Explicit cast of the SQL representation of time-related objects.

Allow the objects to be recognized as the proper type by Postgres in not
strong contexts: problem reported by Peter Eisentraut.

Added tests to check the types are respected in a complete Py -> PG ->
Py roundtrip without context.

ChangeLog

@@ -2,6 +2,9 @@
 
 	* Added typecasters for arrays of specific MX/Py time-related types.
 
+	* psycopg/adapter_[mx]datetime.c: Explicit cast of the SQL representation
+	of time-related objects.
+
 2010-05-03  Daniele Varrazzo  <daniele.varrazzo@gmail.com>
 
 	* psycopg/adapter_binary.c: Adapt buffer objects using an explicit cast on

psycopg/adapter_datetime.c

@@ -57,10 +57,25 @@ static PyObject *
 pydatetime_str(pydatetimeObject *self)
 {
     if (self->type <= PSYCO_DATETIME_TIMESTAMP) {
+
+        /* Select the right PG type to cast into. */
+        char *fmt = NULL;
+        switch (self->type) {
+        case PSYCO_DATETIME_TIME:
+            fmt = "'%s'::time";
+            break;
+        case PSYCO_DATETIME_DATE:
+            fmt = "'%s'::date";
+            break;
+        case PSYCO_DATETIME_TIMESTAMP:
+            fmt = "'%s'::timestamp";
+            break;
+        }
+
         PyObject *res = NULL;
         PyObject *iso = PyObject_CallMethod(self->wrapped, "isoformat", NULL);
         if (iso) {
-            res = PyString_FromFormat("'%s'", PyString_AsString(iso));
+            res = PyString_FromFormat(fmt, PyString_AsString(iso));
             Py_DECREF(iso);
         }
         return res;
@@ -78,7 +93,7 @@ pydatetime_str(pydatetimeObject *self)
         }
         buffer[6] = '\0';
 
-        return PyString_FromFormat("'%d days %d.%s seconds'",
+        return PyString_FromFormat("'%d days %d.%s seconds'::interval",
                                    obj->days, obj->seconds, buffer);
     }
 }

psycopg/adapter_mxdatetime.c

@@ -56,10 +56,10 @@ mxdatetime_str(mxdatetimeObject *self)
     case PSYCO_MXDATETIME_DATE:
         dt = (mxDateTimeObject *)self->wrapped;
         if (dt->year >= 1)
-            PyOS_snprintf(buf, sizeof(buf) - 1, "'%04ld-%02d-%02d'",
+            PyOS_snprintf(buf, sizeof(buf) - 1, "'%04ld-%02d-%02d'::date",
                           dt->year, (int)dt->month, (int)dt->day);
         else
-            PyOS_snprintf(buf, sizeof(buf) - 1, "'%04ld-%02d-%02d BC'",
+            PyOS_snprintf(buf, sizeof(buf) - 1, "'%04ld-%02d-%02d BC'::date",
                           1 - dt->year, (int)dt->month, (int)dt->day);
         break;
 
@@ -67,12 +67,12 @@ mxdatetime_str(mxdatetimeObject *self)
         dt = (mxDateTimeObject *)self->wrapped;
         if (dt->year >= 1)
             PyOS_snprintf(buf, sizeof(buf) - 1,
-                          "'%04ld-%02d-%02dT%02d:%02d:%09.6f'",
+                          "'%04ld-%02d-%02dT%02d:%02d:%09.6f'::timestamp",
                           dt->year, (int)dt->month, (int)dt->day,
                           (int)dt->hour, (int)dt->minute, dt->second);
         else
             PyOS_snprintf(buf, sizeof(buf) - 1,
-                          "'%04ld-%02d-%02dT%02d:%02d:%09.6f BC'",
+                          "'%04ld-%02d-%02dT%02d:%02d:%09.6f BC'::timestamp",
                           1 - dt->year, (int)dt->month, (int)dt->day,
                           (int)dt->hour, (int)dt->minute, dt->second);
         break;
@@ -85,16 +85,16 @@ mxdatetime_str(mxdatetimeObject *self)
            time */
         dtd = (mxDateTimeDeltaObject *)self->wrapped;
         if (0 <= dtd->seconds && dtd->seconds < 24*3600) {
-            PyOS_snprintf(buf, sizeof(buf) - 1, "'%02d:%02d:%09.6f'",
+            PyOS_snprintf(buf, sizeof(buf) - 1, "'%02d:%02d:%09.6f'::time",
                           (int)dtd->hour, (int)dtd->minute, dtd->second);
         } else {
             double ss = dtd->hour*3600.0 + dtd->minute*60.0 + dtd->second;
 
             if (dtd->seconds >= 0)
-                PyOS_snprintf(buf, sizeof(buf) - 1, "'%ld days %.6f seconds'",
+                PyOS_snprintf(buf, sizeof(buf) - 1, "'%ld days %.6f seconds'::interval",
                               dtd->day, ss);
             else
-                PyOS_snprintf(buf, sizeof(buf) - 1, "'-%ld days -%.6f seconds'",
+                PyOS_snprintf(buf, sizeof(buf) - 1, "'-%ld days -%.6f seconds'::interval",
                               dtd->day, ss);
         }
         break;

tests/test_dates.py

@@ -247,6 +247,47 @@ class DatetimeTests(unittest.TestCase, CommonDatetimeTestsMixin):
         self.assertEqual(seconds, -3583504)
         self.assertEqual(int(round((value - seconds) * 1000000)), 123456)
 
