vmg/redcarpet
Redcarpet
Redcarpet is a security-focused Markdown to HTML parser and customizable renderer. It transforms Markdown text into structured HTML output while utilizing a security layer to filter or escape user-provided HTML tags and restrict link protocols to prevent vulnerabilities.
The project distinguishes itself through a framework for custom document formatting, allowing the definition of how specific Markdown elements are converted to HTML via callback functions and custom classes. It also functions as a typographic formatter that converts standard punctuation and dashes into professional curly quotes and en-dashes.
Its capability surface covers extended Markdown syntax support for tables, footnotes, and superscripts, as well as the automated generation of tables of contents through header anchor extraction.
Features
- Markdown to HTML Converters - Transforms Markdown plaintext markup into structured HTML output for web browser display.
- HTML Content Sanitization - Filters and escapes user-provided HTML tags and restricts link protocols to prevent XSS vulnerabilities.
- Secure Markdown Rendering - Implements a secure Markdown rendering process that applies security filters during the HTML conversion.
- Markdown to HTML Renderers - Converts Markdown to HTML while utilizing a security layer to filter or escape dangerous tags and protocols.
- Markdown Render Overrides - Provides a framework to override default rendering rules for specific Markdown tokens using custom callbacks and classes.
- Markup Rendering Rules - Uses a set of defined rendering rules to transform Markdown text into structured HTML.
- Extended Syntax Renderers - Adds support for extended Markdown features including tables, footnotes, and superscripts.
- Markdown Output Customization - Allows precise control over how specific Markdown elements are converted to HTML output.
- Typographic Enhancements - Automatically converts standard punctuation and dashes into professional curly quotes and en-dashes.
- Automatic Table of Contents - Extracts document headers to generate an automated table of contents with navigation anchors.
- Renderer Extensions - Implements a class-based system for creating custom output formats by overriding base renderer methods.
- Rendering Pipeline Interceptors - Provides a callback system to customize how specific Markdown blocks are converted into HTML output.
- Markdown Element Renderers - Allows developers to customize the HTML output of specific Markdown elements via callback functions.
- Header Anchors - Automatically generates unique identifiers for page headings to enable deep linking for a table of contents.
- Markdown Renderer Implementations - Supports the creation of custom output formats by extending a base renderer class.
- Table of Contents Generators - Automatically extracts document headings to generate a linked table of contents.
- Markdown Processors - Fast and extensible Markdown to HTML parser.
