CODEWITHSUNDEEP
pythonhtml
Tomha
Tomha

Reputation: 907

Execute python functions and read variables from html

First off, I am very new to programming and I have a relatively basic understanding of python, and average understanding of html.

Using what I know in python, I am trying to create a basic strategy game, a bit like the likes of Age of Empires, or Command and Conquer, based on collecting resources and using it to build things, except using a simple text or button-clicking type interface. I can do a text interface fine, but its a bit boring, and I would like to use some images. I have had a 1 hour lecture on tkinter, but I have tried and failed to make anything remotely 'usable' from it. What I can do, is make decent looking html pages which would serve my purpose very well.

What I am wondering is if there is a simple way of executing python functions and calling/displaying python variables through a html page? The python functions do all the logic and present variables which represent current resource levels, production, storage capability, levels of buildings, etc. At the most basic level all I need is a way of displaying these variables, and having buttons which execute a function to say, upgrade a building, which recalculates production and all that, and returns the new set of values.

As a really simple example:

<p> Wheat production: *python integer representing production*</p>
<button type="button" onclick="*execute python variable*">Upgrade Wheat</button>

There would also, I imagine, be a need to somehow update the variables which are changed on the html page. So the button executes a function to upgrade wheat production, python now has a new value for the wheat production variable, and this needs to be updated on the page, whether this is automatic, or by some other method. I guess the simple way would be if pressing the button could also reload the page, but that seems a little clumsy.

Does anyone know of a simple way of doing this? Or perhaps a python library which might help me here?

Upvotes: 1

Views: 351

Answers (2)

Peter Gibson
Peter Gibson

Reputation: 19534

Take a look at http://pyjs.org/

What is pyjs?

pyjs is a Rich Internet Application (RIA) Development Platform for both Web and Desktop. With pyjs you can write your JavaScript-powered web applications entirely in Python.

pyjs contains a Python-to-JavaScript compiler, an AJAX framework and a Widget Set API. pyjs started life as a Python port of Google Web Toolkit, the Java-to-JavaScript compiler.

You can compile Python programs to javascript, and also use their Python libraries to generate HTML. Here's an example from their getting started guide:

from pyjamas import Window
from pyjamas.ui import RootPanel, Button

def greet(sender):
    Window.alert("Hello, AJAX!")

class Hello:
    def onModuleLoad(self):
        b = Button("Click me", greet)
        RootPanel().add(b)

Upvotes: 2

AMADANON Inc.
AMADANON Inc.

Reputation: 5919

Yes, there is a way of doing this.

There are two approaches to this. One is to have all the work done on the server, the other approach is to use Javascript.

The first approach is this: write a python script that generates your HTML. If you use Django, you will get a lot of work done for you, but you will also get a lot of stuff you don't want. Django does have a built-in template language. Django is beyond the scope of this answer. You will get to do exactly what you describe above; an example of a template might be <p> Wheat production: {{wheat_production}}</p> - your python code will set up a dict mydict={"wheat_production":10} and you will pass the name of your template file and the dict to a function which will spit out your page. You will also have to learn about HTML forms, if you haven't done so yet.

The other approach is to use Ajax - Javascript that, when your page is displayed (and, perhaps, when buttons are clicked, or at regular intervals) will send/receive some data to allow you to update your page. I suggest looking into JQuery to do some of the lifting for you. This means that you can update bits of the page without having to reload the entire thing. You will still have to write some code on the server to talk to the database, and send the output, usually as JSON, back to the client.

When writing this sort of thing, make sure all of your security is on the server side, and don't trust anything the user tells you. For example, if you store the number of gold pieces in a field on your form, it's going to take someone about 10 seconds to give themselves as much gold as they want. Similarly, if a player can sell a diamond for 20 gold pieces, make sure they have the diamond before giving them the gold pieces - you don't want to end up with a player with 1,000,000 gold pieces and negative a thousand diamonds. Javascript is 100% insecure, anything that Javascript can do, the player can also do.

Upvotes: 2

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