Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.8/site-packages/werkzeug/wrappers/response.py: 28%
290 statements
« prev ^ index » next coverage.py v7.0.1, created at 2022-12-25 06:11 +0000
1import json
2import typing
3import typing as t
4import warnings
5from http import HTTPStatus
7from .._internal import _to_bytes
8from ..datastructures import Headers
9from ..http import remove_entity_headers
10from ..sansio.response import Response as _SansIOResponse
11from ..urls import iri_to_uri
12from ..urls import url_join
13from ..utils import cached_property
14from ..wsgi import ClosingIterator
15from ..wsgi import get_current_url
16from werkzeug._internal import _get_environ
17from werkzeug.http import generate_etag
18from werkzeug.http import http_date
19from werkzeug.http import is_resource_modified
20from werkzeug.http import parse_etags
21from werkzeug.http import parse_range_header
22from werkzeug.wsgi import _RangeWrapper
24if t.TYPE_CHECKING:
25 import typing_extensions as te
26 from _typeshed.wsgi import StartResponse
27 from _typeshed.wsgi import WSGIApplication
28 from _typeshed.wsgi import WSGIEnvironment
29 from .request import Request
32def _warn_if_string(iterable: t.Iterable) -> None:
33 """Helper for the response objects to check if the iterable returned
34 to the WSGI server is not a string.
35 """
36 if isinstance(iterable, str):
37 warnings.warn(
38 "Response iterable was set to a string. This will appear to"
39 " work but means that the server will send the data to the"
40 " client one character at a time. This is almost never"
41 " intended behavior, use 'response.data' to assign strings"
42 " to the response object.",
43 stacklevel=2,
44 )
47def _iter_encoded(
48 iterable: t.Iterable[t.Union[str, bytes]], charset: str
49) -> t.Iterator[bytes]:
50 for item in iterable:
51 if isinstance(item, str):
52 yield item.encode(charset)
53 else:
54 yield item
57def _clean_accept_ranges(accept_ranges: t.Union[bool, str]) -> str:
58 if accept_ranges is True:
59 return "bytes"
60 elif accept_ranges is False:
61 return "none"
62 elif isinstance(accept_ranges, str):
63 return accept_ranges
64 raise ValueError("Invalid accept_ranges value")
67class Response(_SansIOResponse):
68 """Represents an outgoing WSGI HTTP response with body, status, and
69 headers. Has properties and methods for using the functionality
70 defined by various HTTP specs.
72 The response body is flexible to support different use cases. The
73 simple form is passing bytes, or a string which will be encoded as
74 UTF-8. Passing an iterable of bytes or strings makes this a
75 streaming response. A generator is particularly useful for building
76 a CSV file in memory or using SSE (Server Sent Events). A file-like
77 object is also iterable, although the
78 :func:`~werkzeug.utils.send_file` helper should be used in that
79 case.
81 The response object is itself a WSGI application callable. When
82 called (:meth:`__call__`) with ``environ`` and ``start_response``,
83 it will pass its status and headers to ``start_response`` then
84 return its body as an iterable.
86 .. code-block:: python
88 from werkzeug.wrappers.response import Response
90 def index():
91 return Response("Hello, World!")
93 def application(environ, start_response):
94 path = environ.get("PATH_INFO") or "/"
96 if path == "/":
97 response = index()
98 else:
99 response = Response("Not Found", status=404)
101 return response(environ, start_response)
103 :param response: The data for the body of the response. A string or
104 bytes, or tuple or list of strings or bytes, for a fixed-length
105 response, or any other iterable of strings or bytes for a
106 streaming response. Defaults to an empty body.
107 :param status: The status code for the response. Either an int, in
108 which case the default status message is added, or a string in
109 the form ``{code} {message}``, like ``404 Not Found``. Defaults
110 to 200.
111 :param headers: A :class:`~werkzeug.datastructures.Headers` object,
112 or a list of ``(key, value)`` tuples that will be converted to a
113 ``Headers`` object.
114 :param mimetype: The mime type (content type without charset or
115 other parameters) of the response. If the value starts with
116 ``text/`` (or matches some other special cases), the charset
117 will be added to create the ``content_type``.
118 :param content_type: The full content type of the response.
