Gubby

A Zed editor extension for EPUB validation, powered by epub-lsp.

Features

• Diagnostics: Real-time validation errors for EPUB package documents, content documents, and stylesheets
• OPF validation: Metadata, manifest, spine, and guide element checking
• XHTML validation: EPUB content document structure and compliance
• CSS validation: Stylesheet diagnostics within EPUB projects
• NCX validation: EPUB 2 navigation control document checking

Supported File Extensions

Extension	Type
.opf	OPF Package Document
.xhtml	EPUB XHTML Content Document
.ncx	NCX Navigation (EPUB 2)
.html	HTML
.css	CSS

Installation

1. Open Zed
2. Go to Extensions (Cmd+Shift+X)
3. Search for "Gubby"
4. Click Install

The extension automatically downloads the appropriate LSP binary for your platform.

As a Dev Extension (for local development):

1. Clone this repository
2. In Zed, open the command palette (Cmd+Shift+P)
3. Run "zed: install dev extension"
4. Select this directory

See Zed's extension development docs for more details.

Zed Settings

The extension automatically handles .opf, .xhtml, and .ncx files. For .html and .css files, which already have built-in language servers in Zed, add gubby explicitly in your Zed settings (~/.config/zed/settings.json or project .zed/settings.json):

{
  "languages": {
    "HTML": {
      "language_servers": ["gubby", "..."]
    },
    "CSS": {
      "language_servers": ["gubby", "..."]
    }
  }
}

The "..." preserves Zed's default language servers for those languages.

To force specific file extensions to use a particular language, use file_types:

{
  "file_types": {
    "EPUB XHTML": ["xhtml"],
    "OPF Package": ["opf"]
  }
}

Building the Extension

cargo build --target wasm32-wasip1

Credits

toba/epub-lsp - The EPUB LSP server that powers this extension.

License

MIT License - see LICENSE for details.