Register the error handling function \var{error_handler} under the
name \var{name}. \var{error_handler} will be called during encoding
and decoding in case of an error, when \var{name} is specified as the
-errors parameter. \var{error_handler} will be called with an
-\exception{UnicodeEncodeError}, \exception{UnicodeDecodeError} or
-\exception{UnicodeTranslateError} instance and must return a tuple
-with a replacement for the unencodable/undecodable part of the input
-and a position where encoding/decoding should continue.
+errors parameter.
+
+For encoding \var{error_handler} will be called with a
+\exception{UnicodeEncodeError} instance, which contains information about
+the location of the error. The error handler must either raise this or
+a different exception or return a tuple with a replacement for the
+unencodable part of the input and a position where encoding should
+continue. The encoder will encode the replacement and continue encoding
+the original input at the specified position. Negative position values
+will be treated as being relative to the end of the input string. If the
+resulting position is out of bound an IndexError will be raised.
+
+Decoding and translating works similar, except \exception{UnicodeDecodeError}
+or \exception{UnicodeTranslateError} will be passed to the handler and
+that the replacement from the error handler will be put into the output
+directly.
\end{funcdesc}
\begin{funcdesc}{lookup_error}{name}
import test.test_support, unittest
import sys, codecs, htmlentitydefs, unicodedata
+class PosReturn:
+ # this can be used for configurable callbacks
+
+ def __init__(self):
+ self.pos = 0
+
+ def handle(self, exc):
+ oldpos = self.pos
+ realpos = oldpos
+ if realpos<0:
+ realpos = len(exc.object) + realpos
+ # if we don't advance this time, terminate on the next call
+ # otherwise we'd get an endless loop
+ if realpos <= exc.start:
+ self.pos = len(exc.object)
+ return (u"<?>", oldpos)
+
class CodecCallbackTest(unittest.TestCase):
def test_xmlcharrefreplace(self):
codecs.register_error("test.baddecodereturn2", baddecodereturn2)
self.assertRaises(TypeError, "\xff".decode, "ascii", "test.baddecodereturn2")
- pos = [-42]
- def negposreturn(exc):
- pos[0] += 1 # use list to work around scoping problem
- return (u"?", pos[0])
- codecs.register_error("test.negposreturn", negposreturn)
- "\xff".decode("ascii", "test.negposreturn")
+ handler = PosReturn()
+ codecs.register_error("test.posreturn", handler.handle)
+
+ # Valid negative position
+ handler.pos = -1
+ self.assertEquals("\xff0".decode("ascii", "test.posreturn"), u"<?>0")
+
+ # Valid negative position
+ handler.pos = -2
+ self.assertEquals("\xff0".decode("ascii", "test.posreturn"), u"<?><?>")
+
+ # Negative position out of bounds
+ handler.pos = -3
+ self.assertRaises(IndexError, "\xff0".decode, "ascii", "test.posreturn")
+
+ # Valid positive position
+ handler.pos = 1
+ self.assertEquals("\xff0".decode("ascii", "test.posreturn"), u"<?>0")
+
+ # Largest valid positive position (one beyond end of input
+ handler.pos = 2
+ self.assertEquals("\xff0".decode("ascii", "test.posreturn"), u"<?>")
+
+ # Invalid positive position
+ handler.pos = 3
+ self.assertRaises(IndexError, "\xff0".decode, "ascii", "test.posreturn")
- def hugeposreturn(exc):
- return (u"?", 424242)
- codecs.register_error("test.hugeposreturn", hugeposreturn)
- "\xff".decode("ascii", "test.hugeposreturn")
- "\\uyyyy".decode("raw-unicode-escape", "test.hugeposreturn")
+ # Restart at the "0"
+ handler.pos = 6
+ self.assertEquals("\\uyyyy0".decode("raw-unicode-escape", "test.posreturn"), u"<?>0")
class D(dict):
def __getitem__(self, key):
codecs.register_error("test.badencodereturn2", badencodereturn2)
self.assertRaises(TypeError, u"\xff".encode, "ascii", "test.badencodereturn2")
- pos = [-42]
- def negposreturn(exc):
- pos[0] += 1 # use list to work around scoping problem
- return (u"?", pos[0])
- codecs.register_error("test.negposreturn", negposreturn)
- u"\xff".encode("ascii", "test.negposreturn")
+ handler = PosReturn()
+ codecs.register_error("test.posreturn", handler.handle)
+
+ # Valid negative position
+ handler.pos = -1
+ self.assertEquals(u"\xff0".encode("ascii", "test.posreturn"), "<?>0")
+
+ # Valid negative position
+ handler.pos = -2
+ self.assertEquals(u"\xff0".encode("ascii", "test.posreturn"), "<?><?>")
+
+ # Negative position out of bounds
+ handler.pos = -3
+ self.assertRaises(IndexError, u"\xff0".encode, "ascii", "test.posreturn")
+
+ # Valid positive position
+ handler.pos = 1
+ self.assertEquals(u"\xff0".encode("ascii", "test.posreturn"), "<?>0")
+
+ # Largest valid positive position (one beyond end of input
+ handler.pos = 2
+ self.assertEquals(u"\xff0".encode("ascii", "test.posreturn"), "<?>")
+
+ # Invalid positive position
+ handler.pos = 3
+ self.assertRaises(IndexError, u"\xff0".encode, "ascii", "test.posreturn")
- def hugeposreturn(exc):
- return (u"?", 424242)
- codecs.register_error("test.hugeposreturn", hugeposreturn)
- u"\xff".encode("ascii", "test.hugeposreturn")
+ handler.pos = 0
class D(dict):
def __getitem__(self, key):
raise ValueError
- for err in ("strict", "replace", "xmlcharrefreplace", "backslashreplace", "test.hugeposreturn"):
+ for err in ("strict", "replace", "xmlcharrefreplace", "backslashreplace", "test.posreturn"):
self.assertRaises(UnicodeError, codecs.charmap_encode, u"\xff", err, {0xff: None})
self.assertRaises(ValueError, codecs.charmap_encode, u"\xff", err, D())
self.assertRaises(TypeError, codecs.charmap_encode, u"\xff", err, {0xff: 300})
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