Move countrypopulation to utils

Author: Turreted

app/utils/population/__init__.py

@@ -0,0 +1,47 @@
+import requests
+import csv
+from io import StringIO, BytesIO
+from cachetools import cached, TTLCache
+from zipfile import ZipFile, ZipInfo
+from ...utils.countrycodes import *
+
+
+@cached(cache=TTLCache(maxsize=1024, ttl=3600))
+def get_population_dict():
+    """
+    Creates a dictionary containing the population of each country.
+    The data is cached for 1 hour.
+
+    :returns: a dictionary of format country code: population.
+    :rtype: dict
+    """
+
+    # download file and save it to a buffer
+    URL = 'http://api.worldbank.org/v2/en/indicator/SP.POP.TOTL?downloadformat=csv'
+    zip_data = BytesIO(requests.get(URL).content)
+
+    #load buffer as ZipFile object
+    zipfile = ZipFile(zip_data, mode='r')
+
+    # isolate the and open csv file as StringIO object
+    target_file = [x for x in zipfile.namelist() if not x.startswith('Metadata')][0]
+    csv_file = StringIO(zipfile.read(target_file).decode('utf-8'))
+
+    # parse csv file as csv.reader
+    csv_reader = csv.reader(csv_file, delimiter=',')
+    popluation_dict = {}
+
+    for row in csv_reader:
+
+        # verify that row exists 
+        if len(row) > 0:
+
+            # verify that country is in database
+            if country_in_database(row[0]):
+
+                # Populate dict with last non-None value
+                key = country_code(row[0], verbose=False)
+                popluation_dict.update({key: int(next((el for el in row[::-1] if el), None))})
+
+    return popluation_dict
+