implemented aggregate pattern into app/data

app/data/__init__.py

@@ -4,18 +4,29 @@
 from ..services.location.nyt import NYTLocationService
 
 # Mapping of services to data-sources.
-DATA_SOURCES = {
-    "jhu": JhuLocationService(),
-    "csbs": CSBSLocationService(),
-    "nyt": NYTLocationService(),
-}
 
 
-def data_source(source):
-    """
-    Retrieves the provided data-source service.
+class DataSources:
 
-    :returns: The service.
-    :rtype: LocationService
-    """
-    return DATA_SOURCES.get(source.lower())
+    def __init__(self):
+        """
+        Sets __data_source's key-value pairs to be the data-source (key) and data-source service (value) for the supported sources (jhu, csbs, nyt)
+        """
+        self.__data_source = {
+            "jhu": JhuLocationService(),
+            "csbs": CSBSLocationService(),
+            "nyt": NYTLocationService(),
+        }
+
+    def get_data_sources(self):
+        """Return the keys stored in __data_source"""
+        return self.__data_source.keys()
+
+    def get_data_source_service(self, source):
+        """
+        Retrieves the provided data-source service.
+
+        :returns: The service.
+        :rtype: LocationService
+        """
+        return self.__data_source.get(source.lower())

app/main.py

@@ -14,10 +14,15 @@
 from sentry_sdk.integrations.asgi import SentryAsgiMiddleware
 
 from .config import get_settings
-from .data import data_source
+from .data import DataSources
 from .routers import V1, V2
 from .utils.httputils import setup_client_session, teardown_client_session
 
+# ############
+# Constructing DataSources object for retriving data source services
+# ############
+dataSources = DataSources()
+
 # ############
 # FastAPI App
 # ############
@@ -74,8 +79,8 @@ async def add_datasource(request: Request, call_next):
     Attach the data source to the request.state.
     """
     # Retrieve the datas ource from query param.
-    source = data_source(request.query_params.get("source", default="jhu"))
-
+    source = dataSources.get_data_source_service(
+        request.query_params.get("source", default="jhu"))
     # Abort with 404 if source cannot be found.
     if not source:
         return Response("The provided data-source was not found.", status_code=404)

app/routers/v2.py

@@ -3,9 +3,15 @@
 
 from fastapi import APIRouter, HTTPException, Request
 
-from ..data import DATA_SOURCES
+from ..data import DataSources
 from ..models import LatestResponse, LocationResponse, LocationsResponse
 
+# ############
+# Constructing DataSources object for retriving data source services
+# ############
+dataSources = DataSources()
+
+
 V2 = APIRouter()
 
 
@@ -107,4 +113,4 @@ async def sources():
     """
     Retrieves a list of data-sources that are availble to use.
     """
-    return {"sources": list(DATA_SOURCES.keys())}
+    return {"sources": list(dataSources.get_data_sources)}