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"""Object representations for debugging purposes. Unlike the default | |
repr, these expose more information and produce HTML instead of ASCII. | |
Together with the CSS and JavaScript of the debugger this gives a | |
colorful and more compact output. | |
""" | |
from __future__ import annotations | |
import codecs | |
import re | |
import sys | |
import typing as t | |
from collections import deque | |
from traceback import format_exception_only | |
from markupsafe import escape | |
missing = object() | |
_paragraph_re = re.compile(r"(?:\r\n|\r|\n){2,}") | |
RegexType = type(_paragraph_re) | |
HELP_HTML = """\ | |
<div class=box> | |
<h3>%(title)s</h3> | |
<pre class=help>%(text)s</pre> | |
</div>\ | |
""" | |
OBJECT_DUMP_HTML = """\ | |
<div class=box> | |
<h3>%(title)s</h3> | |
%(repr)s | |
<table>%(items)s</table> | |
</div>\ | |
""" | |
def debug_repr(obj: object) -> str: | |
"""Creates a debug repr of an object as HTML string.""" | |
return DebugReprGenerator().repr(obj) | |
def dump(obj: object = missing) -> None: | |
"""Print the object details to stdout._write (for the interactive | |
console of the web debugger. | |
""" | |
gen = DebugReprGenerator() | |
if obj is missing: | |
rv = gen.dump_locals(sys._getframe(1).f_locals) | |
else: | |
rv = gen.dump_object(obj) | |
sys.stdout._write(rv) # type: ignore | |
class _Helper: | |
"""Displays an HTML version of the normal help, for the interactive | |
debugger only because it requires a patched sys.stdout. | |
""" | |
def __repr__(self) -> str: | |
return "Type help(object) for help about object." | |
def __call__(self, topic: t.Any | None = None) -> None: | |
if topic is None: | |
sys.stdout._write(f"<span class=help>{self!r}</span>") # type: ignore | |
return | |
import pydoc | |
pydoc.help(topic) | |
rv = sys.stdout.reset() # type: ignore | |
paragraphs = _paragraph_re.split(rv) | |
if len(paragraphs) > 1: | |
title = paragraphs[0] | |
text = "\n\n".join(paragraphs[1:]) | |
else: | |
title = "Help" | |
text = paragraphs[0] | |
sys.stdout._write(HELP_HTML % {"title": title, "text": text}) # type: ignore | |
helper = _Helper() | |
def _add_subclass_info(inner: str, obj: object, base: type | tuple[type, ...]) -> str: | |
if isinstance(base, tuple): | |
for cls in base: | |
if type(obj) is cls: | |
return inner | |
elif type(obj) is base: | |
return inner | |
module = "" | |
if obj.__class__.__module__ not in ("__builtin__", "exceptions"): | |
module = f'<span class="module">{obj.__class__.__module__}.</span>' | |
return f"{module}{type(obj).__name__}({inner})" | |
def _sequence_repr_maker( | |
left: str, right: str, base: type, limit: int = 8 | |
) -> t.Callable[[DebugReprGenerator, t.Iterable[t.Any], bool], str]: | |
def proxy(self: DebugReprGenerator, obj: t.Iterable[t.Any], recursive: bool) -> str: | |
if recursive: | |
return _add_subclass_info(f"{left}...{right}", obj, base) | |
buf = [left] | |
have_extended_section = False | |
for idx, item in enumerate(obj): | |
if idx: | |
buf.append(", ") | |
if idx == limit: | |
buf.append('<span class="extended">') | |
have_extended_section = True | |
buf.append(self.repr(item)) | |
if have_extended_section: | |
buf.append("</span>") | |
buf.append(right) | |
return _add_subclass_info("".join(buf), obj, base) | |
return proxy | |
class DebugReprGenerator: | |
def __init__(self) -> None: | |
self._stack: list[t.Any] = [] | |
list_repr = _sequence_repr_maker("[", "]", list) | |
tuple_repr = _sequence_repr_maker("(", ")", tuple) | |
set_repr = _sequence_repr_maker("set([", "])", set) | |
frozenset_repr = _sequence_repr_maker("frozenset([", "])", frozenset) | |
deque_repr = _sequence_repr_maker( | |
'<span class="module">collections.</span>deque([', "])", deque | |
) | |
def regex_repr(self, obj: t.Pattern[t.AnyStr]) -> str: | |
pattern = repr(obj.pattern) | |
pattern = codecs.decode(pattern, "unicode-escape", "ignore") | |
pattern = f"r{pattern}" | |
return f're.compile(<span class="string regex">{pattern}</span>)' | |
def string_repr(self, obj: str | bytes, limit: int = 70) -> str: | |
buf = ['<span class="string">'] | |
r = repr(obj) | |