119 Overrides building the value from ``mimetype``.
120 :param direct_passthrough: Pass the response body directly through
121 as the WSGI iterable. This can be used when the body is a binary
122 file or other iterator of bytes, to skip some unnecessary
123 checks. Use :func:`~werkzeug.utils.send_file` instead of setting
124 this manually.
126 .. versionchanged:: 2.0
127 Combine ``BaseResponse`` and mixins into a single ``Response``
128 class. Using the old classes is deprecated and will be removed
129 in Werkzeug 2.1.
131 .. versionchanged:: 0.5
132 The ``direct_passthrough`` parameter was added.
133 """
135 #: if set to `False` accessing properties on the response object will
136 #: not try to consume the response iterator and convert it into a list.
137 #:
138 #: .. versionadded:: 0.6.2
139 #:
140 #: That attribute was previously called `implicit_seqence_conversion`.
141 #: (Notice the typo). If you did use this feature, you have to adapt
142 #: your code to the name change.
143 implicit_sequence_conversion = True
145 #: If a redirect ``Location`` header is a relative URL, make it an
146 #: absolute URL, including scheme and domain.
147 #:
148 #: .. versionchanged:: 2.1
149 #: This is disabled by default, so responses will send relative
150 #: redirects.
151 #:
152 #: .. versionadded:: 0.8
153 autocorrect_location_header = False
155 #: Should this response object automatically set the content-length
156 #: header if possible? This is true by default.
157 #:
158 #: .. versionadded:: 0.8
159 automatically_set_content_length = True
161 #: The response body to send as the WSGI iterable. A list of strings
162 #: or bytes represents a fixed-length response, any other iterable
163 #: is a streaming response. Strings are encoded to bytes as UTF-8.
164 #:
165 #: Do not set to a plain string or bytes, that will cause sending
166 #: the response to be very inefficient as it will iterate one byte
167 #: at a time.
168 response: t.Union[t.Iterable[str], t.Iterable[bytes]]
170 def __init__(
171 self,
172 response: t.Optional[
173 t.Union[t.Iterable[bytes], bytes, t.Iterable[str], str]
174 ] = None,
175 status: t.Optional[t.Union[int, str, HTTPStatus]] = None,
176 headers: t.Optional[
177 t.Union[
178 t.Mapping[str, t.Union[str, int, t.Iterable[t.Union[str, int]]]],
179 t.Iterable[t.Tuple[str, t.Union[str, int]]],
180 ]
181 ] = None,
182 mimetype: t.Optional[str] = None,
183 content_type: t.Optional[str] = None,
184 direct_passthrough: bool = False,
185 ) -> None:
186 super().__init__(
187 status=status,
188 headers=headers,
189 mimetype=mimetype,
190 content_type=content_type,
191 )
193 #: Pass the response body directly through as the WSGI iterable.
194 #: This can be used when the body is a binary file or other
195 #: iterator of bytes, to skip some unnecessary checks. Use
196 #: :func:`~werkzeug.utils.send_file` instead of setting this
197 #: manually.
198 self.direct_passthrough = direct_passthrough
199 self._on_close: t.List[t.Callable[[], t.Any]] = []
201 # we set the response after the headers so that if a class changes
202 # the charset attribute, the data is set in the correct charset.
203 if response is None:
204 self.response = []
205 elif isinstance(response, (str, bytes, bytearray)):
206 self.set_data(response)
207 else:
208 self.response = response
210 def call_on_close(self, func: t.Callable[[], t.Any]) -> t.Callable[[], t.Any]:
211 """Adds a function to the internal list of functions that should
212 be called as part of closing down the response. Since 0.7 this
213 function also returns the function that was passed so that this
214 can be used as a decorator.
216 .. versionadded:: 0.6
217 """
218 self._on_close.append(func)
219 return func
221 def __repr__(self) -> str:
222 if self.is_sequence:
223 body_info = f"{sum(map(len, self.iter_encoded()))} bytes"
224 else:
225 body_info = "streamed" if self.is_streamed else "likely-streamed"
226 return f"<{type(self).__name__} {body_info} [{self.status}]>"
228 @classmethod
229 def force_type(
230 cls, response: "Response", environ: t.Optional["WSGIEnvironment"] = None
231 ) -> "Response":
232 """Enforce that the WSGI response is a response object of the current
233 type. Werkzeug will use the :class:`Response` internally in many
234 situations like the exceptions. If you call :meth:`get_response` on an
235 exception you will get back a regular :class:`Response` object, even
236 if you are using a custom subclass.
