Markdown to HTML Converter

A simple yet powerful Markdown to HTML converter that works both as a command-line tool and a lightweight Flask web app.

It supports headings, lists, code blocks, inline formatting, links, images, tables, and even generates automatic SEO metadata.

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✨ Features

• Markdown Elements

  • Headings (#, ##, etc.)
  • Paragraphs
  • Ordered (1.) and unordered lists (-, +, *)
  • Bold (**bold**), italic (*italic*), strikethrough (~~strike~~)
  • Inline code (`code`)
  • Links ([text](url)) and images (![alt](src))
  • Fenced code blocks (```lang)
  • Blockquotes (> quote)
  • Horizontal rules (---, ***, ___)
  • Tables (| col | col |)

• Automatic SEO

  • <title> from the first heading
  • <meta description> from the first paragraph
  • Open Graph and Twitter card tags for better sharing

• Clean, well-structured HTML output

• Batch directory conversion

• Optional CSS and canonical link support

• Web mode with live Markdown-to-HTML preview and raw output tab

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⚙️ Installation

1. Clone the repository

   git clone https://github.com/datturbomoon/markdown-to-html.git
   cd markdown-to-html

2. (Optional) Create a virtual environment

   python -m venv .venv
   source .venv/bin/activate    # macOS/Linux
   .venv\Scripts\activate       # Windows

3. Install dependencies

   pip install -r requirements.txt

   If you don’t have a requirements.txt, just install Flask:

   pip install flask

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▶️ Running the App

Command-Line Mode

Convert single files, directories, or stdin Markdown input.

• Convert a single file:

  python app.py -i sample.md -o sample.html

• Convert all Markdown files in a directory:

  python app.py -d md_dir -D html_dir

• Read from stdin and output to stdout:

  cat sample.md | python app.py --stdout

• Include a CSS file or canonical link:

  python app.py -i input.md -o output.html --css style.css --canonical "https://example.com/page"

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Web Mode

Run a simple web interface to paste and preview Markdown.

1. Start the web server:

   python app.py --serve

2. Open your browser and go to:

   http://127.0.0.1:5000
   

The web interface includes:

• A live Markdown input area
• Tabs for Preview and Raw HTML
• Clean and responsive design

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🧩 Dependencies

Only Flask is required for web mode.

Install with:

pip install flask

CLI mode runs without Flask.

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📄 Example

Input (Markdown):

# My Page

This is a *sample* **Markdown** document.

- Item 1  
- Item 2  
  - Nested item

> "Markdown is simple but powerful."

```python
print("Hello, world!")

Output (HTML):

<h1>My Page</h1>
<p>This is a <em>sample</em> <strong>Markdown</strong> document.</p>
<ul>
<li>Item 1</li>
<li>Item 2<ul><li>Nested item</li></ul></li>
</ul>
<blockquote>"Markdown is simple but powerful."</blockquote>
<pre><code class="language-python">print("Hello, world!")</code></pre>

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🧠 How It Works

• Uses regular expressions for inline and block-level Markdown parsing.
• Handles nested lists by indentation.
• Converts Markdown into HTML with proper escaping and structure.
• Automatically extracts metadata for SEO tags.
• Optionally wraps output in a complete HTML document.

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📦 Project Structure

app.py           # main script
README.md        # this file
sample.md        # sample Markdown file
md_dir/          # directory for batch conversion (contains 5 markdown text samples)
images/          # project snapshots image folder

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⚖ License

MIT License — feel free to modify and use it in your own projects.