diff options
Diffstat (limited to 'python/skytools/parsing.py')
| -rw-r--r-- | python/skytools/parsing.py | 68 |
1 files changed, 55 insertions, 13 deletions
diff --git a/python/skytools/parsing.py b/python/skytools/parsing.py index d50b14c0..4b92306e 100644 --- a/python/skytools/parsing.py +++ b/python/skytools/parsing.py @@ -14,11 +14,18 @@ _rc_listelem = re.compile(r'( [^,"}]+ | ["] ( [^"\\]+ | [\\]. )* ["] )', re.X) # _parse_pgarray def parse_pgarray(array): - """ Parse Postgres array and return list of items inside it - Used to deserialize data recived from service layer parameters + r"""Parse Postgres array and return list of items inside it. + + Examples: + >>> parse_pgarray('{}') + [] + >>> parse_pgarray('{a,b,null,"null"}') + ['a', 'b', None, 'null'] + >>> parse_pgarray(r'{"a,a","b\"b","c\\c"}') + ['a,a', 'b"b', 'c\\c'] """ - if not array or array[0] != "{": - raise Exception("bad array format: must start with {") + if not array or array[0] != "{" or array[-1] != '}': + raise Exception("bad array format: must be surrounded with {}") res = [] pos = 1 while 1: @@ -27,16 +34,19 @@ def parse_pgarray(array): break pos2 = m.end() item = array[pos:pos2] - if len(item) > 0 and item[0] == '"': - item = item[1:-1] - item = unescape(item) - res.append(item) + if len(item) == 4 and item.upper() == "NULL": + val = None + else: + if len(item) > 0 and item[0] == '"': + item = item[1:-1] + val = unescape(item) + res.append(val) pos = pos2 + 1 if array[pos2] == "}": break elif array[pos2] != ",": - raise Exception("bad array format: expected ,} got " + array[pos2]) + raise Exception("bad array format: expected ,} got " + repr(array[pos2])) return res # @@ -136,26 +146,45 @@ class _logtriga_parser: return dbdict(zip(fields, values)) def parse_logtriga_sql(op, sql): - """Parse partial SQL used by logtriga() back to data values. + return parse_sqltriga_sql(op, sql) + +def parse_sqltriga_sql(op, sql): + """Parse partial SQL used by pgq.sqltriga() back to data values. Parser has following limitations: - Expects standard_quoted_strings = off - Does not support dollar quoting. - Does not support complex expressions anywhere. (hashtext(col1) = hashtext(val1)) - WHERE expression must not contain IS (NOT) NULL - - Does not support updateing pk value. + - Does not support updating pk value. Returns dict of col->data pairs. + + Insert event: + >>> parse_logtriga_sql('I', '(id, data) values (1, null)') + {'data': None, 'id': '1'} + + Update event: + >>> parse_logtriga_sql('U', "data='foo' where id = 1") + {'data': 'foo', 'id': '1'} + + Delete event: + >>> parse_logtriga_sql('D', "id = 1 and id2 = 'str''val'") + {'id2': "str'val", 'id': '1'} """ return _logtriga_parser().parse_sql(op, sql) def parse_tabbed_table(txt): - """Parse a tab-separated table into list of dicts. + r"""Parse a tab-separated table into list of dicts. Expect first row to be column names. Very primitive. + + Example: + >>> parse_tabbed_table('col1\tcol2\nval1\tval2\n') + [{'col2': 'val2', 'col1': 'val1'}] """ txt = txt.replace("\r\n", "\n") @@ -194,9 +223,15 @@ _ext_sql = r"""(?: (?P<str> [E]? %s ) | %s )""" % (_extstr, _base_sql) _std_sql_rc = _ext_sql_rc = None def sql_tokenizer(sql, standard_quoting = False, ignore_whitespace = False): - """Parser SQL to tokens. + r"""Parser SQL to tokens. Iterator, returns (toktype, tokstr) tuples. + + Example + >>> [x for x in sql_tokenizer("select * from a.b", ignore_whitespace=True)] + [('ident', 'select'), ('sym', '*'), ('ident', 'from'), ('ident', 'a'), ('sym', '.'), ('ident', 'b')] + >>> [x for x in sql_tokenizer("\"c olumn\",'str''val'")] + [('ident', '"c olumn"'), ('sym', ','), ('str', "'str''val'")] """ global _std_sql_rc, _ext_sql_rc if not _std_sql_rc: @@ -224,6 +259,9 @@ def parse_statements(sql, standard_quoting = False): """Parse multi-statement string into separate statements. Returns list of statements. + + >>> [sql for sql in parse_statements("begin; select 1; select 'foo'; end;")] + ['begin;', 'select 1;', "select 'foo';", 'end;'] """ global _copy_from_stdin_rc @@ -252,3 +290,7 @@ def parse_statements(sql, standard_quoting = False): if pcount != 0: raise Exception("syntax error - unbalanced parenthesis") +if __name__ == '__main__': + import doctest + doctest.testmod() + |