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dash.py
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from __future__ import print_function
import itertools
import os
import random
import sys
import collections
import importlib
import json
import pkgutil
import threading
import re
import logging
from functools import wraps
import flask
from flask_compress import Compress
from werkzeug.debug.tbtools import get_current_traceback
import plotly
import dash_renderer
from .fingerprint import build_fingerprint, check_fingerprint
from .resources import Scripts, Css
from .development.base_component import ComponentRegistry
from .exceptions import PreventUpdate, InvalidResourceError
from .version import __version__
from ._configs import get_combined_config, pathname_configs
from ._utils import (
AttributeDict,
create_callback_id,
format_tag,
generate_hash,
get_asset_path,
get_relative_path,
inputs_to_dict,
inputs_to_vals,
interpolate_str,
patch_collections_abc,
split_callback_id,
stringify_id,
strip_relative_path,
)
from . import _validate
from . import _watch
_default_index = """<!DOCTYPE html>
<html>
<head>
{%metas%}
<title>{%title%}</title>
{%favicon%}
{%css%}
</head>
<body>
{%app_entry%}
<footer>
{%config%}
{%scripts%}
{%renderer%}
</footer>
</body>
</html>"""
_app_entry = """
<div id="react-entry-point">
<div class="_dash-loading">
Loading...
</div>
</div>
"""
_re_index_entry = "{%app_entry%}", "{%app_entry%}"
_re_index_config = "{%config%}", "{%config%}"
_re_index_scripts = "{%scripts%}", "{%scripts%}"
_re_index_entry_id = 'id="react-entry-point"', "#react-entry-point"
_re_index_config_id = 'id="_dash-config"', "#_dash-config"
_re_index_scripts_id = 'src="[^"]*dash[-_]renderer[^"]*"', "dash-renderer"
_re_renderer_scripts_id = 'id="_dash-renderer', "new DashRenderer"
class _NoUpdate(object):
# pylint: disable=too-few-public-methods
pass
# Singleton signal to not update an output, alternative to PreventUpdate
no_update = _NoUpdate()
_inline_clientside_template = """
var clientside = window.dash_clientside = window.dash_clientside || {{}};
var ns = clientside["{namespace}"] = clientside["{namespace}"] || {{}};
ns["{function_name}"] = {clientside_function};
"""
# pylint: disable=too-many-instance-attributes
# pylint: disable=too-many-arguments, too-many-locals
class Dash(object):
"""Dash is a framework for building analytical web applications.
No JavaScript required.
If a parameter can be set by an environment variable, that is listed as:
env: ``DASH_****``
Values provided here take precedence over environment variables.
:param name: The name Flask should use for your app. Even if you provide
your own ``server``, ``name`` will be used to help find assets.
Typically ``__name__`` (the magic global var, not a string) is the
best value to use. Default ``'__main__'``, env: ``DASH_APP_NAME``
:type name: string
:param server: Sets the Flask server for your app. There are three options:
``True`` (default): Dash will create a new server
``False``: The server will be added later via ``app.init_app(server)``
where ``server`` is a ``flask.Flask`` instance.
``flask.Flask``: use this pre-existing Flask server.
:type server: boolean or flask.Flask
:param assets_folder: a path, relative to the current working directory,
for extra files to be used in the browser. Default ``'assets'``.
All .js and .css files will be loaded immediately unless excluded by
``assets_ignore``, and other files such as images will be served if
requested.
:type assets_folder: string
:param assets_url_path: The local urls for assets will be:
``requests_pathname_prefix + assets_url_path + '/' + asset_path``
where ``asset_path`` is the path to a file inside ``assets_folder``.
Default ``'assets'``.
:type asset_url_path: string
:param assets_ignore: A regex, as a string to pass to ``re.compile``, for
assets to omit from immediate loading. Ignored files will still be
served if specifically requested. You cannot use this to prevent access
to sensitive files.
:type assets_ignore: string
:param assets_external_path: an absolute URL from which to load assets.
