api.py

"""
Arduino PI API
This is a restful api for interacting with
the arduino weather data

It uses the flask microservice to generate a 
interface for which user to get data from the
weather station

Instruction on how to use it are in the readme
in the repo as well as on the index route
of the api

Interaction with the Postgres database is enabled
through flask-sqlalchemy
"""
from flask import Flask, request, abort, render_template
from flask_restful import Resource, Api, fields, marshal_with
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.exc import OperationalError, DataError
from datetime import datetime

# Initialize Flask and API
application = Flask(__name__, template_folder='templates')
api = Api(application)

# Configures application from a config.cfg
application.config.from_pyfile('config.cfg')
db = SQLAlchemy(application)

# Data fields for Weather Object
weather_fields = {
    'id': fields.Integer,
    'date_time': fields.String,
    'humidity': fields.Float,
    'wetness': fields.Integer,
    'wind_speed': fields.Float,
    'temperature': fields.Float,
    'pressure': fields.Float
}


# Weather Forecast Model
# Contains all the column data needed
class WeatherForecasts(db.Model):
    id = db.Column(db.Integer, primary_key=True, nullable=False)
    date_time = db.Column(db.String, nullable=False)
    humidity = db.Column(db.Float, nullable=False)
    wetness = db.Column(db.Integer, nullable=False)
    wind_speed = db.Column(db.Float, nullable=False)
    temperature = db.Column(db.Float, nullable=False)
    pressure = db.Column(db.Float, nullable=False)


# Resource getting all of the weather
class AllWeather(Resource):
    @marshal_with(weather_fields)
    def get(self):
        try:
            # url arguments do "/weather?<arg1>=<val1>&<arg2>=<val2>&..."
            # or just do "/weather" to get all data
            date_begin = request.args.get(
                'begin',
                default='2018-06-27',
                type=str)
            date_end = request.args.get(
                'end',
                default=datetime.now(),
                type=str)
            # query weather data
            forecasts = WeatherForecasts.query \
                .filter(
                    WeatherForecasts.date_time.between(
                        date_begin,
                        date_end
                    )
                ).all()
            # checks if any forecasts were collected
            if forecasts is not None:
                return forecasts
            else:
                return {}
        except DataError:
            abort(400, DataError.statement)
        except OperationalError:
            abort(500, OperationalError.statement)


# Resource getting the most recent weather report
class RecentWeather(Resource):
    @marshal_with(weather_fields)
    def get(self):
        try:
            return WeatherForecasts.query \
                .order_by(
                    WeatherForecasts.id.desc()
                ).first()
        except DataError:
            abort(400, DataError.statement)
        except OperationalError:
            abort(500, OperationalError.statement)


# On Index display a README like instruction file
@application.route('/api/')
def index():
    return render_template('index.html')


# API URLS
# Visit urls to fetch data
api.add_resource(AllWeather, '/api/weather')
api.add_resource(RecentWeather, '/api/weather/recent')


if __name__ == '__main__':
    application.run(host='0.0.0.0', debug=True)