app.py: Use parameterized URI instead of query for /item

Falcon's get_param_as_int() is really nice in that it gets a query
parameter and does validation for you, but I really wanted to have
cleaner URIs for API routes so I am now using a route URI template
with a field converter. This is cleaner, but means that parameters
not matching the template will return HTTP 404.

See: https://falcon.readthedocs.io/en/stable/api/routing.html#field-converters

app.py

@@ -8,10 +8,8 @@ from solr import solr_connection
 
 
 class ItemResource:
-    def on_get(self, req, resp):
+    def on_get(self, req, resp, item_id):
         """Handles GET requests"""
-        # Return HTTPBadRequest if id parameter is not present and valid
-        item_id = req.get_param_as_int("id", required=True, min=0)
 
         # Get views
         res = solr.query(SOLR_CORE, {
@@ -38,6 +36,6 @@ class ItemResource:
         resp.media = statistics
 
 api = falcon.API()
-api.add_route('/item', ItemResource())
+api.add_route('/item/{item_id:int}', ItemResource())
 
 # vim: set sw=4 ts=4 expandtab: