v0.0.6

What's New

MIME Type Filtering with immutable_types

Added immutable_types directive to restrict immutable caching headers to specific MIME types. When not specified, immutable headers apply to all content types (backward compatible).

location /static/ {
    immutable on;
    # Only apply immutable headers to JavaScript and CSS files
    immutable_types application/javascript text/css;
}

This allows fine-grained control over which content types receive immutable caching headers, similar to how gzip_types works for the gzip module.

Example: Mixed Content Location

location /assets/ {
    immutable on;
    # Apply immutable headers only to static assets
    immutable_types application/javascript text/css image/png image/jpeg image/gif image/svg+xml;
}

With this configuration, versioned JavaScript and CSS files get the full immutable caching treatment, while other files (like HTML or JSON) served from the same location don't receive immutable headers.

Full Changelog: v0.0.5...v0.0.6

v0.0.5

What's New

RFC 9211 Cache-Status Header Support

Added immutable_cache_status directive that enables the RFC 9211 Cache-Status header for debugging and observability.

location /static/ {
    immutable on;
    immutable_cache_status on;
}

When enabled, responses include:

Cache-Status: "nginx/immutable"; hit; ttl=31536000

This header helps debug caching behavior across multi-layer caching architectures (NGINX -> CDN -> Browser). Each cache layer can append its own status, creating a chain like:

Cache-Status: "nginx/immutable"; hit; ttl=31536000, "cloudflare"; fwd=uri-miss; stored

Documentation

• Added Directives section to README documenting all configuration options

v0.0.4

Added "stale" directives for better cacheability

v0.0.3

Fix uninitialized compiler error warning

v0.0.2

Compatibility with NGINX 1.23.0 where headers structure changed for Cache-Control, etc.

v0.0.1

First release