Use with ``serve_locally=False``. Dash can still find js and css to
automatically load if you also keep local copies in your assets
folder that Dash can index, but external serving can improve
performance and reduce load on the Dash server.
env: ``DASH_ASSETS_EXTERNAL_PATH``
:type assets_external_path: string
:param include_assets_files: Default ``True``, set to ``False`` to prevent
immediate loading of any assets. Assets will still be served if
specifically requested. You cannot use this to prevent access
to sensitive files. env: ``DASH_INCLUDE_ASSETS_FILES``
:type include_assets_files: boolean
:param url_base_pathname: A local URL prefix to use app-wide.
Default ``'/'``. Both `requests_pathname_prefix` and
`routes_pathname_prefix` default to `url_base_pathname`.
env: ``DASH_URL_BASE_PATHNAME``
:type url_base_pathname: string
:param requests_pathname_prefix: A local URL prefix for file requests.
Defaults to `url_base_pathname`, and must end with
`routes_pathname_prefix`. env: ``DASH_REQUESTS_PATHNAME_PREFIX``
:type requests_pathname_prefix: string
:param routes_pathname_prefix: A local URL prefix for JSON requests.
Defaults to ``url_base_pathname``, and must start and end
with ``'/'``. env: ``DASH_ROUTES_PATHNAME_PREFIX``
:type routes_pathname_prefix: string
:param serve_locally: If ``True`` (default), assets and dependencies
(Dash and Component js and css) will be served from local URLs.
If ``False`` we will use CDN links where available.
:type serve_locally: boolean
:param compress: Use gzip to compress files and data served by Flask.
Default ``True``
:type compress: boolean
:param meta_tags: html <meta> tags to be added to the index page.
Each dict should have the attributes and values for one tag, eg:
``{'name': 'description', 'content': 'My App'}``
:type meta_tags: list of dicts
:param index_string: Override the standard Dash index page.
Must contain the correct insertion markers to interpolate various
content into it depending on the app config and components used.
See https://dash.plotly.com/external-resources for details.
:type index_string: string
:param external_scripts: Additional JS files to load with the page.
Each entry can be a string (the URL) or a dict with ``src`` (the URL)
and optionally other ``<script>`` tag attributes such as ``integrity``
and ``crossorigin``.
:type external_scripts: list of strings or dicts
:param external_stylesheets: Additional CSS files to load with the page.
Each entry can be a string (the URL) or a dict with ``href`` (the URL)
and optionally other ``<link>`` tag attributes such as ``rel``,
``integrity`` and ``crossorigin``.
:type external_stylesheets: list of strings or dicts
:param suppress_callback_exceptions: Default ``False``: check callbacks to
ensure referenced IDs exist and props are valid. Set to ``True``
if your layout is dynamic, to bypass these checks.
env: ``DASH_SUPPRESS_CALLBACK_EXCEPTIONS``
:type suppress_callback_exceptions: boolean
:param show_undo_redo: Default ``False``, set to ``True`` to enable undo
and redo buttons for stepping through the history of the app state.
:type show_undo_redo: boolean
:param plugins: Extend Dash functionality by passing a list of objects
with a ``plug`` method, taking a single argument: this app, which will
be called after the Flask server is attached.
