.MaxCount,
page.Messages.Max(m => m.Position) + 1,
operation.EmbedPayload));
}
links.Add(Constants.Relations.Last, last);
return(links);
}
public async Task <Response> Get(
ReadAllStreamOperation operation,
CancellationToken cancellationToken)
{
if (_useCanonicalUrls && !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.FromPosition,
page.NextPosition,
page.IsEnd
})
.AddLinks(
Links
.FromOperation(operation)
.Index()
.Find()
.Browse()
.AllStreamNavigation(page, operation))
.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)))));
if (operation.FromPositionInclusive == Position.End)
{
var headPosition = streamMessages.Length > 0
? streamMessages[0].Position
: Position.End;
response.Headers[Constants.Headers.HeadPosition] = new[] { $"{headPosition}" };
}
if (page.TryGetETag(operation.FromPositionInclusive, out var eTag))
{
response.Headers.Add(eTag);
response.Headers.Add(CacheControl.NoCache);
}
else
{
response.Headers.Add(CacheControl.OneYear);
}
return(response);
}
