Request / Response Objects¶
The request and response objects wrap the WSGI environment or the return value from a WSGI application so that it is another WSGI application (wraps a whole application).
How they Work¶
Your WSGI application is always passed two arguments. The WSGI “environment”
and the WSGI start_response function that is used to start the response
phase. The Request
class wraps the environ for easier access to
request variables (form data, request headers etc.).
The Response
on the other hand is a standard WSGI application that
you can create. The simple hello world in Werkzeug looks like this:
from werkzeug.wrappers import Response
application = Response('Hello World!')
To make it more useful you can replace it with a function and do some processing:
from werkzeug.wrappers import Request, Response
def application(environ, start_response):
request = Request(environ)
response = Response(f"Hello {request.args.get('name', 'World!')}!")
return response(environ, start_response)
Because this is a very common task the Request
object provides
a helper for that. The above code can be rewritten like this:
from werkzeug.wrappers import Request, Response
@Request.application
def application(request):
return Response(f"Hello {request.args.get('name', 'World!')}!")
The application is still a valid WSGI application that accepts the environment and start_response callable.
Mutability and Reusability of Wrappers¶
The implementation of the Werkzeug request and response objects are trying to guard you from common pitfalls by disallowing certain things as much as possible. This serves two purposes: high performance and avoiding of pitfalls.
For the request object the following rules apply:
The request object is immutable. Modifications are not supported by default, you may however replace the immutable attributes with mutable attributes if you need to modify it.
The request object may be shared in the same thread, but is not thread safe itself. If you need to access it from multiple threads, use locks around calls.
It’s not possible to pickle the request object.
For the response object the following rules apply:
The response object is mutable
The response object can be pickled or copied after freeze() was called.
Since Werkzeug 0.6 it’s safe to use the same response object for multiple WSGI responses.
It’s possible to create copies using copy.deepcopy.
Wrapper Classes¶
- class werkzeug.wrappers.Request(environ, populate_request=True, shallow=False)¶
Represents an incoming WSGI HTTP request, with headers and body taken from the WSGI environment. Has properties and methods for using the functionality defined by various HTTP specs. The data in requests object is read-only.
Text data is assumed to use UTF-8 encoding, which should be true for the vast majority of modern clients. Using an encoding set by the client is unsafe in Python due to extra encodings it provides, such as
zip
. To change the assumed encoding, subclass and replacecharset
.- Parameters:
environ (WSGIEnvironment) – The WSGI environ is generated by the WSGI server and contains information about the server configuration and client request.
populate_request (bool) – Add this request object to the WSGI environ as
environ['werkzeug.request']
. Can be useful when debugging.shallow (bool) – Makes reading from
stream
(and any method that would read from it) raise aRuntimeError
. Useful to prevent consuming the form data in middleware, which would make it unavailable to the final application.
Changed in version 3.0: The
charset
,url_charset
, andencoding_errors
parameters were removed.Changelog
Changed in version 2.1: Old
BaseRequest
and mixin classes were removed.Changed in version 2.1: Remove the
disable_data_descriptor
attribute.Changed in version 2.0: Combine
BaseRequest
and mixins into a singleRequest
class.Changed in version 0.5: Read-only mode is enforced with immutable classes for all data.
- _get_file_stream(total_content_length, content_type, filename=None, content_length=None)¶
Called to get a stream for the file upload.
This must provide a file-like class with read(), readline() and seek() methods that is both writeable and readable.
The default implementation returns a temporary file if the total content length is higher than 500KB. Because many browsers do not provide a content length for the files only the total content length matters.
- Parameters:
total_content_length (int | None) – the total content length of all the data in the request combined. This value is guaranteed to be there.
content_type (str | None) – the mimetype of the uploaded file.
filename (str | None) – the filename of the uploaded file. May be None.
content_length (int | None) – the length of this file. This value is usually not provided because webbrowsers do not provide this value.
- Return type:
- property accept_charsets: CharsetAccept¶
List of charsets this client supports as
CharsetAccept
object.
- property accept_encodings: Accept¶
List of encodings this client accepts. Encodings in a HTTP term are compression encodings such as gzip. For charsets have a look at
accept_charset
.
- property accept_languages: LanguageAccept¶
List of languages this client accepts as
LanguageAccept
object.
- property accept_mimetypes: MIMEAccept¶
List of mimetypes this client supports as
MIMEAccept
object.
- access_control_request_headers¶
Sent with a preflight request to indicate which headers will be sent with the cross origin request. Set
access_control_allow_headers
on the response to indicate which headers are allowed.
- access_control_request_method¶
Sent with a preflight request to indicate which method will be used for the cross origin request. Set
access_control_allow_methods
on the response to indicate which methods are allowed.
