Broken Link Checker Lite

A lightweight WordPress plugin that periodically scans your content for broken links and displays them in an easy-to-use dashboard widget. Perfect for maintaining site health and SEO.

Single File v1.0.0 Updated 2 months ago

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YT Broken Link Checker Lite

A lightweight WordPress plugin that periodically scans your content for broken links and displays them in an easy-to-use dashboard widget. Perfect for maintaining site health and SEO.

Features

Automatic Scanning: Weekly cron job scans all published posts and pages
Manual Scan: Run scans on-demand with a single click
Dashboard Widget: Quick overview of broken links on the main dashboard
URL Validation: Uses wp_remote_head() to check link status
Detailed Reports: View broken links with post titles, URLs, and status codes
Configurable Frequency: Choose between daily, twice daily, or weekly scans
Post Type Selection: Scan posts, pages, or any custom post type
Timeout Control: Adjust request timeout (5-30 seconds)
Search & Filter: Quickly find specific broken links
Click to Copy: Click any URL to copy it to clipboard
Responsive Design: Mobile-friendly admin interface
WPCS Compliant: Follows WordPress coding standards

Installation

Upload the yt-broken-link-checker-lite folder to the /wp-content/plugins/ directory
Activate the plugin through the 'Plugins' menu in WordPress
Go to Tools → Broken Links to view results and configure settings
Check the dashboard widget for a quick overview

How It Works

Automatic Scanning

Plugin activates and schedules a weekly cron job
Cron runs at the scheduled interval
Scans all posts of selected post types
Extracts URLs from post content (links and images)
Checks each URL using wp_remote_head()
Stores broken links in WordPress options
Displays results in dashboard widget and admin page

Link Checking

Uses wp_remote_head() for HEAD requests (faster than full GET)
Follows redirects (up to 5 hops)
Configurable timeout (default: 10 seconds)
Checks both <a> tags (href) and <img> tags (src)
Only checks external URLs (starting with http:// or https://)

Status Codes

200-399: Link is working ✓
400-599: Link is broken ✗
Error: Network error or timeout

Usage

Viewing Broken Links

Navigate to Tools → Broken Links to see:

Statistics:
- Total broken links found
- When last scan was performed
- Time until next scheduled scan
Results Table:
- Post/Page title with edit link
- Broken URL
- HTTP status code or error message
- Quick action to edit the post
Dashboard Widget:
- Shows up to 5 broken links
- Link to view all results
- Last scan time

Manual Scan

Go to Tools → Broken Links
Click "Scan Now" button
Wait for scan to complete (may take a while for many posts)
View results

Configuring Settings

Scan Frequency:

Daily: Scans once per day
Twice Daily: Scans every 12 hours
Weekly: Scans once per week (default)

Post Types to Scan:

Select which post types to check
Default: Posts and Pages
Works with custom post types

Request Timeout:

How long to wait for a response
Range: 5-30 seconds
Default: 10 seconds

Clearing Results

Click "Clear Results" button to remove all broken link data. Useful after fixing links or for a fresh start.

File Structure

yt-broken-link-checker-lite/
├── class-yt-broken-link-checker-lite.php    # Main plugin file (~650 lines)
├── assets/
│   ├── css/
│   │   └── yt-blc-admin.css                 # Admin UI styles
│   └── js/
│       └── yt-blc-admin.js                  # Admin interactions
└── README.md                                 # This file

Prefix Convention

All functions, classes, and elements use the yt_blc prefix:

Class: YT_Broken_Link_Checker_Lite
Constants: YT_BROKEN_LINK_CHECKER_*
Functions: yt_blc_*
CSS Classes: .yt-blc-*
JavaScript Object: ytBlcAdmin
Cron Hook: yt_blc_scan_links
Options: yt_blc_options, yt_blc_broken_links, yt_blc_last_scan
Text Domain: yt-broken-link-checker-lite

Database Storage

The plugin stores data in WordPress options (no custom tables):

yt_blc_options: Plugin settings

array(
   'scan_frequency' => 'weekly',
   'post_types' => array('post', 'page'),
   'timeout' => 10
)

yt_blc_broken_links: Array of broken links

array(
   array(
       'post_id' => 123,
       'url' => 'https://example.com/broken',
       'status_code' => 404,
       'error' => ''
   ),
   // ... more broken links
)

yt_blc_last_scan: Unix timestamp of last scan

Cron Implementation

Scheduling

// On activation
wp_schedule_event( time(), 'weekly', 'yt_blc_scan_links' );

// Hook
add_action( 'yt_blc_scan_links', 'scan_all_links' );

