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Configuration

Basics

In Flask, the configuration system is built on top of the app.config attribute. It's a dict-like attribute; thus you can operate it as a dict.

This app.config attribute will contain the following configuration variables:

  • Flask's built-in configuration variables
  • Flask extension's built-in configuration variables
  • APIFlask's built-in configuration variables
  • Your application's configuration variables

Here is a simple example for basic operates:

from apiflask import APIFlask

app = APIFlask(__name__)

# set a config
app.config['DESCRIPTION'] = 'A wonderful API'

# read a config
description = app.config['DESCRIPTION']

Since it's dict-like object, you can also read a configuration variable with a default value via the app.config.get() method:

my_name = app.config.get('DESCRIPTION', 'default value')

Or update multiple values at once via app.config.update() method:

app.config.update(
    'DESCRIPTION'='A wonderful API',
    'FOO'='bar',
    'ITEMS_PER_PAGE'=15
)

For a large application, you can store all the configuration variable in a separate file, for example, a file called settings.py:

MY_CONFIG = 'A wonderful API'
FOO = 'bar'
ITEMS_PER_PAGE = 15

Now you can set the configuration variables with the app.config.from_pyfile() method:

from apiflask import APIFlask

app = APIFlask(__name__)

# set all configs from settings.py
app.config.from_pyfile('settings.py')

Read more about configuration management in Configuration Handling in Flask's documentation.

Warning

All configuration variables should be in uppercase.

Read a config outside of the application context

If you want to read a configuration variable outside of the application context, you will get an error like: "Working outside of the application context". This usually happened when you use an application factory.

When you use the application factory, you can access the config with current_app.config in the view function:

from flask import current_app

@bp.get('/foo')
def foo():
    bar = current_app.config['BAR']

However, when you define a data schema, there isn't an active application context, so you can't use current_app. In this situation, you can access the configration variables from the module you store them:

from apiflask import Schema

from .settings import CATEGORIES  # import the configuration variable

class PetInSchema(Schema):
    name = String(required=True, validate=Length(0, 10))
    category = String(required=True, validate=OneOf(CATEGORIES))  # use it

Built-in configuration variables

Below are all the built-in configuration variables in APIFlask.

OpenAPI fields

All the configurations of OpenAPI-related fields will be used when generating the OpenAPI spec. They will also be rendered by the API documentation.

OPENAPI_VERSION

The version of OpenAPI Specification (openapi.openapi). This configuration can also be configured from the app.openapi_version attribute.

  • Type: str
  • Default value: '3.0.3'
  • Examples:
app.config['OPENAPI_VERSION'] = '3.0.2'

Or:

app.openapi_version = '3.0.2'

Version >= 0.4.0

This configuration variable was added in the version 0.4.0.

SERVERS

The server information of the API (openapi.servers), accepts multiple server dicts. This configuration can also be configured from the app.servers attribute.

  • Type: List[Dict[str, str]]
  • Default value: None
  • Examples:
app.config['SERVERS'] = [
    {
        'name': 'Production Server',
        'url': 'http://api.example.com'
    }
]

Or:

app.servers = [
    {
        'name': 'Production Server',
        'url': 'http://api.example.com'
    }
]

TAGS

The tag list of the OpenAPI spec documentation (openapi.tags), accepts a list of dicts. You can also pass a simple list contains the tag name string. This configuration can also be configured from the app.tags attribute.

If not set, the blueprint names will use as tags, all the endpoints under the blueprint will be marked with the blueprint tag automatically.

  • Type: Union[List[str], List[Dict[str, str]]]
  • Default value: None
  • Examples:

Simple tag name list example:

app.config['TAGS'] = ['foo', 'bar', 'baz']

With tag description:

app.config['TAGS'] = [
    {'name': 'foo', 'description': 'The description of foo'},
    {'name': 'bar', 'description': 'The description of bar'},
    {'name': 'baz', 'description': 'The description of baz'}
]

Full OpenAPI tags example:

app.config['TAGS'] = [
    {
        'name': 'foo',
        'description': 'tag description',
        'externalDocs': {
            'description': 'Find more info here',
            'url': 'http://example.com'
        }
    }
]

Use attribute app.tags:

app.tags = ['foo', 'bar', 'baz']

EXTERNAL_DOCS

The external documentation information of the API (openapi.externalDocs). This configuration can also be configured from the app.external_docs attribute.

  • Type: Dict[str, str]
  • Default value: None
  • Examples:
app.config['EXTERNAL_DOCS'] = {
    'description': 'Find more info here',
    'url': 'http://docs.example.com'
}

Or:

app.external_docs = {
    'description': 'Find more info here',
    'url': 'http://docs.example.com'
}

INFO

The info field of the API (openapi.info). This configuration can also be configured from the app.info attribute. The info object (openapi.info), it accepts a dict contains following info fields: description, termsOfService, contact, license. You can use separate configuration variables to overwrite this dict.

