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- # -*- coding: utf-8 -*-
- """
- flask.debughelpers
- ~~~~~~~~~~~~~~~~~~
- Various helpers to make the development experience better.
- :copyright: 2010 Pallets
- :license: BSD-3-Clause
- """
- import os
- from warnings import warn
- from ._compat import implements_to_string
- from ._compat import text_type
- from .app import Flask
- from .blueprints import Blueprint
- from .globals import _request_ctx_stack
- class UnexpectedUnicodeError(AssertionError, UnicodeError):
- """Raised in places where we want some better error reporting for
- unexpected unicode or binary data.
- """
- @implements_to_string
- class DebugFilesKeyError(KeyError, AssertionError):
- """Raised from request.files during debugging. The idea is that it can
- provide a better error message than just a generic KeyError/BadRequest.
- """
- def __init__(self, request, key):
- form_matches = request.form.getlist(key)
- buf = [
- 'You tried to access the file "%s" in the request.files '
- "dictionary but it does not exist. The mimetype for the request "
- 'is "%s" instead of "multipart/form-data" which means that no '
- "file contents were transmitted. To fix this error you should "
- 'provide enctype="multipart/form-data" in your form.'
- % (key, request.mimetype)
- ]
- if form_matches:
- buf.append(
- "\n\nThe browser instead transmitted some file names. "
- "This was submitted: %s" % ", ".join('"%s"' % x for x in form_matches)
- )
- self.msg = "".join(buf)
- def __str__(self):
- return self.msg
- class FormDataRoutingRedirect(AssertionError):
- """This exception is raised by Flask in debug mode if it detects a
- redirect caused by the routing system when the request method is not
- GET, HEAD or OPTIONS. Reasoning: form data will be dropped.
- """
- def __init__(self, request):
- exc = request.routing_exception
- buf = [
- "A request was sent to this URL (%s) but a redirect was "
- 'issued automatically by the routing system to "%s".'
- % (request.url, exc.new_url)
- ]
- # In case just a slash was appended we can be extra helpful
- if request.base_url + "/" == exc.new_url.split("?")[0]:
- buf.append(
- " The URL was defined with a trailing slash so "
- "Flask will automatically redirect to the URL "
- "with the trailing slash if it was accessed "
- "without one."
- )
- buf.append(
- " Make sure to directly send your %s-request to this URL "
- "since we can't make browsers or HTTP clients redirect "
- "with form data reliably or without user interaction." % request.method
- )
- buf.append("\n\nNote: this exception is only raised in debug mode")
- AssertionError.__init__(self, "".join(buf).encode("utf-8"))
- def attach_enctype_error_multidict(request):
- """Since Flask 0.8 we're monkeypatching the files object in case a
- request is detected that does not use multipart form data but the files
- object is accessed.
- """
- oldcls = request.files.__class__
- class newcls(oldcls):
- def __getitem__(self, key):
- try:
- return oldcls.__getitem__(self, key)
- except KeyError:
- if key not in request.form:
- raise
- raise DebugFilesKeyError(request, key)
- newcls.__name__ = oldcls.__name__
- newcls.__module__ = oldcls.__module__
- request.files.__class__ = newcls
- def _dump_loader_info(loader):
- yield "class: %s.%s" % (type(loader).__module__, type(loader).__name__)
- for key, value in sorted(loader.__dict__.items()):
- if key.startswith("_"):
- continue
- if isinstance(value, (tuple, list)):
- if not all(isinstance(x, (str, text_type)) for x in value):
- continue
- yield "%s:" % key
- for item in value:
- yield " - %s" % item
- continue
- elif not isinstance(value, (str, text_type, int, float, bool)):
- continue
- yield "%s: %r" % (key, value)
- def explain_template_loading_attempts(app, template, attempts):
- """This should help developers understand what failed"""
- info = ['Locating template "%s":' % template]
- total_found = 0
- blueprint = None
- reqctx = _request_ctx_stack.top
- if reqctx is not None and reqctx.request.blueprint is not None:
- blueprint = reqctx.request.blueprint
- for idx, (loader, srcobj, triple) in enumerate(attempts):
- if isinstance(srcobj, Flask):
- src_info = 'application "%s"' % srcobj.import_name
- elif isinstance(srcobj, Blueprint):
- src_info = 'blueprint "%s" (%s)' % (srcobj.name, srcobj.import_name)
- else:
- src_info = repr(srcobj)
- info.append("% 5d: trying loader of %s" % (idx + 1, src_info))
- for line in _dump_loader_info(loader):
- info.append(" %s" % line)
- if triple is None:
- detail = "no match"
- else:
- detail = "found (%r)" % (triple[1] or "<string>")
- total_found += 1
- info.append(" -> %s" % detail)
- seems_fishy = False
- if total_found == 0:
- info.append("Error: the template could not be found.")
- seems_fishy = True
- elif total_found > 1:
- info.append("Warning: multiple loaders returned a match for the template.")
- seems_fishy = True
- if blueprint is not None and seems_fishy:
- info.append(
- " The template was looked up from an endpoint that "
- 'belongs to the blueprint "%s".' % blueprint
- )
- info.append(" Maybe you did not place a template in the right folder?")
- info.append(" See http://flask.pocoo.org/docs/blueprints/#templates")
- app.logger.info("\n".join(info))
- def explain_ignored_app_run():
- if os.environ.get("WERKZEUG_RUN_MAIN") != "true":
- warn(
- Warning(
- "Silently ignoring app.run() because the "
- "application is run from the flask command line "
- "executable. Consider putting app.run() behind an "
- 'if __name__ == "__main__" guard to silence this '
- "warning."
- ),
- stacklevel=3,
- )
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