public static Links StreamMessageNavigation(
this Links links,
StreamMessage message,
ReadStreamMessageByStreamVersionOperation operation)
{
links.Add(Constants.Relations.First, $"{StreamId(operation)}/0");
if (operation.StreamVersion > 0)
{
links.Add(Constants.Relations.Previous, $"{StreamId(operation)}/{operation.StreamVersion - 1}");
}
if (message.StreamId != default)
{
links.Add(Constants.Relations.Next, $"{StreamId(operation)}/{operation.StreamVersion + 1}");
}
return(links.Add(Constants.Relations.Last, $"{StreamId(operation)}/-1")
.Add(
Constants.Relations.Feed,
Links.FormatBackwardLink(
StreamId(operation),
Constants.MaxCount,
StreamVersion.End,
false),
operation.StreamId)
.Add(
Constants.Relations.Message,
$"{StreamId(operation)}/{operation.StreamVersion}",
$"{operation.StreamId}@{operation.StreamVersion}").Self());
}
private static MidFunc GetStreamMessage(StreamMessageResource streamMessages) => async(context, next) =>
{
var operation = new ReadStreamMessageByStreamVersionOperation(context.Request);
var response = await streamMessages.Get(operation, context.RequestAborted);
await context.WriteResponse(response);
};
public async Task <Response> Get(
ReadStreamMessageByStreamVersionOperation operation,
CancellationToken cancellationToken)
{
var message = await operation.Invoke(_streamStore, cancellationToken);
var links = Links
.FromPath(operation.Path)
.Index()
.Find()
.Browse()
.StreamMessageNavigation(message, operation);
if (message.MessageId == Guid.Empty)
{
return(new HalJsonResponse(
new HALResponse(new
{
operation.StreamId,
operation.StreamVersion
})
.AddLinks(links),
404));
}
if (operation.StreamVersion == StreamVersion.End)
{
return(new HalJsonResponse(new HALResponse(new object()), 307)
{
Headers =
{
[Constants.Headers.Location] = new[] { $"{message.StreamVersion}" }
}
});
}
var payload = await message.GetJsonData(cancellationToken);
var eTag = ETag.FromStreamVersion(message.StreamVersion);
return(new HalJsonResponse(
new StreamMessageHALResponse(message, payload)
.AddEmbeddedResource(
Constants.Relations.DeleteMessage,
DeleteStreamMessage)
.AddLinks(links))
{
Headers =
{
eTag,
CacheControl.OneYear
}
});
}
public static Links StreamMessageNavigation(
this Links links,
StreamMessage message,
ReadStreamMessageByStreamVersionOperation operation)
{
links.Add(
Constants.Relations.First,
LinkFormatter.StreamMessageByStreamVersion(operation.StreamId, 0));
if (operation.StreamVersion > 0)
{
links.Add(
Constants.Relations.Previous,
LinkFormatter.StreamMessageByStreamVersion(operation.StreamId, operation.StreamVersion - 1));
}
if (message.StreamId != default)
{
links.Add(
Constants.Relations.Next,
LinkFormatter.StreamMessageByStreamVersion(operation.StreamId, operation.StreamVersion + 1));
}
return(links
.Add(
Constants.Relations.Last,
LinkFormatter.StreamMessageByStreamVersion(operation.StreamId, -1))
.Add(
Constants.Relations.Feed,
LinkFormatter.ReadStreamBackwards(
operation.StreamId,
StreamVersion.End,
Constants.MaxCount,
false),
operation.StreamId)
.Add(
Constants.Relations.Message,
LinkFormatter.StreamMessageByStreamVersion(operation.StreamId, operation.StreamVersion),
$"{operation.StreamId}@{operation.StreamVersion}")
.Self());
}
private static string StreamId(ReadStreamMessageByStreamVersionOperation operation)
=> $"streams/{operation.StreamId}";
