from __future__ import annotations import itertools import linecache import os import re import sys import sysconfig import traceback import typing as t from markupsafe import escape from ..utils import cached_property from .console import Console HEADER = """\ %(title)s // Werkzeug Debugger
""" FOOTER = """\
Brought to you by DON'T PANIC, your friendly Werkzeug powered traceback interpreter.

Console Locked

The console is locked and needs to be unlocked by entering the PIN. You can find the PIN printed out on the standard output of your shell that runs the server.

PIN:

""" PAGE_HTML = ( HEADER + """\

%(exception_type)s

%(exception)s

Traceback (most recent call last)

%(summary)s

This is the Copy/Paste friendly version of the traceback.

The debugger caught an exception in your WSGI application. You can now look at the traceback which led to the error. If you enable JavaScript you can also use additional features such as code execution (if the evalex feature is enabled), automatic pasting of the exceptions and much more.
""" + FOOTER + """ """ ) CONSOLE_HTML = ( HEADER + """\

Interactive Console

In this console you can execute Python expressions in the context of the application. The initial namespace was created by the debugger automatically.
The Console requires JavaScript.
""" + FOOTER ) SUMMARY_HTML = """\
%(title)s %(description)s
""" FRAME_HTML = """\

File "%(filename)s", line %(lineno)s, in %(function_name)s

%(lines)s
""" def _process_traceback( exc: BaseException, te: traceback.TracebackException | None = None, *, skip: int = 0, hide: bool = True, ) -> traceback.TracebackException: if te is None: te = traceback.TracebackException.from_exception(exc, lookup_lines=False) # Get the frames the same way StackSummary.extract did, in order # to match each frame with the FrameSummary to augment. frame_gen = traceback.walk_tb(exc.__traceback__) limit = getattr(sys, "tracebacklimit", None) if limit is not None: if limit < 0: limit = 0 frame_gen = itertools.islice(frame_gen, limit) if skip: frame_gen = itertools.islice(frame_gen, skip, None) del te.stack[:skip] new_stack: list[DebugFrameSummary] = [] hidden = False # Match each frame with the FrameSummary that was generated. # Hide frames using Paste's __traceback_hide__ rules. Replace # all visible FrameSummary with DebugFrameSummary. for (f, _), fs in zip(frame_gen, te.stack): if hide: hide_value = f.f_locals.get("__traceback_hide__", False) if hide_value in {"before", "before_and_this"}: new_stack = [] hidden = False if hide_value == "before_and_this": continue elif hide_value in {"reset", "reset_and_this"}: hidden = False if hide_value == "reset_and_this": continue elif hide_value in {"after", "after_and_this"}: hidden = True if hide_value == "after_and_this": continue elif hide_value or hidden: continue frame_args: dict[str, t.Any] = { "filename": fs.filename, "lineno": fs.lineno, "name": fs.name, "locals": f.f_locals, "globals": f.f_globals, } if hasattr(fs, "colno"): frame_args["colno"] = fs.colno frame_args["end_colno"] = fs.end_colno # type: ignore[attr-defined] new_stack.append(DebugFrameSummary(**frame_args)) # The codeop module is used to compile code from the interactive # debugger. Hide any codeop frames from the bottom of the traceback. while new_stack: module = new_stack[0].global_ns.get("__name__") if module is None: module = new_stack[0].local_ns.get("__name__") if module == "codeop": del new_stack[0] else: break te.stack[:] = new_stack if te.__context__: context_exc = t.cast(BaseException, exc.__context__) te.__context__ = _process_traceback(context_exc, te.__context__, hide=hide) if te.__cause__: cause_exc = t.cast(BaseException, exc.__cause__) te.__cause__ = _process_traceback(cause_exc, te.__cause__, hide=hide) return te class DebugTraceback: __slots__ = ("_te", "_cache_all_tracebacks", "_cache_all_frames") def __init__( self, exc: BaseException, te: traceback.TracebackException | None = None, *, skip: int = 0, hide: bool = True, ) -> None: self._te = _process_traceback(exc, te, skip=skip, hide=hide) def __str__(self) -> str: return f"<{type(self).__name__} {self._te}>" @cached_property def all_tracebacks( self, ) -> list[tuple[str | None, traceback.TracebackException]]: out = [] current = self._te while current is not None: if current.__cause__ is not None: chained_msg = ( "The above exception was the direct cause of the" " following exception" ) chained_exc = current.__cause__ elif current.__context__ is not None and not current.__suppress_context__: chained_msg = ( "During handling of the above exception, another" " exception occurred" ) chained_exc = current.__context__ else: chained_msg = None chained_exc = None out.append((chained_msg, current)) current = chained_exc return out @cached_property def all_frames(self) -> list[DebugFrameSummary]: return [ f for _, te in self.all_tracebacks for f in te.stack # type: ignore[misc] ] def render_traceback_text(self) -> str: return "".join(self._te.format()) def render_traceback_html(self, include_title: bool = True) -> str: library_frames = [f.is_library for f in self.all_frames] mark_library = 0 < sum(library_frames) < len(library_frames) rows = [] if not library_frames: classes = "traceback noframe-traceback" else: classes = "traceback" for msg, current in reversed(self.all_tracebacks): row_parts = [] if msg is not None: row_parts.append(f'
  • {msg}:
    ') for frame in current.stack: frame = t.cast(DebugFrameSummary, frame) info = f' title="{escape(frame.info)}"' if frame.info else "" row_parts.append(f"{frame.render_html(mark_library)}") rows.append("\n".join(row_parts)) is_syntax_error = issubclass(self._te.exc_type, SyntaxError) if include_title: if is_syntax_error: title = "Syntax Error" else: title = "Traceback (most recent call last):" else: title = "" exc_full = escape("".join(self._te.format_exception_only())) if is_syntax_error: description = f"
    {exc_full}
    " else: description = f"
    {exc_full}
    " return SUMMARY_HTML % { "classes": classes, "title": f"

