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Sente

Realtime web comms library for Clojure/Script

Sente is a small client+server library that makes it easy to build realtime web applications with Clojure + ClojureScript.

Loosely inspired by Socket.IO, it uses core.async, WebSockets, and Ajax under the hood to provide a simple high-level API that enables reliable, high-performance, bidirectional communications.

Sen-te (先手) is a Japanese Go term used to describe a play with such an overwhelming follow-up that it demands an immediate response, leaving its player with the initiative.

Latest release/s

• 2023-08-30 v1.19.2 (stable): release info
• 2024-10-28 v1.20.0-RC1 (dev): release info

See here for earlier releases.

Why Sente?

• Bidirectional a/sync comms over WebSockets with auto Ajax fallback
• It just works: auto keep-alive, buffering, protocol selection, reconnects
• Efficient design with auto event batching for low-bandwidth use, even over Ajax
• Send arbitrary Clojure vals over edn or Transit (JSON, MessagePack, etc.)
• Tiny, easy-to-use API
• Support for users simultaneously connected with multiple clients and/or devices
• Realtime info on which users are connected, and over which protocols
• Standard Ring security model: auth as you like, HTTPS when available, CSRF support, etc.
• Support for several popular web servers, easily extended to other servers.

Capabilities

Protocol	client>server	client>server + ack/reply	server>user push
WebSockets	✓ (native)	✓ (emulated)	✓ (native)
Ajax	✓ (emulated)	✓ (native)	✓ (emulated)

So you can ignore the underlying protocol and deal directly with Sente's unified API that exposes the best of both WebSockets (bidirectionality + performance) and Ajax (optional ack/reply).

Documentation

• Wiki (getting started, usage, etc.)
• API reference: cljdoc, Codox

Funding

You can help support continued work on this project, thank you!! 🙏

License

Copyright © 2012-2024 Peter Taoussanis.
Licensed under EPL 1.0 (same as Clojure).