Perform conversion from Python unicode to string/bytes object via UTF-8.

We used to convert the unicode object directly to a string in the server
encoding by calling Python's PyUnicode_AsEncodedString function. In other
words, we used Python's routines to do the encoding. However, that has a
few problems. First of all, it required keeping a mapping table of Python
encoding names and PostgreSQL encodings. But the real killer was that Python
doesn't support EUC_TW and MULE_INTERNAL encodings at all.

Instead, convert the Python unicode object to UTF-8, and use PostgreSQL's
encoding conversion functions to convert from UTF-8 to server encoding. We
were already doing the same in the other direction in PLyUnicode_FromString,
so this is more consistent, too.

Note: This makes SQL_ASCII to behave more leniently. We used to map
SQL_ASCII to Python's 'ascii', which on Python means strict 7-bit ASCII
only, so you got an error if the python string contained anything but pure
ASCII. You no longer get an error; you get the UTF-8 representation of the
string instead.

Backpatch to 9.0, where these conversions were introduced.

Jan Urbański

diff --git a/src/pl/plpython/expected/plpython_unicode_3.out b/src/pl/plpython/expected/plpython_unicode_3.out
deleted file mode 100644 (file)
index 52d0aa0..0000000
--- a/src/pl/plpython/expected/plpython_unicode_3.out
+++ /dev/null
@@ -1,54 +0,0 @@
---
--- Unicode handling
---
-SET client_encoding TO UTF8;
-CREATE TABLE unicode_test (
-       testvalue  text NOT NULL
-);
-CREATE FUNCTION unicode_return() RETURNS text AS E'
-return u"\\x80"
-' LANGUAGE plpythonu;
-CREATE FUNCTION unicode_trigger() RETURNS trigger AS E'
-TD["new"]["testvalue"] = u"\\x80"
-return "MODIFY"
-' LANGUAGE plpythonu;
-CREATE TRIGGER unicode_test_bi BEFORE INSERT ON unicode_test
-  FOR EACH ROW EXECUTE PROCEDURE unicode_trigger();
-CREATE FUNCTION unicode_plan1() RETURNS text AS E'
-plan = plpy.prepare("SELECT $1 AS testvalue", ["text"])
-rv = plpy.execute(plan, [u"\\x80"], 1)
-return rv[0]["testvalue"]
-' LANGUAGE plpythonu;
-CREATE FUNCTION unicode_plan2() RETURNS text AS E'
-plan = plpy.prepare("SELECT $1 || $2 AS testvalue", ["text", u"text"])
-rv = plpy.execute(plan, ["foo", "bar"], 1)
-return rv[0]["testvalue"]
-' LANGUAGE plpythonu;
-SELECT unicode_return();
-ERROR:  could not convert Python Unicode object to PostgreSQL server encoding
-DETAIL:  UnicodeEncodeError: 'ascii' codec can't encode character u'\x80' in position 0: ordinal not in range(128)
-CONTEXT:  while creating return value
-PL/Python function "unicode_return"
-INSERT INTO unicode_test (testvalue) VALUES ('test');
-ERROR:  could not convert Python Unicode object to PostgreSQL server encoding
-DETAIL:  UnicodeEncodeError: 'ascii' codec can't encode character u'\x80' in position 0: ordinal not in range(128)
-CONTEXT:  while modifying trigger row
-PL/Python function "unicode_trigger"
-SELECT * FROM unicode_test;
- testvalue 
------------
-(0 rows)
-
-SELECT unicode_plan1();
-ERROR:  spiexceptions.InternalError: could not convert Python Unicode object to PostgreSQL server encoding
-DETAIL:  UnicodeEncodeError: 'ascii' codec can't encode character u'\x80' in position 0: ordinal not in range(128)
-CONTEXT:  Traceback (most recent call last):
-  PL/Python function "unicode_plan1", line 3, in <module>
-    rv = plpy.execute(plan, [u"\x80"], 1)
-PL/Python function "unicode_plan1"
-SELECT unicode_plan2();
- unicode_plan2 
----------------
- foobar
-(1 row)
-