  • Type: Dict[str, str]
  • Default value: None
  • Examples:
app.config['INFO'] = {
    'description': '...',
    'termsOfService': 'http://example.com',
    'contact': {
        'name': 'API Support',
        'url': 'http://www.example.com/support',
        'email': 'support@example.com'
    },
    'license': {
        'name': 'Apache 2.0',
        'url': 'http://www.apache.org/licenses/LICENSE-2.0.html'
    }
}

Or:

app.info = {
    'description': '...',
    'termsOfService': 'http://example.com',
    'contact': {
        'name': 'API Support',
        'url': 'http://www.example.com/support',
        'email': 'support@example.com'
    },
    'license': {
        'name': 'Apache 2.0',
        'url': 'http://www.apache.org/licenses/LICENSE-2.0.html'
    }
}

DESCRIPTION

The description of the API (openapi.info.description). This configuration can also be configured from the app.description attribute.

  • Type: str
  • Default value: None
  • Examples:
app.config['DESCRIPTION'] = 'Some description of my API.'

Or:

app.description = 'Some description of my API.'

TERMS_OF_SERVICE

The terms of service URL of the API (openapi.info.termsOfService). This configuration can also be configured from the app.terms_of_service attribute.

  • Type: str
  • Default value: None
  • Examples:
app.config['TERMS_OF_SERVICE'] = 'http://example.com/terms/'

Or:

app.terms_of_service = 'http://example.com/terms/'

CONTACT

The contact information of the API (openapi.info.contact). This configuration can also be configured from the app.contact attribute.

  • Type: Dict[str, str]
  • Default value: None
  • Examples:
app.config['CONTACT'] = {
    'name': 'API Support',
    'url': 'http://example.com',
    'email': 'support@example.com'
}

Or:

app.contact = {
    'name': 'API Support',
    'url': 'http://example.com',
    'email': 'support@example.com'
}

LICENSE

The license of the API (openapi.info.license). This configuration can also be configured from the app.license attribute.

  • Type: Dict[str, str]
  • Default value: None
  • Examples:
app.config['LICENSE'] = {
    'name': 'Apache 2.0',
    'url': 'http://www.apache.org/licenses/LICENSE-2.0.html'
}

Or:

app.license = {
    'name': 'Apache 2.0',
    'url': 'http://www.apache.org/licenses/LICENSE-2.0.html'
}

OpenAPI spec

Customize the generation of the OpenAPI spec.

SPEC_FORMAT

The format of the OpenAPI spec, accepts 'json', 'yaml' or 'yml'. This config will be used in the following conditions:

  • Serve the spec via the built-in route.
  • Execute flask spec without passing the --format/-f option.

Warning

The auto-detection of the format from the APIFlask(spec_path=...) was removed in favor of this config in 0.7.0.

  • Type: str
  • Default value: 'json'
  • Examples:
app.config['SPEC_FORMAT'] = 'yaml'

Version >= 0.7.0

This configuration variable was added in the version 0.7.0.

LOCAL_SPEC_PATH

The path to the local OpenAPI spec file.

  • Type: str
  • Default value: None
  • Examples:
app.config['LOCAL_SPEC_PATH'] = 'openapi.json'

Warning

If the path you passed is relative, do not put a leading slash in it.

Version >= 0.7.0

This configuration variable was added in the version 0.7.0.

LOCAL_SPEC_JSON_INDENT

The indentation of the local OpenAPI spec in JSON format.

  • Type: int
  • Default value: 2
  • Examples:
app.config['LOCAL_SPEC_JSON_INDENT'] = 4

Version >= 0.7.0

This configuration variable was added in the version 0.7.0.

SYNC_LOCAL_SPEC

If True, the local spec will be in sync automatically, see the example usage at Keep the local spec in sync automatically.

  • Type: bool
  • Default value: None
  • Examples:
app.config['SYNC_LOCAL_SPEC'] = True

Version >= 0.7.0

This configuration variable was added in the version 0.7.0.

JSON_SPEC_MIMETYPE

The MIME type string for JSON OpenAPI spec response.

  • Type: str
  • Default value: 'application/json'
  • Examples:
app.config['JSON_SPEC_MIMETYPE'] = 'application/custom-json'

Version >= 0.4.0

This configuration variable was added in the version 0.4.0.

YAML_SPEC_MIMETYPE

The MIME type string for YAML OpenAPI spec response.

  • Type: str
  • Default value: 'text/vnd.yaml'
  • Examples:
app.config['YAML_SPEC_MIMETYPE'] = 'text/x-yaml'

Version >= 0.4.0

This configuration variable was added in the version 0.4.0.

