File size: 8,066 Bytes
9c6594c |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 |
from __future__ import annotations
import html
import inspect
import sys
import traceback
import typing
from starlette._utils import is_async_callable
from starlette.concurrency import run_in_threadpool
from starlette.requests import Request
from starlette.responses import HTMLResponse, PlainTextResponse, Response
from starlette.types import ASGIApp, Message, Receive, Scope, Send
STYLES = """
p {
color: #211c1c;
}
.traceback-container {
border: 1px solid #038BB8;
}
.traceback-title {
background-color: #038BB8;
color: lemonchiffon;
padding: 12px;
font-size: 20px;
margin-top: 0px;
}
.frame-line {
padding-left: 10px;
font-family: monospace;
}
.frame-filename {
font-family: monospace;
}
.center-line {
background-color: #038BB8;
color: #f9f6e1;
padding: 5px 0px 5px 5px;
}
.lineno {
margin-right: 5px;
}
.frame-title {
font-weight: unset;
padding: 10px 10px 10px 10px;
background-color: #E4F4FD;
margin-right: 10px;
color: #191f21;
font-size: 17px;
border: 1px solid #c7dce8;
}
.collapse-btn {
float: right;
padding: 0px 5px 1px 5px;
border: solid 1px #96aebb;
cursor: pointer;
}
.collapsed {
display: none;
}
.source-code {
font-family: courier;
font-size: small;
padding-bottom: 10px;
}
"""
JS = """
<script type="text/javascript">
function collapse(element){
const frameId = element.getAttribute("data-frame-id");
const frame = document.getElementById(frameId);
if (frame.classList.contains("collapsed")){
element.innerHTML = "‒";
frame.classList.remove("collapsed");
} else {
element.innerHTML = "+";
frame.classList.add("collapsed");
}
}
</script>
"""
TEMPLATE = """
<html>
<head>
<style type='text/css'>
{styles}
</style>
<title>Starlette Debugger</title>
</head>
<body>
<h1>500 Server Error</h1>
<h2>{error}</h2>
<div class="traceback-container">
<p class="traceback-title">Traceback</p>
<div>{exc_html}</div>
</div>
{js}
</body>
</html>
"""
FRAME_TEMPLATE = """
<div>
<p class="frame-title">File <span class="frame-filename">{frame_filename}</span>,
line <i>{frame_lineno}</i>,
in <b>{frame_name}</b>
<span class="collapse-btn" data-frame-id="{frame_filename}-{frame_lineno}" onclick="collapse(this)">{collapse_button}</span>
</p>
<div id="{frame_filename}-{frame_lineno}" class="source-code {collapsed}">{code_context}</div>
</div>
""" # noqa: E501
LINE = """
<p><span class="frame-line">
<span class="lineno">{lineno}.</span> {line}</span></p>
"""
CENTER_LINE = """
<p class="center-line"><span class="frame-line center-line">
<span class="lineno">{lineno}.</span> {line}</span></p>
"""
class ServerErrorMiddleware:
"""
Handles returning 500 responses when a server error occurs.
If 'debug' is set, then traceback responses will be returned,
otherwise the designated 'handler' will be called.
This middleware class should generally be used to wrap *everything*
else up, so that unhandled exceptions anywhere in the stack
always result in an appropriate 500 response.
"""
def __init__(
self,
app: ASGIApp,
handler: typing.Callable[[Request, Exception], typing.Any] | None = None,
debug: bool = False,
) -> None:
self.app = app
self.handler = handler
self.debug = debug
async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
if scope["type"] != "http":
await self.app(scope, receive, send)
return
response_started = False
async def _send(message: Message) -> None:
nonlocal response_started, send
if message["type"] == "http.response.start":
response_started = True
await send(message)
try:
await self.app(scope, receive, _send)
except Exception as exc:
request = Request(scope)
if self.debug:
# In debug mode, return traceback responses.
response = self.debug_response(request, exc)
elif self.handler is None:
# Use our default 500 error handler.
response = self.error_response(request, exc)
else:
# Use an installed 500 error handler.
if is_async_callable(self.handler):
response = await self.handler(request, exc)
else:
response = await run_in_threadpool(self.handler, request, exc)
if not response_started:
await response(scope, receive, send)
# We always continue to raise the exception.
# This allows servers to log the error, or allows test clients
# to optionally raise the error within the test case.
raise exc
def format_line(self, index: int, line: str, frame_lineno: int, frame_index: int) -> str:
values = {
# HTML escape - line could contain < or >
"line": html.escape(line).replace(" ", " "),
"lineno": (frame_lineno - frame_index) + index,
}
if index != frame_index:
return LINE.format(**values)
return CENTER_LINE.format(**values)
def generate_frame_html(self, frame: inspect.FrameInfo, is_collapsed: bool) -> str:
code_context = "".join(
self.format_line(
index,
line,
frame.lineno,
frame.index, # type: ignore[arg-type]
)
for index, line in enumerate(frame.code_context or [])
)
values = {
# HTML escape - filename could contain < or >, especially if it's a virtual
# file e.g. <stdin> in the REPL
"frame_filename": html.escape(frame.filename),
"frame_lineno": frame.lineno,
# HTML escape - if you try very hard it's possible to name a function with <
# or >
"frame_name": html.escape(frame.function),
"code_context": code_context,
"collapsed": "collapsed" if is_collapsed else "",
"collapse_button": "+" if is_collapsed else "‒",
}
return FRAME_TEMPLATE.format(**values)
def generate_html(self, exc: Exception, limit: int = 7) -> str:
traceback_obj = traceback.TracebackException.from_exception(exc, capture_locals=True)
exc_html = ""
is_collapsed = False
exc_traceback = exc.__traceback__
if exc_traceback is not None:
frames = inspect.getinnerframes(exc_traceback, limit)
for frame in reversed(frames):
exc_html += self.generate_frame_html(frame, is_collapsed)
is_collapsed = True
if sys.version_info >= (3, 13): # pragma: no cover
exc_type_str = traceback_obj.exc_type_str
else: # pragma: no cover
exc_type_str = traceback_obj.exc_type.__name__
# escape error class and text
error = f"{html.escape(exc_type_str)}: {html.escape(str(traceback_obj))}"
return TEMPLATE.format(styles=STYLES, js=JS, error=error, exc_html=exc_html)
def generate_plain_text(self, exc: Exception) -> str:
return "".join(traceback.format_exception(type(exc), exc, exc.__traceback__))
def debug_response(self, request: Request, exc: Exception) -> Response:
accept = request.headers.get("accept", "")
if "text/html" in accept:
content = self.generate_html(exc)
return HTMLResponse(content, status_code=500)
content = self.generate_plain_text(exc)
return PlainTextResponse(content, status_code=500)
def error_response(self, request: Request, exc: Exception) -> Response:
return PlainTextResponse("Internal Server Error", status_code=500)
|