From 5ce9dec34ca2c38fc154afb19c036148f1e17de4 Mon Sep 17 00:00:00 2001
From: "Fabian P. Schmidt" <kerel-fs@gmx.de>
Date: Sun, 15 Nov 2015 19:21:19 +0100
Subject: [PATCH] Add AprsParseError.

---
 ogn/aprs_parser.py      | 16 ++++++++--------
 ogn/exceptions.py       | 12 ++++++++++++
 ogn/gateway/__init__.py | 11 ++++++-----
 ogn/model/beacon.py     | 11 ++++++-----
 4 files changed, 32 insertions(+), 18 deletions(-)
 create mode 100644 ogn/exceptions.py

diff --git a/ogn/aprs_parser.py b/ogn/aprs_parser.py
index 3cdea88..7db6d47 100644
--- a/ogn/aprs_parser.py
+++ b/ogn/aprs_parser.py
@@ -1,16 +1,16 @@
 from .model import Beacon, AircraftBeacon, ReceiverBeacon
+from ogn.exceptions import AprsParseError
 
-
-def parse_aprs(text):
-    if not isinstance(text, str):
-        raise Exception("Unknown type: %s" % type(text))
-    elif text == "":
-        raise Exception("String is empty")
-    elif text[0] == "#":
+def parse_aprs(packet):
+    if not isinstance(packet, str):
+        raise TypeError("Expected packet to be str, got %s" % type(packet))
+    elif packet == "":
+        raise AprsParseError(substring=packet, expected_type="non-empty aprs packet")
+    elif packet[0] == "#":
         return None
 
     beacon = Beacon()
-    beacon.parse(text)
+    beacon.parse(packet)
 
     # symboltable / symbolcodes used by OGN:
     # I&: used as receiver
diff --git a/ogn/exceptions.py b/ogn/exceptions.py
new file mode 100644
index 0000000..d4d8566
--- /dev/null
+++ b/ogn/exceptions.py
@@ -0,0 +1,12 @@
+"""
+exception definitions
+"""
+
+
+class AprsParseError(Exception):
+    """Parse error while parsing an aprs packet substring."""
+    def __init__(self, substring, expected_type):
+        self.message = "Aprs Substring can't be parsed as %s." % expected_type
+        super(AprsParseError, self).__init__(self.message)
+        self.substring = substring
+        self.expected_type = expected_type
diff --git a/ogn/gateway/__init__.py b/ogn/gateway/__init__.py
index 31a5eff..99a6e3b 100644
--- a/ogn/gateway/__init__.py
+++ b/ogn/gateway/__init__.py
@@ -4,6 +4,7 @@ from time import time
 from ogn.gateway import settings
 from ogn.commands.dbutils import session
 from ogn.aprs_parser import parse_aprs
+from ogn.exceptions import AprsParseError
 
 from sqlalchemy import create_engine
 from sqlalchemy.orm import sessionmaker
@@ -27,14 +28,14 @@ class ognGateway:
         self.sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
         self.sock.connect((settings.APRS_SERVER_HOST, settings.APRS_SERVER_PORT))
 
-        login = 'user %s pass %s vers ogn-gateway-python %s %s\n'  % (aprs_user, settings.APRS_PASSCODE, MODULE_VERSION, settings.APRS_FILTER)
+        login = 'user %s pass %s vers ogn-gateway-python %s %s\n' % (aprs_user, settings.APRS_PASSCODE, MODULE_VERSION, settings.APRS_FILTER)
         self.sock.send(login.encode())
         self.sock_file = self.sock.makefile('rw')
 
     def run(self):
         keepalive_time = time()
         while True:
-            if time()-keepalive_time > 60:
+            if time() - keepalive_time > 60:
                 self.sock.send("#keepalive".encode())
                 keepalive_time = time()
 
@@ -60,9 +61,9 @@ class ognGateway:
     def proceed_line(self, line):
         try:
             beacon = parse_aprs(line)
-        except Exception as e:
-            print('Failed to parse line: %s' % line)
-            print('Reason: %s' % e)
+        except AprsParseError as e:
+            print(e.message)
+            print("Substring: " % e.substring)
             return
 
         if beacon is not None:
diff --git a/ogn/model/beacon.py b/ogn/model/beacon.py
index 4d14955..511a383 100644
--- a/ogn/model/beacon.py
+++ b/ogn/model/beacon.py
@@ -4,12 +4,13 @@ from sqlalchemy import Column, String, Integer, Float, DateTime
 from sqlalchemy.ext.declarative import AbstractConcreteBase
 
 from ogn.aprs_utils import createTimestamp, dmsToDeg, kts2kmh, feet2m
+from ogn.exceptions import AprsParseError
 from .base import Base
 
 
 # "original" pattern from OGN: "(.+?)>APRS,.+,(.+?):/(\\d{6})+h(\\d{4}\\.\\d{2})(N|S).(\\d{5}\\.\\d{2})(E|W).((\\d{3})/(\\d{3}))?/A=(\\d{6}).*?"
 PATTERN_APRS = r"^(.+?)>APRS,.+,(.+?):/(\d{6})+h(\d{4}\.\d{2})(N|S)(.)(\d{5}\.\d{2})(E|W)(.)((\d{3})/(\d{3}))?/A=(\d{6})\s(.*)$"
-prog = re.compile(PATTERN_APRS)
+re_pattern_aprs = re.compile(PATTERN_APRS)
 
 
 class Beacon(AbstractConcreteBase, Base):
@@ -29,9 +30,9 @@ class Beacon(AbstractConcreteBase, Base):
     comment = None
 
     def parse(self, text, reference_time=None):
-        result = prog.match(text)
+        result = re_pattern_aprs.match(text)
         if result is None:
-            raise Exception("String is not valid" % text)
+            raise AprsParseError(substring=text, expected_type="Beacon")
 
         self.name = result.group(1)
         self.receiver_name = result.group(2)
@@ -52,11 +53,11 @@ class Beacon(AbstractConcreteBase, Base):
 
         if result.group(10) is not None:
             self.track = int(result.group(11))
-            self.ground_speed = int(result.group(12))*kts2kmh
+            self.ground_speed = int(result.group(12)) * kts2kmh
         else:
             self.track = 0
             self.ground_speed = 0
 
-        self.altitude = int(result.group(13))*feet2m
+        self.altitude = int(result.group(13)) * feet2m
 
         self.comment = result.group(14)