Keeping checkbox values with gae-sessions

Question

I look for answers but It was all about php. I got this index.html:

 <form method="post">       
   <input type="checkbox" name="opts" value="opt1" opt[0]> option 1<br>
  <input type="checkbox" name="opts" value="opt2" opt[1]> option 2<br>
  <input type="checkbox" name="opts" value="opt3" opt[2]> option 3<br>
  <br>
   <input name="" type="submit" value="Save" >  

</form>

and this main.py

import webapp2
import cgi
import os
import jinja2
from gaesessions import get_current_session
class MainHandler(webapp2.RequestHandler):
    def get(self):
        session=get_current_session()
        opt=session.get('opt',[])        jinja_environment=jinja2.Environment(autoescape=True,loader=jinja2.FileSystemLoader(os.path.join(os.path.dirname(__file__),'templates')))
        tpi_vars={"opt":opt}
        template=jinja_environment.get_template('index.html')

        self.response.write(template.render(tpi_vars))

    def post(self):
        opt=self.request.get("opt", allow_multiple=True)
        session=get_current_session()

        session['opt']=opt

I want to store checked checkboxes and get them. How can I make this possible?

Answer 1

Your Python code seems correct, apart from one weird bug whereby the line using jinja_environment is concatenated to the previous one (?!).

Your Jinja template seems wrong as it doesn't look in the environment, nor does it mark any checkbox as checked . I would recommend something like:

<input type="checkbox" name="opts" value="opt1" {{ops.get('opt1','')}>
    option 1<br>

and so on -- the double braces to check into the environment, and a dictionary ops that you could prepare on the Python side.

Right now what you get as opt is a list such as eg ['opt1'] if that's the only checked checkbox at post time. You could deal with that in the Jinja side, but it's easier on the Python side, I think. So, instead of:

tpi_vars={"opt":opt}

I'd do:

tpi_vars={'ops': dict.fromkeys(opt, 'checked')}

Of course, you don't have to do it just before you render the Jinja2 template -- you could do this list-to-dict translation at any time. But since it is about presentation issues, this seems a good place for it.