Convert fields names into valid Python identifiers in NamedTupleCursor

Close #211.

NEWS

@@ -7,6 +7,8 @@ What's new in psycopg 2.7.4
 - Moving away from installing the wheel package by default.
   Packages installed from wheel raise a warning on import. Added package
   ``psycopg2-binary`` to install from wheel instead (:ticket:`#543`).
+- Convert fields names into valid Python identifiers in
+  `~psycopg2.extras.NamedTupleCursor` (:ticket:`#211`).
 - Fixed Solaris 10 support (:ticket:`#532`).
 - `cursor.mogrify()` can be called on closed cursors (:ticket:`#579`).
 - Fixed setting session characteristics in corner cases on autocommit

lib/extras.py

@@ -368,7 +368,18 @@ class NamedTupleCursor(_cursor):
             raise self._exc
     else:
         def _make_nt(self, namedtuple=namedtuple):
-            return namedtuple("Record", [d[0] for d in self.description or ()])
+            def f(s):
+                # NOTE: Python 3 actually allows unicode chars in fields
+                s = _re.sub('[^a-zA-Z0-9_]', '_', s)
+                # Python identifier cannot start with numbers, namedtuple fields
+                # cannot start with underscore. So...
+                if _re.match('^[0-9_]', s):
+                    s = 'f' + s
+
+                return s
+
+            return namedtuple(
+                "Record", [f(d[0]) for d in self.description or ()])
 
 
 class LoggingConnection(_connection):

tests/test_extras_dictcursor.py

@@ -382,6 +382,15 @@ class NamedTupleCursorTest(ConnectingTestCase):
         curs.execute("update nttest set s = s")
         self.assertRaises(psycopg2.ProgrammingError, curs.fetchall)
 
+    @skip_if_no_namedtuple
+    def test_bad_col_names(self):
+        curs = self.conn.cursor()
+        curs.execute('select 1 as "foo.bar_baz", 2 as "?column?", 3 as "3"')
+        rv = curs.fetchone()
+        self.assertEqual(rv.foo_bar_baz, 1)
+        self.assertEqual(rv.f_column_, 2)
+        self.assertEqual(rv.f3, 3)
+
     @skip_if_no_namedtuple
     def test_minimal_generation(self):
         # Instrument the class to verify it gets called the minimum number of times.