238 This method can enforce a given response type, and it will also
239 convert arbitrary WSGI callables into response objects if an environ
240 is provided::
242 # convert a Werkzeug response object into an instance of the
243 # MyResponseClass subclass.
244 response = MyResponseClass.force_type(response)
246 # convert any WSGI application into a response object
247 response = MyResponseClass.force_type(response, environ)
249 This is especially useful if you want to post-process responses in
250 the main dispatcher and use functionality provided by your subclass.
252 Keep in mind that this will modify response objects in place if
253 possible!
255 :param response: a response object or wsgi application.
256 :param environ: a WSGI environment object.
257 :return: a response object.
258 """
259 if not isinstance(response, Response):
260 if environ is None:
261 raise TypeError(
262 "cannot convert WSGI application into response"
263 " objects without an environ"
264 )
266 from ..test import run_wsgi_app
268 response = Response(*run_wsgi_app(response, environ))
270 response.__class__ = cls
271 return response
273 @classmethod
274 def from_app(
275 cls, app: "WSGIApplication", environ: "WSGIEnvironment", buffered: bool = False
276 ) -> "Response":
277 """Create a new response object from an application output. This
278 works best if you pass it an application that returns a generator all
279 the time. Sometimes applications may use the `write()` callable
280 returned by the `start_response` function. This tries to resolve such
281 edge cases automatically. But if you don't get the expected output
282 you should set `buffered` to `True` which enforces buffering.
284 :param app: the WSGI application to execute.
285 :param environ: the WSGI environment to execute against.
286 :param buffered: set to `True` to enforce buffering.
287 :return: a response object.
288 """
289 from ..test import run_wsgi_app
291 return cls(*run_wsgi_app(app, environ, buffered))
293 @typing.overload
294 def get_data(self, as_text: "te.Literal[False]" = False) -> bytes:
295 ...
297 @typing.overload
298 def get_data(self, as_text: "te.Literal[True]") -> str:
299 ...
301 def get_data(self, as_text: bool = False) -> t.Union[bytes, str]:
302 """The string representation of the response body. Whenever you call
303 this property the response iterable is encoded and flattened. This
304 can lead to unwanted behavior if you stream big data.
306 This behavior can be disabled by setting
307 :attr:`implicit_sequence_conversion` to `False`.
309 If `as_text` is set to `True` the return value will be a decoded
310 string.
312 .. versionadded:: 0.9
313 """
314 self._ensure_sequence()
315 rv = b"".join(self.iter_encoded())
317 if as_text:
318 return rv.decode(self.charset)
320 return rv
322 def set_data(self, value: t.Union[bytes, str]) -> None:
323 """Sets a new string as response. The value must be a string or
324 bytes. If a string is set it's encoded to the charset of the
325 response (utf-8 by default).
327 .. versionadded:: 0.9
328 """
329 # if a string is set, it's encoded directly so that we
330 # can set the content length
331 if isinstance(value, str):
332 value = value.encode(self.charset)
333 else:
334 value = bytes(value)
335 self.response = [value]
336 if self.automatically_set_content_length:
337 self.headers["Content-Length"] = str(len(value))
339 data = property(
340 get_data,
341 set_data,
342 doc="A descriptor that calls :meth:`get_data` and :meth:`set_data`.",
343 )
345 def calculate_content_length(self) -> t.Optional[int]:
346 """Returns the content length if available or `None` otherwise."""
347 try:
348 self._ensure_sequence()
349 except RuntimeError:
350 return None
351 return sum(len(x) for x in self.iter_encoded())
353 def _ensure_sequence(self, mutable: bool = False) -> None:
354 """This method can be called by methods that need a sequence. If
355 `mutable` is true, it will also ensure that the response sequence
356 is a standard Python list.
358 .. versionadded:: 0.6
359 """
360 if self.is_sequence:
361 # if we need a mutable object, we ensure it's a list.
362 if mutable and not isinstance(self.response, list):
363 self.response = list(self.response) # type: ignore
364 return
365 if self.direct_passthrough:
366 raise RuntimeError(
367 "Attempted implicit sequence conversion but the"
368 " response object is in direct passthrough mode."