- property access_route: list[str]¶
If a forwarded header exists this is a list of all ip addresses from the client ip to the last proxy server.
- classmethod application(f)¶
Decorate a function as responder that accepts the request as the last argument. This works like the
responder()
decorator but the function is passed the request object as the last argument and the request object will be closed automatically:@Request.application def my_wsgi_app(request): return Response('Hello World!')
As of Werkzeug 0.14 HTTP exceptions are automatically caught and converted to responses instead of failing.
- Parameters:
f (t.Callable[[Request], WSGIApplication]) – the WSGI callable to decorate
- Returns:
a new WSGI callable
- Return type:
WSGIApplication
- property args: MultiDict[str, str]¶
The parsed URL parameters (the part in the URL after the question mark).
By default an
ImmutableMultiDict
is returned from this function. This can be changed by settingparameter_storage_class
to a different type. This might be necessary if the order of the form data is important.Changelog
Changed in version 2.3: Invalid bytes remain percent encoded.
- property authorization: Authorization | None¶
The
Authorization
header parsed into anAuthorization
object.None
if the header is not present.Changelog
Changed in version 2.3:
Authorization
is no longer adict
. Thetoken
attribute was added for auth schemes that use a token instead of parameters.
- property cache_control: RequestCacheControl¶
A
RequestCacheControl
object for the incoming cache control headers.
- close()¶
Closes associated resources of this request object. This closes all file handles explicitly. You can also use the request object in a with statement which will automatically close it.
Changelog
New in version 0.9.
- Return type:
None
- content_encoding¶
The Content-Encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional content codings have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain the media-type referenced by the Content-Type header field.
Changelog
New in version 0.9.
- property content_length: int | None¶
The Content-Length entity-header field indicates the size of the entity-body in bytes or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET.
- content_md5¶
The Content-MD5 entity-header field, as defined in RFC 1864, is an MD5 digest of the entity-body for the purpose of providing an end-to-end message integrity check (MIC) of the entity-body. (Note: a MIC is good for detecting accidental modification of the entity-body in transit, but is not proof against malicious attacks.)
Changelog
New in version 0.9.
- content_type¶
The Content-Type entity-header field indicates the media type of the entity-body sent to the recipient or, in the case of the HEAD method, the media type that would have been sent had the request been a GET.
- property cookies: ImmutableMultiDict[str, str]¶
A
dict
with the contents of all cookies transmitted with the request.
- property data: bytes¶
The raw data read from
stream
. Will be empty if the request represents form data.To get the raw data even if it represents form data, use
get_data()
.
- date¶
The Date general-header field represents the date and time at which the message was originated, having the same semantics as orig-date in RFC 822.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- dict_storage_class¶
alias of
ImmutableMultiDict
- environ: WSGIEnvironment¶
The WSGI environment containing HTTP headers and information from the WSGI server.
- property files: ImmutableMultiDict[str, FileStorage]¶
MultiDict
object containing all uploaded files. Each key infiles
is the name from the<input type="file" name="">
. Each value infiles
is a WerkzeugFileStorage
object.It basically behaves like a standard file object you know from Python, with the difference that it also has a
save()
function that can store the file on the filesystem.Note that
files
will only contain data if the request method was POST, PUT or PATCH and the<form>
that posted to the request hadenctype="multipart/form-data"
. It will be empty otherwise.See the
MultiDict
/FileStorage
documentation for more details about the used data structure.
- property form: ImmutableMultiDict[str, str]¶
The form parameters. By default an
ImmutableMultiDict
is returned from this function. This can be changed by settingparameter_storage_class
to a different type. This might be necessary if the order of the form data is important.Please keep in mind that file uploads will not end up here, but instead in the
files
attribute.Changelog
Changed in version 0.9: Previous to Werkzeug 0.9 this would only contain form data for POST and PUT requests.
- form_data_parser_class¶
alias of
FormDataParser
- classmethod from_values(*args, **kwargs)¶
Create a new request object based on the values provided. If environ is given missing values are filled from there. This method is useful for small scripts when you need to simulate a request from an URL. Do not use this method for unittesting, there is a full featured client object (
Client
) that allows to create multipart requests, support for cookies etc.This accepts the same options as the
EnvironBuilder
.Changelog
Changed in version 0.5: This method now accepts the same arguments as
EnvironBuilder
. Because of this the environ parameter is now called environ_overrides.
- get_data(cache: bool = True, as_text: Literal[False] = False, parse_form_data: bool = False) bytes ¶
- get_data(cache: bool = True, as_text: Literal[True] = False, parse_form_data: bool = False) str
This reads the buffered incoming data from the client into one bytes object. By default this is cached but that behavior can be changed by setting cache to False.
