Add ability to query API for certain years (#4)

* Add explicitly-handled start_year and end_year args

* Organize year range handling into own function, add more value checks

atlas_core/query_processing.py

@@ -25,9 +25,33 @@ def request_to_query(request):
         }
 
     query["arguments"] = arguments
+    query['year_range'] = handle_year_range(request)
+
     return query
 
 
+def handle_year_range(request):
+    start_year = request.args.get("start_year", None)
+    end_year = request.args.get("end_year", None)
+
+    if start_year and not start_year.isdigit():
+        msg = "Start year ({}) is not integer."\
+                .format(start_year)
+        abort(400, message=msg)
+    if end_year and not end_year.isdigit():
+        msg = "End year ({}) is not integer."\
+                .format(end_year)
+        abort(400, message=msg)
+
+    if start_year and end_year:
+        if start_year > end_year:
+            msg = "Start year specified ({}) must be less than or equal to end year ({})."\
+                .format(start_year, end_year)
+            abort(400, message=msg)
+
+    return {"start": start_year, "end": end_year}
+
+
 def get_or_fail(name, dictionary):
     """Lookup a key in a dict, abort with helpful error on failure."""
     thing = dictionary.get(name, None)

atlas_core/slice_lookup.py

@@ -52,6 +52,17 @@ def fetch(self, slice_def, query, json=True):
         level_predicate = (level_column == query["result"]["level"])
         filter_predicates.append(level_predicate)
 
+        # Filter by year ranges
+        year_column = self.get_column_by_name('year')
+
+        if query['year_range']['start']:
+            start_predicate = (year_column >= query['year_range']['start'])
+            filter_predicates.append(start_predicate)
+
+        if query['year_range']['end']:
+            end_predicate = (year_column <= query['year_range']['end'])
+            filter_predicates.append(end_predicate)
+
         q = list(db.session.query(*self.get_all_model_columns()).filter(*filter_predicates).all())
 
         return lima.marshal(self.schema, q, json=json)
@@ -66,4 +77,3 @@ def __init__(self, df, schema=None):
 
     def fetch(self, slice_def, query):
         raise NotImplementedError()
-