369 )
370 if not self.implicit_sequence_conversion:
371 raise RuntimeError(
372 "The response object required the iterable to be a"
373 " sequence, but the implicit conversion was disabled."
374 " Call make_sequence() yourself."
375 )
376 self.make_sequence()
378 def make_sequence(self) -> None:
379 """Converts the response iterator in a list. By default this happens
380 automatically if required. If `implicit_sequence_conversion` is
381 disabled, this method is not automatically called and some properties
382 might raise exceptions. This also encodes all the items.
384 .. versionadded:: 0.6
385 """
386 if not self.is_sequence:
387 # if we consume an iterable we have to ensure that the close
388 # method of the iterable is called if available when we tear
389 # down the response
390 close = getattr(self.response, "close", None)
391 self.response = list(self.iter_encoded())
392 if close is not None:
393 self.call_on_close(close)
395 def iter_encoded(self) -> t.Iterator[bytes]:
396 """Iter the response encoded with the encoding of the response.
397 If the response object is invoked as WSGI application the return
398 value of this method is used as application iterator unless
399 :attr:`direct_passthrough` was activated.
400 """
401 if __debug__:
402 _warn_if_string(self.response)
403 # Encode in a separate function so that self.response is fetched
404 # early. This allows us to wrap the response with the return
405 # value from get_app_iter or iter_encoded.
406 return _iter_encoded(self.response, self.charset)
408 @property
409 def is_streamed(self) -> bool:
410 """If the response is streamed (the response is not an iterable with
411 a length information) this property is `True`. In this case streamed
412 means that there is no information about the number of iterations.
413 This is usually `True` if a generator is passed to the response object.
415 This is useful for checking before applying some sort of post
416 filtering that should not take place for streamed responses.
417 """
418 try:
419 len(self.response) # type: ignore
420 except (TypeError, AttributeError):
421 return True
422 return False
424 @property
425 def is_sequence(self) -> bool:
426 """If the iterator is buffered, this property will be `True`. A
427 response object will consider an iterator to be buffered if the
428 response attribute is a list or tuple.
430 .. versionadded:: 0.6
431 """
432 return isinstance(self.response, (tuple, list))
434 def close(self) -> None:
435 """Close the wrapped response if possible. You can also use the object
436 in a with statement which will automatically close it.
438 .. versionadded:: 0.9
439 Can now be used in a with statement.
440 """
441 if hasattr(self.response, "close"):
442 self.response.close() # type: ignore
443 for func in self._on_close:
444 func()
446 def __enter__(self) -> "Response":
447 return self
449 def __exit__(self, exc_type, exc_value, tb): # type: ignore
450 self.close()
452 def freeze(self) -> None:
453 """Make the response object ready to be pickled. Does the
454 following:
456 * Buffer the response into a list, ignoring
457 :attr:`implicity_sequence_conversion` and
458 :attr:`direct_passthrough`.
459 * Set the ``Content-Length`` header.
460 * Generate an ``ETag`` header if one is not already set.
462 .. versionchanged:: 2.1
463 Removed the ``no_etag`` parameter.
465 .. versionchanged:: 2.0
466 An ``ETag`` header is added, the ``no_etag`` parameter is
467 deprecated and will be removed in Werkzeug 2.1.
469 .. versionchanged:: 0.6
470 The ``Content-Length`` header is set.
471 """
472 # Always freeze the encoded response body, ignore
473 # implicit_sequence_conversion and direct_passthrough.
474 self.response = list(self.iter_encoded())
475 self.headers["Content-Length"] = str(sum(map(len, self.response)))
476 self.add_etag()
478 def get_wsgi_headers(self, environ: "WSGIEnvironment") -> Headers:
479 """This is automatically called right before the response is started
480 and returns headers modified for the given environment. It returns a
481 copy of the headers from the response with some modifications applied
482 if necessary.
484 For example the location header (if present) is joined with the root
485 URL of the environment. Also the content length is automatically set
486 to zero here for certain status codes.
488 .. versionchanged:: 0.6
489 Previously that function was called `fix_headers` and modified
490 the response object in place. Also since 0.6, IRIs in location
491 and content-location headers are handled properly.
493 Also starting with 0.6, Werkzeug will attempt to set the content
494 length if it is able to figure it out on its own. This is the
495 case if all the strings in the response iterable are already
496 encoded and the iterable is buffered.
498 :param environ: the WSGI environment of the request.
