243 lines
8.0 KiB
Python
243 lines
8.0 KiB
Python
# Copyright (c) 2013 Rackspace, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may not
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# use this file except in compliance with the License. You may obtain a copy
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# of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations under
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# the License.
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import falcon
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import jsonschema
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from oslo_log import log as logging
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from zaqar.i18n import _
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from zaqar.transport import utils
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from zaqar.transport.wsgi import errors
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JSONObject = dict
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"""Represents a JSON object in Python."""
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JSONArray = list
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"""Represents a JSON array in Python."""
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LOG = logging.getLogger(__name__)
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#
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# TODO(kgriffs): Create Falcon "before" hooks adapters for these functions
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#
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def deserialize(stream, len):
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"""Deserializes JSON from a file-like stream.
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This function deserializes JSON from a stream, including
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translating read and parsing errors to HTTP error types.
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:param stream: file-like object from which to read an object or
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array of objects.
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:param len: number of bytes to read from stream
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:raises HTTPBadRequest: if the request is invalid
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:raises HTTPServiceUnavailable: if the http service is unavailable
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"""
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if len is None:
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description = _(u'Request body can not be empty')
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raise errors.HTTPBadRequestBody(description)
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try:
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# TODO(kgriffs): read_json should stream the resulting list
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# of messages, returning a generator rather than buffering
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# everything in memory (bp/streaming-serialization).
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return utils.read_json(stream, len)
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except utils.MalformedJSON as ex:
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LOG.debug(ex)
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description = _(u'Request body could not be parsed.')
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raise errors.HTTPBadRequestBody(description)
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except utils.OverflowedJSONInteger as ex:
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LOG.debug(ex)
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description = _(u'JSON contains integer that is too large.')
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raise errors.HTTPBadRequestBody(description)
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except Exception as ex:
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# Error while reading from the network/server
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LOG.exception(ex)
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description = _(u'Request body could not be read.')
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raise errors.HTTPServiceUnavailable(description)
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def sanitize(document, spec=None, doctype=JSONObject):
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"""Validates a document and drops undesired fields.
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:param document: A dict to verify according to `spec`.
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:param spec: (Default None) Iterable describing expected fields,
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yielding tuples with the form of:
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(field_name, value_type, default_value)
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Note that value_type may either be a Python type, or the
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special string '*' to accept any type. default_value is the
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default to give the field if it is missing, or None to require
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that the field be present.
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If spec is None, the incoming documents will not be validated.
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:param doctype: type of document to expect; must be either
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JSONObject or JSONArray.
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:raises HTTPBadRequestBody: if the request is invalid
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:returns: A sanitized, filtered version of the document. If the
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document is a list of objects, each object will be filtered
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and returned in a new list. If, on the other hand, the document
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is expected to contain a single object, that object's fields will
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be filtered and the resulting object will be returned.
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"""
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if doctype is JSONObject:
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if not isinstance(document, JSONObject):
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raise errors.HTTPDocumentTypeNotSupported()
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return document if spec is None else filter(document, spec)
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if doctype is JSONArray:
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if not isinstance(document, JSONArray):
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raise errors.HTTPDocumentTypeNotSupported()
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if spec is None:
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return document
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return [filter(obj, spec) for obj in document]
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raise TypeError('doctype must be either a JSONObject or JSONArray')
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def filter(document, spec):
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"""Validates and retrieves typed fields from a single document.
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Sanitizes a dict-like document by checking it against a
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list of field spec, and returning only those fields
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specified.
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:param document: dict-like object
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:param spec: iterable describing expected fields, yielding
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tuples with the form of: (field_name, value_type). Note that
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value_type may either be a Python type, or the special
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string '*' to accept any type.
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:raises HTTPBadRequest: if any field is missing or not an
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instance of the specified type
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:returns: A filtered dict containing only the fields
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listed in the spec
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"""
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filtered = {}
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for name, value_type, default_value in spec:
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filtered[name] = get_checked_field(document, name,
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value_type, default_value)
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return filtered
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def get_checked_field(document, name, value_type, default_value):
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"""Validates and retrieves a typed field from a document.
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This function attempts to look up doc[name], and raises
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appropriate HTTP errors if the field is missing or not an
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instance of the given type.
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:param document: dict-like object
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:param name: field name
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:param value_type: expected value type, or '*' to accept any type
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:param default_value: Default value to use if the value is missing,
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or None to make the value required.
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:raises HTTPBadRequest: if the field is missing or not an
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instance of value_type
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:returns: value obtained from doc[name]
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"""
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try:
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value = document[name]
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except KeyError:
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if default_value is not None:
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value = default_value
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else:
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description = _(u'Missing "{name}" field.').format(name=name)
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raise errors.HTTPBadRequestBody(description)
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# PERF(kgriffs): We do our own little spec thing because it is way
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# faster than jsonschema.
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if value_type == '*' or isinstance(value, value_type):
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return value
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description = _(u'The value of the "{name}" field must be a {vtype}.')
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description = description.format(name=name, vtype=value_type.__name__)
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raise errors.HTTPBadRequestBody(description)
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def load(req):
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"""Reads request body, raising an exception if it is not JSON.
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:param req: The request object to read from
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:type req: falcon.Request
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:return: a dictionary decoded from the JSON stream
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:rtype: dict
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:raises HTTPBadRequestBody: if JSON could not be parsed
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"""
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try:
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return utils.read_json(req.stream, req.content_length)
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except (utils.MalformedJSON, utils.OverflowedJSONInteger) as ex:
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LOG.exception(ex)
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raise errors.HTTPBadRequestBody(
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'JSON could not be parsed.'
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)
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# TODO(cpp-cabrera): generalize this
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def validate(validator, document):
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"""Verifies a document against a schema.
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:param validator: a validator to use to check validity
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:type validator: jsonschema.Draft4Validator
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:param document: document to check
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:type document: dict
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:raises HTTPBadRequestBody: if the request is invalid
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"""
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try:
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validator.validate(document)
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except jsonschema.ValidationError as ex:
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raise errors.HTTPBadRequestBody(
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'{0}: {1}'.format(ex.args, ex.message)
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)
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def message_url(message, base_path, claim_id=None):
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path = "/".join([base_path, 'messages', message['id']])
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if claim_id:
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path += falcon.to_query_str({'claim_id': claim_id})
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return path
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def format_message_v1(message, base_path, claim_id=None):
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return {
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'href': message_url(message, base_path, claim_id),
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'ttl': message['ttl'],
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'age': message['age'],
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'body': message['body'],
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}
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def format_message_v1_1(message, base_path, claim_id=None):
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url = message_url(message, base_path, claim_id)
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return {
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'id': message['id'],
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'href': url,
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'ttl': message['ttl'],
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'age': message['age'],
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'body': message['body'],
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}
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