structural pattern applied

Author: Ali Tayyabi

app/location/__init__.py

@@ -1,8 +1,6 @@
 """app.location"""
 from ..coordinates import Coordinates
-from ..utils import countries
-from ..utils.populations import country_population
-
+from ..utils import lookup
 
 # pylint: disable=redefined-builtin,invalid-name
 class Location:  # pylint: disable=too-many-instance-attributes
@@ -35,7 +33,7 @@ def country_code(self):
         :returns: The country code.
         :rtype: str
         """
-        return (countries.country_code(self.country) or countries.DEFAULT_COUNTRY_CODE).upper()
+        return lookup.get('country_code',self.country).upper()
 
     @property
     def country_population(self):
@@ -45,7 +43,7 @@ def country_population(self):
         :returns: The population.
         :rtype: int
         """
-        return country_population(self.country_code)
+        return lookup.get('country_population',self.country_code)
 
     def serialize(self):
         """

app/services/location/jhu.py

@@ -12,7 +12,7 @@
 from ...coordinates import Coordinates
 from ...location import TimelinedLocation
 from ...models import Timeline
-from ...utils import countries
+from ...utils import lookup
 from ...utils import date as date_util
 from ...utils import httputils
 from . import LocationService
@@ -98,7 +98,7 @@ async def get_category(category):
                 {
                     # General info.
                     "country": country,
-                    "country_code": countries.country_code(country),
+                    "country_code": lookup.get('country_code',country),
                     "province": item["Province/State"],
                     # Coordinates.
                     "coordinates": {"lat": item["Lat"], "long": item["Long"],},

app/utils/__init__.py

@@ -0,0 +1,3 @@
+import lookup
+import countries
+import populations

app/utils/countries.py

@@ -1,5 +1,7 @@
 """app.utils.countries.py"""
 import logging
+import lookup
+from lookup import Lookup
 
 LOGGER = logging.getLogger(__name__)
 
@@ -367,14 +369,25 @@
 }
 
 # fmt: on
-def country_code(value):
+
+class CountryCodeLookup(Lookup):
     """
-    Return two letter country code (Alpha-2) according to https://en.wikipedia.org/wiki/ISO_3166-1
-    Defaults to "XX".
+        This is a Lookup data class for returning the country code for county name
     """
-    code = COUNTRY_NAME__COUNTRY_CODE.get(value, DEFAULT_COUNTRY_CODE)
-    if code == DEFAULT_COUNTRY_CODE:
-        # log at sub DEBUG level
-        LOGGER.log(5, f"No country code found for '{value}'. Using '{code}'!")
+    def __init__(self):
+        self.type = "country_code"
+
+    def get(self, value, default=DEFAULT_COUNTRY_CODE):
+        """
+        Return two letter country code (Alpha-2) according to https://en.wikipedia.org/wiki/ISO_3166-1
+        Defaults to "XX".
+        """
+        code = COUNTRY_NAME__COUNTRY_CODE.get(value, default)
+        if code == default:
+            # log at sub DEBUG level
+            LOGGER.log(5, f"No country code found for '{value}'. Using '{code}'!")
+
+        return code
 
-    return code
+# register an instance of CountryCodeLookup in lookup registry
+lookup.register_lookup(CountryCodeLookup())

app/utils/lookup.py

@@ -0,0 +1,30 @@
+
+class Lookup():
+  """
+    abstract lookup class
+  """
+
+  def __init__(self, type):
+    self.type = type
+
+  @abstractmethod
+  def get(self, value, default):
+    raise NotImplementedError
+
+# this will keep track of all the lookup data classes
+data_lookup_list = dict()
+
+def register_lookup(lookupObject : Lookup)->None:
+  """
+    add the lookup class instance to the lookup registry list
+  """
+  data_lookup_list[lookupObject.type] = lookupObject
+
+def get(lookup_type, key):
+  """
+    return the lookup value associated with the `key` for the lookup 
+    data type `typev`
+  """
+  if lookup_type in data_lookup_list:
+    return data_lookup_list[lookup_type].get(key)
+  return None

app/utils/populations.py

@@ -5,6 +5,8 @@
 import requests
 
 import app.io
+import lookup
+from lookup import Lookup
 
 LOGGER = logging.getLogger(__name__)
 GEONAMES_URL = "http://api.geonames.org/countryInfoJSON"
@@ -49,12 +51,21 @@ def fetch_populations(save=False):
 # Mapping of alpha-2 codes country codes to population.
 POPULATIONS = fetch_populations()
 
-# Retrieving.
-def country_population(country_code, default=None):
+class CountryPopulationLookup(Lookup):
     """
-    Fetches the population of the country with the provided country code.
-
-    :returns: The population.
-    :rtype: int
+        This is a lookup data class for returning population for a country code
     """
-    return POPULATIONS.get(country_code, default)
+    def __init__(self):
+        self.type = "country_population"
+
+    def get(self, value, default=DEFAULT_COUNTRY_CODE):
+        """
+        Fetches the population of the country with the provided country code.
+
+        :returns: The population.
+        :rtype: int
+        """
+        return POPULATIONS.get(country_code, default)
+
+# register an instance of CountryPopulationLookup in lookup registry
+lookup.register_lookup(CountryPopulationLookup())

tests/test_countries.py

@@ -1,6 +1,7 @@
 import pytest
 
 from app.utils import countries
+from app.utils import lookup
 
 """
 Todo:
@@ -20,4 +21,4 @@
     ],
 )
 def test_countries_country_name__country_code(country_name, expected_country_code):
-    assert countries.country_code(country_name) == expected_country_code
+    assert lookup.get('country_code',country_name) == expected_country_code