diff --git a/src/pl/plpython/plpy_util.c b/src/pl/plpython/plpy_util.c
index 4aabafc139f8d4dd4e720d9784ffe66b79ded71d..9a921d92906e64ca8239c6505d319a26cb6a0930 100644 (file)
--- a/src/pl/plpython/plpy_util.c
+++ b/src/pl/plpython/plpy_util.c
@@ -61,66 +61,56 @@ PLy_free(void *ptr)
 PyObject *
 PLyUnicode_Bytes(PyObject *unicode)
 {
-       PyObject   *rv;
-       const char *serverenc;
+       PyObject        *bytes, *rv;
+       char            *utf8string, *encoded;
+
+       /* First encode the Python unicode object with UTF-8. */
+       bytes = PyUnicode_AsUTF8String(unicode);
+       if (bytes == NULL)
+               PLy_elog(ERROR, "could not convert Python Unicode object to bytes");
+
+       utf8string = PyBytes_AsString(bytes);
+       if (utf8string == NULL) {
+               Py_DECREF(bytes);
+               PLy_elog(ERROR, "could not extract bytes from encoded string");
+       }
 
        /*
-        * Map PostgreSQL encoding to a Python encoding name.
+        * Then convert to server encoding if necessary.
+        *
+        * PyUnicode_AsEncodedString could be used to encode the object directly
+        * in the server encoding, but Python doesn't support all the encodings
+        * that PostgreSQL does (EUC_TW and MULE_INTERNAL). UTF-8 is used as an
+        * intermediary in PLyUnicode_FromString as well.
         */
-       switch (GetDatabaseEncoding())
+       if (GetDatabaseEncoding() != PG_UTF8)
        {
-               case PG_SQL_ASCII:
-                       /*
-                        * Mapping SQL_ASCII to Python's 'ascii' is a bit bogus. Python's
-                        * 'ascii' means true 7-bit only ASCII, while PostgreSQL's
-                        * SQL_ASCII means that anything is allowed, and the system doesn't
-                        * try to interpret the bytes in any way. But not sure what else
-                        * to do, and we haven't heard any complaints...
-                        */
-                       serverenc = "ascii";
-                       break;
-               case PG_WIN1250:
-                       serverenc = "cp1250";
-                       break;
-               case PG_WIN1251:
-                       serverenc = "cp1251";
-                       break;
-               case PG_WIN1252:
-                       serverenc = "cp1252";
-                       break;
-               case PG_WIN1253:
-                       serverenc = "cp1253";
-                       break;
-               case PG_WIN1254:
-                       serverenc = "cp1254";
-                       break;
-               case PG_WIN1255:
-                       serverenc = "cp1255";
-                       break;
-               case PG_WIN1256:
-                       serverenc = "cp1256";
-                       break;
-               case PG_WIN1257:
-                       serverenc = "cp1257";
-                       break;
-               case PG_WIN1258:
-                       serverenc = "cp1258";
-                       break;
-               case PG_WIN866:
-                       serverenc = "cp866";
-                       break;
-               case PG_WIN874:
-                       serverenc = "cp874";
-                       break;
-               default:
-                       /* Other encodings have the same name in Python. */
-                       serverenc = GetDatabaseEncodingName();
-                       break;
+               PG_TRY();
+               {
+                       encoded = (char *) pg_do_encoding_conversion(
+                               (unsigned char *) utf8string,
+                               strlen(utf8string),
+                               PG_UTF8,
+                               GetDatabaseEncoding());
+               }
+               PG_CATCH();
+               {
+                       Py_DECREF(bytes);
+                       PG_RE_THROW();
+               }
+               PG_END_TRY();
        }
+       else
+               encoded = utf8string;
+
+       /* finally, build a bytes object in the server encoding */
+       rv = PyBytes_FromStringAndSize(encoded, strlen(encoded));
+
+       /* if pg_do_encoding_conversion allocated memory, free it now */
+       if (utf8string != encoded)
+               pfree(encoded);
 
-       rv = PyUnicode_AsEncodedString(unicode, serverenc, "strict");
-       if (rv == NULL)
-               PLy_elog(ERROR, "could not convert Python Unicode object to PostgreSQL server encoding");
+       Py_DECREF(bytes);
        return rv;
 }