Added support for arrays of hstores

NEWS

@@ -3,6 +3,7 @@ What's new in psycopg 2.4.3
 
   - Added 'new_array_type()' function for easy creation of array
     typecasters.
+  - Added support for arrays of hstores (ticket #66).
   - Fixed segfault in case of transaction started with connection lost
     (and possibly other events).
   - Rollback connections in transaction or in error before putting them

lib/extras.py

@@ -699,7 +699,8 @@ WHERE typname = 'hstore';
 
         return tuple(rv0), tuple(rv1)
 
-def register_hstore(conn_or_curs, globally=False, unicode=False, oid=None):
+def register_hstore(conn_or_curs, globally=False, unicode=False,
+        oid=None, array_oid=None):
     """Register adapter and typecaster for `!dict`\-\ |hstore| conversions.
 
     :param conn_or_curs: a connection or cursor: the typecaster will be
@@ -709,14 +710,18 @@ def register_hstore(conn_or_curs, globally=False, unicode=False, oid=None):
         will be `!unicode` instead of `!str`. The option is not available on
         Python 3
     :param oid: the OID of the |hstore| type if known. If not, it will be
-        queried on *conn_or_curs*
+        queried on *conn_or_curs*.
+    :param array_oid: the OID of the |hstore| array type if known. If not, it
+        will be queried on *conn_or_curs*.
 
     The connection or cursor passed to the function will be used to query the
     database and look for the OID of the |hstore| type (which may be different
     across databases). If querying is not desirable (e.g. with
     :ref:`asynchronous connections <async-support>`) you may specify it in the
-    *oid* parameter (it can be found using a query such as :sql:`SELECT
+    *oid* parameter, which can be found using a query such as :sql:`SELECT
-    'hstore'::regtype::oid;`).
+    'hstore'::regtype::oid`. Analogously you can obtain a value for *array_oid*
+    using a query such as :sql:`SELECT 'hstore[]'::regtype::oid`.
+
 
     Note that, when passing a dictionary from Python to the database, both
     strings and unicode keys and values are supported. Dictionaries returned
@@ -730,6 +735,10 @@ def register_hstore(conn_or_curs, globally=False, unicode=False, oid=None):
         added the *oid* parameter. If not specified, the typecaster is
         installed also if |hstore| is not installed in the :sql:`public`
         schema.
+
+    .. versionchanged:: 2.4.3
+        added support for |hstore| array.
+
     """
     if oid is None:
         oid = HstoreAdapter.get_oids(conn_or_curs)
@@ -738,11 +747,18 @@ def register_hstore(conn_or_curs, globally=False, unicode=False, oid=None):
                 "hstore type not found in the database. "
                 "please install it from your 'contrib/hstore.sql' file")
         else:
-            oid = oid[0]  # for the moment we don't have a HSTOREARRAY
+            array_oid = oid[1]
+            oid = oid[0]
 
     if isinstance(oid, int):
         oid = (oid,)
 
+    if array_oid is not None:
+        if isinstance(array_oid, int):
+            array_oid = (array_oid,)
+        else:
+            array_oid = tuple([x for x in array_oid if x])
+
     # create and register the typecaster
     if sys.version_info[0] < 3 and unicode:
         cast = HstoreAdapter.parse_unicode
@@ -753,6 +769,10 @@ def register_hstore(conn_or_curs, globally=False, unicode=False, oid=None):
     _ext.register_type(HSTORE, not globally and conn_or_curs or None)
     _ext.register_adapter(dict, HstoreAdapter)
 
+    if array_oid:
+        HSTOREARRAY = _ext.new_array_type(array_oid, "HSTOREARRAY", HSTORE)
+        _ext.register_type(HSTOREARRAY, not globally and conn_or_curs or None)
+
 
 class CompositeCaster(object):
     """Helps conversion of a PostgreSQL composite type into a Python object.

tests/types_extras.py

@@ -22,7 +22,7 @@ import re
 import sys
 from datetime import date
 
-from testutils import unittest, skip_if_no_uuid
+from testutils import unittest, skip_if_no_uuid, skip_before_postgres
 
 import psycopg2
 import psycopg2.extras
@@ -357,6 +357,63 @@ class HstoreTestCase(unittest.TestCase):
         finally:
             psycopg2.extensions.string_types.pop(oid)
 
+    @skip_if_no_hstore
+    @skip_before_postgres(8, 3)
+    def test_roundtrip_array(self):
+        from psycopg2.extras import register_hstore
+        register_hstore(self.conn)
+
+        ds = []
+        ds.append({})
+        ds.append({'a': 'b', 'c': None})
+
+        ab = map(chr, range(32, 128))
+        ds.append(dict(zip(ab, ab)))
+        ds.append({''.join(ab): ''.join(ab)})
+
+        self.conn.set_client_encoding('latin1')
+        if sys.version_info[0] < 3:
+            ab = map(chr, range(32, 127) + range(160, 255))
+        else:
+            ab = bytes(range(32, 127) + range(160, 255)).decode('latin1')
+
+        ds.append({''.join(ab): ''.join(ab)})
+        ds.append(dict(zip(ab, ab)))
+
+        cur = self.conn.cursor()
+        cur.execute("select %s", (ds,))
+        ds1 = cur.fetchone()[0]
+        self.assertEqual(ds, ds1)
+
+    @skip_if_no_hstore
+    @skip_before_postgres(8, 3)
+    def test_array_cast(self):
+        from psycopg2.extras import register_hstore
+        register_hstore(self.conn)
+        cur = self.conn.cursor()
+        cur.execute("select array['a=>1'::hstore, 'b=>2'::hstore];")
+        a = cur.fetchone()[0]
+        self.assertEqual(a, [{'a': '1'}, {'b': '2'}])
+
+    @skip_if_no_hstore
+    def test_array_cast_oid(self):
+        cur = self.conn.cursor()
+        cur.execute("select 'hstore'::regtype::oid, 'hstore[]'::regtype::oid")
+        oid, aoid = cur.fetchone()
+
+        from psycopg2.extras import register_hstore
+        register_hstore(None, globally=True, oid=oid, array_oid=aoid)
+        try:
+            cur.execute("select null::hstore, ''::hstore, 'a => b'::hstore, '{a=>b}'::hstore[]")
+            t = cur.fetchone()
+            self.assert_(t[0] is None)
+            self.assertEqual(t[1], {})
+            self.assertEqual(t[2], {'a': 'b'})
+            self.assertEqual(t[3], [{'a': 'b'}])
+
+        finally:
+            psycopg2.extensions.string_types.pop(oid)
+            psycopg2.extensions.string_types.pop(aoid)
 
 def skip_if_no_composite(f):
     def skip_if_no_composite_(self):