一段时间以来，我们一直在使用Django admindocs中的simple_regex函数来为我们的文档生成可读的url。
从Django 1.8.7升级到Django 1.11.15时，我们在功能上遇到了重大变化-现在，我们的大多数URL都带有双正斜杠。
示例：
urlpattern (concatenated): 'api/^v1//^^some/path/$'
old return value: '/api/v1/some/path/'
new return value: '/api/v1//some/path/'
此更改是否有意进行？这是错误吗？看来功能已发生重大变化，我看到“ .replace（'//'，'/'）”已删除，不确定原因。
旧版本（1.8.7）：
named_group_matcher = re.compile(r'\(\?P(<\w+>).+?\)')
non_named_group_matcher = re.compile(r'\(.*?\)')
def simplify_regex(pattern):
"""
Clean up urlpattern regexes into something somewhat readable by Mere Humans:
turns something like "^(?P<sport_slug>\w+)/athletes/(?P<athlete_slug>\w+)/$"
into "<sport_slug>/athletes/<athlete_slug>/"
"""
# handle named groups first
pattern = named_group_matcher.sub(lambda m: m.group(1), pattern)
# handle non-named groups
pattern = non_named_group_matcher.sub("<var>", pattern)
# clean up any outstanding regex-y characters.
pattern = pattern.replace('^', '').replace('$', '').replace('?', '').replace('//', '/').replace('\\', '')
if not pattern.startswith('/'):
pattern = '/' + pattern
return pattern
新实施（1.11.15）：
def simplify_regex(pattern):
r"""
Clean up urlpattern regexes into something more readable by humans. For
example, turn "^(?P<sport_slug>\w+)/athletes/(?P<athlete_slug>\w+)/$"
into "/<sport_slug>/athletes/<athlete_slug>/".
"""
pattern = replace_named_groups(pattern)
pattern = replace_unnamed_groups(pattern)
# clean up any outstanding regex-y characters.
pattern = pattern.replace('^', '').replace('$', '').replace('?', '')
if not pattern.startswith('/'):
pattern = '/' + pattern
return pattern
# Match the beginning of a named or unnamed group.
named_group_matcher = re.compile(r'\(\?P(<\w+>)')
unnamed_group_matcher = re.compile(r'\(')
def replace_named_groups(pattern):
r"""
Find named groups in `pattern` and replace them with the group name. E.g.,
1. ^(?P<a>\w+)/b/(\w+)$ ==> ^<a>/b/(\w+)$
2. ^(?P<a>\w+)/b/(?P<c>\w+)/$ ==> ^<a>/b/<c>/$
"""
named_group_indices = [
(m.start(0), m.end(0), m.group(1))
for m in named_group_matcher.finditer(pattern)
]
# Tuples of (named capture group pattern, group name).
group_pattern_and_name = []
# Loop over the groups and their start and end indices.
for start, end, group_name in named_group_indices:
# Handle nested parentheses, e.g. '^(?P<a>(x|y))/b'.
unmatched_open_brackets, prev_char = 1, None
for idx, val in enumerate(list(pattern[end:])):
# If brackets are balanced, the end of the string for the current
# named capture group pattern has been reached.
if unmatched_open_brackets == 0:
group_pattern_and_name.append((pattern[start:end + idx], group_name))
break
# Check for unescaped `(` and `)`. They mark the start and end of a
# nested group.
if val == '(' and prev_char != '\\':
unmatched_open_brackets += 1
elif val == ')' and prev_char != '\\':
unmatched_open_brackets -= 1
prev_char = val
# Replace the string for named capture groups with their group names.
for group_pattern, group_name in group_pattern_and_name:
pattern = pattern.replace(group_pattern, group_name)
return pattern
def replace_unnamed_groups(pattern):
r"""
Find unnamed groups in `pattern` and replace them with '<var>'. E.g.,
1. ^(?P<a>\w+)/b/(\w+)$ ==> ^(?P<a>\w+)/b/<var>$
2. ^(?P<a>\w+)/b/((x|y)\w+)$ ==> ^(?P<a>\w+)/b/<var>$
"""
unnamed_group_indices = [m.start(0) for m in unnamed_group_matcher.finditer(pattern)]
# Indices of the start of unnamed capture groups.
group_indices = []
# Loop over the start indices of the groups.
for start in unnamed_group_indices:
# Handle nested parentheses, e.g. '^b/((x|y)\w+)$'.
unmatched_open_brackets, prev_char = 1, None
for idx, val in enumerate(list(pattern[start + 1:])):
if unmatched_open_brackets == 0:
group_indices.append((start, start + 1 + idx))
break
# Check for unescaped `(` and `)`. They mark the start and end of
# a nested group.
if val == '(' and prev_char != '\\':
unmatched_open_brackets += 1
elif val == ')' and prev_char != '\\':
unmatched_open_brackets -= 1
prev_char = val
# Remove unnamed group matches inside other unnamed capture groups.
group_start_end_indices = []
prev_end = None
for start, end in group_indices:
if prev_end and start > prev_end or not prev_end:
group_start_end_indices.append((start, end))
prev_end = end
if group_start_end_indices:
# Replace unnamed groups with <var>. Handle the fact that replacing the
# string between indices will change string length and thus indices
# will point to the wrong substring if not corrected.
final_pattern, prev_end = [], None
for start, end in group_start_end_indices:
if prev_end:
final_pattern.append(pattern[prev_end:start])
final_pattern.append(pattern[:start] + '<var>')
prev_end = end
final_pattern.append(pattern[prev_end:])
return ''.join(final_pattern)
else:
return pattern