Iss pass error handling

app.py

@@ -74,39 +74,40 @@ def tle_info():
 @jsonp
 @json
 def iss_pass():
-
-    # Sanitize inputs
-    lat = request.args.get('lat', False)
-    if lat:
-        lat = safe_float(lat, (-90.0, 90.0))
-        if not lat:
-            return {"message": "failure", "reason": "Latitude must be number between -90.0 and 90.0"}, 400
-    else:
-        return {"message": "failure", "reason": "Latitude must be specified"}, 400
-
-    lon = request.args.get('lon', False)
-    if lon:
-        lon = safe_float(lon, (-180.0, 180.0))
-        if not lon:
-            return {"message": "failure", "reason": "Longitue must be number between -180.0 and 180.0"}, 400
-    else:
-        return {"message": "failure", "reason": "Longitude must be specified"}, 400
-
-    alt = request.args.get('alt', False)
-    if alt:
-        alt = safe_float(alt, (0, 10000))
-        if not alt:
-            return {"message": "failure", "reason": "Altitude must be number between 0 and 10,000"}, 400
-    else:
-        alt = 100
-
-    n = request.args.get('n', False)
-    if n:
-        n = safe_float(n, (1, 100))
-        if not n:
-            return {"message": "failure", "reason": "Number of passes must be number between 1 and 100"}, 400
-    else:
-        n = 5
+    try:
+        # Sanitize inputs
+        lat = request.args.get('lat', False)
+        if lat:
+            lat = safe_float(lat, (-90.0, 90.0))
+            if not lat:
+                raise ValueError("Latitude must be number between -90.0 and 90.0")
+        else:
+            raise ValueError("Latitude must be specified.")
+        lon = request.args.get('lon', False)
+        if lon:
+            lon = safe_float(lon, (-180.0, 180.0))
+            if not lon:
+                ValueError("Longitude must be number between -180.0 and 180.0")
+        else:
+            raise ValueError("Longitude must be specified.")
+        alt = request.args.get('alt', False)
+        if alt:
+            alt = safe_float(alt, (0, 10000))
+            if not alt:
+                raise ValueError("Altitude must be number between 0 and 10,000")
+        else:
+            alt = 100
+
+        n = request.args.get('n', False)
+        if n:
+            n = safe_float(n, (1, 100))
+            if not n:
+                raise ValueError("Number of passes must be number between 1 and 100")
+        else:
+            n = 5
+    except ValueError as e:
+        error_response = {"message": "failure", "reason": e.message, "request": request.args}
+        return error_response, 400
 
     # Calculate data and return
     d = iss.get_passes(lon, lat, alt, int(n))

iss.py

@@ -43,30 +43,29 @@ def get_tle_update():
 
 
 def get_passes(lon, lat, alt, n):
-    """Compute n number of passes of the ISS for a location"""
-
+    """Compute up to n number of passes of the ISS for a location"""
     # Get latest TLE from redis
     tle = json.loads(r.get("iss_tle"))
     iss = ephem.readtle(str(tle[0]), str(tle[1]), str(tle[2]))
-
     # Set location
     location = ephem.Observer()
     location.lat = str(lat)
     location.long = str(lon)
     location.elevation = alt
-
     # Override refration calculation
     location.pressure = 0
     location.horizon = '10:00'
-
     # Set time now
     now = datetime.datetime.utcnow()
     location.date = now
-
     # Predict passes
     passes = []
     for p in xrange(n):
-        tr, azr, tt, altt, ts, azs = location.next_pass(iss)
+        try:
+            tr, azr, tt, altt, ts, azs = location.next_pass(iss)
+        except ValueError as e:
+            # next_pass returns "that satellite seems to stay always below your horizon"
+            break
         duration = int((ts - tr) * 60 * 60 * 24)
         year, month, day, hour, minute, second = tr.tuple()
         dt = datetime.datetime(year, month, day, hour, minute, int(second))
@@ -76,7 +75,6 @@ def get_passes(lon, lat, alt, n):
 
         # Increase the time by more than a pass and less than an orbit
         location.date = tr + 25*ephem.minute
-
     # Return object
     obj = {"request": {
         "datetime": timegm(now.timetuple()),
@@ -87,5 +85,4 @@ def get_passes(lon, lat, alt, n):
         },
         "response": passes,
     }
-
     return obj

testsuite/api.py

@@ -3,6 +3,35 @@
 import json
 from app import app
 
+class IssPassTest(TestCase):
+    """Test ISS-pass API"""
+    def setUp(self):
+        self.app = app
+        self.w = TestApp(self.app)
+        self.endpoint = '/iss-pass.json'
+
+    def format_uri(self, lat, lon):
+        return self.endpoint + '?lat={0}&lon={1}'.format(lat, lon) 
+
+    def test_berkeley(self):
+        berkeley = self.format_uri(37.8715926, -122.27274699999998)
+        r = self.w.get(berkeley)
+        r.charset = 'utf8'
+        data = json.loads(r.text)
+        self.assertEqual(r.status_code, 200)
+
+    def test_no_passes_found(self):
+        mcmurdo_station = self.format_uri(-77.8418779, 166.6863449)
+        r = self.w.get(mcmurdo_station)
+        self.assertEqual(r.status_code, 200)
+        data = r.json
+        self.assertEqual(len(data['response']), 0)
+
+    def test_bad_lat(self):
+        bad_lat = self.format_uri(-91, 50)
+        r = self.w.get(bad_lat, expect_errors=True)
+        self.assertEqual(r.status_code, 400)
+
 
 class IssNowTest(TestCase):
     """Test the ISS-now API"""
@@ -26,7 +55,7 @@ def test_data(self):
         try:
             data = json.loads(r.text)
         except:
-            self.fail("ISS API not a valid JSON responce")
+            self.fail("ISS API not a valid JSON response")
 
         # Success message
         self.assertEqual(data['message'], "success", "ISS API Did not return 'sucess' message")