# shorten the repr when the hidden part would be at least 3 chars | |
if len(r) - limit > 2: | |
buf.extend( | |
( | |
escape(r[:limit]), | |
'<span class="extended">', | |
escape(r[limit:]), | |
"</span>", | |
) | |
) | |
else: | |
buf.append(escape(r)) | |
buf.append("</span>") | |
out = "".join(buf) | |
# if the repr looks like a standard string, add subclass info if needed | |
if r[0] in "'\"" or (r[0] == "b" and r[1] in "'\""): | |
return _add_subclass_info(out, obj, (bytes, str)) | |
# otherwise, assume the repr distinguishes the subclass already | |
return out | |
def dict_repr( | |
self, | |
d: dict[int, None] | dict[str, int] | dict[str | int, int], | |
recursive: bool, | |
limit: int = 5, | |
) -> str: | |
if recursive: | |
return _add_subclass_info("{...}", d, dict) | |
buf = ["{"] | |
have_extended_section = False | |
for idx, (key, value) in enumerate(d.items()): | |
if idx: | |
buf.append(", ") | |
if idx == limit - 1: | |
buf.append('<span class="extended">') | |
have_extended_section = True | |
buf.append( | |
f'<span class="pair"><span class="key">{self.repr(key)}</span>:' | |
f' <span class="value">{self.repr(value)}</span></span>' | |
) | |
if have_extended_section: | |
buf.append("</span>") | |
buf.append("}") | |
return _add_subclass_info("".join(buf), d, dict) | |
def object_repr(self, obj: t.Any) -> str: | |
r = repr(obj) | |
return f'<span class="object">{escape(r)}</span>' | |
def dispatch_repr(self, obj: t.Any, recursive: bool) -> str: | |
if obj is helper: | |
return f'<span class="help">{helper!r}</span>' | |
if isinstance(obj, (int, float, complex)): | |
return f'<span class="number">{obj!r}</span>' | |
if isinstance(obj, str) or isinstance(obj, bytes): | |
return self.string_repr(obj) | |
if isinstance(obj, RegexType): | |
return self.regex_repr(obj) | |
if isinstance(obj, list): | |
return self.list_repr(obj, recursive) | |
if isinstance(obj, tuple): | |
return self.tuple_repr(obj, recursive) | |
if isinstance(obj, set): | |
return self.set_repr(obj, recursive) | |
if isinstance(obj, frozenset): | |
return self.frozenset_repr(obj, recursive) | |
if isinstance(obj, dict): | |
return self.dict_repr(obj, recursive) | |
if isinstance(obj, deque): | |
return self.deque_repr(obj, recursive) | |
return self.object_repr(obj) | |
def fallback_repr(self) -> str: | |
try: | |
info = "".join(format_exception_only(*sys.exc_info()[:2])) | |
except Exception: | |
info = "?" | |
return ( | |
'<span class="brokenrepr">' | |
f"<broken repr ({escape(info.strip())})></span>" | |
) | |
def repr(self, obj: object) -> str: | |
recursive = False | |
for item in self._stack: | |
if item is obj: | |
recursive = True | |
break | |
self._stack.append(obj) | |
try: | |
try: | |
return self.dispatch_repr(obj, recursive) | |
except Exception: | |
return self.fallback_repr() | |
finally: | |
self._stack.pop() | |
def dump_object(self, obj: object) -> str: | |
repr = None | |
items: list[tuple[str, str]] | None = None | |
if isinstance(obj, dict): | |
title = "Contents of" | |
items = [] | |
for key, value in obj.items(): | |
if not isinstance(key, str): | |
items = None | |
break | |
items.append((key, self.repr(value))) | |
if items is None: | |
items = [] | |
repr = self.repr(obj) | |
for key in dir(obj): | |
try: | |
items.append((key, self.repr(getattr(obj, key)))) | |
except Exception: | |
pass | |
title = "Details for" | |
title += f" {object.__repr__(obj)[1:-1]}" | |
return self.render_object_dump(items, title, repr) | |
def dump_locals(self, d: dict[str, t.Any]) -> str: | |
items = [(key, self.repr(value)) for key, value in d.items()] | |
return self.render_object_dump(items, "Local variables in frame") | |
def render_object_dump( | |
self, items: list[tuple[str, str]], title: str, repr: str | None = None | |
) -> str: | |
html_items = [] | |
for key, value in items: | |
html_items.append(f"<tr><th>{escape(key)}<td><pre class=repr>{value}</pre>") | |
if not html_items: | |
html_items.append("<tr><td><em>Nothing</em>") | |
return OBJECT_DUMP_HTML % { | |
"title": escape(title), | |
"repr": f"<pre class=repr>{repr if repr else ''}</pre>", | |
"items": "\n".join(html_items), | |
} | |