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- # -*- coding: utf-8 -*-
- """
- flask.debughelpers
- ~~~~~~~~~~~~~~~~~~
- Various helpers to make the development experience better.
- :copyright: © 2010 by the Pallets team.
- :license: BSD, see LICENSE for more details.
- """
- import os
- from warnings import warn
- from ._compat import implements_to_string, 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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