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handle Deferred from render

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This commit is contained in:
Jean-Paul Calderone 2020-10-15 11:43:42 -04:00
parent fd70715a8b
commit 69c7c40510
6 changed files with 188 additions and 93 deletions
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5
src/allmydata/test/web/test_grid.py
View File

@ -18,6 +18,10 @@ from allmydata.storage.shares import get_share_file
from allmydata.scripts.debug import CorruptShareOptions, corrupt_share
from allmydata.immutable import upload
from allmydata.mutable import publish
from ...web.common import (
render_exception,
)
from .. import common_util as testutil
from ..common import WebErrorMixin, ShouldFailMixin
from ..no_network import GridTestMixin
@ -34,6 +38,7 @@ class CompletelyUnhandledError(Exception):
pass
class ErrorBoom(object, resource.Resource):
@render_exception
def render(self, req):
raise CompletelyUnhandledError("whoops")

198
src/allmydata/web/common.py
View File

@ -3,15 +3,43 @@ import time
import json
from functools import wraps
from hyperlink import (
DecodedURL,
)
from twisted.web import (
http,
resource,
server,
template,
)
from twisted.web.template import (
tags,
)
from twisted.web.util import (
FailureElement,
redirectTo,
)
from twisted.python.reflect import (
fullyQualifiedName,
)
from twisted.python.urlpath import (
URLPath,
)
from twisted.python import log
from twisted.python.failure import (
Failure,
)
from twisted.internet.defer import (
Deferred,
maybeDeferred,
)
from twisted.web.resource import (
IResource,
)
from nevow import appserver
from nevow.inevow import IRequest
from allmydata import blacklist
from allmydata.interfaces import (
EmptyPathnameComponentError,
@ -320,48 +348,10 @@ def humanize_failure(f):
class MyExceptionHandler(appserver.DefaultExceptionHandler, object):
def simple(self, ctx, text, code=http.BAD_REQUEST):
req = IRequest(ctx)
req.setResponseCode(code)
#req.responseHeaders.setRawHeaders("content-encoding", [])
#req.responseHeaders.setRawHeaders("content-disposition", [])
req.setHeader("content-type", "text/plain;charset=utf-8")
if isinstance(text, unicode):
text = text.encode("utf-8")
req.setHeader("content-length", b"%d" % len(text))
req.write(text)
# TODO: consider putting the requested URL here
req.finishRequest(False)
def renderHTTP_exception(self, ctx, f):
try:
text, code = humanize_failure(f)
except:
log.msg("exception in humanize_failure")
log.msg("argument was %s" % (f,))
log.err()
text, code = str(f), None
if code is not None:
return self.simple(ctx, text, code)
if f.check(server.UnsupportedMethod):
# twisted.web.server.Request.render() has support for transforming
# this into an appropriate 501 NOT_IMPLEMENTED or 405 NOT_ALLOWED
# return code, but nevow does not.
req = IRequest(ctx)
method = req.method
return self.simple(ctx,
"I don't know how to treat a %s request." % method,
http.NOT_IMPLEMENTED)
req = IRequest(ctx)
accept = req.getHeader("accept")
if not accept:
accept = "*/*"
if "*/*" in accept or "text/*" in accept or "text/html" in accept:
super = appserver.DefaultExceptionHandler
return super.renderHTTP_exception(self, ctx, f)
# use plain text
traceback = f.getTraceback()
return self.simple(ctx, traceback, http.INTERNAL_SERVER_ERROR)
req.write(_renderHTTP_exception(req, f))
req.finishRequest(False)
class NeedOperationHandleError(WebError):
@ -481,16 +471,130 @@ def exception_to_child(f):
return g
