Use Python-Markdown to Convert Markdown to HTML

The Markdown markup language is a good choice for text formatting. Unfortunately, the Markdown syntax does not align with HTML conventions. Without further modification, Markdown can only be shared as plain text. The Python-Markdown library is an open source Python module that converts Markdown text into standards-compliant HTML markup. This guide explains how to install and use the Python-Markdown module and provides some background information about it.

What is Markdown?

Markdown is a lightweight markup language. It has a simple, straightforward syntax and is designed to be highly readable. Markdown allows users to create standardized formatted text using any text editor. The Markdown syntax can stipulate headings, lists, tables, links, images, and text attributes. Markdown and HTML are not equivalent, but it is relatively easy to convert from one format to another.

Markdown is widely used in technical documentation, online help, blogging, publishing, and online forums. GitHub, Reddit, Stack Exchange, and many other sites use Markdown. Modern implementations follow the CommonMark standard, which resolves earlier issues and is unambiguous. Markdown Extra is an enhanced version of Markdown with many additional features.

What is Python-Markdown?

Python-Markdown is a free and open source Python library for converting Markdown code to HTML markup. It can either accept interactive input or process a Markdown file. Python-Markdown follows the rules of the original Markdown specification as much as possible. Its behavior makes it suitable for use in web server environments.

Here are some of the main advantages of Python-Markdown:

• It supports a large number of extensions to change or extend the behavior of the parser. For more details about the various extensions, see the Python-Markdown extensions reference.
• It supports international character sets, including all Unicode-supported languages.
• It is able to convert Markdown documents into either HTML or XHTML formats.
• The Python-Markdown API can be incorporated into Python code or accessed from the command line.
• It does not raise exceptions or write errors to standard output.

There are a few minor differences between the behavior of Python-Markdown and the official Markdown syntax rules. Some of the distinctions involve indentation and tab length and how consecutive lists are processed. For more information, see the Python-Markdown documentation.

Before You Begin

1. If you have not already done so, create a Linode account and Compute Instance. See our Getting Started with Linode and Creating a Compute Instance guides.

2. Follow our Setting Up and Securing a Compute Instance guide to update your system. You may also wish to set the timezone, configure your hostname, create a limited user account, and harden SSH access.

3. Ensure Python is properly installed on the Linode. You must be able to launch and use the Python programming environment and have some basic knowledge of the Python programming language. For information on how to install and use Python, see the Linode guide to Python.

How to Install Python-Markdown

The Python-Markdown library can be installed using pip, a Python package for installing libraries. To install Python-Markdown, follow these steps. These instructions are designed for Ubuntu 22.04 LTS, but are generally applicable to all Linux distributions.

1. Ensure pip is installed. To verify the pip release, use the following command.

   pip -V

   pip 22.0.2 from /usr/lib/python3/dist-packages/pip (python 3.10)
       

2. If pip is not installed, use apt to install it.

   sudo apt install python3-pip

3. Use pip to install the Python-Markdown library.

   pip install markdown

   Successfully installed markdown-3.4.1
       

How to Use Python-Markdown

There are several different ways to use Python-Markdown. It can be used interactively to translate small amounts of Markdown text to HTML markup. Functions from the library can also be incorporated into Python programs and scripts. Finally, Python-Markdown is available from the command line. This mode allows users to specify files for the raw Markdown input and the HTML output.

At the core of the markdown class is the markdown method. markdown.markdown accepts a string of Markdown text as a parameter and returns the HTML equivalent.

How to Use Python-Markdown Interactively

After accessing the Python interactive shell, source the Python-Markdown library to activate the parser interface. This method is useful for learning purposes, software development, and testing.

To use Python-Markdown interactively, follow these steps.

1. Enter the Python interactive shell. You should see the Python >>> prompt.

   python3

2. To access the Python-Markdown API, source the markdown module.

   import markdown

3. Pass the string of Markdown text to the markdown.markdown method as a parameter. Enclose the text inside single quotes. The method translates the Markdown text into HTML and displays the result.

   markdown.markdown('## Work Tasks')

   '<h2>Work Tasks</h2>'
       

4. For longer sections of Markdown, enclose the text in triple quotes. Triple quoting permits text to span multiple lines. The result is a long string of HTML markup.

   markdown.markdown('''
   # To Do
   ## At Home
   * Wash dishes
   ## At Work
   * Finish Report
   ''')

   '<h1>To Do</h1>\n<h2>At Home</h2>\n<ul>\n<li>Wash dishes</li>\n</ul>\n<h2>At Work</h2>\n<ul>\n<li>Finish Report</li>\n</ul>'
       

5. For properly formatted HTML, store the intermediate output in a temporary variable before printing it.

   tempHTML = markdown.markdown('''
   # To Do
   ## At Home
   * Wash dishes
   ## At Work
   * Finish Report
   ''')
   print(tempHTML)

   <h1>To Do</h1>
   <h2>At Home</h2>
   <ul>
   <li>Wash dishes</li>
   </ul>
   <h2>At Work</h2>
   <ul>
   <li>Finish Report</li>
   </ul>
       

When done, you can exit the Python interactive shell using the CTRL+D key combination.