:type plugins: list of objects
"""
def __init__(
self,
name=None,
server=True,
assets_folder="assets",
assets_url_path="assets",
assets_ignore="",
assets_external_path=None,
eager_loading=False,
include_assets_files=True,
url_base_pathname=None,
requests_pathname_prefix=None,
routes_pathname_prefix=None,
serve_locally=True,
compress=None,
meta_tags=None,
index_string=_default_index,
external_scripts=None,
external_stylesheets=None,
suppress_callback_exceptions=None,
show_undo_redo=False,
plugins=None,
**obsolete
):
_validate.check_obsolete(obsolete)
# We have 3 cases: server is either True (we create the server), False
# (defer server creation) or a Flask app instance (we use their server)
if isinstance(server, flask.Flask):
self.server = server
if name is None:
name = getattr(server, "name", "__main__")
elif isinstance(server, bool):
name = name if name else "__main__"
self.server = flask.Flask(name) if server else None
else:
raise ValueError("server must be a Flask app or a boolean")
base_prefix, routes_prefix, requests_prefix = pathname_configs(
url_base_pathname, routes_pathname_prefix, requests_pathname_prefix
)
self.config = AttributeDict(
name=name,
assets_folder=os.path.join(
flask.helpers.get_root_path(name), assets_folder
),
assets_url_path=assets_url_path,
assets_ignore=assets_ignore,
assets_external_path=get_combined_config(
"assets_external_path", assets_external_path, ""
),
eager_loading=eager_loading,
include_assets_files=get_combined_config(
"include_assets_files", include_assets_files, True
),
url_base_pathname=base_prefix,
routes_pathname_prefix=routes_prefix,
requests_pathname_prefix=requests_prefix,
serve_locally=serve_locally,
compress=get_combined_config("compress", compress, True),
meta_tags=meta_tags or [],
external_scripts=external_scripts or [],
external_stylesheets=external_stylesheets or [],
suppress_callback_exceptions=get_combined_config(
"suppress_callback_exceptions", suppress_callback_exceptions, False
),
show_undo_redo=show_undo_redo,
)
self.config.set_read_only(
[
"name",
"assets_folder",
"assets_url_path",
"eager_loading",
"url_base_pathname",
"routes_pathname_prefix",
"requests_pathname_prefix",
"serve_locally",
"compress",
],
"Read-only: can only be set in the Dash constructor",
)
self.config.finalize(
"Invalid config key. Some settings are only available "
"via the Dash constructor"
)
# list of dependencies - this one is used by the back end for dispatching
self.callback_map = {}
# same deps as a list to catch duplicate outputs, and to send to the front end
self._callback_list = []
# list of inline scripts
self._inline_scripts = []
# index_string has special setter so can't go in config
self._index_string = ""
self.index_string = index_string
self._favicon = None
# default renderer string
self.renderer = "var renderer = new DashRenderer();"
# static files from the packages
self.css = Css(serve_locally)
self.scripts = Scripts(serve_locally, eager_loading)
self.registered_paths = collections.defaultdict(set)
# urls
self.routes = []
self._layout = None
self._cached_layout = None
self._setup_dev_tools()
self._hot_reload = AttributeDict(
hash=None,
hard=False,
lock=threading.RLock(),
watch_thread=None,
changed_assets=[],
)
self._assets_files = []
self.logger = logging.getLogger(name)
self.logger.addHandler(logging.StreamHandler(stream=sys.stdout))
if isinstance(plugins, patch_collections_abc("Iterable")):
for plugin in plugins:
plugin.plug(self)
if self.server is not None:
self.init_app()
def init_app(self, app=None):
"""Initialize the parts of Dash that require a flask app."""
config = self.config
if app is not None:
self.server = app
assets_blueprint_name = "{}{}".format(
config.routes_pathname_prefix.replace("/", "_"), "dash_assets"
)
self.server.register_blueprint(
flask.Blueprint(
assets_blueprint_name,
config.name,
static_folder=self.config.assets_folder,
static_url_path="{}{}".format(
config.routes_pathname_prefix,
self.config.assets_url_path.lstrip("/"),
),
)
)
if config.compress:
# gzip
Compress(self.server)
@self.server.errorhandler(PreventUpdate)
def _handle_error(_):
"""Handle a halted callback and return an empty 204 response."""
