Fixes #50 - materialize the properties for completion (#52)

* Fixes #50 - materialize the properties for completion

This also fixes a bug where captions and aliases weren't being populated
into the multidict correctly due to insufficient testing on my part
originally

* fixing example to be correct

* really fix it this time

* Add docstrings for is_* properties

* Cleaner version of get for mld

* Move to is not instead of standard equality and fixed py3

Author: Russell Hay

Examples/GetFields/show_fields.py

@@ -20,8 +20,8 @@
     if field.calculation:
         print('      the formula is {}'.format(field.calculation))
         blank_line = True
-    if field.aggregation:
-        print('      the default aggregation is {}'.format(field.aggregation))
+    if field.default_aggregation:
+        print('      the default aggregation is {}'.format(field.default_aggregation))
         blank_line = True
 
     if blank_line:

tableaudocumentapi/field.py

@@ -41,12 +41,6 @@ def apply_metadata(self, metadata_record):
     def from_xml(cls, xmldata):
         return cls(xmldata)
 
-    def __getattr__(self, item):
-        private_name = '_{}'.format(item)
-        if item in _ATTRIBUTES or item in _METADATA_ATTRIBUTES:
-            return getattr(self, private_name)
-        raise AttributeError(item)
-
     def _apply_attribute(self, xmldata, attrib, default_func):
         if hasattr(self, '_read_{}'.format(attrib)):
             value = getattr(self, '_read_{}'.format(attrib))(xmldata)
@@ -71,6 +65,62 @@ def name(self):
 
         return self.id
 
+    @property
+    def id(self):
+        """ Name of the field as specified in the file, usually surrounded by [ ] """
+        return self._id
+
+    @property
+    def caption(self):
+        """ Name of the field as displayed in Tableau unless an aliases is defined """
+        return self._caption
+
+    @property
+    def alias(self):
+        """ Name of the field as displayed in Tableau if the default name isn't wanted """
+        return self._alias
+
+    @property
+    def datatype(self):
+        """ Type of the field within Tableau (string, integer, etc) """
+        return self._datatype
+
+    @property
+    def role(self):
+        """ Dimension or Measure """
+        return self._role
+
+    @property
+    def is_quantitative(self):
+        """ A dependent value, usually a measure of something
+
+        e.g. Profit, Gross Sales """
+        return self._type == 'quantitative'
+
+    @property
+    def is_ordinal(self):
+        """ Is this field a categorical field that has a specific order
+
+        e.g. How do you feel? 1 - awful, 2 - ok, 3 - fantastic """
+        return self._type == 'ordinal'
+
+    @property
+    def is_nominal(self):
+        """ Is this field a categorical field that does not have a specific order
+
+        e.g. What color is your hair? """
+        return self._type == 'nominal'
+
+    @property
+    def calculation(self):
+        """ If this field is a calculated field, this will be the formula """
+        return self._calculation
+
+    @property
+    def default_aggregation(self):
+        """ The default type of aggregation on the field (e.g Sum, Avg)"""
+        return self._aggregation
+
     ######################################
     # Special Case handling methods for reading the values from the XML
     ######################################

tableaudocumentapi/multilookup_dict.py

@@ -1,11 +1,17 @@
 import weakref
 
 
+_no_default_value = object()
+
+
 def _resolve_value(key, value):
+    retval = None
     try:
-        retval = value.get(key, None)
+        if hasattr(value, 'get'):
+            retval = value.get(key, None)
+
         if retval is None:
-            retval = value.getattr(key, None)
+            retval = getattr(value, key, None)
     except AttributeError:
         retval = None
     return retval
@@ -43,6 +49,14 @@ def __setitem__(self, key, value):
 
         dict.__setitem__(self, key, value)
 
+    def get(self, key, default_value=_no_default_value):
+        try:
+            return self[key]
+        except KeyError:
+            if default_value is not _no_default_value:
+                return default_value
+            raise
+
     def __getitem__(self, key):
         if key in self._indexes['alias']:
             key = self._indexes['alias'][key]

test/assets/datasource_test.tds

@@ -77,7 +77,7 @@
   </column>
   <column caption='A' datatype='string' name='[a]' role='dimension' type='nominal' />
   <column caption='Today&apos;s Date' datatype='string' name='[Today&apos;s Date]' role='dimension' type='nominal' />
-  <column caption='X' datatype='integer' name='[x]' role='measure' type='quantitative' />
+  <column caption='X' datatype='integer' name='[x]' role='measure' type='ordinal' />
   <column caption='Y' datatype='integer' name='[y]' role='measure' type='quantitative' />
   <layout dim-ordering='alphabetic' dim-percentage='0.5' measure-ordering='alphabetic' measure-percentage='0.5' show-structure='true' />
   <semantic-values>

test/test_datasource.py

@@ -1,6 +1,5 @@
 import unittest
 import os.path
-import functools
 
 from tableaudocumentapi import Datasource
 
@@ -23,7 +22,23 @@ def test_datasource_returns_calculation_from_fields(self):
         self.assertEqual('1', self.ds.fields['[Number of Records]'].calculation)
 
     def test_datasource_uses_metadata_record(self):
-        self.assertEqual('Sum', self.ds.fields['[x]'].aggregation)
+        self.assertEqual('Sum', self.ds.fields['[x]'].default_aggregation)
 
     def test_datasource_column_name_contains_apostrophy(self):
         self.assertIsNotNone(self.ds.fields.get("[Today's Date]", None))
+
+    def test_datasource_field_can_get_caption(self):
+        self.assertEqual(self.ds.fields['[a]'].caption, 'A')
+        self.assertEqual(getattr(self.ds.fields['[a]'], 'caption', None), 'A')
+
+    def test_datasource_field_caption_can_be_used_to_query(self):
+        self.assertIsNotNone(self.ds.fields.get('A', None))
+
+    def test_datasource_field_is_nominal(self):
+        self.assertTrue(self.ds.fields['[a]'].is_nominal)
+
+    def test_datasource_field_is_quantitative(self):
+        self.assertTrue(self.ds.fields['[y]'].is_quantitative)
+
+    def test_datasource_field_is_ordinal(self):
+        self.assertTrue(self.ds.fields['[x]'].is_ordinal)

test/test_multidict.py

@@ -45,3 +45,19 @@ def test_mutlilookupdict_can_still_find_caption_even_with_alias(self):
     def test_mutlilookupdict_can_still_find_id_even_with_caption(self):
         actual = self.mld['[bar]']
         self.assertEqual(2, actual['value'])
+
+    def test_multilookupdict_gives_key_error_on_invalid_key(self):
+        try:
+            self.mld.get('foobar')
+            self.fail('should have thrown key error')
+        except KeyError as ex:
+            self.assertEqual(str(ex), "'foobar'")
+
+    def test_multilookupdict_get_returns_default_value(self):
+        default_value = ('default', 'return', 'value')
+        actual = self.mld.get('foobar', default_value)
+        self.assertEqual(actual, default_value)
+
+    def test_multilookupdict_get_returns_value(self):
+        actual = self.mld.get('baz')
+        self.assertEqual(1, actual['value'])