New Jasper Alpha for HTTP Services

Jasper is the name of an OSS project I’ve been working on for a disturbingly long time that’s the spiritual successor to FubuMVC. In more concrete terms, Jasper is built around what I think is a unique Roslyn-powered command execution pipeline that can be used as any combination of:

  1. An alternative to MVC Core for authoring HTTP services
  2. An in-memory service bus or command executor ala MediatR, but with more functionality
  3. A lightweight service bus
  4. A full fledged service bus when used in conjunction with real messaging infrastructure like Rabbit MQ or Azure Service Bus (Jasper fills the mediator rule between your code and the underlying transport)

To get you started on Jasper and to see what it’s capable, there’s actually a set of tutorials so far:

  1. Getting Started
  2. Jasper as an In Memory Command Executor / Mediator
  3. Using Jasper as a Lightweight Service Bus
  4. Building HTTP Services with Jasper
  5. Hybrid Jasper/MVC Core Application


What’s changed recently?

I changed Jasper’s direction a little bit starting last September. I’ve gone through the internals and tried very hard to replace any bit of code or infrastructure that was specific to Jasper that I thought could be adequately replaced by stuff built into ASP.Net Core. To that end, a lot of Jasper’s custom bootstrapping code was thrown out and replaced by fully embracing ASP.Net Core’s IWebHostBuilder infrastructure — even when Jasper is running “headless” with no real HTTP server.

I also replaced Jasper’s built in error handling and retry policies it had inherited from FubuMVC with a few extensions to Polly so users have the full power of Polly available to them — and I and any eventual Jasper community have a lot less code to document and support;)

I had quite a bit of free time at CodeMash and NDC London recently, so was able to work quite a bit on Jasper’s HTTP service support, including the new “MVC Extender” functionality that allows you to mix and match MVC Core elements into Jasper endpoints.


What’s Next

There’s going to be another pre-1.0 alpha within the next two weeks that will focus mostly on the messaging functionality. I can justify some day job time on it in the next couple weeks where I’ll be working on improving the Rabbit MQ integration, finishing the Azure Service Bus integration, and testing out the custom Azure AppInsights extension.

Beyond that? Performance optimization maybe, but I’d like to push for a 1.0 release soon and try to start building some interest and community around it. The only thing that will slow that down is to see if I wanna try to make Jasper 1.0 wait for ASP.Net Core 3.0 because every single OSS tool I maintain that depends on ASP.Net Core has been broken by every single ASP.Net Core release.


I’m very interested in whatever feedback you might have, either here, on twitter, or the Gitter room for Jasper.



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