return "", 204
self.server.before_first_request(self._setup_server)
# add a handler for components suites errors to return 404
self.server.errorhandler(InvalidResourceError)(self._invalid_resources_handler)
self._add_url(
"_dash-component-suites/<string:package_name>/<path:fingerprinted_path>",
self.serve_component_suites,
)
self._add_url("_dash-layout", self.serve_layout)
self._add_url("_dash-dependencies", self.dependencies)
self._add_url("_dash-update-component", self.dispatch, ["POST"])
self._add_url("_reload-hash", self.serve_reload_hash)
self._add_url("_favicon.ico", self._serve_default_favicon)
self._add_url("", self.index)
# catch-all for front-end routes, used by dcc.Location
self._add_url("<path:path>", self.index)
def _add_url(self, name, view_func, methods=("GET",)):
full_name = self.config.routes_pathname_prefix + name
self.server.add_url_rule(
full_name, view_func=view_func, endpoint=full_name, methods=list(methods)
)
# record the url in Dash.routes so that it can be accessed later
# e.g. for adding authentication with flask_login
self.routes.append(full_name)
@property
def layout(self):
return self._layout
def _layout_value(self):
if isinstance(self._layout, patch_collections_abc("Callable")):
self._cached_layout = self._layout()
else:
self._cached_layout = self._layout
return self._cached_layout
@layout.setter
def layout(self, value):
_validate.validate_layout_type(value)
self._cached_layout = None
self._layout = value
@property
def index_string(self):
return self._index_string
@index_string.setter
def index_string(self, value):
checks = (_re_index_entry, _re_index_config, _re_index_scripts)
_validate.validate_index("index string", checks, value)
self._index_string = value
def serve_layout(self):
layout = self._layout_value()
# TODO - Set browser cache limit - pass hash into frontend
return flask.Response(
json.dumps(layout, cls=plotly.utils.PlotlyJSONEncoder),
mimetype="application/json",
)
def _config(self):
# pieces of config needed by the front end
config = {
"url_base_pathname": self.config.url_base_pathname,
"requests_pathname_prefix": self.config.requests_pathname_prefix,
"ui": self._dev_tools.ui,
"props_check": self._dev_tools.props_check,
"show_undo_redo": self.config.show_undo_redo,
"suppress_callback_exceptions": self.config.suppress_callback_exceptions,
}
if self._dev_tools.hot_reload:
config["hot_reload"] = {
# convert from seconds to msec as used by js `setInterval`
"interval": int(self._dev_tools.hot_reload_interval * 1000),
"max_retry": self._dev_tools.hot_reload_max_retry,
}
return config
def serve_reload_hash(self):
_reload = self._hot_reload
with _reload.lock:
hard = _reload.hard
changed = _reload.changed_assets
_hash = _reload.hash
_reload.hard = False
_reload.changed_assets = []
return flask.jsonify(
{
"reloadHash": _hash,
"hard": hard,
"packages": list(self.registered_paths.keys()),
"files": list(changed),
}
)
def _collect_and_register_resources(self, resources):
# now needs the app context.
# template in the necessary component suite JS bundles
# add the version number of the package as a query parameter
# for cache busting
def _relative_url_path(relative_package_path="", namespace=""):
module_path = os.path.join(
os.path.dirname(sys.modules[namespace].__file__), relative_package_path
)
modified = int(os.stat(module_path).st_mtime)
return "{}_dash-component-suites/{}/{}".format(
self.config.requests_pathname_prefix,
namespace,
build_fingerprint(
relative_package_path,
importlib.import_module(namespace).__version__,
modified,
),
)
srcs = []
for resource in resources:
is_dynamic_resource = resource.get("dynamic", False)
if "relative_package_path" in resource:
paths = resource["relative_package_path"]
paths = [paths] if isinstance(paths, str) else paths
for rel_path in paths:
self.registered_paths[resource["namespace"]].add(rel_path)
if not is_dynamic_resource:
srcs.append(
_relative_url_path(
relative_package_path=rel_path,
namespace=resource["namespace"],
)
)
elif "external_url" in resource:
if not is_dynamic_resource:
if isinstance(resource["external_url"], str):
srcs.append(resource["external_url"])
else:
srcs += resource["external_url"]
elif "absolute_path" in resource:
raise Exception("Serving files from absolute_path isn't supported yet")
elif "asset_path" in resource:
static_url = self.get_asset_url(resource["asset_path"])
# Add a cache-busting query param
static_url += "?m={}".format(resource["ts"])
srcs.append(static_url)
return srcs
def _generate_css_dist_html(self):
external_links = self.config.external_stylesheets
links = self._collect_and_register_resources(self.css.get_all_css())
return "\n".join(
[
format_tag("link", link, opened=True)
if isinstance(link, dict)
else '<link rel="stylesheet" href="{}">'.format(link)
for link in (external_links + links)
]
)
def _generate_scripts_html(self):
