Changed telnet parser from fixed size to regex

ogn/parser/pattern.py

@@ -114,6 +114,30 @@ PATTERN_RECEIVER_STATUS_COMMENT = re.compile(r"""
     )?
 """, re.VERBOSE | re.MULTILINE)
 
+PATTERN_TELNET_50001 = re.compile(r"""
+    (?P<pps_offset>\d\.\d+)sec:(?P<frequency>\d+\.\d+)MHz:\s+
+    (?P<aircraft_type>\d):(?P<address_type>\d):(?P<address>[A-F0-9]{6})\s
+    (?P<timestamp>\d{6}):\s
+    \[\s*(?P<latitude>[+-]\d+\.\d+),\s*(?P<longitude>[+-]\d+\.\d+)\]deg\s*
+    (?P<altitude>\d+)m\s*
+    (?P<climb_rate>[+-]\d+\.\d+)m/s\s*
+    (?P<ground_speed>\d+\.\d+)m/s\s*
+    (?P<track>\d+\.\d+)deg\s*
+    (?P<turn_rate>[+-]\d+\.\d+)deg/sec\s*
+    (?P<magic_number>\d+)\s*
+    (?P<gps_status>[0-9x]+)m\s*
+    (?P<channel>\d+)(?P<flarm_timeslot>[f_])(?P<ogn_timeslot>[o_])\s*
+    (?P<frequency_offset>[+-]\d+\.\d+)kHz\s*
+    (?P<decode_quality>\d+\.\d+)/(?P<signal_quality>\d+\.\d+)dB/(?P<demodulator_type>\d+)\s+
+    (?P<error_count>\d+)e\s*
+    (?P<distance>\d+\.\d+)km\s*
+    (?P<bearing>\d+\.\d+)deg\s*
+    (?P<phi>[+-]\d+\.\d+)deg\s*
+    (?P<multichannel>\+)?\s*
+    \?\s*
+    R?\s*
+    (B(?P<baro_altitude>\d+))?
+""", re.VERBOSE | re.MULTILINE)
 
 # The following regexp patterns are part of the ruby ogn-client.
 # source: https://github.com/svoop/ogn_client-ruby

ogn/parser/telnet_parser.py

@@ -1,40 +1,43 @@
+import re
 from datetime import datetime
 
-from ogn.parser import ParseError
 from ogn.parser.utils import createTimestamp
+from ogn.parser.pattern import PATTERN_TELNET_50001
+
+telnet_50001_pattern = re.compile(PATTERN_TELNET_50001)
 
 
 def parse(telnet_data):
     reference_timestamp = datetime.utcnow()
 
