geocode.py

   1 #!/usr/bin/env python3
   2
   3 """Wrapper around US Census address geocoder API described here:
   4 https://www2.census.gov/geo/pdfs/maps-data/data/Census_Geocoder_User_Guide.pdf"""
   5
   6 import logging
   7 import re
   8 from typing import Dict, Optional
   9
  10 import requests
  11 from bs4 import BeautifulSoup
  12 from requests.utils import quote
  13
  14 logger = logging.getLogger(__name__)
  15
  16
  17 def geocode_address(address: str) -> Optional[Dict[str, str]]:
  18     """Send a single address to the US Census geocoding API.
  19
  20     >>> out = geocode_address('5 Shelbern Dr,,, 07738')
  21     >>> out['Matched Address']
  22     '5 SHELBERN DR, LINCROFT, NJ, 07738'
  23
  24     """
  25     encoded_address = quote(address)
  26     url = 'https://geocoding.geo.census.gov/geocoder/geographies/onelineaddress'
  27     url += f'?address={encoded_address}'
  28     url += '&layers=all&benchmark=4&vintage=4'
  29     logger.debug('GET: %s', url)
  30     r = requests.get(url)
  31     if r.status_code != 200:
  32         logger.error(f'Unexpected response code {r.status_code}, wanted 200.  Fail.')
  33         return None
  34     else:
  35         soup = BeautifulSoup(r.text, 'html.parser')
  36         result = soup.find('div', id='pl_gov_census_geo_geocoder_domain_AddressResult')
  37         logger.debug('Unhelpful result blurb: "%s"', result)
  38         output = result.get_text('\n')
  39         label = None
  40         out = {}
  41         for line in output.split('\n'):
  42             if re.match(r'.*: *$', line):
  43                 label = line[:-2].strip()
  44                 logger.debug('Label is: "%s"', label)
  45             else:
  46                 if label:
  47                     out[label] = line.strip()
  48                     logger.debug('Value is: "%s"', out[label])
  49     return out
  50
  51
  52 if __name__ == '__main__':
  53     import doctest
  54
  55     doctest.testmod()