"""API Blueprint
This is a subclass of Flask's Blueprint
It provides added features:
- Decorators to specify Marshmallow schema for view functions I/O
- API documentation registration
Documentation process works in several steps:
- At import time
- When a MethodView or a view function is decorated, relevant information
is automatically added to the object's ``_apidoc`` attribute.
- The ``Blueprint.doc`` decorator stores additional information in a separate
``_api_manual_doc``. It allows the user to specify documentation
information that flask-rest-api can not - or does not yet - infer from the
code.
- The ``Blueprint.route`` decorator registers the endpoint in the Blueprint
and gathers all information about the endpoint in
``Blueprint._auto_docs[endpoint]`` and
``Blueprint._manual_docs[endpoint]``.
- At initialization time
- Schema instances are replaced either by their reference in the `schemas`
section of the spec if applicable, otherwise by their json representation.
- Automatic documentation is adapted to OpenAPI version and deep-merged with
manual documentation.
- Endpoints documentation is registered in the APISpec object.
"""
from collections import OrderedDict
from functools import wraps
from copy import deepcopy
from flask import Blueprint as FlaskBlueprint
from flask.views import MethodViewType
from .utils import deepupdate, load_info_from_docstring
from .arguments import ArgumentsMixin
from .response import ResponseMixin
from .pagination import PaginationMixin
from .etag import EtagMixin
from .spec import (
DEFAULT_REQUEST_BODY_CONTENT_TYPE, DEFAULT_RESPONSE_CONTENT_TYPE)
[docs]class Blueprint(
FlaskBlueprint,
ArgumentsMixin, ResponseMixin, PaginationMixin, EtagMixin):
"""Blueprint that registers info in API documentation"""
# Order in which the methods are presented in the spec
HTTP_METHODS = ['OPTIONS', 'HEAD', 'GET', 'POST', 'PUT', 'PATCH', 'DELETE']
DEFAULT_LOCATION_CONTENT_TYPE_MAPPING = {
"json": "application/json",
"form": "application/x-www-form-urlencoded",
"files": "multipart/form-data",
}
DOCSTRING_INFO_DELIMITER = "---"
def __init__(self, *args, **kwargs):
self.description = kwargs.pop('description', '')
super().__init__(*args, **kwargs)
# _[manual|auto]_docs are ordered dicts storing endpoints documentation
# {
# endpoint: {
# 'get': documentation,
# 'post': documentation,
# ...
# },
# ...
# }
self._auto_docs = OrderedDict()
self._manual_docs = OrderedDict()
self._endpoints = []
[docs] def route(self, rule, *, parameters=None, **options):
"""Decorator to register url rule in application
Also stores doc info for later registration
Use this to decorate a :class:`MethodView <flask.views.MethodView>` or
a resource function.
:param str rule: URL rule as string.
:param str endpoint: Endpoint for the registered URL rule (defaults
to function name).
:param list parameters: List of parameters relevant to all operations
in this path, only used to document the resource.
:param dict options: Options to be forwarded to the underlying
:class:`werkzeug.routing.Rule <Rule>` object.
"""
def decorator(func):
# By default, endpoint name is function name
endpoint = options.pop('endpoint', func.__name__)
# Prevent registering several times the same endpoint
# by silently renaming the endpoint in case of collision
if endpoint in self._endpoints:
endpoint = '{}_{}'.format(endpoint, len(self._endpoints))
self._endpoints.append(endpoint)
if isinstance(func, MethodViewType):
view_func = func.as_view(endpoint)
else:
view_func = func
# Add URL rule in Flask and store endpoint documentation
self.add_url_rule(rule, endpoint, view_func, **options)
self._store_endpoint_docs(endpoint, func, parameters, **options)
return func
return decorator
def _store_endpoint_docs(self, endpoint, obj, parameters, **options):
"""Store view or function doc info"""
endpoint_auto_doc = self._auto_docs.setdefault(
endpoint, OrderedDict())
endpoint_manual_doc = self._manual_docs.setdefault(
endpoint, OrderedDict())
def store_method_docs(method, function):
"""Add auto and manual doc to table for later registration"""
# Get auto documentation from decorators
# and summary/description from docstring
# Get manual documentation from @doc decorator
auto_doc = getattr(function, '_apidoc', {})
auto_doc.update(
load_info_from_docstring(
function.__doc__,
delimiter=self.DOCSTRING_INFO_DELIMITER
)
)
manual_doc = getattr(function, '_api_manual_doc', {})
# Store function auto and manual docs for later registration
method_l = method.lower()
endpoint_auto_doc[method_l] = auto_doc
endpoint_manual_doc[method_l] = manual_doc
# MethodView (class)
if isinstance(obj, MethodViewType):
for method in self.HTTP_METHODS:
if method in obj.methods:
func = getattr(obj, method.lower())
store_method_docs(method, func)
# Function
else:
methods = options.pop('methods', None) or ['GET']
for method in methods:
store_method_docs(method, obj)
endpoint_auto_doc['parameters'] = parameters
[docs] def register_views_in_doc(self, app, spec):
"""Register views information in documentation
If a schema in a parameter or a response appears in the spec
`schemas` section, it is replaced by a reference in the parameter or
response documentation:
"schema":{"$ref": "#/components/schemas/MySchema"}
"""
