app.py

#setting up dependencies
import datetime as dt
import numpy as np
import pandas as pd
import sqlalchemy
from sqlalchemy.ext.automap import automap_base
from sqlalchemy.orm import Session
from sqlalchemy import create_engine, func
from flask import Flask, jsonify

#setting up create_engine and automap_base and prepare
engine = create_engine("sqlite:///hawaii.sqlite",\
    connect_args={'check_same_thread':False})
Base = automap_base()
Base.prepare(engine, reflect=True)

#setting up table references
Measurement = Base.classes.measurement
Station = Base.classes.station

#setting up session link
session = Session(engine)

#Creating a new flask instance called app
app = Flask(__name__)

#create flask route
@app.route('/')
def welcome():
	return(
    '''
    Welcome to the Climate Analysis API!<br/>
    Available Routes:<br/>
    /api/v1.0/precipitation<br/>
    /api/v1.0/stations<br/>
    /api/v1.0/tobs<br/>
    /api/v1.0/temp/start/end <br/>
    ''')

@app.route("/api/v1.0/precipitation")
def precipitation():
    prev_year = dt.date(2017, 8, 23) - dt.timedelta(days=365)
    precipitation = session.query(\
        Measurement.date, Measurement.prcp).filter(\
            Measurement.date >= prev_year).all()
    precip = {date: prcp for date, prcp in precipitation}
    return jsonify(precip)

@app.route("/api/v1.0/stations")
def stations():
    results = session.query(Station.station).all()
    stations = list(np.ravel(results))
    return jsonify(stations=stations)

@app.route("/api/v1.0/tobs")
def temp_monthly():
    prev_year = dt.date(2017, 8, 23) - dt.timedelta(days=365)
    results = session.query(Measurement.tobs).filter(\
        Measurement.station == 'USC00519281').filter(\
        Measurement.date >= prev_year).all()
    temps = list(np.ravel(results))
    return jsonify(temps=temps)

@app.route("/api/v1.0/temp/<start>")

@app.route("/api/v1.0/temp/<start>/<end>")
def stats(start=None, end=None):
    sel = [func.min(Measurement.tobs), func.avg(\
        Measurement.tobs),func.max(Measurement.tobs)]

    if not end:
        results = session.query(*sel).filter(\
            Measurement.date <= start).all()
        temps = list(np.ravel(results))
        return jsonify(temps)

    results = session.query(*sel).filter(\
        Measurement.date >= start).filter(\
            Measurement.date <= end).all()
    temps = list(np.ravel(results))
    return jsonify(temps=temps)