Current Weather PWS

Using Python (language), Flask (framework) and Jinja2 (template) to GET and display current weather conditions from WUnderground API. From one station in WU's 250,000+ Personal Weather Station Network

Note: Weather Underground no longer provides free API keys.

Imports

from flask import Flask, flash, redirect, render_template, request
from urllib3 import PoolManager
import json

Dependencies

The Anaconda Python distribution was used to develop this app, so related dependencies have been linked below:

• python 3.6.4
• flask 0.12.2
  • click 6.7
  • itsdangerous 0.24
  • jinja2 2.10
  • werkzeug 0.14.1
• urllib3 1.22
• simplejson 3.13.2 (PyPI)

Sudden changes may not reflect the list above. Additional required modules may be overlooked.

NOTE: virtual environments should act jointly with development environments, since operating systems use a subset of Python. Added modules may modify important dependencies which potentially corrupt the system.

Jinja2

Jinja2 is inclusive, just as templates live in a specific directory, e.g. /templates. Since templates specify HTML document structure. Notice the handlebar structure insertion below, e.g. {{ co['weather'] }}.

<table>
    <tr>
      <td><span class="blue">Weather condition</span></td>
      <td>{{ co['weather'] }}</td>
    </tr>
...

current_cond()

The current_cond() method assigns a dictionary variable for insertion of URL parts.

@app.route("/current/")
def current_cond():
    d = {'api_key': '51857b97d97c71a0',
         'state_code': 'IL',
         'personal_weather_station': 'pws:KILMORRI2'}
    pm = PoolManager()

Values from that dictionary are spliced into the URL to GET raw weather data from the API.

    r = pm.request('GET', 'http://api.wunderground.com/api/' +
                   d['api_key'] + '/conditions/q/' + d['state_code'] +
                   '/' + d['personal_weather_station'] + '.json')

Try/Except Block

Sometimes leaf_wetness data is omitted, which causes a KeyError, so the following try/except block was added.

try:
   lw = co['leaf_wetness']
except KeyError:
   pass