app.py

from dotenv import load_dotenv
from flask import Flask, render_template, request
from redis.commands.search.query import Query
from shapely import from_geojson, from_wkt, to_geojson, to_wkt
import os
import json
import redis

load_dotenv()

app = Flask(__name__)

# Connect to Redis
redis_client = redis.from_url(os.getenv("REDIS_URL"))

@app.route("/search", methods = ["POST"])
def search():
    wkt_string = ""
    geo_operator = ""

    # See if we got a point or a polygon search...
    if "point" in request.json:
        # Get the lat/lng and create a WKT point.
        wkt_string=f"POINT({request.json['point']['lng']} {request.json['point']['lat']})"
        geo_operator = "CONTAINS"
    else:
        # Unpack the GeoJSON request body and get the polygon out...
        # and turn it into a WKT string representation.
        shape = from_geojson(json.dumps(request.json["polygon"]["geometry"]))
        wkt_string = to_wkt(shape)
        geo_operator = "WITHIN"

    # ft.search idx:regions "@boundaries:[WITHIN $poly]" PARAMS 2 poly 'POLYGON((-12.655691 61.48076, 0.176516 63.66576, 7.735213 59.265881, -12.655691 61.48076))' DIALECT 3 RETURN 1 name

    # ft.search idx:regions "@boundaries:[CONTAINS $poly]" PARAMS 2 poly 'POLYGON((-12.655691 61.48076, 0.176516 63.66576, 7.735213 59.265881, -12.655691 61.48076))' DIALECT 3 RETURN 1 name

    # Point in polygon... 55.128996, -1.159153
    # ft.search idx:regions "@boundaries:[CONTAINS $point]" PARAMS 2 point 'POINT(-1.159153 55.128996)' DIALECT 3 RETURN 1 name

    search_response = redis_client.ft("idx:regions").search(
        Query(f"@boundaries:[{geo_operator} $wkt]").dialect(3).paging(0, 100),
        query_params = { "wkt": wkt_string }
    )

    matching_regions = []

    if len(search_response.docs) > 0:
        for doc in search_response.docs:
            region = json.loads(doc.json)[0]

            # Convert WKT polygon in "boundaries" to a 
            # GeoJSON representation to send to the front end.
            shape = from_wkt(region["boundaries"])
            region["boundaries"] = json.loads(to_geojson(shape))
            
            matching_regions.append(region)

    return ({ 
        "data": matching_regions
    })

@app.route("/")
def home():
    return render_template('homepage.html')