public static IEnumerable <Link> Navigation(
ReadStreamMessageOptions options,
StreamMessage message = default(StreamMessage))
{
yield return(First());
if (options.StreamVersion > 0)
{
yield return(Previous(options));
}
if (message.MessageId != default(Guid))
{
yield return(Next(options));
}
yield return(Last());
}
private static MidFunc GetStreamMessage(StreamResource stream) => next => async env =>
{
var context = new OwinContext(env);
var options = new ReadStreamMessageOptions(context.Request);
var response = await stream.GetMessage(options, context.Request.CallCancelled);
if (options.StreamVersion == StreamVersion.End)
{
context.Response.StatusCode = 307;
context.Response.ReasonPhrase = "Moved Temporarily";
context.Response.Headers["Location"] = $"{((dynamic) response.Hal.Model).StreamVersion}";
return;
}
await context.WriteHalResponse(response);
};
public async Task <Response> GetMessage(
ReadStreamMessageOptions options,
CancellationToken cancellationToken)
{
var operation = options.GetReadOperation();
var message = await operation.Invoke(_streamStore, cancellationToken);
if (message.MessageId == Guid.Empty)
{
return(new Response(
new HALResponse(new
{
options.StreamId,
options.StreamVersion
})
.AddLinks(StreamMessageLinks.Self(options))
.AddLinks(StreamMessageLinks.Navigation(options))
.AddLinks(StreamLinks.Feed(options)),
404));
}
var payload = await message.GetJsonData(cancellationToken);
return(new Response(
new HALResponse(new
{
message.MessageId,
message.CreatedUtc,
message.Position,
message.StreamId,
message.StreamVersion,
message.Type,
payload
})
.AddLinks(StreamMessageLinks.Self(options))
.AddLinks(StreamMessageLinks.Navigation(options, message))
.AddLinks(StreamLinks.Feed(options))));
}
public static Link Self(ReadStreamMessageOptions options) => new Link(
Relations.Self,
$"{options.StreamVersion}");
public static Link Feed(ReadStreamMessageOptions options) => new Link(
Relations.Feed,
LinkFormatter.FormatBackwardLink($"../{options.StreamId}", 20, StreamVersion.End));
private static Link Next(ReadStreamMessageOptions options) => new Link(
Relations.Next,
$"{options.StreamVersion + 1}");
private static Link Previous(ReadStreamMessageOptions options) => new Link(
Relations.Previous,
$"{options.StreamVersion - 1}");
