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- import os
- import typing as t
- from warnings import warn
- 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.
- """
- 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 = [
- f"You tried to access the file {key!r} in the request.files"
- " dictionary but it does not exist. The mimetype for the"
- f" request is {request.mimetype!r} 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.'
- ]
- if form_matches:
- names = ", ".join(repr(x) for x in form_matches)
- buf.append(
- "\n\nThe browser instead transmitted some file names. "
- f"This was submitted: {names}"
- )
- 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 = [
- f"A request was sent to this URL ({request.url}) but a"
- " redirect was issued automatically by the routing system"
- f" to {exc.new_url!r}."
- ]
- # In case just a slash was appended we can be extra helpful
- if f"{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"
- f" {request.method}-request to this URL since we can't make"
- " browsers or HTTP clients redirect with form data reliably"
- " or without user interaction."
- )
- 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 as e:
- if key not in request.form:
- raise
- raise DebugFilesKeyError(request, key) from e
- newcls.__name__ = oldcls.__name__
- newcls.__module__ = oldcls.__module__
- request.files.__class__ = newcls
- def _dump_loader_info(loader) -> t.Generator:
- yield f"class: {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) for x in value):
- continue
- yield f"{key}:"
- for item in value:
- yield f" - {item}"
- continue
- elif not isinstance(value, (str, int, float, bool)):
- continue
- yield f"{key}: {value!r}"
- def explain_template_loading_attempts(app: Flask, template, attempts) -> None:
- """This should help developers understand what failed"""
- info = [f"Locating template {template!r}:"]
- 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 = f"application {srcobj.import_name!r}"
- elif isinstance(srcobj, Blueprint):
- src_info = f"blueprint {srcobj.name!r} ({srcobj.import_name})"
- else:
- src_info = repr(srcobj)
- info.append(f"{idx + 1:5}: trying loader of {src_info}")
- for line in _dump_loader_info(loader):
- info.append(f" {line}")
- if triple is None:
- detail = "no match"
- else:
- detail = f"found ({triple[1] or '<string>'!r})"
- total_found += 1
- info.append(f" -> {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"
- f" to the blueprint {blueprint!r}."
- )
- info.append(" Maybe you did not place a template in the right folder?")
- info.append(" See https://flask.palletsprojects.com/blueprints/#templates")
- app.logger.info("\n".join(info))
- def explain_ignored_app_run() -> None:
- 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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