py08-query-form.md

Change fuel type with URL query string

from django.shortcuts import render
from django.http import HttpResponse

from fuel_scraper import get_fuel_data, gen_fuel, fuel_types, regions, day

def index(request):
    # Getting fuel type from URL query string
    product_num = request.GET['product']

    # Getting fuel prices
    urls = gen_fuel([product_num], regions, day)
    fuel_data = get_fuel_data(urls)

    for value in fuel_data:
        fuel_data_rows_string += """
            <tr>
                <td>{price} </td><td>{address} </td><td>{location} </td><td>{brand}</td>
            </tr>
        """.format(**value)

    # Formats the html.
    fuel_data_html = "<table>" + fuel_data_rows_string + "</table></tbody></body></html>"
    return HttpResponse(fuel_data_html)

Default dictionary key value

If you apply the code above, you will find that you will be getting KeyError.

If you try to run the following code, there is no problem.

d = {'preferred_colour': 'red'}
colour = d['preferred_colour']

If you do this, you will get the KeyError.

d = {}
colour = d['preferred_colour']

Let's say you want to default to 'blue' if a preferred colour is not specified, you can do:

if 'preferred_colour' in d:
  colour = d['preferred_colour']
else:
  colour = 'blue'

Which is same as:

colour = d.get('preferred_colour', 'blue')

Change fuel type with Form

Changing the form actually changes the URL

from django.shortcuts import render
from django.http import HttpResponse

from fuel_scraper import get_fuel_data, gen_fuel, fuel_types, regions, day

def index(request):
    product_num = request.GET['product']

    # Getting fuel prices
    urls = gen_fuel([product_num], regions, day)
    fuel_data = get_fuel_data(urls)

    fuel_data_rows_string = """
        <form>
            <select name="product">
                <option value="1">Unleaded</option>
                option value="2">Premium Unleaded</option>
            </select>
            <button type="submit">Filter</button>
        </form>
    """
    for value in fuel_data:
        fuel_data_rows_string += """
            <tr>
                <td>{price} </td><td>{address} </td><td>{location} </td><td>{brand}</td>
            </tr>
        """.format(**value)

    # Formats the html.
    fuel_data_html = "<table>" + fuel_data_rows_string + "</table></tbody></body></html>"
    return HttpResponse(fuel_data_html)