-    try:
+    match = telnet_50001_pattern.match(telnet_data)
-        return {'pps_offset': float(telnet_data[0:5]),
+    if match:
-                'frequency': float(telnet_data[9:16]),
+        return {'pps_offset': float(match.group('pps_offset')),
-                'aircraft_type': int(telnet_data[20:24]),
+                'frequency': float(match.group('frequency')),
-                'address_type': int(telnet_data[25]),
+                'aircraft_type': int(match.group('aircraft_type')),
-                'address': telnet_data[27:33],
+                'address_type': int(match.group('address_type')),
-                'timestamp': createTimestamp(telnet_data[34:40] + 'h', reference_timestamp),
+                'address': match.group('address'),
-                'latitude': float(telnet_data[43:53]),
+                'timestamp': createTimestamp(match.group('timestamp') + 'h', reference_timestamp),
-                'longitude': float(telnet_data[54:64]),
+                'latitude': float(match.group('latitude')),
-                'altitude': int(telnet_data[68:73]),
+                'longitude': float(match.group('longitude')),
-                'climb_rate': float(telnet_data[74:80]),
+                'altitude': int(match.group('altitude')),
-                'ground_speed': float(telnet_data[83:89]),
+                'climb_rate': float(match.group('climb_rate')),
-                'track': float(telnet_data[92:98]),
+                'ground_speed': float(match.group('ground_speed')),
-                'turn_rate': float(telnet_data[101:107]),
+                'track': float(match.group('track')),
-                'magic_number': int(telnet_data[114:116]),
+                'turn_rate': float(match.group('turn_rate')),
-                'gps_status': telnet_data[117:122],
+                'magic_number': int(match.group('magic_number')),
-                'channel': int(telnet_data[124:126]),
+                'gps_status': match.group('gps_status'),
-                'flarm_timeslot': telnet_data[126] == 'f',
+                'channel': int(match.group('channel')),
-                'ogn_timeslot': telnet_data[127] == 'o',
+                'flarm_timeslot': match.group('flarm_timeslot') == 'f',
-                'frequency_offset': float(telnet_data[128:134]),
+                'ogn_timeslot': match.group('ogn_timeslot') == 'o',
-                'decode_quality': float(telnet_data[137:142]),
+                'frequency_offset': float(match.group('frequency_offset')),
-                'signal_quality': float(telnet_data[143:147]),
+                'decode_quality': float(match.group('decode_quality')),
-                'demodulator_type': int(telnet_data[150:151]),
+                'signal_quality': float(match.group('signal_quality')),
-                'error_count': float(telnet_data[151:154]),
+                'demodulator_type': int(match.group('demodulator_type')),
-                'distance': float(telnet_data[155:162]),
+                'error_count': float(match.group('error_count')),
-                'bearing': float(telnet_data[164:170]),
+                'distance': float(match.group('distance')),
-                'phi': float(telnet_data[173:179]),
+                'bearing': float(match.group('bearing')),
-                'multichannel': telnet_data[183] == '+'}
+                'phi': float(match.group('phi')),
-
+                'multichannel': match.group('multichannel') == '+'}
-    except Exception:
+    else:
-        raise ParseError
+        return None

tests/parser/test_parse_telnet.py

@@ -14,11 +14,11 @@ class TestStringMethods(unittest.TestCase):
             parse('This is rubbish')
 
     @mock.patch('ogn.parser.telnet_parser.datetime')
-    def test_telnet_parse(self, datetime_mock):
+    def test_telnet_parse_complete(self, datetime_mock):
         # set the utcnow-mock near to the time in the test string
         datetime_mock.utcnow.return_value = datetime(2015, 1, 1, 10, 0, 55)
 
-        message = parse('0.181sec:868.394MHz:   1:2:DDA411 103010: [ +50.86800, +12.15279]deg  988m  +0.1m/s  25.7m/s 085.4deg  -3.5deg/sec 5 03x04m 01f_-12.61kHz  5.8/15.5dB/2 10e   30.9km 099.5deg  +1.1deg + ?')
+        message = parse('0.181sec:868.394MHz:   1:2:DDA411 103010: [ +50.86800, +12.15279]deg  988m  +0.1m/s  25.7m/s 085.4deg  -3.5deg/sec 5 03x04m 01f_-12.61kHz  5.8/15.5dB/2 10e   30.9km 099.5deg  +1.1deg + ?     R     B8949')
 
         self.assertEqual(message['pps_offset'], 0.181)
         self.assertEqual(message['frequency'], 868.394)
@@ -48,6 +48,11 @@ class TestStringMethods(unittest.TestCase):
         self.assertEqual(message['phi'], 1.1)
         self.assertEqual(message['multichannel'], True)
 
+    def test_telnet_parse_corrupt(self):
+        message = parse('0.397sec:868.407MHz:  sA:1:784024 205656: [  +5.71003, +20.48951]deg 34012m +14.5m/s 109.7m/s 118.5deg +21.0deg/sec 0 27x40m 01_o +7.03kHz 17.2/27.0dB/2 12e 4719.5km 271.1deg  -8.5deg   ?     R     B34067')
+
+        self.assertIsNone(message)
+
 
 if __name__ == '__main__':
     unittest.main()