Introducing Template - templates.py file

app.yaml

runtime: python27
api_version: 1
threadsafe: true

handlers:
- url: /.*
  script: templates.app

libraries:
  - name: jinja2
    version: latest

shopping_list.html

<form>
<h2>Add a food </h2>
<input type="text" name="food">
<button>Add</button>
</form>

templates.py

import os
import jinja2

import webapp2

template_dir = os.path.join(os.path.dirname(templates.py), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir))


form_html = """
<form>
<h2>Add a food </h2>
<input type="text" name="food">
%s
<button>Add</button>
</form>
"""
hidden_html = """
<input type="hidden" name="food" value="%s">
"""

hidden_item = "<li> %s </li>"


shopping_list_html = """
<br>
<br>
<h2>Shopping List</h2>
<ul>
%s
</ul>
"""


class Handler(webapp2.RequestHandler):
    def write(self, *a, **kw):
        self.response.out.write(*a, **kw)

    def render_str(self, template, **params):
        t = jinja_env.get_template(template)
        return t.render(params)

    def render(self, template, **kw):
        self.write(self.render_str(template, **kw))


class MainPage(Handler):
    def get(self):
        output = form_html
        output_hidden = ""
        items = self.request.get_all("food")
        print "the items are ", items
        if items:
            output_items = ""
            for item in items:
                output_hidden += hidden_html % item
                output_items += hidden_item % item

            output_shopping = shopping_list_html % output_items
            output += output_shopping

        output = output % output_hidden
        self.write(output)

app = webapp2.WSGIApplication([('/', MainPage),
                                 ],
                                  debug=True)