+    def _test_type_roundtrip(self, o1):
+        o2 = self.execute("select %s;", (o1,))
+        self.assertEqual(type(o1), type(o2))
+
+    def _test_type_roundtrip_array(self, o1):
+        o1 = [o1]
+        o2 = self.execute("select %s;", (o1,))
+        self.assertEqual(type(o1[0]), type(o2[0]))
+
+    def test_type_roundtrip_date(self):
+        from datetime import date
+        self._test_type_roundtrip(date(2010,05,03))
+
+    def test_type_roundtrip_datetime(self):
+        from datetime import datetime
+        self._test_type_roundtrip(datetime(2010,05,03,10,20,30))
+
+    def test_type_roundtrip_time(self):
+        from datetime import time
+        self._test_type_roundtrip(time(10,20,30))
+
+    def test_type_roundtrip_interval(self):
+        from datetime import timedelta
+        self._test_type_roundtrip(timedelta(seconds=30))
+
+    def test_type_roundtrip_date_array(self):
+        from datetime import date
+        self._test_type_roundtrip_array(date(2010,05,03))
+
+    def test_type_roundtrip_datetime_array(self):
+        from datetime import datetime
+        self._test_type_roundtrip_array(datetime(2010,05,03,10,20,30))
+
+    def test_type_roundtrip_time_array(self):
+        from datetime import time
+        self._test_type_roundtrip_array(time(10,20,30))
+
+    def test_type_roundtrip_interval_array(self):
+        from datetime import timedelta
+        self._test_type_roundtrip_array(timedelta(seconds=30))
+
 
 # Only run the datetime tests if psycopg was compiled with support.
 if not hasattr(psycopg2._psycopg, 'PYDATETIME'):
@@ -264,6 +305,15 @@ class mxDateTimeTests(unittest.TestCase, CommonDatetimeTestsMixin):
         self.DATETIME = psycopg2._psycopg.MXDATETIME
         self.INTERVAL = psycopg2._psycopg.MXINTERVAL
 
+        psycopg2.extensions.register_type(self.DATE, self.conn)
+        psycopg2.extensions.register_type(self.TIME, self.conn)
+        psycopg2.extensions.register_type(self.DATETIME, self.conn)
+        psycopg2.extensions.register_type(self.INTERVAL, self.conn)
+        psycopg2.extensions.register_type(psycopg2.extensions.MXDATEARRAY, self.conn)
+        psycopg2.extensions.register_type(psycopg2.extensions.MXTIMEARRAY, self.conn)
+        psycopg2.extensions.register_type(psycopg2.extensions.MXDATETIMEARRAY, self.conn)
+        psycopg2.extensions.register_type(psycopg2.extensions.MXINTERVALARRAY, self.conn)
+
     def tearDown(self):
         self.conn.close()
 
@@ -370,6 +420,47 @@ class mxDateTimeTests(unittest.TestCase, CommonDatetimeTestsMixin):
         self.assertEqual(seconds, -3583504)
         self.assertEqual(int(round((value - seconds) * 1000000)), 123456)
 
+    def _test_type_roundtrip(self, o1):
+        o2 = self.execute("select %s;", (o1,))
+        self.assertEqual(type(o1), type(o2))
+
+    def _test_type_roundtrip_array(self, o1):
+        o1 = [o1]
+        o2 = self.execute("select %s;", (o1,))
+        self.assertEqual(type(o1[0]), type(o2[0]))
+
+    def test_type_roundtrip_date(self):
+        from mx.DateTime import Date
+        self._test_type_roundtrip(Date(2010,05,03))
+
+    def test_type_roundtrip_datetime(self):
+        from mx.DateTime import DateTime
+        self._test_type_roundtrip(DateTime(2010,05,03,10,20,30))
+
+    def test_type_roundtrip_time(self):
+        from mx.DateTime import Time
+        self._test_type_roundtrip(Time(10,20,30))
+
+    def test_type_roundtrip_interval(self):
+        from mx.DateTime import DateTimeDeltaFrom
+        self._test_type_roundtrip(DateTimeDeltaFrom(seconds=30))
+
+    def test_type_roundtrip_date_array(self):
+        from mx.DateTime import Date
+        self._test_type_roundtrip_array(Date(2010,05,03))
+
+    def test_type_roundtrip_datetime_array(self):
+        from mx.DateTime import DateTime
+        self._test_type_roundtrip_array(DateTime(2010,05,03,10,20,30))
+
+    def test_type_roundtrip_time_array(self):
+        from mx.DateTime import Time
+        self._test_type_roundtrip_array(Time(10,20,30))
+
+    def test_type_roundtrip_interval_array(self):
+        from mx.DateTime import DateTimeDeltaFrom
+        self._test_type_roundtrip_array(DateTimeDeltaFrom(seconds=30))
+
 
 # Only run the mx.DateTime tests if psycopg was compiled with support.
 if not hasattr(psycopg2._psycopg, 'MXDATETIME'):