Automation behavior control

The following configuration variables are used to control the automation behavior of APIFlask. The default values of all these configuration variables are True, you can disable them if you needed.

AUTO_TAGS

Enable or disable auto tags (openapi.tags) generation from the name of the blueprint.

Tip

This automation behavior only happens when app.tags or config TAGS is not set.

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_TAGS'] = False

AUTO_OPERATION_SUMMARY

Enable or disable auto path summary from the name or docstring of the view function.

Tip

This automation behavior only happens when the view function doesn't decorate with @doc(summary=...).

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_OPERATION_SUMMARY'] = False

Warning

This variable was renamed from AUTO_PATH_SUMMARY to AUTO_OPERATION_SUMMARY since version 0.8.0.

AUTO_OPERATION_DESCRIPTION

Enable or disable auto path description from the docstring of the view function.

Tip

This automation behavior only happens when the view function doesn't decorate with @doc(description=...).

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_OPERATION_DESCRIPTION'] = False

Warning

This variable was renamed from AUTO_PATH_DESCRIPTION to AUTO_OPERATION_DESCRIPTION since version 0.8.0.

AUTO_OPERATION_ID

Version >= 0.10.0

This feature was added in the version 0.10.0.

Enable or disable auto operationId from the method and endpoint of the view function. See more details in Set operationId.

  • Type: bool
  • Default value: False
  • Examples:
app.config['AUTO_OPERATION_ID'] = True

AUTO_200_RESPONSE

If a view function doesn't decorate with either @input, @output, @auth_required or @doc, APIFlask will add a default 200 response for this view into OpenAPI spec. Set this config to False to disable this behavior.

Tip

You can change the description of the default 200 response with config SUCCESS_DESCRIPTION.

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_200_RESPONSE'] = False

AUTO_404_RESPONSE

If a view function's URL rule contains a variable. By default, APIFlask will add a 404 response for this view into OpenAPI spec. Set this config to False to disable this behavior.

Tip

You can change the description of the automatic 404 response with config NOT_FOUND_DESCRIPTION.

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_404_RESPONSE'] = False

Version >= 0.8.0

This configuration variable was added in the version 0.8.0.

AUTO_VALIDATION_ERROR_RESPONSE

If a view function uses @input to validate input request data, APIFlask will add a validation error response into OpenAPI spec for this view. Set this config to False to disable this behavior.

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_VALIDATION_ERROR_RESPONSE'] = False

AUTO_AUTH_ERROR_RESPONSE

If a view function uses @auth_required to restrict the access, APIFlask will add an authentication error response into OpenAPI spec for this view. Set this config to False to disable this behavior.

  • Type: bool
  • Default value: True
  • Examples:
app.config['AUTO_AUTH_ERROR_RESPONSE'] = False

Response customization

The following configuration variables are used to customize auto-responses.

SUCCESS_DESCRIPTION

The default description of the 2XX responses.

  • Type: str
  • Default value: Successful response
  • Examples:
app.config['SUCCESS_DESCRIPTION'] = 'Success!'

Version >= 0.4.0

This configuration variable was added in the version 0.4.0.

NOT_FOUND_DESCRIPTION

The default description of the 404 response.

  • Type: str
  • Default value: Not found
  • Examples:
app.config['NOT_FOUND_DESCRIPTION'] = 'Missing'

Version >= 0.8.0

This configuration variable was added in the version 0.8.0.

VALIDATION_ERROR_STATUS_CODE

The status code of validation error response.

  • Type: int
  • Default value: 400
  • Examples:
app.config['VALIDATION_ERROR_STATUS_CODE'] = 422

VALIDATION_ERROR_DESCRIPTION

The description of validation error response.

  • Type: str
  • Default value: 'Validation error'
  • Examples:
app.config['VALIDATION_ERROR_DESCRIPTION'] = 'Invalid JSON body'

VALIDATION_ERROR_SCHEMA

The schema of validation error response, accepts a schema class or a dict of OpenAPI schema definition.

  • Type: Union[Schema, dict]
  • Default value: apiflask.schemas.validation_error_schema
  • Examples:
app.config['VALIDATION_ERROR_SCHEMA'] = CustomValidationErrorSchema

AUTH_ERROR_STATUS_CODE

The status code of authentication error response.

  • Type: int
  • Default value: 401
  • Examples:
app.config['AUTH_ERROR_STATUS_CODE'] = 403

AUTH_ERROR_DESCRIPTION

The description of authentication error response.

  • Type: str
  • Default value: 'Authentication error'
  • Examples:
app.config['AUTH_ERROR_DESCRIPTION'] = 'Auth error'

HTTP_ERROR_SCHEMA

The schema of generic HTTP error response, accepts a schema class or a dict of OpenAPI schema definition.

