156 lines
5.9 KiB
Python
156 lines
5.9 KiB
Python
# -*- coding: utf-8 -*-
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"""
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flask.debughelpers
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~~~~~~~~~~~~~~~~~~
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Various helpers to make the development experience better.
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:copyright: (c) 2015 by Armin Ronacher.
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:license: BSD, see LICENSE for more details.
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"""
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from ._compat import implements_to_string, text_type
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from .app import Flask
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from .blueprints import Blueprint
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from .globals import _request_ctx_stack
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class UnexpectedUnicodeError(AssertionError, UnicodeError):
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"""Raised in places where we want some better error reporting for
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unexpected unicode or binary data.
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"""
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@implements_to_string
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class DebugFilesKeyError(KeyError, AssertionError):
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"""Raised from request.files during debugging. The idea is that it can
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provide a better error message than just a generic KeyError/BadRequest.
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"""
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def __init__(self, request, key):
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form_matches = request.form.getlist(key)
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buf = ['You tried to access the file "%s" in the request.files '
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'dictionary but it does not exist. The mimetype for the request '
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'is "%s" instead of "multipart/form-data" which means that no '
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'file contents were transmitted. To fix this error you should '
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'provide enctype="multipart/form-data" in your form.' %
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(key, request.mimetype)]
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if form_matches:
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buf.append('\n\nThe browser instead transmitted some file names. '
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'This was submitted: %s' % ', '.join('"%s"' % x
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for x in form_matches))
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self.msg = ''.join(buf)
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def __str__(self):
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return self.msg
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class FormDataRoutingRedirect(AssertionError):
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"""This exception is raised by Flask in debug mode if it detects a
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redirect caused by the routing system when the request method is not
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GET, HEAD or OPTIONS. Reasoning: form data will be dropped.
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"""
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def __init__(self, request):
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exc = request.routing_exception
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buf = ['A request was sent to this URL (%s) but a redirect was '
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'issued automatically by the routing system to "%s".'
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% (request.url, exc.new_url)]
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# In case just a slash was appended we can be extra helpful
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if request.base_url + '/' == exc.new_url.split('?')[0]:
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buf.append(' The URL was defined with a trailing slash so '
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'Flask will automatically redirect to the URL '
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'with the trailing slash if it was accessed '
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'without one.')
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buf.append(' Make sure to directly send your %s-request to this URL '
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'since we can\'t make browsers or HTTP clients redirect '
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'with form data reliably or without user interaction.' %
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request.method)
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buf.append('\n\nNote: this exception is only raised in debug mode')
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AssertionError.__init__(self, ''.join(buf).encode('utf-8'))
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def attach_enctype_error_multidict(request):
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"""Since Flask 0.8 we're monkeypatching the files object in case a
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request is detected that does not use multipart form data but the files
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object is accessed.
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"""
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oldcls = request.files.__class__
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class newcls(oldcls):
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def __getitem__(self, key):
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try:
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return oldcls.__getitem__(self, key)
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except KeyError:
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if key not in request.form:
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raise
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raise DebugFilesKeyError(request, key)
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newcls.__name__ = oldcls.__name__
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newcls.__module__ = oldcls.__module__
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request.files.__class__ = newcls
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def _dump_loader_info(loader):
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yield 'class: %s.%s' % (type(loader).__module__, type(loader).__name__)
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for key, value in sorted(loader.__dict__.items()):
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if key.startswith('_'):
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continue
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if isinstance(value, (tuple, list)):
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if not all(isinstance(x, (str, text_type)) for x in value):
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continue
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yield '%s:' % key
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for item in value:
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yield ' - %s' % item
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continue
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elif not isinstance(value, (str, text_type, int, float, bool)):
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continue
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yield '%s: %r' % (key, value)
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def explain_template_loading_attempts(app, template, attempts):
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"""This should help developers understand what failed"""
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info = ['Locating template "%s":' % template]
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total_found = 0
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blueprint = None
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reqctx = _request_ctx_stack.top
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if reqctx is not None and reqctx.request.blueprint is not None:
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blueprint = reqctx.request.blueprint
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for idx, (loader, srcobj, triple) in enumerate(attempts):
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if isinstance(srcobj, Flask):
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src_info = 'application "%s"' % srcobj.import_name
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elif isinstance(srcobj, Blueprint):
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src_info = 'blueprint "%s" (%s)' % (srcobj.name,
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srcobj.import_name)
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else:
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src_info = repr(srcobj)
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info.append('% 5d: trying loader of %s' % (
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idx + 1, src_info))
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for line in _dump_loader_info(loader):
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info.append(' %s' % line)
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if triple is None:
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detail = 'no match'
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else:
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detail = 'found (%r)' % (triple[1] or '<string>')
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total_found += 1
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info.append(' -> %s' % detail)
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seems_fishy = False
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if total_found == 0:
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info.append('Error: the template could not be found.')
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seems_fishy = True
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elif total_found > 1:
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info.append('Warning: multiple loaders returned a match for the template.')
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seems_fishy = True
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if blueprint is not None and seems_fishy:
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info.append(' The template was looked up from an endpoint that '
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'belongs to the blueprint "%s".' % blueprint)
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info.append(' Maybe you did not place a template in the right folder?')
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info.append(' See http://flask.pocoo.org/docs/blueprints/#templates')
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app.logger.info('\n'.join(info))
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