=== Simple Page Cache ===
Contributors: peterarends
Tags: cache, performance, static, woocommerce, edd
Requires at least: 5.0
Tested up to: 6.8
Stable tag: 1.1.1
License: GPLv2 or later

Simple, blazing fast static page cache for WordPress. Caches HTML for non-logged-in users with intelligent cache clearing for e-commerce sites.

== Description ==

**Simple Page Cache** is an extremely simple, super-fast page cache for WordPress. The plugin stores full HTML pages on disk for non-logged-in visitors. The cache is automatically cleared when content is updated, ensuring visitors always see fresh content. Ideal for small to medium-sized sites and webshops that want maximum speed without complex settings.

**Main features:**
- Caching for non-logged-in users (GET requests only)
- **Path-based cache structure** for nginx direct serving (`/host/path/index.html`)
- Cache files are stored in `/wp-content/uploads/simple-page-cache/`
- Drop-in (`advanced-cache.php`) for maximum speed before WordPress loads
- **Nginx configuration generation** for direct cache serving
- **Automatic cache clearing** when posts/pages are updated
- **E-commerce integration** with intelligent cache clearing for:
  - WooCommerce (orders, stock updates, product changes)
  - Easy Digital Downloads (purchases, download updates)
  - BigCommerce for WordPress (product updates)
  - Generic e-commerce plugins (product post types)
- Automatic detection of dynamic pages (cart, checkout, account, wishlist) for:
  - WooCommerce
  - BigCommerce for WordPress
  - Easy Digital Downloads
  - iThemes Exchange
  - Jigoshop
  - WP-Shop
- Detected dynamic pages are automatically excluded from caching
- Manual cache clearing via admin bar button
- **Nginx config regeneration** via admin bar button
- Performance comments in cached HTML files
- No complex settings, no database writes

== Installation ==

1. Upload the plugin to the `/wp-content/plugins/simple-page-cache/` directory.
2. Activate the plugin through the WordPress plugins screen.
3. Upon activation:
   - The cache directory is created (`/wp-content/uploads/simple-page-cache/`).
   - The drop-in `advanced-cache.php` is placed in `/wp-content/`.
   - `define('WP_CACHE', true);` is automatically added to `wp-config.php` (or replaced if it already exists).
   - An `nginx.conf` file is generated in the cache directory for nginx direct serving.

== Nginx Configuration ==

For maximum performance, you can configure nginx to serve cached files directly without PHP processing:

1. **Copy the nginx configuration** from `/wp-content/uploads/simple-page-cache/nginx.conf`
2. **Add the configuration** to your nginx server block for your domain
3. **Test nginx configuration**: `sudo nginx -t`
4. **Reload nginx**: `sudo systemctl reload nginx`

The nginx configuration includes:
- Internal location block for serving cached files
- Automatic cache bypass for logged-in users
- Automatic cache bypass for requests with query strings
- Debug headers to identify cache hits

**Benefits of nginx direct serving:**
- Faster response times (no PHP processing)
- Lower server load
- Better scalability
- Direct file serving from disk

== How it works ==

- For every non-logged-in visitor and every GET request, a static HTML file is created and served.
- **Path-based cache structure**: Cache files are organized as `/host/path/index.html` for direct nginx serving.
- Pages with characteristics of dynamic e-commerce pages (such as cart, checkout, account, wishlist) are automatically detected and excluded from caching. The plugin recognizes WooCommerce, BigCommerce, Easy Digital Downloads, iThemes Exchange, Jigoshop, and WP-Shop.
- The list of excluded pages is automatically maintained in a file in the cache directory.
- **Automatic cache clearing**: When posts or pages are updated, the plugin efficiently clears cache using the new path-based structure and scans for related content.
- **E-commerce integration**: For WooCommerce, when orders are placed or product stock is updated, the plugin automatically clears cache for the affected products and related pages (categories, tags, shop pages, homepage).
- **Performance comments**: Each cached HTML file includes a comment with timestamp and host information for debugging and transparency.
- **Nginx integration**: Generated nginx configuration allows direct serving of cached files without PHP processing for maximum performance.

== Clearing the cache ==

- Click the "Clear Page Cache" button in the admin bar (visible to administrators only) to remove all cache files.
- Click the "Regenerate nginx.conf" button in the admin bar to regenerate the nginx configuration file.

== Deactivation ==

- When deactivating the plugin:
  - The drop-in `advanced-cache.php` is removed.
  - The `define('WP_CACHE', true);` line (if placed by this plugin) is removed from `wp-config.php`.

== Frequently Asked Questions ==

= Are pages automatically removed from the cache? =
Yes! The plugin automatically clears cache when posts/pages are updated. For e-commerce sites, it also clears cache when orders are placed or product stock changes.

= Can I manually exclude pages? =
The plugin automatically detects most dynamic e-commerce pages. Manual exclusion is not possible without editing code.

= Does this work with other cache plugins? =
Always use only one page cache plugin/drop-in at a time.

= How does the automatic cache clearing work? =
The plugin scans all cached HTML files and looks for URLs that match the updated content. This ensures that any page linking to the updated content is refreshed.

= What happens when a product goes out of stock? =
For WooCommerce sites, when a product's stock status changes, the plugin automatically clears cache for that product page and all related pages (categories, shop pages, homepage) that might display the product.

== Changelog ==
= 1.1.1 =
* **Bug fix**: Fixed 404 errors when browsing the website while logged in
* **Query parameter handling**: Plugin now properly checks for $_GET parameters and skips caching for requests with query strings

= 1.1.0 =
* **Path-based cache structure**: Cache files now use `/host/path/index.html` structure for nginx direct serving
* **Nginx configuration generation**: Automatic generation of nginx.conf file for direct cache serving
* **Nginx admin management**: Added "Regenerate nginx.conf" button in admin bar
* **Improved cache clearing**: Optimized cache clearing using new path-based structure
* **Better performance**: Cache files can now be served directly by nginx without PHP processing
* **Enhanced documentation**: Added nginx configuration section to readme
* **Cache directory change**: Moved cache directory to `/wp-content/uploads/simple-page-cache/` for better compatibility

= 1.0.3 =
* **Automatic cache clearing**: Cache is now automatically cleared when posts/pages are updated
* **E-commerce integration**: Added intelligent cache clearing for WooCommerce, Easy Digital Downloads, and BigCommerce
* **HTML content scanning**: Implements precise cache clearing by scanning HTML content for URLs
* **Performance optimization**: File size filtering and optimized scanning for better performance
* **Cache transparency**: Added performance comments to cached HTML files with timestamp and host info
* **WooCommerce support**: Automatic cache clearing for orders, stock updates, and product changes
* **Generic e-commerce support**: Works with any plugin using product post types
* **Webshop optimization**: Handles large product overview pages efficiently

= 1.0.2 =
* Enhanced caching logic with HTTP status code validation
* Skip caching for redirects (3xx status codes)
* Skip caching for most error responses (except 403 and 404)
* Skip caching for pages smaller than 1KB (likely empty/error pages)
* Added automatic drop-in regeneration after plugin updates
* Implemented secure random filename for settings file (unguessable)
* Improved version tracking and update detection
* Updated tested up to WordPress 6.8

= 1.0.1 =
* Bug fixes and improvements

= 1.0.0 =
* First release: simple page cache with automatic e-commerce detection.