Usually it’s a bad idea to call this method without checking the content length first as a client could send dozens of megabytes or more to cause memory problems on the server.
Note that if the form data was already parsed this method will not return anything as form data parsing does not cache the data like this method does. To implicitly invoke form data parsing function set parse_form_data to True. When this is done the return value of this method will be an empty string if the form parser handles the data. This generally is not necessary as if the whole data is cached (which is the default) the form parser will used the cached data to parse the form data. Please be generally aware of checking the content length first in any case before calling this method to avoid exhausting server memory.
If as_text is set to True the return value will be a decoded string.
Changelog
New in version 0.9.
- get_json(force: bool = False, silent: Literal[False] = False, cache: bool = True) Any ¶
- get_json(force: bool = False, silent: bool = False, cache: bool = True) Any | None
Parse
data
as JSON.If the mimetype does not indicate JSON (application/json, see
is_json
), or parsing fails,on_json_loading_failed()
is called and its return value is used as the return value. By default this raises a 415 Unsupported Media Type resp.- Parameters:
force – Ignore the mimetype and always try to parse JSON.
silent – Silence mimetype and parsing errors, and return
None
instead.cache – Store the parsed JSON to return for subsequent calls.
Changelog
Changed in version 2.3: Raise a 415 error instead of 400.
Changed in version 2.1: Raise a 400 error if the content type is incorrect.
- headers¶
The headers received with the request.
- property host: str¶
The host name the request was made to, including the port if it’s non-standard. Validated with
trusted_hosts
.
- property if_modified_since: datetime | None¶
The parsed If-Modified-Since header as a datetime object.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- property if_none_match: ETags¶
An object containing all the etags in the If-None-Match header.
- Return type:
- property if_range: IfRange¶
The parsed
If-Range
header.Changelog
Changed in version 2.0:
IfRange.date
is timezone-aware.New in version 0.7.
- property if_unmodified_since: datetime | None¶
The parsed If-Unmodified-Since header as a datetime object.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- input_stream¶
The raw WSGI input stream, without any safety checks.
This is dangerous to use. It does not guard against infinite streams or reading past
content_length
ormax_content_length
.Use
stream
instead.
- property is_json: bool¶
Check if the mimetype indicates JSON data, either application/json or application/*+json.
- is_multiprocess¶
boolean that is True if the application is served by a WSGI server that spawns multiple processes.
- is_multithread¶
boolean that is True if the application is served by a multithreaded WSGI server.
- is_run_once¶
boolean that is True if the application will be executed only once in a process lifetime. This is the case for CGI for example, but it’s not guaranteed that the execution only happens one time.
- property json: Any | None¶
The parsed JSON data if
mimetype
indicates JSON (application/json, seeis_json
).Calls
get_json()
with default arguments.If the request content type is not
application/json
, this will raise a 415 Unsupported Media Type error.Changelog
Changed in version 2.3: Raise a 415 error instead of 400.
Changed in version 2.1: Raise a 400 error if the content type is incorrect.
- json_module = <module 'json' from '/usr/lib/python3.11/json/__init__.py'>¶
A module or other object that has
dumps
andloads
functions that match the API of the built-injson
module.
- list_storage_class¶
alias of
ImmutableList
- make_form_data_parser()¶
Creates the form data parser. Instantiates the
form_data_parser_class
with some parameters.Changelog
New in version 0.8.
- Return type:
- max_content_length: int | None = None¶
the maximum content length. This is forwarded to the form data parsing function (
parse_form_data()
). When set and theform
orfiles
attribute is accessed and the parsing fails because more than the specified value is transmitted aRequestEntityTooLarge
exception is raised.Changelog
New in version 0.5.
- max_form_memory_size: int | None = None¶
the maximum form field size. This is forwarded to the form data parsing function (
parse_form_data()
). When set and theform
orfiles
attribute is accessed and the data in memory for post data is longer than the specified value aRequestEntityTooLarge
exception is raised.Changelog
New in version 0.5.
- max_form_parts = 1000¶
The maximum number of multipart parts to parse, passed to
form_data_parser_class
. Parsing form data with more than this many parts will raiseRequestEntityTooLarge
.Changelog
New in version 2.2.3.
- max_forwards¶
The Max-Forwards request-header field provides a mechanism with the TRACE and OPTIONS methods to limit the number of proxies or gateways that can forward the request to the next inbound server.
- method¶
The method the request was made with, such as
GET
.
- property mimetype: str¶
Like
content_type
, but without parameters (eg, without charset, type etc.) and always lowercase. For example if the content type istext/HTML; charset=utf-8
the mimetype would be'text/html'
.
