Merge pull request 'Sort, filter, and limit results at /packets' (#23) from sort-filter into main

Reviewed-on: #23

README.md

@@ -10,15 +10,19 @@ direwolf logs into a REST API in JSON format.
 1. Set up database file with `python init_db.py`.
 2. Run `app.py` with either a Python call or a real WSGI server.
 You can use screen to detach the session.
-    - Default URL is http://127.0.0.1:5000
+    - Default URL is http://127.0.0.1:5001
     - Example `waitress` and `screen` scripts are included, see
       - `api_waitress.py` and
       - `start-aprs_api.sh`
 3. Access the API from whatever other system you want.
 
 ## Endpoints:
--`/packets` - gives the most recent packets, with the fields from the Dire Wolf
-User Guide.
+-`/packets` - gives the most recent packets, sorted descending by time received.
+    - argument `n` will return a specific number of packets, default 10. E.g.,
+    `https://digi.w1cdn.net/aprs_api/packets?n=1` returns one packet.
+    - argument `from` will return packets from the named station-SSID (no wildcards).
+    E.g., `https://digi.w1cdn.net/aprs_api/packets?n=1&from=W1CDN-1` returns
+    one packet from W1CDN-1.
 
 Example of an object packet sent by W1CDN-1 and digipeated by K0UND-2:
 ```

api_app.py

@@ -1,15 +1,18 @@
-from flask import Flask
+from flask import Flask, request
 from flask_restful import Resource, Api, reqparse
 from datetime import date, timedelta
 import configparser
 import csv
 import ast
 import glob
-import json
+import json, operator
 import sqlite3
 api_app = Flask(__name__)
 api = Api(api_app)
 
+# TODO this is duplicated from kiss_and_db.py, can I avoid that?
+import constants
+
 def read_config():
     config = configparser.ConfigParser()
     config.read('config.ini')
@@ -51,7 +54,6 @@ def dict_factory(cursor, row):
 
 def get_db_connection():
     conn = sqlite3.connect('database.db')
-    #conn.row_factory = sqlite3.Row
     conn.row_factory = dict_factory
     return conn
 
@@ -66,18 +68,46 @@ def select_all_frames(conn):
     rows = cur.fetchall()
     return rows
 
+def select_frames(conn, n, from_, url_params):
+
+    # Should pass this a dict of fields and values (request.args)
+    # TODO clean data before sending to DB
+    # Filter out any keys that don't match db fields
+    # From https://stackoverflow.com/a/20256491
+    dictfilt = lambda x, y: dict([ (i,x[i]) for i in x if i in set(y) ])
+    field_where = dictfilt(url_params, constants.db_frames_fields)
+    # Then loop through fields to create query parts
+    # From https://stackoverflow.com/a/73512269/2152245
+    field_where_str = ' AND '.join([f'"{k}" LIKE \'{v}\'' for k,v in field_where.items()])
+
+    cur = conn.cursor()
+    # Workaround to deal with missing value in WHERE
+    field_where_query = "" if field_where_str == "" else "WHERE "+field_where_str
+    sql = 'SELECT * FROM frames {field_where_query} ORDER BY created DESC LIMIT {n}'.format(field_where_query=field_where_query, n=n)
+    print(sql)
+    cur.execute(sql)
+    rows = cur.fetchall()
+    return rows
+
 class Packets(Resource):
     def get(self):
-        #data = read_logs(log_folder)
+        # Handle arguments that may or may not exist
+        try:
+            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()
-        data = select_all_frames(conn)
+        # Limit to number of records requested
+        data = select_frames(conn, n = n, from_ = from_, url_params = request.args.to_dict())
+        # Sort by created date, descending (https://stackoverflow.com/a/45266808)
+        #data.sort(key=operator.itemgetter('created'), reverse=True)
         return {'data': data}, 200  # return data and 200 OK code
 
 # Read config
 config = read_config()
 log_folder = config['Settings']['log_folder']
-# Load logs first (just to check for errors before page loads)
-#data = read_logs(log_folder)
 
 # Start subprocess to watch KISS connection
 import subprocess

constants.py

@@ -0,0 +1,49 @@
+# Tuple of frames table fields
+db_frames_fields = ("id",
+"addresse",
+"alive",
+"altitude",
+"comment",
+"course",
+"created",
+"created_unix",
+"format",
+"frame",
+"from",
+"gpsfixstatus",
+"latitude",
+"longitude",
+"mbits",
+"messagecapable",
+"message_text",
+"msgNo",
+"mtype",
+"object_format",
+"object_name",
+"path",
+"phg",
+"phg_dir",
+"phg_gain",
+"phg_height",
+"phg_power",
+"phg_range",
+"posambiguity",
+"raw",
+"raw_timestamp",
+"speed",
+"station_call",
+"station_lat",
+"station_lon",
+"status",
+"subpacket",
+"symbol",
+"symbol_table",
+"telemetry",
+"timestamp",
+"to",
+"tEQNS",
+"tPARM",
+"tUNIT",
+"via",
+"weather",
+"wx_raw_timestamp")

kiss_and_db.py

@@ -5,53 +5,7 @@ import aprs
 import json
 import aprslib
 import configparser
-
-db_fields = ("id",
-"addresse",
-"alive",
-"altitude",
-"comment",
-"course",
-"created",
-"format",
-"frame",
-"from",
-"gpsfixstatus",
-"latitude",
-"longitude",
-"mbits",
-"messagecapable",
-"message_text",
-"mtype",
-"object_format",
-"object_name",
-"path",
-"phg",
-"phg_dir",
-"phg_gain",
-"phg_height",
-"phg_power",
-"phg_range",
-"posambiguity",
-"raw",
-"raw_timestamp",
-"speed",
-"station_call",
-"station_lat",
-"station_lon",
-"status",
-"subpacket",
-"symbol",
-"symbol_table",
-"telemetry",
-"timestamp",
-"to",
-"tEQNS",
-"tPARM",
-"tUNIT",
-"via",
-"weather",
-"wx_raw_timestamp")
+import time
 
 def read_config():
     config = configparser.ConfigParser()
@@ -82,16 +36,18 @@ def main():
         path=["WIDE1-1"],
         info=b">Hello World!",
     )
-    ki.write(frame)
+    #ki.write(frame)
 
     # Watch for new packets to come in
     while True:
         conn = get_db_connection()
         for frame in ki.read(min_frames=1):
+            try:
                 a = aprslib.parse(str(frame))
                 a['station_call'] = config['Settings']['station_call']
                 a['station_lat'] = config['Settings']['station_lat']
                 a['station_lon'] = config['Settings']['station_lon']
+                a['created_unix'] = int(time.time())
                 print(a)
                 # Make this a string and deal with it later (probably a mistake)
                 a['path'] = str(a['path'])
@@ -116,6 +72,9 @@ def main():
                     conn.commit()
                 except:
                     print("Error with SQLite!")
+            except:
+                print("Frame could not be parsed.")
+
 
         conn.close()
 

requirements.txt

@@ -2,3 +2,5 @@ flask
 flask_restful
 aprs
 aprslib
+sqlite3
+json

schema.sql

@@ -8,6 +8,7 @@ CREATE TABLE frames (
     comment TEXT,
     course REAL,
     created TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    created_unix INT,
     format TEXT,
     frame TEXT,
     "from" TEXT,
@@ -17,6 +18,7 @@ CREATE TABLE frames (
     mbits INT,
     messagecapable INT,
     message_text TEXT,
+    msgNo INT,
     mtype TEXT,
     object_format TEXT,
     object_name TEXT,