5 Packers

Sente uses a pluggable "packer" to control the format used for all client<->server communications.

The following packers are available out-the-box:

Format	Packer	Type	Comments
edn	Link	Text	Mature, default
Transit	Link	Text (JSON)	Mature
MessagePack	Link	Binary	New high-speed implementation
gzip	Link	Text+Binary	Wraps any other packer

Custom packers can also be easily written by implementing the relevant protocol.

Config

To use a packer you'll import it and provide it as an option to both your Sente server and client, e.g.:

;; Server (clj)
(def my-sente-server
  (let [packer (taoensso.sente.packers.msgpack/get-packer)]
    (sente/make-channel-socket-server! ... {:packer packer ...})))

;; Client (cljs)
(def my-sente-client
  (let [packer (taoensso.sente.packers.msgpack/get-packer)]
    (sente/make-channel-socket-client! ... {:packer packer ...})))

To add gzip you'll wrap the underlying packer:

;; Server (clj)
(def my-sente-server
  (let [mp-packer (taoensso.sente.packers.msgpack/get-packer)
        gz-packer (taoensso.sente.packers.gzip/wrap-packer mp-packer {:binary? true})]
    (sente/make-channel-socket-server! ... {:packer gz-packer ...})))

;; Client (cljs)
(def my-sente-client
  (let [mp-packer (taoensso.sente.packers.msgpack/get-packer)
        gz-packer (taoensso.sente.packers.gzip/wrap-packer mp-packer {:binary? true})]
    (sente/make-channel-socket-client! ... {:packer gz-packer ...})))

Which to use

A few things to consider include:

1. Packer speed and output size
2. Extra dependencies
3. Browser support and support for Clojure's data types

You can see the relevant packer docs for info re: (2) and (3).

Re: (1) very broadly:

• For speed: MessagePack ~ Transit >> edn
• For small size: MessagePack > Transit >> edn

Adding gzip will decrease speed in exchange for smaller size (often a good tradeoff).

There's some benchmarks in the unit tests which you can tweak and run in your own environment. With the defaults (smaller bars are better):

Sente's Reference example also allows you to easily switch between different packers for testing, etc.