    {title}

    ", "frames": "\n".join(rows), "description": description, } def render_debugger_html( self, evalex: bool, secret: str, evalex_trusted: bool ) -> str: exc_lines = list(self._te.format_exception_only()) plaintext = "".join(self._te.format()) return PAGE_HTML % { "evalex": "true" if evalex else "false", "evalex_trusted": "true" if evalex_trusted else "false", "console": "false", "title": escape(exc_lines[0]), "exception": escape("".join(exc_lines)), "exception_type": escape(self._te.exc_type.__name__), "summary": self.render_traceback_html(include_title=False), "plaintext": escape(plaintext), "plaintext_cs": re.sub("-{2,}", "-", plaintext), "secret": secret, } class DebugFrameSummary(traceback.FrameSummary): """A :class:`traceback.FrameSummary` that can evaluate code in the frame's namespace. """ __slots__ = ( "local_ns", "global_ns", "_cache_info", "_cache_is_library", "_cache_console", ) def __init__( self, *, locals: dict[str, t.Any], globals: dict[str, t.Any], **kwargs: t.Any, ) -> None: super().__init__(locals=None, **kwargs) self.local_ns = locals self.global_ns = globals @cached_property def info(self) -> str | None: return self.local_ns.get("__traceback_info__") @cached_property def is_library(self) -> bool: return any( self.filename.startswith((path, os.path.realpath(path))) for path in sysconfig.get_paths().values() ) @cached_property def console(self) -> Console: return Console(self.global_ns, self.local_ns) def eval(self, code: str) -> t.Any: return self.console.eval(code) def render_html(self, mark_library: bool) -> str: context = 5 lines = linecache.getlines(self.filename) line_idx = self.lineno - 1 # type: ignore[operator] start_idx = max(0, line_idx - context) stop_idx = min(len(lines), line_idx + context + 1) rendered_lines = [] def render_line(line: str, cls: str) -> None: line = line.expandtabs().rstrip() stripped_line = line.strip() prefix = len(line) - len(stripped_line) colno = getattr(self, "colno", 0) end_colno = getattr(self, "end_colno", 0) if cls == "current" and colno and end_colno: arrow = ( f'\n{" " * prefix}' f'{" " * (colno - prefix)}{"^" * (end_colno - colno)}' ) else: arrow = "" rendered_lines.append( f'
    {" " * prefix}'
                f"{escape(stripped_line) if stripped_line else ' '}"
                f"{arrow if arrow else ''}
    " ) if lines: for line in lines[start_idx:line_idx]: render_line(line, "before") render_line(lines[line_idx], "current") for line in lines[line_idx + 1 : stop_idx]: render_line(line, "after") return FRAME_HTML % { "id": id(self), "filename": escape(self.filename), "lineno": self.lineno, "function_name": escape(self.name), "lines": "\n".join(rendered_lines), "library": "library" if mark_library and self.is_library else "", } def render_console_html(secret: str, evalex_trusted: bool) -> str: return CONSOLE_HTML % { "evalex": "true", "evalex_trusted": "true" if evalex_trusted else "false", "console": "true", "title": "Console", "secret": secret, }