Add basic API call to select by "from" station.

api_app.py

@@ -65,6 +65,17 @@ def select_all_frames(conn):
     rows = cur.fetchall()
     return rows
 
+def select_frames(conn, n, from_):
+    cur = conn.cursor()
+    # Workaround to deal with missing value in WHERE
+    from_ = "IS NOT NULL" if from_ == None else "='"+from_+"'"
+    #sql = "SELECT * FROM frames LIMIT "+n
+    sql = 'SELECT * FROM frames WHERE "from" {from_} LIMIT {n}'.format(from_=from_, n=n)
+    print(sql)
+    cur.execute(sql)
+    rows = cur.fetchall()
+    return rows
+
 class Packets(Resource):
     def get(self):
         # Handle arguments that may or may not exist
@@ -72,10 +83,11 @@ class Packets(Resource):
             n = int(request.args.get('n'))
         except:
             n = 10
+        from_ = None if request.args.get('from') == None else request.args.get('from')
 
         conn = get_db_connection()
         # Limit to number of records requested
-        data = select_all_frames(conn)[-n:]
+        data = select_frames(conn, n = n, from_ = from_)
         # Sort by created date, descending (https://stackoverflow.com/a/45266808)
         data.sort(key=operator.itemgetter('created'), reverse=True)
         #data.sort(key=created, reverse=True)