499 :return: returns a new :class:`~werkzeug.datastructures.Headers`
500 object.
501 """
502 headers = Headers(self.headers)
503 location: t.Optional[str] = None
504 content_location: t.Optional[str] = None
505 content_length: t.Optional[t.Union[str, int]] = None
506 status = self.status_code
508 # iterate over the headers to find all values in one go. Because
509 # get_wsgi_headers is used each response that gives us a tiny
510 # speedup.
511 for key, value in headers:
512 ikey = key.lower()
513 if ikey == "location":
514 location = value
515 elif ikey == "content-location":
516 content_location = value
517 elif ikey == "content-length":
518 content_length = value
520 # make sure the location header is an absolute URL
521 if location is not None:
522 old_location = location
523 if isinstance(location, str):
524 # Safe conversion is necessary here as we might redirect
525 # to a broken URI scheme (for instance itms-services).
526 location = iri_to_uri(location, safe_conversion=True)
528 if self.autocorrect_location_header:
529 current_url = get_current_url(environ, strip_querystring=True)
530 if isinstance(current_url, str):
531 current_url = iri_to_uri(current_url)
532 location = url_join(current_url, location)
533 if location != old_location:
534 headers["Location"] = location
536 # make sure the content location is a URL
537 if content_location is not None and isinstance(content_location, str):
538 headers["Content-Location"] = iri_to_uri(content_location)
540 if 100 <= status < 200 or status == 204:
541 # Per section 3.3.2 of RFC 7230, "a server MUST NOT send a
542 # Content-Length header field in any response with a status
543 # code of 1xx (Informational) or 204 (No Content)."
544 headers.remove("Content-Length")
545 elif status == 304:
546 remove_entity_headers(headers)
548 # if we can determine the content length automatically, we
549 # should try to do that. But only if this does not involve
550 # flattening the iterator or encoding of strings in the
551 # response. We however should not do that if we have a 304
552 # response.
553 if (
554 self.automatically_set_content_length
555 and self.is_sequence
556 and content_length is None
557 and status not in (204, 304)
558 and not (100 <= status < 200)
559 ):
560 try:
561 content_length = sum(len(_to_bytes(x, "ascii")) for x in self.response)
562 except UnicodeError:
563 # Something other than bytes, can't safely figure out
564 # the length of the response.
565 pass
566 else:
567 headers["Content-Length"] = str(content_length)
569 return headers
571 def get_app_iter(self, environ: "WSGIEnvironment") -> t.Iterable[bytes]:
572 """Returns the application iterator for the given environ. Depending
573 on the request method and the current status code the return value
574 might be an empty response rather than the one from the response.
576 If the request method is `HEAD` or the status code is in a range
577 where the HTTP specification requires an empty response, an empty
578 iterable is returned.
580 .. versionadded:: 0.6
582 :param environ: the WSGI environment of the request.
583 :return: a response iterable.
584 """
585 status = self.status_code
586 if (
587 environ["REQUEST_METHOD"] == "HEAD"
588 or 100 <= status < 200
589 or status in (204, 304)
590 ):
591 iterable: t.Iterable[bytes] = ()
592 elif self.direct_passthrough:
593 if __debug__:
594 _warn_if_string(self.response)
595 return self.response # type: ignore
596 else:
597 iterable = self.iter_encoded()
598 return ClosingIterator(iterable, self.close)
600 def get_wsgi_response(
601 self, environ: "WSGIEnvironment"
602 ) -> t.Tuple[t.Iterable[bytes], str, t.List[t.Tuple[str, str]]]:
603 """Returns the final WSGI response as tuple. The first item in
604 the tuple is the application iterator, the second the status and
605 the third the list of headers. The response returned is created
606 specially for the given environment. For example if the request
607 method in the WSGI environment is ``'HEAD'`` the response will
608 be empty and only the headers and status code will be present.
610 .. versionadded:: 0.6
612 :param environ: the WSGI environment of the request.
613 :return: an ``(app_iter, status, headers)`` tuple.
614 """
615 headers = self.get_wsgi_headers(environ)
616 app_iter = self.get_app_iter(environ)
617 return app_iter, self.status, headers.to_wsgi_list()
619 def __call__(
620 self, environ: "WSGIEnvironment", start_response: "StartResponse"
621 ) -> t.Iterable[bytes]:
622 """Process this response as WSGI application.