- property mimetype_params: dict[str, str]¶
The mimetype parameters as dict. For example if the content type is
text/html; charset=utf-8
the params would be{'charset': 'utf-8'}
.
- on_json_loading_failed(e)¶
Called if
get_json()
fails and isn’t silenced.If this method returns a value, it is used as the return value for
get_json()
. The default implementation raisesBadRequest
.- Parameters:
e (ValueError | None) – If parsing failed, this is the exception. It will be
None
if the content type wasn’tapplication/json
.- Return type:
Changelog
Changed in version 2.3: Raise a 415 error instead of 400.
- origin¶
The host that the request originated from. Set
access_control_allow_origin
on the response to indicate which origins are allowed.
- parameter_storage_class¶
alias of
ImmutableMultiDict
- path¶
The path part of the URL after
root_path
. This is the path used for routing within the application.
- property pragma: HeaderSet¶
The Pragma general-header field is used to include implementation-specific directives that might apply to any recipient along the request/response chain. All pragma directives specify optional behavior from the viewpoint of the protocol; however, some systems MAY require that behavior be consistent with the directives.
- query_string¶
The part of the URL after the “?”. This is the raw value, use
args
for the parsed values.
- referrer¶
The Referer[sic] request-header field allows the client to specify, for the server’s benefit, the address (URI) of the resource from which the Request-URI was obtained (the “referrer”, although the header field is misspelled).
- remote_addr¶
The address of the client sending the request.
- remote_user¶
If the server supports user authentication, and the script is protected, this attribute contains the username the user has authenticated as.
- root_path¶
The prefix that the application is mounted under, without a trailing slash.
path
comes after this.
- property root_url: str¶
The request URL scheme, host, and root path. This is the root that the application is accessed from.
- scheme¶
The URL scheme of the protocol the request used, such as
https
orwss
.
- property script_root: str¶
Alias for
self.root_path
.environ["SCRIPT_ROOT"]
without a trailing slash.
- server¶
The address of the server.
(host, port)
,(path, None)
for unix sockets, orNone
if not known.
- shallow: bool¶
Set when creating the request object. If
True
, reading from the request body will cause aRuntimeException
. Useful to prevent modifying the stream from middleware.
- property stream: IO[bytes]¶
The WSGI input stream, with safety checks. This stream can only be consumed once.
Use
get_data()
to get the full data as bytes or text. Thedata
attribute will contain the full bytes only if they do not represent form data. Theform
attribute will contain the parsed form data in that case.Unlike
input_stream
, this stream guards against infinite streams or reading pastcontent_length
ormax_content_length
.If
max_content_length
is set, it can be enforced on streams ifwsgi.input_terminated
is set. Otherwise, an empty stream is returned.If the limit is reached before the underlying stream is exhausted (such as a file that is too large, or an infinite stream), the remaining contents of the stream cannot be read safely. Depending on how the server handles this, clients may show a “connection reset” failure instead of seeing the 413 response.
Changelog
Changed in version 2.3: Check
max_content_length
preemptively and while reading.Changed in version 0.9: The stream is always set (but may be consumed) even if form parsing was accessed first.
- trusted_hosts: list[str] | None = None¶
Valid host names when handling requests. By default all hosts are trusted, which means that whatever the client says the host is will be accepted.
Because
Host
andX-Forwarded-Host
headers can be set to any value by a malicious client, it is recommended to either set this property or implement similar validation in the proxy (if the application is being run behind one).Changelog
New in version 0.9.
- property url_root: str¶
Alias for
root_url
. The URL with scheme, host, and root path. For example,https://example.com/app/
.
- property user_agent: UserAgent¶
The user agent. Use
user_agent.string
to get the header value. Setuser_agent_class
to a subclass ofUserAgent
to provide parsing for the other properties or other extended data.Changelog
Changed in version 2.1: The built-in parser was removed. Set
user_agent_class
to aUserAgent
subclass to parse data from the string.
- property values: CombinedMultiDict[str, str]¶
A
werkzeug.datastructures.CombinedMultiDict
that combinesargs
andform
.For GET requests, only
args
are present, notform
.Changelog
Changed in version 2.0: For GET requests, only
args
are present, notform
.
- class werkzeug.wrappers.Response(response=None, status=None, headers=None, mimetype=None, content_type=None, direct_passthrough=False)¶
Represents an outgoing WSGI HTTP response with body, status, and headers. Has properties and methods for using the functionality defined by various HTTP specs.
