Compression

The Compression Middleware automatically compresses HTTP responses to reduce bandwidth usage and improve performance. It supports gzip, deflate, and raw deflate compression formats, automatically detecting client support via the Accept-Encoding header.

Response compression can significantly reduce data transfer sizes (often 70-90% for text-based content), leading to faster page loads and reduced server bandwidth costs.

Basic Usage

import { createCompressionMiddleware } from "cerces/compression"

const app = new App({
	middleware: [ 
		createCompressionMiddleware("gzip"),
	]
})

Compression Formats

The middleware supports three compression formats:

Format	Description	Use Case
"gzip"	Gzip compression (most common)	General web content, best compression ratio
"deflate"	DEFLATE compression	Legacy support, slightly faster than gzip
"deflate-raw"	Raw DEFLATE (no headers)	Specialized use cases requiring raw compressed data

Configuration

The createCompressionMiddleware function accepts a single parameter:

createCompressionMiddleware(format: "gzip" | "deflate" | "deflate-raw")

Performance Considerations

• CPU Usage: Compression adds server processing overhead
• Memory: Minimal memory impact with streaming compression
• Cache Compatibility: Works with HTTP caching (ETags, Last-Modified)
• Content Types: Most effective for text-based content (HTML, JSON, CSS, JS)

Browser Support

Modern browsers automatically send Accept-Encoding: gzip, deflate and decompress responses transparently. The middleware ensures compatibility across all HTTP clients.

Debugging

To verify compression is working:

• Check response headers for Content-Encoding: gzip
• Monitor network tab in browser dev tools
• Compare response sizes with/without middleware

The middleware includes built-in polyfills for environments without native CompressionStream support (e.g. Bun, older Node.js versions), ensuring consistent behavior across runtimes.