=== 404 Solution ===
Contributors: aaron13100
Website: https://www.ajexperience.com/404-solution/
Tags: 404, redirect, 301, 302
Requires at least: 5.0
Requires PHP: 7.4
Tested up to: 6.9
Stable tag: 3.1.1
License: GPL-3.0-or-later
License URI: https://www.gnu.org/licenses/gpl-3.0.html

The smartest 404 plugin for WordPress - finds what your visitors were actually looking for.

== Description ==

Stop losing visitors to broken links. **404 Solution doesn't just redirect errors to your homepage** – it uses advanced spell-checking and intelligent matching algorithms to **find the actual page your visitor was trying to reach**.

When a visitor hits a broken link like `/prodcut/awesome-item` (typo), most plugins redirect them to your homepage where they get lost and leave. 404 Solution is different – it **automatically finds `/product/awesome-item`** and redirects them to the right place.

= Why 404 Solution is Different =

**Intelligent URL Matching** – Uses sophisticated algorithms (N-gram similarity, Levenshtein distance, multi-word matching) to find the closest existing page, not just blindly redirect to homepage.

**Spell-Checking Technology** – Automatically handles typos and URL variations so visitors find what they want even when they misspell URLs.

**Zero Configuration** – Works perfectly out of the box with smart defaults. Advanced users have full control over every aspect.

**WooCommerce Optimized** – Specifically designed to work with products, categories, variations, and custom post types.

= Core Features =

* **Automatic intelligent redirects** based on the best possible match for the URL
* **404 error logging** with detailed visitor data and referrer information
* **Manual redirect creation** for specific URLs to any existing page
* **Page suggestions shortcode** to display matches on custom 404 pages
* **Automatic cleanup** removes redirects when URLs match new pages or are no longer used
* **Regular expression support** for advanced redirect patterns
* **Debug logging** to troubleshoot redirect behavior
* **Performance optimized** for sites with 10,000+ pages

= How It Works =

1. Visitor hits a broken link (404 error)
2. 404 Solution analyzes the URL and compares it to all your existing pages
3. Intelligent matching finds the closest match using spell-checking algorithms
4. Visitor is automatically redirected to the correct page
5. You can review all 404s and create custom redirects as needed

= Perfect For =

* **eCommerce sites** (WooCommerce, Easy Digital Downloads) with changing product URLs
* **Content sites** with evolving permalink structures
* **Migrated sites** where old URLs need to map to new content
* **Large sites** with thousands of pages where manual redirects are impractical
* **Any WordPress site** that wants to provide better user experience

= What Makes This Different From Other Redirect Plugins? =

**vs. Redirection** – Redirection requires manual redirect rules. 404 Solution automatically finds matches using intelligent algorithms.

**vs. 404 to 301** – 404 to 301 redirects everything to your homepage. 404 Solution finds the actual page visitors want.

**vs. Simple 301 Redirects** – Simple 301 only does manual redirects. 404 Solution creates intelligent automatic redirects based on URL similarity.

= Technical Details =

* Supports 301 (permanent) and 302 (temporary) redirects
* N-gram similarity scoring for fast matching
* Spell-checking with Levenshtein distance calculation
* Custom post type support (products, events, portfolios, etc.)
* Taxonomy-aware (categories, tags, custom taxonomies)
* Query parameter preservation
* Referrer tracking and logging
* IP address logging (GDPR-compliant hashing available)
* Automatic performance optimization for large sites

**Note:** For high-traffic sites with thousands of simultaneous users, disable "Create automatic redirects" and avoid using the shortcode to ensure optimal performance.

== Installation ==

1. Unzip the files and upload the contents to `/wp-content/plugins/`.
2. Activate the plugin.
3. Use the `Settings -> 404 Solution` options page to set the options.

== Frequently Asked Questions ==

= How is this different from Redirection plugin? =

**Redirection** requires you to manually create redirect rules for each broken URL. **404 Solution automatically finds the best matching page** using intelligent algorithms.