The response body is flexible to support different use cases. The simple form is passing bytes, or a string which will be encoded as UTF-8. Passing an iterable of bytes or strings makes this a streaming response. A generator is particularly useful for building a CSV file in memory or using SSE (Server Sent Events). A file-like object is also iterable, although the
send_file()
helper should be used in that case.The response object is itself a WSGI application callable. When called (
__call__()
) withenviron
andstart_response
, it will pass its status and headers tostart_response
then return its body as an iterable.from werkzeug.wrappers.response import Response def index(): return Response("Hello, World!") def application(environ, start_response): path = environ.get("PATH_INFO") or "/" if path == "/": response = index() else: response = Response("Not Found", status=404) return response(environ, start_response)
- Parameters:
response (Iterable[str] | Iterable[bytes]) – The data for the body of the response. A string or bytes, or tuple or list of strings or bytes, for a fixed-length response, or any other iterable of strings or bytes for a streaming response. Defaults to an empty body.
status (int | str | HTTPStatus | None) – The status code for the response. Either an int, in which case the default status message is added, or a string in the form
{code} {message}
, like404 Not Found
. Defaults to 200.headers (Headers) – A
Headers
object, or a list of(key, value)
tuples that will be converted to aHeaders
object.mimetype (str | None) – The mime type (content type without charset or other parameters) of the response. If the value starts with
text/
(or matches some other special cases), the charset will be added to create thecontent_type
.content_type (str | None) – The full content type of the response. Overrides building the value from
mimetype
.direct_passthrough (bool) – Pass the response body directly through as the WSGI iterable. This can be used when the body is a binary file or other iterator of bytes, to skip some unnecessary checks. Use
send_file()
instead of setting this manually.
Changelog
Changed in version 2.1: Old
BaseResponse
and mixin classes were removed.Changed in version 2.0: Combine
BaseResponse
and mixins into a singleResponse
class.Changed in version 0.5: The
direct_passthrough
parameter was added.- __call__(environ, start_response)¶
Process this response as WSGI application.
- Parameters:
environ (WSGIEnvironment) – the WSGI environment.
start_response (StartResponse) – the response callable provided by the WSGI server.
- Returns:
an application iterator
- Return type:
t.Iterable[bytes]
- _ensure_sequence(mutable=False)¶
This method can be called by methods that need a sequence. If mutable is true, it will also ensure that the response sequence is a standard Python list.
Changelog
New in version 0.6.
- Parameters:
mutable (bool) –
- Return type:
None
- accept_ranges¶
The Accept-Ranges header. Even though the name would indicate that multiple values are supported, it must be one string token only.
The values
'bytes'
and'none'
are common.Changelog
New in version 0.7.
- property access_control_allow_credentials: bool¶
Whether credentials can be shared by the browser to JavaScript code. As part of the preflight request it indicates whether credentials can be used on the cross origin request.
- access_control_allow_headers¶
Which headers can be sent with the cross origin request.
- access_control_allow_methods¶
Which methods can be used for the cross origin request.
- access_control_allow_origin¶
The origin or ‘*’ for any origin that may make cross origin requests.
- access_control_expose_headers¶
Which headers can be shared by the browser to JavaScript code.
- access_control_max_age¶
The maximum age in seconds the access control settings can be cached for.
- add_etag(overwrite=False, weak=False)¶
Add an etag for the current response if there is none yet.
Changelog
Changed in version 2.0: SHA-1 is used to generate the value. MD5 may not be available in some environments.
- age¶
The Age response-header field conveys the sender’s estimate of the amount of time since the response (or its revalidation) was generated at the origin server.
Age values are non-negative decimal integers, representing time in seconds.
- property allow: HeaderSet¶
The Allow entity-header field lists the set of methods supported by the resource identified by the Request-URI. The purpose of this field is strictly to inform the recipient of valid methods associated with the resource. An Allow header field MUST be present in a 405 (Method Not Allowed) response.
- autocorrect_location_header = False¶
If a redirect
Location
header is a relative URL, make it an absolute URL, including scheme and domain.Changelog
Changed in version 2.1: This is disabled by default, so responses will send relative redirects.
New in version 0.8.
- automatically_set_content_length = True¶
Should this response object automatically set the content-length header if possible? This is true by default.
Changelog
New in version 0.8.
- property cache_control: ResponseCacheControl¶
The Cache-Control general-header field is used to specify directives that MUST be obeyed by all caching mechanisms along the request/response chain.
- calculate_content_length()¶
Returns the content length if available or None otherwise.
- Return type:
int | None
- call_on_close(func)¶
Adds a function to the internal list of functions that should be called as part of closing down the response. Since 0.7 this function also returns the function that was passed so that this can be used as a decorator.
Changelog
New in version 0.6.
- close()¶
Close the wrapped response if possible. You can also use the object in a with statement which will automatically close it.
Changelog
New in version 0.9: Can now be used in a with statement.