624 :param environ: the WSGI environment.
625 :param start_response: the response callable provided by the WSGI
626 server.
627 :return: an application iterator
628 """
629 app_iter, status, headers = self.get_wsgi_response(environ)
630 start_response(status, headers)
631 return app_iter
633 # JSON
635 #: A module or other object that has ``dumps`` and ``loads``
636 #: functions that match the API of the built-in :mod:`json` module.
637 json_module = json
639 @property
640 def json(self) -> t.Optional[t.Any]:
641 """The parsed JSON data if :attr:`mimetype` indicates JSON
642 (:mimetype:`application/json`, see :attr:`is_json`).
644 Calls :meth:`get_json` with default arguments.
645 """
646 return self.get_json()
648 def get_json(self, force: bool = False, silent: bool = False) -> t.Optional[t.Any]:
649 """Parse :attr:`data` as JSON. Useful during testing.
651 If the mimetype does not indicate JSON
652 (:mimetype:`application/json`, see :attr:`is_json`), this
653 returns ``None``.
655 Unlike :meth:`Request.get_json`, the result is not cached.
657 :param force: Ignore the mimetype and always try to parse JSON.
658 :param silent: Silence parsing errors and return ``None``
659 instead.
660 """
661 if not (force or self.is_json):
662 return None
664 data = self.get_data()
666 try:
667 return self.json_module.loads(data)
668 except ValueError:
669 if not silent:
670 raise
672 return None
674 # Stream
676 @cached_property
677 def stream(self) -> "ResponseStream":
678 """The response iterable as write-only stream."""
679 return ResponseStream(self)
681 def _wrap_range_response(self, start: int, length: int) -> None:
682 """Wrap existing Response in case of Range Request context."""
683 if self.status_code == 206:
684 self.response = _RangeWrapper(self.response, start, length) # type: ignore
686 def _is_range_request_processable(self, environ: "WSGIEnvironment") -> bool:
687 """Return ``True`` if `Range` header is present and if underlying
688 resource is considered unchanged when compared with `If-Range` header.
689 """
690 return (
691 "HTTP_IF_RANGE" not in environ
692 or not is_resource_modified(
693 environ,
694 self.headers.get("etag"),
695 None,
696 self.headers.get("last-modified"),
697 ignore_if_range=False,
698 )
699 ) and "HTTP_RANGE" in environ
701 def _process_range_request(
702 self,
703 environ: "WSGIEnvironment",
704 complete_length: t.Optional[int] = None,
705 accept_ranges: t.Optional[t.Union[bool, str]] = None,
706 ) -> bool:
707 """Handle Range Request related headers (RFC7233). If `Accept-Ranges`
708 header is valid, and Range Request is processable, we set the headers
709 as described by the RFC, and wrap the underlying response in a
710 RangeWrapper.
712 Returns ``True`` if Range Request can be fulfilled, ``False`` otherwise.
714 :raises: :class:`~werkzeug.exceptions.RequestedRangeNotSatisfiable`
715 if `Range` header could not be parsed or satisfied.
717 .. versionchanged:: 2.0
718 Returns ``False`` if the length is 0.
719 """
720 from ..exceptions import RequestedRangeNotSatisfiable
722 if (
723 accept_ranges is None
724 or complete_length is None
725 or complete_length == 0
726 or not self._is_range_request_processable(environ)
727 ):
728 return False
730 parsed_range = parse_range_header(environ.get("HTTP_RANGE"))
732 if parsed_range is None:
733 raise RequestedRangeNotSatisfiable(complete_length)
735 range_tuple = parsed_range.range_for_length(complete_length)
736 content_range_header = parsed_range.to_content_range_header(complete_length)
738 if range_tuple is None or content_range_header is None:
739 raise RequestedRangeNotSatisfiable(complete_length)
741 content_length = range_tuple[1] - range_tuple[0]
742 self.headers["Content-Length"] = content_length
743 self.headers["Accept-Ranges"] = accept_ranges
744 self.content_range = content_range_header # type: ignore
745 self.status_code = 206
746 self._wrap_range_response(range_tuple[0], content_length)
747 return True
749 def make_conditional(
750 self,
751 request_or_environ: t.Union["WSGIEnvironment", "Request"],
752 accept_ranges: t.Union[bool, str] = False,
753 complete_length: t.Optional[int] = None,
754 ) -> "Response":
755 """Make the response conditional to the request. This method works
756 best if an etag was defined for the response already. The `add_etag`
757 method can be used to do that. If called without etag just the date
758 header is set.
