app.py

from base64 import b64decode
from flask import Flask, request, render_template
from waitress import serve
import json
import decimal
import sys
from modules import db, model, logger, config
import geopandas as gpd
from geojson import Feature, FeatureCollection, Polygon
from shapely import wkt
import gzip
try:
    from StringIO import StringIO ## for Python 2
except ImportError:
    from io import StringIO ## for Python 3
    
APP_SECRET_KEY = config.App().SECRET_KEY
APP_HOST = config.App().HOST
APP_PORT = config.App().PORT
APP_THREADS = int(config.App().THREADS)

# create flask app
app = Flask(__name__)
app.debug = True
app.secret_key = APP_SECRET_KEY

# logger
logger = logger.init()

# route for main page
@app.route('/')
def index():
    poi = json.dumps(db.get_poi())
    demand_cols = db.get_demand_columns()
    supply_cols = db.get_supply_columns()
    capacity_cols = db.get_capacity_columns()
    
    # basemap token
    basemap_token = config.Basemap().TOKEN
    html = config.html()
    
    return render_template('index.html', poi=poi, supply_cols=supply_cols, demand_cols=demand_cols, capacity_cols=capacity_cols, basemap_token=basemap_token,
    html=html)

# route for running enhanced 3SFCA model
@app.route('/model',methods=['POST'])
def run_model():
    req = request.get_json()
    
    try:
        beta = float(req['beta'])
        transportation = req['transportation']
        threshold = int(req['threshold']) * 1000 # multiply to get the minute threshold to match distance matrix meter units
        bounds = req['bounds']
        logger.info(f'User parameters include beta: {beta}, transport: {transportation}, threshold: {threshold}')
    except Exception as e:
        logger.error(f'Parameters provided are incorrect: {e}')
        return e

    supply = req['supply']
    demand = req['demand']
    capacity = req['capacity']

    scores = model.accessibility(bounds, beta, transportation, threshold, demand, supply, capacity)
    scores_col = str(list(scores.columns.values))
    scores_row = str(scores.index)
    max = scores['scores'].max()
    
    try:
        scores['boundary'] = scores['boundary'].apply(wkt.loads)
        features = scores.apply(
            lambda row: Feature(geometry=row['boundary'], properties={'geouid':row['geouid'], 'score':row['scores']}),
            axis=1).tolist()
        feature_collection = FeatureCollection(score_vals=scores['scores'].tolist(), max=max, features=features)
        feature_collection = json.dumps(feature_collection)
        return feature_collection
    except Exception as e:
        logger.error(f'{scores_row}')
        logger.error(f'{scores_col}')
        logger.error(f'Could not return results as geojson: {e}')
        return e

# route for bad HTTP requests
@app.errorhandler(400)
def error(e):
    return render_template('error.html')

if __name__ == '__main__':
    serve(app, host=APP_HOST,port=APP_PORT,threads=APP_THREADS)