omnistreams is a specification defining a data streaming system. The project has the following core goals:
- Language-agnostic interfaces and semantics for barebones readable (producer) and writable (consumer) streams, including piping, cancellation, and operation (ie map, filter, etc) support.
- Dead-simple wire protocol with multiplexing. This is for sending streams between networked machines, processes, threads, coroutines, etc. The only requirement is an underlying reliable, in-order message passing system (ie WebSockets, WebRTC, ZeroMQ, reliable UDP, Go channels, etc)
- Pull-based (ie client-controlled) backpressure.
- Reference implementations and base classes/interfaces in JavaScript, Rust, and Go. This includes convenience functionality for setting up networked streams over WebSockets, ie a Multiplexer implementation for WebSockets.
- Extremely simple to understand and implement. If a reasonable amount of performance loss means a greatly simplified design, choose the simple option. A first-year undergrad CS student should be able to make a usefully complete implementation in an arbitrary programming language.
You can read the specification here
omnistreams are heavily influenced by prior work, especially the excellent Reactive Streams, and ReactiveX. The primary differences are that omnistreams have less functionality (no semantics for multiple subscribers, no built-in operators, etc) and have a heavy focus on streaming data between different programming languages across a network. The most important thing we stole from reactive streams is the pull-based backpressure semantics (see also pull streams).
There's also a lot of overlap with node streams. There are several excellent projects to bring node streams to the browser, and even between the browser and node backend over websockets (see ws-streamify, websocket-stream). In terms of functionality offered (if you only need JavaScript support), omnistreams is very close to binaryjs. Unfortunately, that project appears to be defunct. You can think of omnistreams as an attempt to generalize node streams to work in any programming language, and between any two languages over a network.
The WHATWG Streams API was not as much of a direct influence as the previous, but omnistreams shares a lot of similarity in API. They were both designed with a focus on I/O streaming.
I discovered rsocket some time after completing a working JavaScript implementation of omnistreams. The goals of the two projects appear to be very similar, with rsocket being far more complete and mature. If I had found it when I went looking for a language-agnostic backpressured WebSocket stream multiplexer, I would have spent some time trying to make it work before implementing my own solution. As it stands, the biggest advantage of omnistreams that I see is that it has a much simpler protocol, mostly because it offers far fewer features. This makes it faster to implement for new languages and easier for developers to pick up and use. Knowing that rsocket exists gives me confidence in choosing to keep omnistreams as simple as possible. Also, omnistreams was built from the ground up to support raw byte streams, ie transferring files, in addition to streaming things like JSON or Protobuf objects. Everything is just bytes and the application is responsible for encoding and decoding. I'm sure other systems support byte streams, but it doesn't seem to be a focus. omnistreams is very agnostic to the datatype.