Racket

Datastar Brotli Compression🔗ℹ

This package provides Brotli compression support for the datastar SDK. Pass the resulting write profile to datastar-sse via the #:write-profile keyword argument to compress SSE events on the wire. The SDK automatically falls back to uncompressed output when the client does not advertise br in its Accept-Encoding header.

1 Usage🔗ℹ

(require datastar
         datastar-brotli)

(define brotli-profile (make-brotli-write-profile #:quality 5))

(define (handler req)
  (datastar-sse req
    (lambda (sse)
      (patch-elements sse "<div id=\"out\">Hello, compressed!</div>"))
    #:write-profile brotli-profile))

2 API🔗ℹ

procedure
(make-brotli-write-profile [ #:quality quality
#:window window
#:mode mode]) → write-profile?
  quality : (integer-in 0 11) = 5
  window : (integer-in 10 24) = 22
  mode : mode/c = BROTLI_MODE_TEXT

Creates a write-profile? that compresses SSE output with Brotli.

quality — Compression level from 0 (fastest) to 11 (smallest). Default 5 is a reasonable balance for streaming.
window — Sliding window size from 10 to 24. Larger values may improve compression at the cost of memory.
mode — One of BROTLI_MODE_GENERIC, BROTLI_MODE_TEXT, or BROTLI_MODE_FONT. Use BROTLI_MODE_TEXT (the default) for SSE, which is UTF-8 text.

value
BROTLI_MODE_GENERIC : mode/c

Generic mode, no assumptions about content type. Re-exported from libbrotli.

value
BROTLI_MODE_TEXT : mode/c

Text mode, optimized for UTF-8 input. Re-exported from libbrotli.

value
BROTLI_MODE_FONT : mode/c

Font mode, optimized for WOFF 2.0 fonts. Re-exported from libbrotli.