Relocate the error __str__ implementation into postgresql.sys.

James William Pye · James William Pye · commit e16074f51903 · 2009-06-04T16:39:12.000-07:00
While users could just monkey patch it, it would likely be a bit more preferable
to have an explicitly designated place to override the method's implementation.
diff --git a/postgresql/exceptions.py b/postgresql/exceptions.py
@@ -34,8 +34,7 @@
 from functools import partial
 from operator import attrgetter
 from . import api as pg_api
-from .python.element import format_element
-from .python.string import indent
+from . import sys as pg_sys
 
 PythonException = Exception
 class Exception(Exception):
@@ -92,25 +91,8 @@ class Error(pg_api.Message, Exception):
 	code = ''
 
 	def __str__(self):
-		it = self._e_metas()
-		if self.creator is not None:
-			# Protect against element traceback failures.
-			try:
-				after = os.linesep + format_element(self.creator)
-			except PythonException:
-				after = 'Element Traceback of %r caused exception:%s' %(
-					type(self.creator).__name__,
-					os.linesep
-				)
-				after += indent(traceback.format_exc())
-				after = os.linesep + indent(after).rstrip()
-		else:
-			after = ''
-		return next(it)[1] \
-			+ os.linesep + '  ' \
-			+ (os.linesep + '  ').join(
-				k + ': ' + v for k, v in it
-			) + after
+		'Call .sys.errformat(self)'
+		return pg_sys.errformat(self)
 
 	@property
 	def fatal(self):
diff --git a/postgresql/sys.py b/postgresql/sys.py
@@ -10,13 +10,49 @@
 
  ``libpath``
   The local file system paths that contain query libraries.
+
+Overridable Functions
+---------------------
+
+ excformat
+  Information that makes up an exception's displayed "body".
+  Effectively, the implementation of `postgresql.exception.Error.__str__`
+
+ msghook
+  Display a message.
 """
 import sys
 import os
+import traceback
 from .python.element import format_element
+from .python.string import indent
 
 libpath = []
 
+def default_errformat(val):
+	"""
+	Built-in error formatter. DON'T TOUCH!
+	"""
+	it = val._e_metas()
+	if val.creator is not None:
+		# Protect against element traceback failures.
+		try:
+			after = os.linesep + format_element(val.creator)
+		except Exception:
+			after = 'Element Traceback of %r caused exception:%s' %(
+				type(val.creator).__name__,
+				os.linesep
+			)
+			after += indent(traceback.format_exc())
+			after = os.linesep + indent(after).rstrip()
+	else:
+		after = ''
+	return next(it)[1] \
+		+ os.linesep + '  ' \
+		+ (os.linesep + '  ').join(
+			k + ': ' + v for k, v in it
+		) + after
+
 def default_msghook(msg, format_message = format_element):
 	"""
 	Built-in message hook. DON'T TOUCH!
@@ -31,14 +67,28 @@ def default_msghook(msg, format_message = format_element):
 				# gasp.
 				pass
 
-def msghook(msg):
+def errformat(*args, **kw):
+	"""
+	Raised Database Error formatter pointing to default_excformat.
+
+	Override if you like. All postgresql.exceptions.Error's are formatted using
+	this function.
+	"""
+	return default_errformat(*args, **kw)
+
+def msghook(*args, **kw):
 	"""
 	Message hook pointing to default_msghook.
 
-	Overload if you like. All untrapped messages raised by
+	Override if you like. All untrapped messages raised by
 	driver connections come here to be printed to stderr.
 	"""
-	return default_msghook(msg)
+	return default_msghook(*args, **kw)
+
+def reset_errformat(with_func = errformat):
+	'restore the original excformat function'
+	global errformat
+	errformat = with_func
 
 def reset_msghook(with_func = msghook):
 	'restore the original msghook function'