def render_exception(f):
def render_exception(render):
"""
Decorate a ``render_*`` method with exception handling behavior to render
an error page reflecting the exception.
"""
@wraps(f)
@wraps(render)
def g(self, request):
try:
return f(self, request)
except Exception as e:
description, status = humanize_exception(e)
return resource.ErrorPage(status, "Error", description).render(request)
bound_render = render.__get__(self, type(self))
result = maybeDeferred(bound_render, request)
if isinstance(result, Deferred):
result.addBoth(_finish, bound_render, request)
return server.NOT_DONE_YET
elif isinstance(result, bytes):
return result
elif result == server.NOT_DONE_YET:
return server.NOT_DONE_YET
else:
raise Exception("{!r} returned unusable {!r}".format(
fullyQualifiedName(bound_render),
result,
))
return g
def _finish(result, render, request):
if isinstance(result, Failure):
_finish(
_renderHTTP_exception(request, result),
render,
request,
)
elif IResource.providedBy(result):
# If result is also using @render_exception then we don't want to
# double-apply the logic. This leads to an attempt to double-finish
# the request. If it isn't using @render_exception then you should
# fix it so it is.
result.render(request)
elif isinstance(result, bytes):
request.write(result)
request.finish()
elif isinstance(result, URLPath):
if result.netloc == b"":
root = URLPath.fromRequest(request)
result.scheme = root.scheme
result.netloc = root.netloc
_finish(redirectTo(str(result), request), render, request)
elif isinstance(result, DecodedURL):
_finish(redirectTo(str(result), request), render, request)
elif result is None:
request.finish()
elif result == server.NOT_DONE_YET:
pass
else:
log.err("Request for {!r} handled by {!r} returned unusable {!r}".format(
request.uri,
fullyQualifiedName(render),
result,
))
request.setResponseCode(http.INTERNAL_SERVER_ERROR)
_finish(b"", render, request)
def _renderHTTP_exception(request, failure):
try:
text, code = humanize_failure(failure)
except:
log.msg("exception in humanize_failure")
log.msg("argument was %s" % (failure,))
log.err()
text = str(failure)
code = None
if code is not None:
return _renderHTTP_exception_simple(request, text, code)
if failure.check(server.UnsupportedMethod):
# twisted.web.server.Request.render() has support for transforming
# this into an appropriate 501 NOT_IMPLEMENTED or 405 NOT_ALLOWED
# return code, but nevow does not.
method = request.method
return _renderHTTP_exception_simple(
request,
"I don't know how to treat a %s request." % (method,),
http.NOT_IMPLEMENTED,
)
accept = request.getHeader("accept")
if not accept:
accept = "*/*"
if "*/*" in accept or "text/*" in accept or "text/html" in accept:
request.setResponseCode(http.INTERNAL_SERVER_ERROR)
return template.renderElement(
request,
tags.html(
tags.head(
tags.title(u"Exception"),
),
tags.body(
FailureElement(failure),
),
),
)
# use plain text
traceback = failure.getTraceback()
return _renderHTTP_exception_simple(
request,
traceback,
http.INTERNAL_SERVER_ERROR,
)
def _renderHTTP_exception_simple(request, text, code):
request.setResponseCode(code)
request.setHeader("content-type", "text/plain;charset=utf-8")
if isinstance(text, unicode):
text = text.encode("utf-8")
request.setHeader("content-length", b"%d" % len(text))
return text
def handle_when_done(req, d):
when_done = get_arg(req, "when_done", None)
if when_done:
d.addCallback(lambda res: DecodedURL.from_text(when_done.decode("utf-8")))
return d