# Dash renderer has dependencies like React which need to be rendered
# before every other script. However, the dash renderer bundle
# itself needs to be rendered after all of the component's
# scripts have rendered.
# The rest of the scripts can just be loaded after React but before
# dash renderer.
# pylint: disable=protected-access
mode = "dev" if self._dev_tools["props_check"] is True else "prod"
deps = []
for js_dist_dependency in dash_renderer._js_dist_dependencies:
dep = {}
for key, value in js_dist_dependency.items():
dep[key] = value[mode] if isinstance(value, dict) else value
deps.append(dep)
dev = self._dev_tools.serve_dev_bundles
srcs = (
self._collect_and_register_resources(
self.scripts._resources._filter_resources(deps, dev_bundles=dev)
)
+ self.config.external_scripts
+ self._collect_and_register_resources(
self.scripts.get_all_scripts(dev_bundles=dev)
+ self.scripts._resources._filter_resources(
dash_renderer._js_dist, dev_bundles=dev
)
)
)
return "\n".join(
[
format_tag("script", src)
if isinstance(src, dict)
else '<script src="{}"></script>'.format(src)
for src in srcs
]
+ ["<script>{}</script>".format(src) for src in self._inline_scripts]
)
def _generate_config_html(self):
return ('<script id="_dash-config" type="application/json">{}</script>').format(
json.dumps(self._config())
)
def _generate_renderer(self):
return (
'<script id="_dash-renderer" type="application/javascript">'
"{}"
"</script>"
).format(self.renderer)
def _generate_meta_html(self):
meta_tags = self.config.meta_tags
has_ie_compat = any(
x.get("http-equiv", "") == "X-UA-Compatible" for x in meta_tags
)
has_charset = any("charset" in x for x in meta_tags)
tags = []
if not has_ie_compat:
tags.append('<meta http-equiv="X-UA-Compatible" content="IE=edge">')
if not has_charset:
tags.append('<meta charset="UTF-8">')
tags += [format_tag("meta", x, opened=True) for x in meta_tags]
return "\n ".join(tags)
# Serve the JS bundles for each package
def serve_component_suites(self, package_name, fingerprinted_path):
path_in_pkg, has_fingerprint = check_fingerprint(fingerprinted_path)
_validate.validate_js_path(self.registered_paths, package_name, path_in_pkg)
mimetype = (
{
"js": "application/javascript",
"css": "text/css",
"map": "application/json",
}
)[path_in_pkg.split(".")[-1]]
package = sys.modules[package_name]
self.logger.debug(
"serving -- package: %s[%s] resource: %s => location: %s",
package_name,
package.__version__,
path_in_pkg,
package.__path__,
)
response = flask.Response(
pkgutil.get_data(package_name, path_in_pkg), mimetype=mimetype
)
if has_fingerprint:
# Fingerprinted resources are good forever (1 year)
# No need for ETag as the fingerprint changes with each build
response.cache_control.max_age = 31536000 # 1 year
else:
# Non-fingerprinted resources are given an ETag that
# will be used / check on future requests
response.add_etag()
tag = response.get_etag()[0]
request_etag = flask.request.headers.get("If-None-Match")
if '"{}"'.format(tag) == request_etag:
response = flask.Response(None, status=304)
return response
def index(self, *args, **kwargs): # pylint: disable=unused-argument
scripts = self._generate_scripts_html()
css = self._generate_css_dist_html()
config = self._generate_config_html()
metas = self._generate_meta_html()
renderer = self._generate_renderer()
title = getattr(self, "title", "Dash")
if self._favicon:
favicon_mod_time = os.path.getmtime(
os.path.join(self.config.assets_folder, self._favicon)
)
favicon_url = self.get_asset_url(self._favicon) + "?m={}".format(
favicon_mod_time
)
else:
favicon_url = "{}_favicon.ico?v={}".format(
self.config.requests_pathname_prefix, __version__
)
favicon = format_tag(
"link",
{"rel": "icon", "type": "image/x-icon", "href": favicon_url},
opened=True,
)
index = self.interpolate_index(
metas=metas,
title=title,
css=css,
config=config,
scripts=scripts,
app_entry=_app_entry,
favicon=favicon,
renderer=renderer,
)
checks = (
_re_index_entry_id,
_re_index_config_id,
_re_index_scripts_id,
_re_renderer_scripts_id,
)
_validate.validate_index("index", checks, index)
return index
def interpolate_index(
self,
metas="",
title="",
css="",
config="",
scripts="",
app_entry="",
favicon="",
renderer="",
):
"""Called to create the initial HTML string that is loaded on page.
