CastorisCausa

Personal blog and hacks by Raymundo Cassani

Using PyScript with Pelican: Toy example

This post shows a simple game created using PyScript in this static website created with Pelican and Markdown files.

The game

How it's implemented

The implementation is quite eclectic (as Frankenstein's monster), it consist of 3 parts:

  1. Markdown post: This is used by Pelican to create the post entry in the website, the code is here: https://github.com/rcassani/castoriscausa/blob/master/content/posts/pyscript_toy_example.md

    It's very important to modify the Pelican theme to add the link to PyScript in <head>:

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    <script defer src="https://pyscript.net/latest/pyscript.js"></script>

    I made an update in my Pelican theme to do so. The modification can be found here

  2. An HTML block in the Markdown file: Indicates which Python script will be used, and how it's connected to the UI elements in the page:

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    <div style="border: 2px solid black;padding: 10px;">
    <py-script src="/scripts/guess_game.py" id="py-internal-0"></py-script>
    <strong><p id="game-message-txt"></p></strong>
    <input id="new-guess-txt" class="py-input" type="text">
    <button id="new-guess-btn" class="py-button" type="submit" py-click="new_guess()">
    Submit guess
    </button>
    <button id="reset-game-btn" class="py-button" type="submit" py-click="new_game()">
    Reset
    </button>
</div>

  3. A Python script: Gets input from the HTML elements, does the game logic and writes on the HTML

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    import random

game_message_txt = Element("game-message-txt")
new_guess_txt = Element("new-guess-txt")

def new_game():
    'Print instructions and set secret number'
    global x_target
    game_message_txt.write('Guess the secret number between 0 and 42')
    x_target = random.randint(0, 42)

new_game()

def new_guess(*args, **kws):
    # ignore empty input
    if not new_guess_txt.element.value:
        return None
    x_str = new_guess_txt.element.value
    # must be a number
    if not x_str.isnumeric():
        game_message_txt.write('Come on, it needs to be a number')
        return None
    else:
        try:
            # check it's an integer
            x = int(x_str)
        except ValueError as ve:
            game_message_txt.write('It needs to be an integer')
    # check it's in range
    if x < 0 or x > 42:
        game_message_txt.write('It needs to be in the range 0 to 42')
        return None
    # game logic
    if x > x_target:
        game_message_txt.write('Go lower than {0}'.format(x))
    elif x < x_target:
        game_message_txt.write('Go higher than {0}'.format(x))
    elif x == x_target:
        game_message_txt.write('Success!!!')

def new_guess_event(e):
    if e.key == "Enter":
        new_guess()

new_guess_txt.element.onkeypress = new_guess_event

Conclusion

This was a fun experiment, it opens the gates to do very interesting stuff with Python in my website 😎

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