760 This does nothing if the request method in the request or environ is
761 anything but GET or HEAD.
763 For optimal performance when handling range requests, it's recommended
764 that your response data object implements `seekable`, `seek` and `tell`
765 methods as described by :py:class:`io.IOBase`. Objects returned by
766 :meth:`~werkzeug.wsgi.wrap_file` automatically implement those methods.
768 It does not remove the body of the response because that's something
769 the :meth:`__call__` function does for us automatically.
771 Returns self so that you can do ``return resp.make_conditional(req)``
772 but modifies the object in-place.
774 :param request_or_environ: a request object or WSGI environment to be
775 used to make the response conditional
776 against.
777 :param accept_ranges: This parameter dictates the value of
778 `Accept-Ranges` header. If ``False`` (default),
779 the header is not set. If ``True``, it will be set
780 to ``"bytes"``. If ``None``, it will be set to
781 ``"none"``. If it's a string, it will use this
782 value.
783 :param complete_length: Will be used only in valid Range Requests.
784 It will set `Content-Range` complete length
785 value and compute `Content-Length` real value.
786 This parameter is mandatory for successful
787 Range Requests completion.
788 :raises: :class:`~werkzeug.exceptions.RequestedRangeNotSatisfiable`
789 if `Range` header could not be parsed or satisfied.
791 .. versionchanged:: 2.0
792 Range processing is skipped if length is 0 instead of
793 raising a 416 Range Not Satisfiable error.
794 """
795 environ = _get_environ(request_or_environ)
796 if environ["REQUEST_METHOD"] in ("GET", "HEAD"):
797 # if the date is not in the headers, add it now. We however
798 # will not override an already existing header. Unfortunately
799 # this header will be overridden by many WSGI servers including
800 # wsgiref.
801 if "date" not in self.headers:
802 self.headers["Date"] = http_date()
803 accept_ranges = _clean_accept_ranges(accept_ranges)
804 is206 = self._process_range_request(environ, complete_length, accept_ranges)
805 if not is206 and not is_resource_modified(
806 environ,
807 self.headers.get("etag"),
808 None,
809 self.headers.get("last-modified"),
810 ):
811 if parse_etags(environ.get("HTTP_IF_MATCH")):
812 self.status_code = 412
813 else:
814 self.status_code = 304
815 if (
816 self.automatically_set_content_length
817 and "content-length" not in self.headers
818 ):
819 length = self.calculate_content_length()
820 if length is not None:
821 self.headers["Content-Length"] = length
822 return self
824 def add_etag(self, overwrite: bool = False, weak: bool = False) -> None:
825 """Add an etag for the current response if there is none yet.
827 .. versionchanged:: 2.0
828 SHA-1 is used to generate the value. MD5 may not be
829 available in some environments.
830 """
831 if overwrite or "etag" not in self.headers:
832 self.set_etag(generate_etag(self.get_data()), weak)
835class ResponseStream:
836 """A file descriptor like object used by :meth:`Response.stream` to
837 represent the body of the stream. It directly pushes into the
838 response iterable of the response object.
839 """
841 mode = "wb+"
843 def __init__(self, response: Response):
844 self.response = response
845 self.closed = False
847 def write(self, value: bytes) -> int:
848 if self.closed:
849 raise ValueError("I/O operation on closed file")
850 self.response._ensure_sequence(mutable=True)
851 self.response.response.append(value) # type: ignore
852 self.response.headers.pop("Content-Length", None)
853 return len(value)
855 def writelines(self, seq: t.Iterable[bytes]) -> None:
856 for item in seq:
857 self.write(item)
859 def close(self) -> None:
860 self.closed = True
862 def flush(self) -> None:
863 if self.closed:
864 raise ValueError("I/O operation on closed file")
866 def isatty(self) -> bool:
867 if self.closed:
868 raise ValueError("I/O operation on closed file")
869 return False
871 def tell(self) -> int:
872 self.response._ensure_sequence()
873 return sum(map(len, self.response.response))
875 @property
876 def encoding(self) -> str:
877 return self.response.charset