Cloudy File Manager: Safe Access in wp-admin

The challenge

• It installs into WordPress sites with unknown themes and plugin stacks: conflicts cannot be debugged after the fact on someone else’s production site.
• File management is inherently dangerous functionality: read, write, move and delete on the server.
• Large file uploads run straight into PHP execution and memory limits that vary by host.
• Bulk operations across thousands of files cannot block the request or exhaust memory.

What we built

• Every destructive operation is gated behind WordPress capability checks and nonce verification, with input sanitised at the boundary.
• Resumable uploads so large files survive a dropped connection or a host’s execution limit rather than restarting.
• HTTP Range downloads so large files stream instead of being loaded into memory.
• Copy, move and delete operations are queued rather than run inline, so bulk work across 10,000+ files does not time out.
• Directory scanning to locate files across a large tree, plus zip compress and extract in place.
• Syntax-highlighted code editing for the cases where the reason you opened a file manager was to fix one line.
• Tested across multiple live WordPress installations to catch conflicts before release, not after.

The result

• Shipped and maintained at v1.11.0, supporting WordPress 5.6+ and PHP 7.4+.
• Handles installations with 10,000+ files without blocking or timing out.
• Capability-gated and nonce-verified throughout.
• Actively maintained: released, supported and updated by us.

What this means for you

A plugin that touches the filesystem needs the strictest checks WordPress offers. Capability checks, nonce verification and sanitised input on every destructive action are what stop a useful tool becoming a way in.

Hosting limits differ from one server to the next, so large files and bulk work have to be designed around them: uploads that resume, downloads that stream, and operations that queue instead of running in one long request.

A plugin runs alongside themes and plugins its authors have never seen. Testing on several live installations before each release is how conflicts are caught before they reach someone else’s production site.