# This method uses the documentation information associated with each
# endpoint in self._[auto|manual]_docs to provide documentation for
# corresponding route to the spec object.
# Deepcopy to avoid mutating the source
# Allows registering blueprint multiple times (e.g. when creating
# multiple apps during tests)
auto_docs = deepcopy(self._auto_docs)
for endpoint, endpoint_auto_doc in auto_docs.items():
parameters = endpoint_auto_doc.pop('parameters')
doc = OrderedDict()
for method_l, endpoint_doc in endpoint_auto_doc.items():
# Format operations documentation in OpenAPI structure
self._prepare_doc(endpoint_doc, spec.openapi_version)
# Tag all operations with Blueprint name
endpoint_doc['tags'] = [self.name]
# Merge auto_doc and manual_doc into doc
manual_doc = self._manual_docs[endpoint][method_l]
doc[method_l] = deepupdate(endpoint_doc, manual_doc)
# Thanks to self.route, there can only be one rule per endpoint
full_endpoint = '.'.join((self.name, endpoint))
rule = next(app.url_map.iter_rules(full_endpoint))
spec.path(rule=rule, operations=doc, parameters=parameters)
def _prepare_doc(self, operation, openapi_version):
"""Format operation documentation in OpenAPI structure
The decorators store all documentation information in a dict structure
that is close to OpenAPI doc structure, so this information could
_almost_ be copied as is. Yet, some adjustemnts may have to be
performed, especially if the spec structure differs between OpenAPI
versions: the OpenAPI version is not known when the decorators are
applied but only at registration time when this method is called.
"""
# OAS 2
if openapi_version.major < 3:
if 'responses' in operation:
for resp in operation['responses'].values():
if 'example' in resp:
resp['examples'] = {
DEFAULT_RESPONSE_CONTENT_TYPE: resp.pop('example')}
if 'parameters' in operation:
for param in operation['parameters']:
if param['in'] in (
self.DEFAULT_LOCATION_CONTENT_TYPE_MAPPING
):
content_type = (
param.pop('content_type', None) or
self.DEFAULT_LOCATION_CONTENT_TYPE_MAPPING[
param['in']]
)
if content_type != DEFAULT_REQUEST_BODY_CONTENT_TYPE:
operation['consumes'] = [content_type, ]
# body and formData are mutually exclusive
break
# OAS 3
else:
if 'responses' in operation:
for resp in operation['responses'].values():
for field in ('schema', 'example', 'examples'):
if field in resp:
(
resp
.setdefault('content', {})
.setdefault(DEFAULT_RESPONSE_CONTENT_TYPE, {})
[field]
) = resp.pop(field)
if 'parameters' in operation:
for param in operation['parameters']:
if param['in'] in (
self.DEFAULT_LOCATION_CONTENT_TYPE_MAPPING
):
request_body = {
x: param[x]
for x in ('description', 'required')
if x in param
}
fields = {
x: param.pop(x)
for x in ('schema', 'example', 'examples')
if x in param
}
content_type = (
param.pop('content_type', None) or
self.DEFAULT_LOCATION_CONTENT_TYPE_MAPPING[
param['in']]
)
request_body['content'] = {content_type: fields}
operation['requestBody'] = request_body
# There can be only one requestBody
operation['parameters'].remove(param)
if not operation['parameters']:
del operation['parameters']
break
[docs] @staticmethod
def doc(**kwargs):
"""Decorator adding description attributes to a view function
Values passed as kwargs are copied verbatim in the docs
Example: ::
@blp.doc(description="Return pets based on ID",
summary="Find pets by ID"
)
def get(...):
...
"""
def decorator(func):
@wraps(func)
def wrapper(*f_args, **f_kwargs):
return func(*f_args, **f_kwargs)
# Don't merge manual doc with auto-documentation right now.
# Store it in a separate attribute to merge it later.
# The deepcopy avoids modifying the wrapped function doc
wrapper._api_manual_doc = deepupdate(
deepcopy(getattr(wrapper, '_api_manual_doc', {})), kwargs)
return wrapper
return decorator
