skytools: separate psycopg specific code

1 files changed, 68 insertions, 0 deletions

diff --git a/python/skytools/psycopgwrapper.py b/python/skytools/psycopgwrapper.py
new file mode 100644
index 00000000..36b41124
--- /dev/null
+++ b/python/skytools/psycopgwrapper.py
@@ -0,0 +1,68 @@
+
+"""Wrapper around psycopg1/2.
+
+Preferred is psycopg2, fallback to psycopg1.
+
+Interface provided is psycopg1:
+    - dict* methods.
+    - new columns can be assigned to row.
+
+"""
+
+__all__ = ["QuotedString", "connect_database"]
+
+try:
+    ##from psycopg2.psycopg1 import connect as _pgconnect
+    # psycopg2.psycopg1.cursor is too backwards compatible,
+    # to the point of avoiding optimized access.
+    # only backwards compat thing we need is dict* methods
+
+    import psycopg2.extensions, psycopg2.extras
+    from psycopg2.extensions import QuotedString
+
+    class _CompatRow(psycopg2.extras.DictRow):
+        """Allow setting fields by name."""
+        def __setitem__(self, k, v):
+            if type(k) != int:
+                if k not in self._index:
+                    self._index[k] = len(self._index)
+                k = self._index[k]
+                while k >= len(self):
+                    self.append(None)
+            return list.__setitem__(self, k, v)
+
+    class _CompatCursor(psycopg2.extras.DictCursor):
+        """Regular psycopg2 DictCursor with dict* methods."""
+        def __init__(self, *args, **kwargs):
+            psycopg2.extras.DictCursor.__init__(self, *args, **kwargs)
+            self.row_factory = _CompatRow
+        dictfetchone = psycopg2.extras.DictCursor.fetchone
+        dictfetchall = psycopg2.extras.DictCursor.fetchall
+        dictfetchmany = psycopg2.extras.DictCursor.fetchmany
+    
+    class _CompatConnection(psycopg2.extensions.connection):
+        """Connection object that uses _CompatCursor."""
+        def cursor(self):
+            return psycopg2.extensions.connection.cursor(self, cursor_factory = _CompatCursor)
+    
+    def _pgconnect(cstr):
+        """Create a psycopg2 connection."""
+        return _CompatConnection(cstr)
+
+except ImportError:
+    # use psycopg 1
+    from psycopg import connect as _pgconnect
+
+def connect_database(connstr):
+    """Create a db connection with connect_timeout option.
+    
+    Default connect_timeout is 15, to change put it directly into dsn.
+    """
+
+    # allow override
+    if connstr.find("connect_timeout") < 0:
+        connstr += " connect_timeout=15"
+
+    # create connection
+    return _pgconnect(connstr)
+