10
src/allmydata/web/directory.py
View File

@ -58,6 +58,7 @@ from allmydata.web.common import (
SlotsSequenceElement,
exception_to_child,
render_exception,
handle_when_done,
)
from allmydata.web.filenode import ReplaceMeMixin, \
FileNodeHandler, PlaceHolderNodeHandler
@ -206,6 +207,7 @@ class DirectoryNodeHandler(ReplaceMeMixin, Resource, object):
)
return make_handler_for(node, self.client, self.node, name)
@render_exception
def render_DELETE(self, req):
assert self.parentnode and self.name
d = self.parentnode.delete(self.name)
@ -310,13 +312,7 @@ class DirectoryNodeHandler(ReplaceMeMixin, Resource, object):
else:
raise WebError("POST to a directory with bad t=%s" % t)
when_done = get_arg(req, "when_done", None)
if when_done:
def done(res):
req.redirect(when_done)
return res
d.addCallback(done)
return d
return handle_when_done(req, d)
def _POST_mkdir(self, req):
name = get_arg(req, "name", "")

43
src/allmydata/web/filenode.py
View File

@ -1,6 +1,10 @@
import json
from hyperlink import (
DecodedURL,
)
from twisted.web import http, static
from twisted.internet import defer
from twisted.web.resource import (
@ -8,8 +12,6 @@ from twisted.web.resource import (
ErrorPage,
)
from nevow import url
from allmydata.interfaces import ExistingChildError
from allmydata.monitor import Monitor
from allmydata.immutable.upload import FileHandle
@ -34,8 +36,8 @@ from allmydata.web.common import (
render_exception,
should_create_intermediate_directories,
text_plain,
MyExceptionHandler,
WebError,
handle_when_done,
)
from allmydata.web.check_results import (
CheckResultsRenderer,
@ -150,10 +152,7 @@ class PlaceHolderNodeHandler(Resource, ReplaceMeMixin):
# placeholder.
raise WebError("POST to a file: bad t=%s" % t)
when_done = get_arg(req, "when_done", None)
if when_done:
d.addCallback(lambda res: when_done)
return d
return handle_when_done(req, d)
class FileNodeHandler(Resource, ReplaceMeMixin, object):
@ -315,10 +314,7 @@ class FileNodeHandler(Resource, ReplaceMeMixin, object):
else:
raise WebError("POST to file: bad t=%s" % t)
when_done = get_arg(req, "when_done", None)
if when_done:
d.addCallback(lambda res: url.URL.fromString(when_done))
return d
return handle_when_done(req, d)
def _maybe_literal(self, res, Results_Class):
if res:
@ -485,23 +481,11 @@ class FileDownloader(Resource, object):
if req.method == "HEAD":
return ""
finished = []
def _request_finished(ign):
finished.append(True)
req.notifyFinish().addBoth(_request_finished)
d = self.filenode.read(req, first, size)
def _finished(ign):
if not finished:
req.finish()
def _error(f):
lp = log.msg("error during GET", facility="tahoe.webish", failure=f,
level=log.UNUSUAL, umid="xSiF3w")
if finished:
log.msg("but it's too late to tell them", parent=lp,
level=log.UNUSUAL, umid="j1xIbw")
return
req._tahoe_request_had_error = f # for HTTP-style logging
if req.startedWriting:
# The content-type is already set, and the response code has
@ -513,15 +497,16 @@ class FileDownloader(Resource, object):
# error response be shorter than the intended results.
#
# We don't have a lot of options, unfortunately.
req.write("problem during download\n")
req.finish()
return b"problem during download\n"
else:
# We haven't written anything yet, so we can provide a
# sensible error message.
eh = MyExceptionHandler()
eh.renderHTTP_exception(req, f)
d.addCallbacks(_finished, _error)
return req.deferred
return f
d.addCallbacks(
lambda ignored: None,
_error,
)
return d
def _file_json_metadata(req, filenode, edge_metadata):

20
src/allmydata/web/operations.py
View File

@ -1,10 +1,15 @@
import time
from nevow import url
from hyperlink import (
DecodedURL,
)
from twisted.web.template import (
renderer,
tags as T,
)
from twisted.python.urlpath import (
URLPath,
)
from twisted.python.failure import Failure
from twisted.internet import reactor, defer
from twisted.web import resource
@ -84,17 +89,14 @@ class OphandleTable(resource.Resource, service.Service):
"""
:param allmydata.webish.MyRequest req:
"""
ophandle = get_arg(req, "ophandle")
ophandle = get_arg(req, "ophandle").decode("utf-8")
assert ophandle
target = get_root(req) + "/operations/" + ophandle
root = DecodedURL.from_text(unicode(URLPath.fromRequest(req)))
target = root.click(u"/").child(u"operations", ophandle)
output = get_arg(req, "output")
if output:
target = target + "?output=%s" % output
# XXX: We have to use nevow.url here because nevow.appserver
# is unhappy with anything else; so this gets its own ticket.
# https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3314
return url.URL.fromString(target)
target = target.add(u"output", output.decode("utf-8"))
return target
@exception_to_child
def getChild(self, name, req):

5
src/allmydata/web/unlinked.py
View File

@ -2,6 +2,9 @@
import urllib
from twisted.web import http
from twisted.internet import defer
from twisted.python.urlpath import (
URLPath,
)
from twisted.python.filepath import FilePath
from twisted.web.resource import Resource
from twisted.web.template import (
@ -66,7 +69,7 @@ def POSTUnlinkedCHK(req, client):
def _done(upload_results, redir_to):
if "%(uri)s" in redir_to:
redir_to = redir_to.replace("%(uri)s", urllib.quote(upload_results.get_uri()))
return url.URL.fromString(redir_to)
return URLPath.fromString(redir_to)
d.addCallback(_done, when_done)
else:
# return the Upload Results page, which includes the URI