How to Use Python-Markdown to Convert a Markdown File to HTML

The interactive method works well with short Markdown strings. For larger amounts of text, it is more efficient to read the Markdown code from a file.

There are two ways to convert a Markdown file to HTML output. The first technique creates a Python file object and reads the text into a temporary variable. It then uses the markdown method to convert the contents into HTML. When processing is complete, the program writes the final HTML code to a second file.

The second technique takes an even simpler approach. It invokes the markdownFromFile method to convert the Markdown file to HTML in a single step.

1. To use the first method, create a file containing the original Markdown text. List.md is a Markdown file that expands the “To Do” list used in the previous section.

   File: List.md

   1 2 3 4 5 6 7

   # To Do ## At Home * Wash dishes * Install winter tires ## At Work * Finish Report * Book Team **101** meeting

2. Create a short Python program named mdConverter.py to translate the Markdown file into HTML output. This program performs the following tasks:

   • Imports the markdown library.
   • Opens List.md using the file object f, and retrieves the contents using the Python read command. It stores the input in the tempMd variable.
   • Translates the source material into HTML using markdown.markdown and stores the output in tempHtml.
   • Writes the HTML markup to List.html using the Python write command.
   Note

   Open the initial file in r (read) mode, and the second in w (write) mode. When handling files, use the with statement to ensure Python closes them later on. In actual practice, this program would prompt the user for the names of the Markdown and HTML files. For more information on file processing, see the Python file documentation.

   File: mdConverter.py

   1 2 3 4 5 6 7 8 9 10 11

   import markdown # Open the file for reading and read the input to a temp variable with open('List.md', 'r') as f: tempMd= f.read() # Convert the input to HTML tempHtml = markdown.markdown(tempMd) # If necessary, could print or edit the results at this point. # Open the HTML file and write the output. with open('List.html', 'w') as f: f.write(tempHtml)

3. Run mdConverter.py to generate the HTML output.

   python3 mdConverter.py

4. Use cat to print the contents of List.html and ensure the Markdown code was translated correctly.

   <h1>To Do</h1>
   <h2>At Home</h2>
   <ul>
   <li>Wash dishes</li>
   <li>Install winter tires</li>
   </ul>
   <h2>At Work</h2>
   <ul>
   <li>Finish Report</li>
   <li>Book Team <strong>101</strong> meeting </li>
       

In many cases, no intermediate processing is required, and the program can be simplified to a few lines. The markdownFromFile method converts Markdown code into HTML output in a single step. It accepts an input file and output file as parameters. This approach does not require any file objects or intermediate variables.

Create a new Python program named mdAutoConverter.py and enter the following lines of code.

File: mdAutoConverter.py

1 2 3

import markdown markdown.markdownFromFile(input='List.md', output='List.html')

Run the program using the command python3 mdAutoConverter.py. The contents of List.html should be identical to the file generated by mdConverter.py.

How to Use Python-Markdown From the Command Line

Use Python’s -m option to run the markdown module as a script from the command line. The script requires the name of the Markdown file. It writes the HTML results to either the console or an output file.

To write the HTML output to the console, run the markdown script. Append the name of the input Markdown file.

python3 -m markdown List.md

Python translates the results to HTML and displays the output in the console window.

<h1>To Do</h1>
<h2>At Home</h2>
<ul>
<li>Wash dishes</li>
<li>Install winter tires</li>
</ul>
<h2>At Work</h2>
<ul>
<li>Finish Report</li>
<li>Book Team <strong>101</strong> meeting </li>

To write the HTML output to a new file, use the -f option and specify the name of the output file.

python3 -m markdown List.md -f List.html

To see which markdown options are available from the command line, append the --help flag.

python3 -m markdown --help

Conclusion

The Python-Markdown library is a Markdown parser for converting Markdown text to HTML markup. The library supports international language sets and several useful extensions. The parser routines can be used interactively or incorporated into Python programs. Python-Markdown can also run as a command line script.

The markdown method converts a string of Markdown text to HTML. In comparison, the markdownFromFile function reads a Markdown file and writes the HTML translation to a second file. For more information about the Python-Markdown library, see the Python-Markdown website.

More Information

You may wish to consult the following resources for additional information on this topic. While these are provided in the hope that they will be useful, please note that we cannot vouch for the accuracy or timeliness of externally hosted materials.

• Python-Markdown website
• Python-Markdown library reference
• Python-Markdown extensions
• Markdown page on Wikpedia
• Markdown guide
• HTML Standard
• Python Input/Output documentation