Frequencies

daily: Once per day
twicedaily: Every 12 hours
weekly: Once per week

Changing Frequency

When you change the frequency in settings:

Old cron schedule is cleared
New cron schedule is created
Takes effect immediately

Security Features

Capability Checks: All admin actions require manage_options
Nonce Verification: CSRF protection on all forms
Input Sanitization: All inputs sanitized before storage
Output Escaping: All output properly escaped
Safe HTTP Requests: Uses wp_remote_head() with timeouts
User Agent: Custom user agent for identification

Performance Considerations

Scan Performance

Uses HEAD requests (faster than GET)
Processes posts sequentially
Configurable timeout prevents hanging
Only scans published posts
Caches results until next scan

Impact on Site

Cron job runs in background: Doesn't affect front-end
No database tables: Uses standard WordPress options
Minimal queries: Loads all posts once, then processes
Throttled requests: Respects timeout settings

Optimization Tips

Reduce post types: Only scan necessary post types
Increase timeout: For slow external sites
Less frequent scans: Weekly instead of daily
Exclude old posts: Manually if needed (custom code)

Troubleshooting

Cron not running?

WordPress cron requires site visits to trigger. If your site has low traffic:

Use a real cron job (server-level)
Use a plugin like WP Crontrol
Set up external monitoring service

Scans timing out?

If scans never complete:

Increase PHP max_execution_time
Reduce number of post types
Increase request timeout
Run manual scans during off-peak hours

False positives?

Some sites may block automated requests:

Check manually to verify
Some sites require specific headers
Firewall may block the server's IP
Rate limiting may cause temporary failures

Links not detected?

The plugin extracts links from:

<a href="..."> tags
<img src="..."> tags

It does NOT check:

Links in shortcodes (unless they render)
JavaScript-generated links
Links in custom fields
Links in widgets

Best Practices

Schedule during low traffic: Choose frequency based on site traffic
Review regularly: Check dashboard widget weekly
Fix promptly: Broken links hurt SEO and user experience
Export data: Screenshot or note broken links before fixing
Re-scan after fixes: Verify links are now working
Monitor patterns: Repeated broken links may indicate an issue

Limitations

Current Version

HEAD requests only: Some servers don't support HEAD properly
No link statistics: Doesn't track when links broke
No notifications: Doesn't email about broken links
No link editing: Must manually edit posts
No link replacement: Can't find and replace links
No external link management: Just detection, not management

Not Included

Email notifications
Link statistics/history
Bulk link editing
Link replacement
External site monitoring
API integration
Custom headers for requests
Proxy support

Uninstallation

When the plugin is deleted via WordPress admin:

All plugin options are removed
Cron job is cleared
WordPress cache is flushed
No data is left behind

Requirements

WordPress 5.8 or higher
PHP 7.4 or higher
Server must allow outgoing HTTP requests
wp_cron must be working (or real cron setup)

Complexity

Main PHP File: ~650 lines (with comments)
CSS File: ~170 lines
JS File: ~145 lines
Total: ~965 lines across all files

FAQ

How often should I scan for broken links?

For most sites, weekly is sufficient. High-traffic sites or sites with frequently changing content may benefit from daily scans.

Does it slow down my site?

No! The scanning happens in the background via cron and doesn't affect your front-end performance.

Can I test specific URLs?

Not directly through the plugin. You would need to add a post with that URL and run a scan.

What happens to broken links from deleted posts?

When you delete a post, its broken links remain in the results until the next scan or until you clear results.

Can I export the results?

Not currently. You can copy the data from the admin page or use a screenshot.

Does it check internal links?

No, it only checks external links (starting with http:// or https://). Internal links should always work if your site is configured correctly.

Will it detect links in custom fields?

No, it only scans the main post content (post_content). Custom fields and meta data are not checked.

Can I schedule scans for specific times?

Not through the plugin UI. You can modify the cron schedule using WP-CLI or a cron management plugin.

Changelog

1.0.0

Initial release
Weekly automated scanning
Dashboard widget
Manual scan option
Configurable scan frequency
Post type selection
Request timeout control
Search and filter functionality
Click to copy URLs
Responsive admin design

License

GPL v2 or later

Author

Krasen Slavov

Website: https://krasenslavov.com
GitHub: https://github.com/krasenslavov

Support

For issues and feature requests, please visit the GitHub repository.

Future Enhancements

Potential features for future versions:

Email notifications for broken links
Link editing/replacement interface
Link statistics and history
Bulk link operations
Custom HTTP headers support
Exclude specific URLs or domains
REST API endpoints
White-label reporting
Integration with Google Search Console
Link monitoring dashboard