- Return type:
None
- content_encoding¶
The Content-Encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional content codings have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain the media-type referenced by the Content-Type header field.
- property content_language: HeaderSet¶
The Content-Language entity-header field describes the natural language(s) of the intended audience for the enclosed entity. Note that this might not be equivalent to all the languages used within the entity-body.
- content_length¶
The Content-Length entity-header field indicates the size of the entity-body, in decimal number of OCTETs, sent to the recipient or, in the case of the HEAD method, the size of the entity-body that would have been sent had the request been a GET.
- content_location¶
The Content-Location entity-header field MAY be used to supply the resource location for the entity enclosed in the message when that entity is accessible from a location separate from the requested resource’s URI.
- content_md5¶
The Content-MD5 entity-header field, as defined in RFC 1864, is an MD5 digest of the entity-body for the purpose of providing an end-to-end message integrity check (MIC) of the entity-body. (Note: a MIC is good for detecting accidental modification of the entity-body in transit, but is not proof against malicious attacks.)
- property content_range: ContentRange¶
The
Content-Range
header as aContentRange
object. Available even if the header is not set.Changelog
New in version 0.7.
- property content_security_policy: ContentSecurityPolicy¶
The
Content-Security-Policy
header as aContentSecurityPolicy
object. Available even if the header is not set.The Content-Security-Policy header adds an additional layer of security to help detect and mitigate certain types of attacks.
- property content_security_policy_report_only: ContentSecurityPolicy¶
The
Content-Security-policy-report-only
header as aContentSecurityPolicy
object. Available even if the header is not set.The Content-Security-Policy-Report-Only header adds a csp policy that is not enforced but is reported thereby helping detect certain types of attacks.
- content_type¶
The Content-Type entity-header field indicates the media type of the entity-body sent to the recipient or, in the case of the HEAD method, the media type that would have been sent had the request been a GET.
- cross_origin_embedder_policy¶
Prevents a document from loading any cross-origin resources that do not explicitly grant the document permission. Values must be a member of the
werkzeug.http.COEP
enum.
- cross_origin_opener_policy¶
Allows control over sharing of browsing context group with cross-origin documents. Values must be a member of the
werkzeug.http.COOP
enum.
- property data: bytes | str¶
A descriptor that calls
get_data()
andset_data()
.
- date¶
The Date general-header field represents the date and time at which the message was originated, having the same semantics as orig-date in RFC 822.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- default_status = 200¶
the default status if none is provided.
- delete_cookie(key, path='/', domain=None, secure=False, httponly=False, samesite=None)¶
Delete a cookie. Fails silently if key doesn’t exist.
- Parameters:
key (str) – the key (name) of the cookie to be deleted.
path (str | None) – if the cookie that should be deleted was limited to a path, the path has to be defined here.
domain (str | None) – if the cookie that should be deleted was limited to a domain, that domain has to be defined here.
secure (bool) – If
True
, the cookie will only be available via HTTPS.httponly (bool) – Disallow JavaScript access to the cookie.
samesite (str | None) – Limit the scope of the cookie to only be attached to requests that are “same-site”.
- Return type:
None
- direct_passthrough¶
Pass the response body directly through as the WSGI iterable. This can be used when the body is a binary file or other iterator of bytes, to skip some unnecessary checks. Use
send_file()
instead of setting this manually.
- expires¶
The Expires entity-header field gives the date/time after which the response is considered stale. A stale cache entry may not normally be returned by a cache.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- classmethod force_type(response, environ=None)¶
Enforce that the WSGI response is a response object of the current type. Werkzeug will use the
Response
internally in many situations like the exceptions. If you callget_response()
on an exception you will get back a regularResponse
object, even if you are using a custom subclass.This method can enforce a given response type, and it will also convert arbitrary WSGI callables into response objects if an environ is provided:
# convert a Werkzeug response object into an instance of the # MyResponseClass subclass. response = MyResponseClass.force_type(response) # convert any WSGI application into a response object response = MyResponseClass.force_type(response, environ)
This is especially useful if you want to post-process responses in the main dispatcher and use functionality provided by your subclass.
Keep in mind that this will modify response objects in place if possible!
- freeze()¶
Make the response object ready to be pickled. Does the following:
Buffer the response into a list, ignoring
implicity_sequence_conversion
anddirect_passthrough
.Set the
Content-Length
header.Generate an
ETag
header if one is not already set.
Changelog
Changed in version 2.1: Removed the
no_etag
parameter.Changed in version 2.0: An
ETag
header is always added.Changed in version 0.6: The
Content-Length
header is set.- Return type:
None
- classmethod from_app(app, environ, buffered=False)¶
Create a new response object from an application output. This works best if you pass it an application that returns a generator all the time. Sometimes applications may use the write() callable returned by the start_response function. This tries to resolve such edge cases automatically. But if you don’t get the expected output you should set buffered to True which enforces buffering.