Override this method to provide you own custom HTML.
:Example:
class MyDash(dash.Dash):
def interpolate_index(self, **kwargs):
return '''<!DOCTYPE html>
<html>
<head>
<title>My App</title>
</head>
<body>
<div id="custom-header">My custom header</div>
{app_entry}
{config}
{scripts}
{renderer}
<div id="custom-footer">My custom footer</div>
</body>
</html>'''.format(app_entry=kwargs.get('app_entry'),
config=kwargs.get('config'),
scripts=kwargs.get('scripts'),
renderer=kwargs.get('renderer'))
:param metas: Collected & formatted meta tags.
:param title: The title of the app.
:param css: Collected & formatted css dependencies as <link> tags.
:param config: Configs needed by dash-renderer.
:param scripts: Collected & formatted scripts tags.
:param renderer: A script tag that instantiates the DashRenderer.
:param app_entry: Where the app will render.
:param favicon: A favicon <link> tag if found in assets folder.
:return: The interpolated HTML string for the index.
"""
return interpolate_str(
self.index_string,
metas=metas,
title=title,
css=css,
config=config,
scripts=scripts,
favicon=favicon,
renderer=renderer,
app_entry=app_entry,
)
def dependencies(self):
return flask.jsonify(self._callback_list)
def _insert_callback(self, output, inputs, state):
_validate.validate_callback(output, inputs, state)
callback_id = create_callback_id(output)
callback_spec = {
"output": callback_id,
"inputs": [c.to_dict() for c in inputs],
"state": [c.to_dict() for c in state],
"clientside_function": None,
}
self.callback_map[callback_id] = {
"inputs": callback_spec["inputs"],
"state": callback_spec["state"],
}
self._callback_list.append(callback_spec)
return callback_id
def clientside_callback(self, clientside_function, output, inputs, state=()):
"""Create a callback that updates the output by calling a clientside
(JavaScript) function instead of a Python function.
Unlike `@app.callback`, `clientside_callback` is not a decorator:
it takes either a
`dash.dependencies.ClientsideFunction(namespace, function_name)`
argument that describes which JavaScript function to call
(Dash will look for the JavaScript function at
`window.dash_clientside[namespace][function_name]`), or it may take
a string argument that contains the clientside function source.
For example, when using a `dash.dependencies.ClientsideFunction`:
```
app.clientside_callback(
ClientsideFunction('my_clientside_library', 'my_function'),
Output('my-div' 'children'),
[Input('my-input', 'value'),
Input('another-input', 'value')]
)
```
With this signature, Dash's front-end will call
`window.dash_clientside.my_clientside_library.my_function` with the
current values of the `value` properties of the components `my-input`
and `another-input` whenever those values change.
Include a JavaScript file by including it your `assets/` folder. The
file can be named anything but you'll need to assign the function's
namespace to the `window.dash_clientside` namespace. For example,
this file might look:
```
window.dash_clientside = window.dash_clientside || {};
window.dash_clientside.my_clientside_library = {
my_function: function(input_value_1, input_value_2) {
return (
parseFloat(input_value_1, 10) +
parseFloat(input_value_2, 10)
);
}
}
```
Alternatively, you can pass the JavaScript source directly to
`clientside_callback`. In this case, the same example would look like:
```
app.clientside_callback(
'''
function(input_value_1, input_value_2) {
return (
parseFloat(input_value_1, 10) +
parseFloat(input_value_2, 10)
);
}
''',
Output('my-div' 'children'),
[Input('my-input', 'value'),
Input('another-input', 'value')]
)
```
"""
self._insert_callback(output, inputs, state)
