sanic/sanic/exceptions.py
Jeong YunWon 413c92c631 Let exception handler handle inherited exceptions
Original sanic exception handler only could handle exact matching
exceptions. New `lookup` method will provide ability to looking up
their ancestors without additional cost of performance.
2017-02-07 21:08:31 +09:00

222 lines
5.6 KiB
Python

from .response import text, html
from .log import log
from traceback import format_exc, extract_tb
import sys
TRACEBACK_STYLE = '''
<style>
body {
padding: 20px;
font-family: Arial, sans-serif;
}
p {
margin: 0;
}
.summary {
padding: 10px;
}
h1 {
margin-bottom: 0;
}
h3 {
margin-top: 10px;
}
h3 code {
font-size: 24px;
}
.frame-line > * {
padding: 5px 10px;
}
.frame-line {
margin-bottom: 5px;
}
.frame-code {
font-size: 16px;
padding-left: 30px;
}
.tb-wrapper {
border: 1px solid #f3f3f3;
}
.tb-header {
background-color: #f3f3f3;
padding: 5px 10px;
}
.frame-descriptor {
background-color: #e2eafb;
}
.frame-descriptor {
font-size: 14px;
}
</style>
'''
TRACEBACK_WRAPPER_HTML = '''
<html>
<head>
{style}
</head>
<body>
<h1>{exc_name}</h1>
<h3><code>{exc_value}</code></h3>
<div class="tb-wrapper">
<p class="tb-header">Traceback (most recent call last):</p>
{frame_html}
<p class="summary">
<b>{exc_name}: {exc_value}</b>
while handling uri <code>{uri}</code>
</p>
</div>
</body>
</html>
'''
TRACEBACK_LINE_HTML = '''
<div class="frame-line">
<p class="frame-descriptor">
File {0.filename}, line <i>{0.lineno}</i>,
in <code><b>{0.name}</b></code>
</p>
<p class="frame-code"><code>{0.line}</code></p>
</div>
'''
INTERNAL_SERVER_ERROR_HTML = '''
<h1>Internal Server Error</h1>
<p>
The server encountered an internal error and cannot complete
your request.
</p>
'''
class SanicException(Exception):
def __init__(self, message, status_code=None):
super().__init__(message)
if status_code is not None:
self.status_code = status_code
class NotFound(SanicException):
status_code = 404
class InvalidUsage(SanicException):
status_code = 400
class ServerError(SanicException):
status_code = 500
class FileNotFound(NotFound):
status_code = 404
def __init__(self, message, path, relative_url):
super().__init__(message)
self.path = path
self.relative_url = relative_url
class RequestTimeout(SanicException):
status_code = 408
class PayloadTooLarge(SanicException):
status_code = 413
class Handler:
handlers = None
cached_handlers = None
_missing = object()
def __init__(self):
self.handlers = []
self.cached_handlers = {}
self.debug = False
def _render_traceback_html(self, exception, request):
exc_type, exc_value, tb = sys.exc_info()
frames = extract_tb(tb)
frame_html = []
for frame in frames:
frame_html.append(TRACEBACK_LINE_HTML.format(frame))
return TRACEBACK_WRAPPER_HTML.format(
style=TRACEBACK_STYLE,
exc_name=exc_type.__name__,
exc_value=exc_value,
frame_html=''.join(frame_html),
uri=request.url)
def add(self, exception, handler):
self.handlers.append((exception, handler))
def lookup(self, exception):
handler = self.cached_handlers.get(exception, self._missing)
if handler is self._missing:
for exception_class, handler in self.handlers:
if isinstance(exception, exception_class):
self.cached_handlers[type(exception)] = handler
return handler
self.cached_handlers[type(exception)] = None
handler = None
return handler
def response(self, request, exception):
"""
Fetches and executes an exception handler and returns a response object
:param request: Request
:param exception: Exception to handle
:return: Response object
"""
handler = self.lookup(exception)
try:
response = handler and handler(
request=request, exception=exception)
if response is None:
response = self.default(request=request, exception=exception)
except:
log.error(format_exc())
if self.debug:
response_message = (
'Exception raised in exception handler "{}" '
'for uri: "{}"\n{}').format(
handler.__name__, request.url, format_exc())
log.error(response_message)
return text(response_message, 500)
else:
return text('An error occurred while handling an error', 500)
return response
def default(self, request, exception):
log.error(format_exc())
if isinstance(exception, SanicException):
return text(
'Error: {}'.format(exception),
status=getattr(exception, 'status_code', 500))
elif self.debug:
html_output = self._render_traceback_html(exception, request)
response_message = (
'Exception occurred while handling uri: "{}"\n{}'.format(
request.url, format_exc()))
log.error(response_message)
return html(html_output, status=500)
else:
return html(INTERNAL_SERVER_ERROR_HTML, status=500)