- get_app_iter(environ)¶
Returns the application iterator for the given environ. Depending on the request method and the current status code the return value might be an empty response rather than the one from the response.
If the request method is HEAD or the status code is in a range where the HTTP specification requires an empty response, an empty iterable is returned.
Changelog
New in version 0.6.
- Parameters:
environ (WSGIEnvironment) – the WSGI environment of the request.
- Returns:
a response iterable.
- Return type:
t.Iterable[bytes]
- get_data(as_text: Literal[False] = False) bytes ¶
- get_data(as_text: Literal[True]) str
The string representation of the response body. Whenever you call this property the response iterable is encoded and flattened. This can lead to unwanted behavior if you stream big data.
This behavior can be disabled by setting
implicit_sequence_conversion
to False.If as_text is set to True the return value will be a decoded string.
Changelog
New in version 0.9.
- get_etag()¶
Return a tuple in the form
(etag, is_weak)
. If there is no ETag the return value is(None, None)
.
- get_json(force: bool = False, silent: Literal[False] = False) Any ¶
- get_json(force: bool = False, silent: bool = False) Any | None
Parse
data
as JSON. Useful during testing.If the mimetype does not indicate JSON (application/json, see
is_json
), this returnsNone
.Unlike
Request.get_json()
, the result is not cached.- Parameters:
force – Ignore the mimetype and always try to parse JSON.
silent – Silence parsing errors and return
None
instead.
- get_wsgi_headers(environ)¶
This is automatically called right before the response is started and returns headers modified for the given environment. It returns a copy of the headers from the response with some modifications applied if necessary.
For example the location header (if present) is joined with the root URL of the environment. Also the content length is automatically set to zero here for certain status codes.
Changelog
Changed in version 0.6: Previously that function was called fix_headers and modified the response object in place. Also since 0.6, IRIs in location and content-location headers are handled properly.
Also starting with 0.6, Werkzeug will attempt to set the content length if it is able to figure it out on its own. This is the case if all the strings in the response iterable are already encoded and the iterable is buffered.
- get_wsgi_response(environ)¶
Returns the final WSGI response as tuple. The first item in the tuple is the application iterator, the second the status and the third the list of headers. The response returned is created specially for the given environment. For example if the request method in the WSGI environment is
'HEAD'
the response will be empty and only the headers and status code will be present.Changelog
New in version 0.6.
- implicit_sequence_conversion = True¶
if set to False accessing properties on the response object will not try to consume the response iterator and convert it into a list.
Changelog
New in version 0.6.2: That attribute was previously called implicit_seqence_conversion. (Notice the typo). If you did use this feature, you have to adapt your code to the name change.
- property is_json: bool¶
Check if the mimetype indicates JSON data, either application/json or application/*+json.
- property is_sequence: bool¶
If the iterator is buffered, this property will be True. A response object will consider an iterator to be buffered if the response attribute is a list or tuple.
Changelog
New in version 0.6.
- property is_streamed: bool¶
If the response is streamed (the response is not an iterable with a length information) this property is True. In this case streamed means that there is no information about the number of iterations. This is usually True if a generator is passed to the response object.
This is useful for checking before applying some sort of post filtering that should not take place for streamed responses.
- iter_encoded()¶
Iter the response encoded with the encoding of the response. If the response object is invoked as WSGI application the return value of this method is used as application iterator unless
direct_passthrough
was activated.
- property json: Any | None¶
The parsed JSON data if
mimetype
indicates JSON (application/json, seeis_json
).Calls
get_json()
with default arguments.
- json_module = <module 'json' from '/usr/lib/python3.11/json/__init__.py'>¶
A module or other object that has
dumps
andloads
functions that match the API of the built-injson
module.
- last_modified¶
The Last-Modified entity-header field indicates the date and time at which the origin server believes the variant was last modified.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- location¶
The Location response-header field is used to redirect the recipient to a location other than the Request-URI for completion of the request or identification of a new resource.
- make_conditional(request_or_environ, accept_ranges=False, complete_length=None)¶
Make the response conditional to the request. This method works best if an etag was defined for the response already. The add_etag method can be used to do that. If called without etag just the date header is set.
This does nothing if the request method in the request or environ is anything but GET or HEAD.
