Rendering markdown from Flask

February 04, 2020

In this post I am going to plug about a cool trick(probably useless) that I discovered geeking around the internet.

I was building a tiny microservice which would let the client side application securely authenticate with GitHub. After writing the only required API, I wanted to render the README.md file on the index page.

So I planned to convert markdown to html and serve the resultant string everytime we hit the index.

Let's go hacking

Required packages

pip3 install Flask markdown

app.py

import markdown
from flask import Flask
import markdown.extensions.fenced_code

app = Flask(__name__)


@app.route("/")
def index():
    readme_file = open("README.md", "r")
    md_template_string = markdown.markdown(
        readme_file.read(), extensions=["fenced_code"]
    )

    return md_template_string


if __name__ == "__main__":
    app.run()

In the above snippet we are using Flask(my current favorite) as the web framework, Python-Markdown to convert markdown files to HTML, and fenced_code extension to support code blocks.

And it looked something like this

markdown render1

Not quite there yet!

Well even though Richard Stallman remains my hero, fortunately I do not share his taste on web design. So without over-engineering our little snippet I thought of adding syntax highlighting with pygments and CodeHilite extension.

Let's generate css for syntax highlighting using pygments

from pygments.formatters import HtmlFormatter

formatter = HtmlFormatter(style="emacs",full=True,cssclass="codehilite")
css_string = formatter.get_style_defs()

ow we need to append the css_string to the markdown converted HTML string.

md_css_string = "<style>" + css_string + "</style>"
md_template = md_css_string + md_template_string
return md_template

Alternatively we can use pygments-css repository to get pre-generated CSS files.

Let's see how the final version looks!

markdown render hl

Much better if you ask me!

Gimme the code!

Here is the full source code running on Glitch.

Feel free to remix and play around. Adios!