  • Type: Union[Schema, dict]
  • Default value: apiflask.schemas.http_error_schema
  • Examples:
app.config['HTTP_ERROR_SCHEMA'] = CustomHTTPErrorSchema

BASE_RESPONSE_SCHEMA

The schema of base response schema, accepts a schema class or a dict of OpenAPI schema definition.

  • Type: Union[Schema, dict]
  • Default value: None
  • Examples:
from apiflask import APIFlask, Schema
from apiflask.fields import String, Integer, Field

app = APIFlask(__name__)

class BaseResponseSchema(Schema):
    message = String()
    status_code = Integer()
    data = Field()

app.config['BASE_RESPONSE_SCHEMA'] = BaseResponseSchema

Version >= 0.9.0

This configuration variable was added in the version 0.9.0.

BASE_RESPONSE_DATA_KEY

The data key of the base response, it should match the data field name in the base response schema.

  • Type: str
  • Default value: 'data'
  • Examples:
app.config['BASE_RESPONSE_DATA_KEY'] = 'data'

Version >= 0.9.0

This configuration variable was added in the version 0.9.0.

Swagger UI and Redoc

The following configuration variables used to customize Swagger UI and Redoc documentation.

DOCS_FAVICON

The absolute or relative URL of the favicon image file of API documentations.

  • Type: str
  • Default value: 'https://apiflask.com/_assets/favicon.png'
  • Examples:
app.config['DOCS_FAVICON'] = 'https://cdn.example.com/favicon.png'

REDOC_USE_GOOGLE_FONT

Enable or disable Google font in Redoc documentation.

  • Type: bool
  • Default value: True
  • Examples:
app.config['REDOC_USE_GOOGLE_FONT'] = False

REDOC_CONFIG

The configuration options pass to Redoc. See the available options in the Redoc documentation.

  • Type: dict
  • Default value: None
  • Examples:
app.config['REDOC_CONFIG'] = {'disableSearch': True, 'hideLoading': True}

Version >= 0.9.0

This configuration variable was added in the version 0.9.0.

REDOC_STANDALONE_JS

The absolute or relative URL of the Redoc standalone JavaScript file.

  • Type: str
  • Default value: 'https://cdn.jsdelivr.net/npm/redoc@next/bundles/redoc.standalone.js'
  • Examples:
app.config['REDOC_STANDALONE_JS'] = 'https://cdn.example.com/filename.js'

SWAGGER_UI_CSS

The absolute or relative URL of the Swagger UI CSS file.

  • Type: str
  • Default value: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@3/swagger-ui.css'
  • Examples:
app.config['SWAGGER_UI_CSS'] = 'https://cdn.example.com/filename.js'

SWAGGER_UI_BUNDLE_JS

The absolute or relative URL of the Swagger UI bundle JavaScript file.

  • Type: str
  • Default value: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@3/swagger-ui-bundle.js'
  • Examples:
app.config['SWAGGER_UI_BUNDLE_JS'] = 'https://cdn.example.com/filename.js'

SWAGGER_UI_STANDALONE_PRESET_JS

The absolute or relative URL of the Swagger UI standalone preset JavaScript file.

  • Type: str
  • Default value: 'https://cdn.jsdelivr.net/npm/swagger-ui-dist@3/swagger-ui-standalone-preset.js'
  • Examples:
app.config['SWAGGER_UI_STANDALONE_PRESET_JS'] = 'https://cdn.example.com/filename.js'

SWAGGER_UI_LAYOUT

The layout of Swagger UI, one of 'BaseLayout' and 'StandaloneLayout'.

  • Type: str
  • Default value: 'BaseLayout'
  • Examples:
app.config['SWAGGER_UI_LAYOUT'] = 'StandaloneLayout'

SWAGGER_UI_CONFIG

The config for Swagger UI, this config value will overwrite the existing config, such as SWAGGER_UI_LAYOUT.

Tip

See Configuration of the Swagger UI docs for more details.

  • Type: dict
  • Default value: None
  • Examples:
app.config['SWAGGER_UI_CONFIG'] = {
    'layout': 'StandaloneLayout'
}

SWAGGER_UI_OAUTH_CONFIG

The config for Swagger UI OAuth:

ui.initOAuth(yourConfig)

Tip

See the OAuth 2.0 configuration in Swagger UI docs for more details.

  • Type: dict
  • Default value: None
  • Examples:
app.config['SWAGGER_UI_OAUTH_CONFIG'] = {
    'realm': 'foo'
}

Flask built-in configuration variables

See Builtin Configuration Values for the built-in configuration variables provided by Flask.