For optimal performance when handling range requests, it’s recommended that your response data object implements seekable, seek and tell methods as described by
io.IOBase
. Objects returned bywrap_file()
automatically implement those methods.It does not remove the body of the response because that’s something the
__call__()
function does for us automatically.Returns self so that you can do
return resp.make_conditional(req)
but modifies the object in-place.- Parameters:
request_or_environ (WSGIEnvironment | Request) – a request object or WSGI environment to be used to make the response conditional against.
accept_ranges (bool | str) – This parameter dictates the value of Accept-Ranges header. If
False
(default), the header is not set. IfTrue
, it will be set to"bytes"
. If it’s a string, it will use this value.complete_length (int | None) – Will be used only in valid Range Requests. It will set Content-Range complete length value and compute Content-Length real value. This parameter is mandatory for successful Range Requests completion.
- Raises:
RequestedRangeNotSatisfiable
if Range header could not be parsed or satisfied.- Return type:
Changelog
Changed in version 2.0: Range processing is skipped if length is 0 instead of raising a 416 Range Not Satisfiable error.
- make_sequence()¶
Converts the response iterator in a list. By default this happens automatically if required. If implicit_sequence_conversion is disabled, this method is not automatically called and some properties might raise exceptions. This also encodes all the items.
Changelog
New in version 0.6.
- Return type:
None
- max_cookie_size = 4093¶
Warn if a cookie header exceeds this size. The default, 4093, should be safely supported by most browsers. A cookie larger than this size will still be sent, but it may be ignored or handled incorrectly by some browsers. Set to 0 to disable this check.
Changelog
New in version 0.13.
- property mimetype_params: dict[str, str]¶
The mimetype parameters as dict. For example if the content type is
text/html; charset=utf-8
the params would be{'charset': 'utf-8'}
.Changelog
New in version 0.5.
- response: Iterable[str] | Iterable[bytes]¶
The response body to send as the WSGI iterable. A list of strings or bytes represents a fixed-length response, any other iterable is a streaming response. Strings are encoded to bytes as UTF-8.
Do not set to a plain string or bytes, that will cause sending the response to be very inefficient as it will iterate one byte at a time.
- property retry_after: datetime | None¶
The Retry-After response-header field can be used with a 503 (Service Unavailable) response to indicate how long the service is expected to be unavailable to the requesting client.
Time in seconds until expiration or date.
Changelog
Changed in version 2.0: The datetime object is timezone-aware.
- set_cookie(key, value='', max_age=None, expires=None, path='/', domain=None, secure=False, httponly=False, samesite=None)¶
Sets a cookie.
A warning is raised if the size of the cookie header exceeds
max_cookie_size
, but the header will still be set.- Parameters:
key (str) – the key (name) of the cookie to be set.
value (str) – the value of the cookie.
max_age (timedelta | int | None) – should be a number of seconds, or None (default) if the cookie should last only as long as the client’s browser session.
expires (str | datetime | int | float | None) – should be a datetime object or UNIX timestamp.
path (str | None) – limits the cookie to a given path, per default it will span the whole domain.
domain (str | None) – if you want to set a cross-domain cookie. For example,
domain="example.com"
will set a cookie that is readable by the domainwww.example.com
,foo.example.com
etc. Otherwise, a cookie will only be readable by the domain that set it.secure (bool) – If
True
, the cookie will only be available via HTTPS.httponly (bool) – Disallow JavaScript access to the cookie.
samesite (str | None) – Limit the scope of the cookie to only be attached to requests that are “same-site”.
- Return type:
None
- set_data(value)¶
Sets a new string as response. The value must be a string or bytes. If a string is set it’s encoded to the charset of the response (utf-8 by default).
Changelog
New in version 0.9.
- set_etag(etag, weak=False)¶
Set the etag, and override the old one if there was one.
- property stream: ResponseStream¶
The response iterable as write-only stream.
- property vary: HeaderSet¶
The Vary field value indicates the set of request-header fields that fully determines, while the response is fresh, whether a cache is permitted to use the response to reply to a subsequent request without revalidation.
- property www_authenticate: WWWAuthenticate¶
The
WWW-Authenticate
header parsed into aWWWAuthenticate
object. Modifying the object will modify the header value.This header is not set by default. To set this header, assign an instance of
WWWAuthenticate
to this attribute.response.www_authenticate = WWWAuthenticate( "basic", {"realm": "Authentication Required"} )
Multiple values for this header can be sent to give the client multiple options. Assign a list to set multiple headers. However, modifying the items in the list will not automatically update the header values, and accessing this attribute will only ever return the first value.
To unset this header, assign
None
or usedel
.Changelog
Changed in version 2.3: This attribute can be assigned to to set the header. A list can be assigned to set multiple header values. Use
del
to unset the header.Changed in version 2.3:
WWWAuthenticate
is no longer adict
. Thetoken
attribute was added for auth challenges that use a token instead of parameters.