Add FAA airport status driver

python/conf/faa.ini

@@ -0,0 +1,18 @@
+# The driver expects an IATA code to specify the desired airport
+
+[/]
+type = Collection
+uuid = 60e424b7-e258-436f-bb00-83daf50db781
+
+[/airportstatus]
+type = Collection
+uuid = b4d015bb-f6d5-4e79-936a-0512d1fc64bb
+Metadata/SourceName = FAA Airport Service
+
+[/airportstatus/SFO]
+type = smap.drivers.faa.FAADriver
+iata = SFO
+
+[/airportstatus/MSP]
+type = smap.drivers.faa.FAADriver
+iata = MSP

python/smap/drivers/faa.py

@@ -0,0 +1,111 @@
+import time
+import urllib
+from xml.etree import ElementTree
+
+FAA_URL = ('http://services.faa.gov/airport/status/{}'
+           + '?format=application/xml')
+DELAY_TYPES = {
+    'Ground Delay': '/delay/ground'
+}
+DIR_TO_ANG = {
+    'North': 0,
+    'Northeast': 45,
+    'East': 90,
+    'Southeast': 135,
+    'South': 180,
+    'Southwest': 225,
+    'West': 270,
+    'Northwest': 315,
+}
+
+from smap import driver, util
+
+class FAADriver(driver.SmapDriver):
+    def setup(self, opts):
+        self.add_timeseries('/weather/temp', 'F', data_type='double')
+        self.add_timeseries('/weather/visibility', 'miles',
+                            data_type='double')
+        self.add_timeseries('/weather/wind/speed', 'mph',
+                            data_type='double')
+        self.add_timeseries('/weather/wind/direction', 'degrees')
+
+        self.add_timeseries('/delay/ground', 'minutes')
+
+        # International Association of Travel Agents Airport Code
+        self.iata = opts.get('iata')
+
+    def start(self):
+        util.periodicSequentialCall(self.read).start(60)
+
+    def read(self):
+        try:
+            xmlstr = urllib.urlopen(FAA_URL.format(self.iata)).read()
+            root = ElementTree.fromstring(xmlstr)
+        except:
+            print('FAA sMAP Driver error: Unexpected response! '
+                  + 'Could not parse XML.')
+            return
+
+        def nav(tree, *args):
+            for arg in args:
+                tree = tree.find(arg)
+                if tree is None:
+                    return None
+            return tree
+
+        # Warn if expected keys are missing
+        for key in [('Weather', 'Temp'),
+                    ('Weather', 'Visibility'),
+                    ('Weather', 'Wind'),
+                    ('Status', 'Type'),
+                    ('Status', 'AvgDelay')]:
+            if nav(root, *key) is None:
+                print('Warning: Expected key "{}" was not found!'
+                      .format(key))
+
+        # Temperature
+        if nav(root, 'Weather', 'Temp') is not None:
+            self.add('/weather/temp',
+                     float(nav(root, 'Weather', 'Temp').text
+                                                       .split()[0]))
+
+        # Visibility
+        if nav(root, 'Weather', 'Visibility') is not None:
+            self.add('/weather/visibility',
+                     float(nav(root, 'Weather', 'Visibility').text))
+
+        # Wind direction and speed
+        if nav(root, 'Weather', 'Wind') is not None:
+            direction, speed = self._parse_wind(
+                nav(root, 'Weather', 'Wind').text)
+            self.add('/weather/wind/speed', speed)
+            self.add('/weather/wind/direction', direction)
+
+        if ((nav(root, 'Status', 'Type') is not None) and
+            (nav(root, 'Status', 'AvgDelay') is not None)):
+
+            # Delay for current delay type
+            this_delay_type = nav(root, 'Status', 'Type').text
+            if this_delay_type == 'Ground Delay':
+                delaystr = nav(root, 'Status', 'AvgDelay').text
+                self.add('/delay/ground', self._parse_avgdelay(delaystr))
+
+            # All other delay types have value 0
+            for delay_type in DELAY_TYPES:
+                if delay_type != this_delay_type:
+                    self.add(DELAY_TYPES[delay_type], 0)
+
+    def _parse_wind(self, windstr):
+        s = windstr.split()
+        direction = DIR_TO_ANG[s[0]]
+        speed = float(s[2][:-3])  # remove the 'mph'
+        return direction, speed
+
+    def _parse_avgdelay(self, delaystr):
+        if not delaystr:
+            return 0
+        s = delaystr.split()
+        if len(s) == 5:
+            return int(s[0])*60 + int(s[3])
+        else:
+            return int(s[0])