**Example:** If a visitor tries `/prodcut/awesome-item` (typo), Redirection won't do anything unless you manually created that specific redirect. 404 Solution automatically finds `/product/awesome-item` and redirects them there.

**Use Redirection when:** You need complete manual control over every redirect.
**Use 404 Solution when:** You want automatic intelligent redirects that understand typos and URL variations.

= How is this different from 404 to 301? =

**404 to 301** redirects ALL 404 errors to your homepage (or one specific page). **404 Solution finds the actual page** the visitor was looking for.

**Example:** A visitor tries to access `/category/electronics` which doesn't exist. 404 to 301 sends them to your homepage where they're lost. 404 Solution finds `/shop/electronics` and redirects them there.

**404 to 301** is simpler but provides a worse user experience. **404 Solution** is smarter and keeps visitors engaged.

= Will this slow down my site? =

No, 404 Solution is highly optimized and has minimal performance impact for most sites. The plugin uses:
* N-gram indexing for fast URL matching
* Performance optimizations for large sites (10,000+ pages)
* Efficient database queries with proper caching

**Important:** For very high-traffic sites with thousands of simultaneous users, disable "Create automatic redirects" and don't use the shortcode to ensure optimal performance.

= Does it work with WooCommerce? =

Yes! 404 Solution is specifically optimized for WooCommerce and handles:
* Products and product variations
* Product categories and tags
* Custom product URLs
* Shop pages and archives

When products are renamed or URLs change, 404 Solution automatically redirects old URLs to the new product pages.

= How does the intelligent matching work? =

404 Solution uses multiple algorithms to find the best match:

1. **Spell-checking** – Uses Levenshtein distance to find pages with similar spelling
2. **N-gram similarity** – Compares character sequences to find similar URLs
3. **Word matching** – Identifies pages with similar words in the URL
4. **URL structure** – Considers the structure and length of URLs

These algorithms work together to find the most likely page the visitor intended to reach.

= Will it redirect existing pages by mistake? =

No. 404 Solution ONLY processes actual 404 errors (pages that don't exist). It will never redirect an existing page.

If you're experiencing unexpected redirects, check:
1. Did the page exist when the redirect was created?
2. Are other plugins causing conflicts?
3. Enable debug logging (Options page) to see exactly what's happening

= How long does it take for 404 URLs to start showing up? =

Immediately! As long as "Capture incoming 404 URLs" is enabled, 404 errors appear in the captured list as soon as a visitor hits a 404 page.

= Will this plugin handle permalink changes? =

Yes! 404 Solution records the page/post ID number and looks up the most current permalink before redirecting. This means:
* If you change your permalink structure, redirects automatically update
* If you rename a page, redirects point to the new URL
* No manual updates needed when URLs change

= Can I redirect all 404s to a specific page? =

Yes. Go to **404 Solution → Options → Redirect all unhandled 404s to** and select your preferred page. This is useful for:
* Custom 404 pages with special messaging
* Fallback pages when no good match is found
* Temporary catch-all during site migrations

= How do I manage log files and disk usage? =

Log cleanup is automatic! Configure it under **Options → General Settings → Maximum log disk usage**. You can:
* Set maximum log size (as low as 1MB)
* Auto-delete old entries when limit is reached
* Manually clear logs anytime from the Logs page

= What does "captured 404 URLs to be processed" mean? =

This just means visitors tried to access pages that don't exist – completely normal! You can:

**Option 1:** Ignore the message by adjusting **Options → General Settings → Admin notification level**

**Option 2:** Process them by going to **Captured 404 URLs** page and either:
* Let automatic redirects handle them
* Create manual redirects to specific pages
* Mark them to ignore

= Can I exclude certain URLs from being processed? =

Yes! Go to **Options → Advanced Settings → Files and Folders Ignore Strings** and add the paths you want to ignore. Common exclusions:
* `/wp-admin/*` – Admin pages
* `/wp-content/*` – Media files
* `*.jpg`, `*.png` – Image files
* `/feed/*` – RSS feeds

= How do I see IP addresses in the logs? =

Enable **"Log raw IPs"** in the settings. Note: For GDPR compliance, consider using hashed IPs instead of raw IP addresses.

