Add boundary check for SubArrayElement function

- Fixes Issue 34

check_http_json.py

@@ -108,6 +108,7 @@ class JsonHelper:
         index = int(key[key.find(self.arrayOpener) +
                         1:key.find(self.arrayCloser)])
         remainingKey = key[key.find(self.arrayCloser + self.separator) + 2:]
+
         if key.find(self.arrayCloser + self.separator) == -1:
             remainingKey = key[key.find(self.arrayCloser) + 1:]
         if subElemKey in data:
@@ -115,6 +116,8 @@ class JsonHelper:
                 return self.get(remainingKey, data[subElemKey][index])
             else:
                 return (None, 'not_found')
+        if index >= len(data):
+                return (None, 'not_found')
         else:
             if not subElemKey:
                 return self.get(remainingKey, data[index])

test/test_check_http_json.py

@@ -220,3 +220,26 @@ class UtilTest(unittest.TestCase):
             { "gauges": { "jvm.buffers.direct.capacity": [
             {"value": 215415},{"value": 1235}]}}]''',
             WARNING_CODE)
+
+    def test_array_with_missing_element(self):
+        """
+        See https://github.com/drewkerrigan/nagios-http-json/issues/34
+        """
+        rules = RulesHelper()
+
+        # This should simply work
+        data = '[{"Node": "there"}]'
+        self.check_data(rules.dash_q(['(0).Node,there']), data, OK_CODE)
+
+        # This should warn us
+        data = '[{"Node": "othervalue"}]'
+        self.check_data(rules.dash_q(['(0).Node,there']), data, WARNING_CODE)
+
+        # # This should not throw an IndexError
+        data = '[{"Node": "foobar"}]'
+        self.check_data(rules.dash_q(['(0).Node,foobar', '(1).Node,missing']), data, WARNING_CODE)
+        self.check_data(rules.dash_q(['(0).Node,foobar', '(1).Node,missing', '(2).Node,alsomissing']), data, WARNING_CODE)
+
+        # This should not throw a KeyError
+        data = '{}'
+        self.check_data(rules.dash_q(['(0).Node,foobar', '(1).Node,missing']), data, WARNING_CODE)