Added ConnectionInfo.parameter_status()

4 files changed, 97 insertions, 39 deletions

diff --git a/doc/src/connection.rst b/doc/src/connection.rst
index 9c88b77..5310458 100644
--- a/doc/src/connection.rst
+++ b/doc/src/connection.rst
@@ -614,45 +614,6 @@ The ``connection`` class
 
 
     .. index::
-        pair: Backend; PID
-
-    .. method:: get_backend_pid()
-
-        Returns the process ID (PID) of the backend server process handling
-        this connection.
-
-        Note that the PID belongs to a process executing on the database
-        server host, not the local host!
-
-        .. seealso:: libpq docs for `PQbackendPID()`__ for details.
-
-            .. __: https://www.postgresql.org/docs/current/static/libpq-status.html#LIBPQ-PQBACKENDPID
-
-        .. versionadded:: 2.0.8
-
-
-    .. index::
-        pair: Server; Parameters
-
-    .. method:: get_parameter_status(parameter)
-
-        Look up a current parameter setting of the server.
-
-        Potential values for ``parameter`` are: ``server_version``,
-        ``server_encoding``, ``client_encoding``, ``is_superuser``,
-        ``session_authorization``, ``DateStyle``, ``TimeZone``,
-        ``integer_datetimes``, and ``standard_conforming_strings``.
-
-        If server did not report requested parameter, return `!None`.
-
-        .. seealso:: libpq docs for `PQparameterStatus()`__ for details.
-
-            .. __: https://www.postgresql.org/docs/current/static/libpq-status.html#LIBPQ-PQPARAMETERSTATUS
-
-        .. versionadded:: 2.0.12
-
-
-    .. index::
         pair: Connection; Parameters
 
     .. method:: get_dsn_parameters()
@@ -847,6 +808,51 @@ The ``connection`` class
         .. versionadded:: 2.0.12
 
 
+    .. index::
+        pair: Backend; PID
+
+    .. method:: get_backend_pid()
+
+        Also available as `~connection.info`\ `!.`\
+        `~psycopg2.extensions.ConnectionInfo.backend_pid`.
+
+        Returns the process ID (PID) of the backend server process handling
+        this connection.
+
+        Note that the PID belongs to a process executing on the database
+        server host, not the local host!
+
+        .. seealso:: libpq docs for `PQbackendPID()`__ for details.
+
+            .. __: https://www.postgresql.org/docs/current/static/libpq-status.html#LIBPQ-PQBACKENDPID
+
+        .. versionadded:: 2.0.8
+
+
+    .. index::
+        pair: Server; Parameters
+
+    .. method:: get_parameter_status(parameter)
+
+        Also available as `~connection.info`\ `!.`\
+        `~psycopg2.extensions.ConnectionInfo.parameter_status()`.
+
+        Look up a current parameter setting of the server.
+
+        Potential values for ``parameter`` are: ``server_version``,
+        ``server_encoding``, ``client_encoding``, ``is_superuser``,
+        ``session_authorization``, ``DateStyle``, ``TimeZone``,
+        ``integer_datetimes``, and ``standard_conforming_strings``.
+
+        If server did not report requested parameter, return `!None`.
+
+        .. seealso:: libpq docs for `PQparameterStatus()`__ for details.
+
+            .. __: https://www.postgresql.org/docs/current/static/libpq-status.html#LIBPQ-PQPARAMETERSTATUS
+
+        .. versionadded:: 2.0.12
+
+
 .. testcode::
     :hide:
 
diff --git a/doc/src/extensions.rst b/doc/src/extensions.rst
index 0293740..10ed81a 100644
--- a/doc/src/extensions.rst
+++ b/doc/src/extensions.rst
@@ -167,6 +167,7 @@ introspection etc.
     .. autoattribute:: options
     .. autoattribute:: status
     .. autoattribute:: transaction_status
+    .. automethod:: parameter_status(name)
 
     .. autoattribute:: protocol_version
 
diff --git a/psycopg/conninfo_type.c b/psycopg/conninfo_type.c
index c7a2111..ed89c6c 100644
--- a/psycopg/conninfo_type.c
+++ b/psycopg/conninfo_type.c
@@ -208,6 +208,40 @@ transaction_status_get(connInfoObject *self)
 }
 
 
+static const char parameter_status_doc[] =
+"Looks up a current parameter setting of the server.\n"
+"\n"
+":param name: The name of the parameter to return.\n"
+":type name: `!str`\n"
+":return: The parameter value, `!None` if the parameter is unknown.\n"
+":rtype: `!str`\n"
+"\n"
+".. seealso:: libpq docs for `PQparameterStatus()`__ for details.\n"
+".. __: https://www.postgresql.org/docs/current/static/libpq-status.html"
+    "#LIBPQ-PQPARAMETERSTATUS";
+
+static PyObject *
+parameter_status(connInfoObject *self, PyObject *args, PyObject *kwargs)
+{
+    static char *kwlist[] = {"name", NULL};
+    const char *name;
+    const char *val;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s", kwlist, &name)) {
+        return NULL;
+    }
+
+    val = PQparameterStatus(self->conn->pgconn, name);
+
+    if (!val) {
+        Py_RETURN_NONE;
+    }
+    else {
+        return conn_text_from_chars(self->conn, val);
+    }
+}
+
+
 static const char protocol_version_doc[] =
 "The frontend/backend protocol being used.\n"
 "\n"
@@ -468,6 +502,8 @@ static struct PyGetSetDef connInfoObject_getsets[] = {
 static struct PyMethodDef connInfoObject_methods[] = {
     {"ssl_attribute", (PyCFunction)ssl_attribute,
      METH_VARARGS|METH_KEYWORDS, ssl_attribute_doc},
+    {"parameter_status", (PyCFunction)parameter_status,
+     METH_VARARGS|METH_KEYWORDS, parameter_status_doc},
     {NULL}
 };
 
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 0c8d40d..0b68389 100755
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -1736,6 +1736,21 @@ class TestConnectionInfo(ConnectingTestCase):
         self.assertEqual(self.conn.info.transaction_status, 2)
         self.assertEqual(self.bconn.info.transaction_status, 4)
 
+    def test_parameter_status(self):
+        cur = self.conn.cursor()
+        try:
+            cur.execute("show server_version")
+        except psycopg2.DatabaseError:
+            self.assertIsInstance(
+                self.conn.info.parameter_status('server_version'), str)
+        else:
+            self.assertEqual(
+                self.conn.info.parameter_status('server_version'),
+                cur.fetchone()[0])
+
+        self.assertIsNone(self.conn.info.parameter_status('wat'))
+        self.assertIsNone(self.bconn.info.parameter_status('server_version'))
+
     def test_protocol_version(self):
         self.assertEqual(self.conn.info.protocol_version, 3)
         self.assertEqual(self.bconn.info.protocol_version, 0)