= Does this work with custom post types? =

Yes! 404 Solution supports ALL custom post types including:
* WooCommerce products
* Events (The Events Calendar, Event Espresso)
* Portfolios
* Team members
* Custom content types

= Can I use regular expressions for redirects? =

Yes! 404 Solution supports regex patterns for advanced redirect rules. This is useful for:
* Redirecting multiple similar URLs with one rule
* Pattern-based matching
* Complex URL transformations

= Is this GDPR compliant? =

Yes. 404 Solution includes GDPR-friendly features:
* Option to hash IP addresses before storage
* Automatic log cleanup/retention limits
* No external data transmission
* Full control over what data is logged

= What kind of support is available? =

404 Solution is actively maintained with:
* WordPress.org support forum (free community support)
* Regular updates and bug fixes
* Debug logging to troubleshoot issues
* Comprehensive documentation

For urgent issues, enable debug logging and post in the support forum with details.

= Have you written any other programs? =

Check out [AJ Experience](https://www.ajexperience.com/) for other useful tools and resources.

== Screenshots ==

1. **Intelligent Redirect Dashboard** - See automatic matches in action with confidence scores
2. **404 Error Logs** - Track all 404 errors with visitor data, referrers, and timestamps
3. **Easy Redirect Creation** - Create manual redirects with autocomplete and validation
4. **Captured URLs Management** - Review and process 404s with one-click redirect creation
5. **Performance Statistics** - Monitor redirect effectiveness and site performance
6. **Advanced Options** - Fine-tune intelligent matching, logging, and behavior

== Changelog ==

= Version 3.1.1 (Dec 11, 2025) =
* FIX: Make index creation idempotent for `idx_requested_url_timestamp` (skip existing index, use IF NOT EXISTS when supported) to stop duplicate-key errors during upgrades.
* FIX: Harden log queue flushing with validation/sanitization, duplicate-tolerant inserts, and better error reporting to avoid lost 404 log entries.
* Compatibility: Explicit `str_getcsv` escape parameter for PHP 8.4+ to silence deprecation notices.
* Security: Escaped `filterText` SQL path in ajax pagination to block the reported SQL injection vector (only exploitable by authenticated admin users).

= Version 3.1.0 (Dec 6, 2025) =
* Feature: Async 404 page suggestions - Custom 404 pages sometimes load instantly while suggestions compute in the background.
* Feature: Per-post redirect toggle - Control automatic slug-change redirects on individual posts/pages in Classic Editor, Gutenberg, and Quick Edit.
* Feature: Add Arabic language and RTL layout support.
* Improvement: Optimize category/tag queries for better performance.
* Improvement: Accessibility - WCAG 2.1 AA compliance with table headers, focus indicators, ARIA labels, modal focus trapping, and reduced motion support.
* Improvement: Performance optimization for spell-checking on large sites (N-gram indexing, reduced database queries, memory optimization).
* FIX: Handle corrupted database records gracefully without PHP warnings.

= Version 3.0.8 (Nov 29, 2025) =
* Improvement: Feedback emails now include database collation info even on locked-down hosts (fallback chain for information_schema restrictions).
* FIX: Tooltip z-index issue where destination tooltips appeared behind sticky table header.

= Version 3.0.7 (Nov 28, 2025) =
* Improvement: Load admin pages faster. Load redirects faster.
* Improvement: Add a two question wizard/setup screen for new users.
* Improvement: Add warning icon when a redirect URL looks like regex but isn't marked as one.
* Improvement: Add loading spinner when searching for redirect destinations.
* Security: Multiple security hardening improvements including CSRF protection and XSS prevention.
* FIX: Save settings correctly when using simple mode on the options page.
* FIX: Simple page allows changing the default 404 page destination now.
* FIX: Dark mode checkbox no longer flashes on page load.
* FIX: Setup wizard form submission now works correctly.