# If JS source is explicitly given, create a namespace and function
# name, then inject the code.
if isinstance(clientside_function, str):
out0 = output
if isinstance(output, (list, tuple)):
out0 = output[0]
namespace = "_dashprivate_{}".format(out0.component_id)
function_name = "{}".format(out0.component_property)
self._inline_scripts.append(
_inline_clientside_template.format(
namespace=namespace.replace('"', '\\"'),
function_name=function_name.replace('"', '\\"'),
clientside_function=clientside_function,
)
)
# Callback is stored in an external asset.
else:
namespace = clientside_function.namespace
function_name = clientside_function.function_name
self._callback_list[-1]["clientside_function"] = {
"namespace": namespace,
"function_name": function_name,
}
def callback(self, output, inputs, state=()):
callback_id = self._insert_callback(output, inputs, state)
multi = isinstance(output, (list, tuple))
def wrap_func(func):
@wraps(func)
def add_context(*args, **kwargs):
output_spec = kwargs.pop("outputs_list")
# don't touch the comment on the next line - used by debugger
output_value = func(*args, **kwargs) # %% callback invoked %%
if isinstance(output_value, _NoUpdate):
raise PreventUpdate
# wrap single outputs so we can treat them all the same
# for validation and response creation
if not multi:
output_value, output_spec = [output_value], [output_spec]
_validate.validate_multi_return(output_spec, output_value, callback_id)
component_ids = collections.defaultdict(dict)
has_update = False
for val, spec in zip(output_value, output_spec):
if isinstance(val, _NoUpdate):
continue
for vali, speci in (
zip(val, spec) if isinstance(spec, list) else [[val, spec]]
):
if not isinstance(vali, _NoUpdate):
has_update = True
id_str = stringify_id(speci["id"])
component_ids[id_str][speci["property"]] = vali
if not has_update:
raise PreventUpdate
response = {"response": component_ids, "multi": True}
try:
jsonResponse = json.dumps(
response, cls=plotly.utils.PlotlyJSONEncoder
)
except TypeError:
_validate.fail_callback_output(output_value, output)
return jsonResponse
self.callback_map[callback_id]["callback"] = add_context
return add_context
return wrap_func
def dispatch(self):
body = flask.request.get_json()
flask.g.inputs_list = inputs = body.get("inputs", [])
flask.g.states_list = state = body.get("state", [])
output = body["output"]
outputs_list = body.get("outputs") or split_callback_id(output)
flask.g.outputs_list = outputs_list
flask.g.input_values = input_values = inputs_to_dict(inputs)
flask.g.state_values = inputs_to_dict(state)
changed_props = body.get("changedPropIds", [])
flask.g.triggered_inputs = [
{"prop_id": x, "value": input_values.get(x)} for x in changed_props
]
response = flask.g.dash_response = flask.Response(mimetype="application/json")
args = inputs_to_vals(inputs) + inputs_to_vals(state)
func = self.callback_map[output]["callback"]
response.set_data(func(*args, outputs_list=outputs_list))
return response
def _setup_server(self):
# Apply _force_eager_loading overrides from modules
eager_loading = self.config.eager_loading
for module_name in ComponentRegistry.registry:
module = sys.modules[module_name]
eager = getattr(module, "_force_eager_loading", False)
eager_loading = eager_loading or eager
# Update eager_loading settings
self.scripts.config.eager_loading = eager_loading
if self.config.include_assets_files:
self._walk_assets_directory()
_validate.validate_layout(self.layout, self._layout_value())
self._generate_scripts_html()
self._generate_css_dist_html()
def _add_assets_resource(self, url_path, file_path):
res = {"asset_path": url_path, "filepath": file_path}
if self.config.assets_external_path:
res["external_url"] = "{}{}".format(
self.config.assets_external_path, url_path
)
self._assets_files.append(file_path)
return res
def _walk_assets_directory(self):
walk_dir = self.config.assets_folder
slash_splitter = re.compile(r"[\\/]+")