ba9b432993
* Default error handler now only logs traceback on 500 errors and all responses are HTML formatted. * Tests passing. * Ability to flag any exception object with self.quiet = True following @ashleysommer suggestion. * Refactor HTML formatting into errorpages.py. String escapes for debug tracebacks. * Remove extra includes * Auto-set quiet flag also when decorator is used. * Cleanup, make error pages (probably) HTML5-compliant and similar for debug and non-debug modes. * Fix lookup of non-existant status codes * No logging of 503 errors after all. * lint
118 lines
3.6 KiB
Python
118 lines
3.6 KiB
Python
import sys
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from traceback import extract_tb
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from sanic.exceptions import SanicException
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from sanic.helpers import STATUS_CODES
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from sanic.response import html
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# Here, There Be Dragons (custom HTML formatting to follow)
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def escape(text):
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"""Minimal HTML escaping, not for attribute values (unlike html.escape)."""
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return f"{text}".replace("&", "&").replace("<", "<")
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def exception_response(request, exception, debug):
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status = 500
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text = (
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"The server encountered an internal error "
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"and cannot complete your request."
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)
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headers = {}
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if isinstance(exception, SanicException):
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text = f"{exception}"
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status = getattr(exception, "status_code", status)
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headers = getattr(exception, "headers", headers)
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elif debug:
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text = f"{exception}"
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status_text = STATUS_CODES.get(status, b"Error Occurred").decode()
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title = escape(f"{status} — {status_text}")
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text = escape(text)
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if debug and not getattr(exception, "quiet", False):
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return html(
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f"<!DOCTYPE html><meta charset=UTF-8><title>{title}</title>"
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f"<style>{TRACEBACK_STYLE}</style>\n"
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f"<h1>⚠️ {title}</h1><p>{text}\n"
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f"{_render_traceback_html(request, exception)}",
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status=status,
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)
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# Keeping it minimal with trailing newline for pretty curl/console output
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return html(
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f"<!DOCTYPE html><meta charset=UTF-8><title>{title}</title>"
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"<style>html { font-family: sans-serif }</style>\n"
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f"<h1>⚠️ {title}</h1><p>{text}\n",
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status=status,
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headers=headers,
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)
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def _render_exception(exception):
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frames = extract_tb(exception.__traceback__)
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frame_html = "".join(TRACEBACK_LINE_HTML.format(frame) for frame in frames)
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return TRACEBACK_WRAPPER_HTML.format(
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exc_name=escape(exception.__class__.__name__),
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exc_value=escape(exception),
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frame_html=frame_html,
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)
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def _render_traceback_html(request, exception):
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exc_type, exc_value, tb = sys.exc_info()
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exceptions = []
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while exc_value:
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exceptions.append(_render_exception(exc_value))
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exc_value = exc_value.__cause__
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traceback_html = TRACEBACK_BORDER.join(reversed(exceptions))
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appname = escape(request.app.name)
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name = escape(exception.__class__.__name__)
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value = escape(exception)
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path = escape(request.path)
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return (
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f"<h2>Traceback of {appname} (most recent call last):</h2>"
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f"{traceback_html}"
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"<div class=summary><p>"
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f"<b>{name}: {value}</b> while handling path <code>{path}</code>"
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)
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TRACEBACK_STYLE = """
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html { font-family: sans-serif }
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h2 { color: #888; }
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.tb-wrapper p { margin: 0 }
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.frame-border { margin: 1rem }
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.frame-line > * { padding: 0.3rem 0.6rem }
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.frame-line { margin-bottom: 0.3rem }
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.frame-code { font-size: 16px; padding-left: 4ch }
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.tb-wrapper { border: 1px solid #eee }
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.tb-header { background: #eee; padding: 0.3rem; font-weight: bold }
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.frame-descriptor { background: #e2eafb; font-size: 14px }
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"""
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TRACEBACK_WRAPPER_HTML = (
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"<div class=tb-header>{exc_name}: {exc_value}</div>"
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"<div class=tb-wrapper>{frame_html}</div>"
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)
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TRACEBACK_BORDER = (
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"<div class=frame-border>"
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"The above exception was the direct cause of the following exception:"
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"</div>"
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)
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TRACEBACK_LINE_HTML = (
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"<div class=frame-line>"
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"<p class=frame-descriptor>"
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"File {0.filename}, line <i>{0.lineno}</i>, "
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"in <code><b>{0.name}</b></code>"
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"<p class=frame-code><code>{0.line}</code>"
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"</div>"
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)
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