= Version 3.0.6 (Nov 27, 2025) =
* FIX: Resolve fatal error "Class ABJ_404_Solution_DataAccess not found" during plugin uninstallation. The Uninstaller now works standalone without requiring the plugin's autoloader.

= Version 3.0.5 (Nov 27, 2025) =
* Improvement: Options page has Simple/Advanced mode.
* Improvement: Made the plugin prettier in general.

= Version 3.0.4 (Nov 24, 2025) =
* FIX: Resolve SQL error "Could not perform query because it contains invalid data" caused by invalid UTF-8 byte sequences in URLs. Added sanitization to strip invalid UTF-8 characters before database storage.
* FIX: Resolve "Table doesn't exist" errors on case-sensitive MySQL installations (lower_case_table_names=0) with mixed-case WordPress prefixes. All plugin table references now use normalized lowercase prefixes to match table creation behavior.

= Version 3.0.3 (Nov 23, 2025) =
* Improved: GDPR compliance in log files (just in case). 
* Improved: Some missing translation keys.
* Improved: Deactivation feedback. 

= Version 3.0.2 (Nov 22, 2025) =
* FIX: Table creation issues on multisite. (Thanks to debug file participants!)

= Version 3.0.1 (Nov 20, 2025) =
* Improvement: Use accordions on the settings screen instead of chips.
* FIX: Division by 0 in the new ngram filter.
* FIX: Language file format issues for various languages. 
* FIX: Correct the deactivate feedback trigger.
* FIX: Log slow query content correctly. 
* FIX: Table creation issues on multisites.

= Version 3.0.0 (Nov 17, 2025) =
* Improvement: Add themes. Add automatic dark mode detection for WordPress admin.
* Improvement: Better support and faster suggestions for sites with 10k+ pages.
* FIX: Resolve MAX_JOIN_SIZE errors for large sites during maintenance operations by using SQL_BIG_SELECTS for cleanup queries.
* FIX: Resolve MySQL Server Gone Away errors during long-running operations by checking and restoring database connections.
* FIX: Resolve PHP 8.2 deprecation error when mb_substr receives null for domain root URLs (e.g., http://example.com).
* FIX: Fix duplicate subpage parameters in admin URLs that were causing URLs like '?page=x&subpage=y&subpage=y'.
* FIX: Add isset() checks before accessing $_POST array elements to prevent PHP 8.0+ warnings.

= Version 2.36.10 (April 29, 2025) =
* FIX: Fix the '_load_textdomain_just_in_time was called incorrectly' issue again, this time for @apos37.

= Version 2.36.9 (April 25, 2025) =
* FIX: Avoid throwing an error when releasing a synchronization lock not owned by the current process, for leehodson.

= Version 2.36.8 (April 25, 2025) =
* FIX: Avoid a logging issue while logging a DB error for leehodson.

= Version 2.36.7 (April 25, 2025) =
* FIX: Avoid a logging issue while logging a DB error for leehodson.
* Improvement: Fix some warnings and code issues brought up by intelephense.

= Version 2.36.6 (April 15, 2025) =
* Improvement: Page suggestions: when an admin user clicks the score after a suggestion link it gives them some more information about the link like author, post date, etc.
* Improvement: Page suggestions: add an option to exclude certain URLs from the list of suggested pages on a custom 404 page based on user defined regex patterns.

= Version 2.36.5 (February 3, 2025) =
* FIX: Use SHOW CREATE TABLE instead of select from information_schema to get collation data.

= Version 2.36.4 (December 13, 2024) =
* FIX: Ensure parent classes are loaded before their children to possibly resolve inheritance issues with autoloading. (thanks debug file participants)

= Version 2.36.3 (November 28, 2024) =
* FIX: Handle arrays in query parameters without logging an error.
