/
dash.py
2124 lines (1799 loc) · 80 KB
/
dash.py
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import functools
import os
import sys
import collections
import importlib
from contextvars import copy_context
from importlib.machinery import ModuleSpec
import pkgutil
import threading
import re
import logging
import time
import mimetypes
import hashlib
import base64
import traceback
from urllib.parse import urlparse
from textwrap import dedent
import flask
from flask_compress import Compress
from pkg_resources import get_distribution, parse_version
from dash import dcc
from dash import html
from dash import dash_table
from .fingerprint import build_fingerprint, check_fingerprint
from .resources import Scripts, Css
from .dependencies import (
Output,
Input,
)
from .development.base_component import ComponentRegistry
from .exceptions import (
PreventUpdate,
InvalidResourceError,
ProxyError,
DuplicateCallback,
)
from .version import __version__
from ._configs import get_combined_config, pathname_configs, pages_folder_config
from ._utils import (
AttributeDict,
format_tag,
generate_hash,
inputs_to_dict,
inputs_to_vals,
interpolate_str,
patch_collections_abc,
split_callback_id,
to_json,
convert_to_AttributeDict,
gen_salt,
)
from . import _callback
from . import _get_paths
from . import _dash_renderer
from . import _validate
from . import _watch
from . import _get_app
from ._grouping import map_grouping, grouping_len, update_args_group
from . import _pages
from ._pages import (
_parse_path_variables,
_parse_query_string,
)
_flask_compress_version = parse_version(get_distribution("flask-compress").version)
# Add explicit mapping for map files
mimetypes.add_type("application/json", ".map", True)
_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"
_ID_CONTENT = "_pages_content"
_ID_LOCATION = "_pages_location"
_ID_STORE = "_pages_store"
_ID_DUMMY = "_pages_dummy"
# Handles the case in a newly cloned environment where the components are not yet generated.
try:
page_container = html.Div(
[
dcc.Location(id=_ID_LOCATION),
html.Div(id=_ID_CONTENT),
dcc.Store(id=_ID_STORE),
html.Div(id=_ID_DUMMY),
]
)
except AttributeError:
page_container = None
def _get_traceback(secret, error: Exception):
try:
# pylint: disable=import-outside-toplevel
from werkzeug.debug import tbtools
except ImportError:
tbtools = None
def _get_skip(text, divider=2):
skip = 0
for i, line in enumerate(text):
if "%% callback invoked %%" in line:
skip = int((i + 1) / divider)
break
return skip
# werkzeug<2.1.0
if hasattr(tbtools, "get_current_traceback"):
tb = tbtools.get_current_traceback()
skip = _get_skip(tb.plaintext.splitlines())
return tbtools.get_current_traceback(skip=skip).render_full()
if hasattr(tbtools, "DebugTraceback"):
tb = tbtools.DebugTraceback(error) # pylint: disable=no-member
skip = _get_skip(tb.render_traceback_text().splitlines())
# pylint: disable=no-member
return tbtools.DebugTraceback(error, skip=skip).render_debugger_html(
True, secret, True
)
tb = traceback.format_exception(type(error), error, error.__traceback__)
skip = _get_skip(tb, 1)
return tb[0] + "".join(tb[skip:])
# Singleton signal to not update an output, alternative to PreventUpdate
no_update = _callback.NoUpdate() # pylint: disable=protected-access
# pylint: disable=too-many-instance-attributes
# pylint: disable=too-many-arguments, too-many-locals
class Dash:
"""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 pages_folder: a path, relative to the current working directory,
for pages of a multi-page app. Default ``'pages'``.
:type pages_folder: string
:param use_pages: Default False, or True if you set a non-default ``pages_folder``.
When True, the ``pages`` feature for multi-page apps is enabled.
:type pages: boolean
: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``. assets_external_path is joined
with assets_url_path to determine the absolute url to the
asset folder. 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 ``False``
: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 prevent_initial_callbacks: Default ``False``: Sets the default value
of ``prevent_initial_call`` for all callbacks added to the app.
Normally all callbacks are fired when the associated outputs are first
added to the page. You can disable this for individual callbacks by
setting ``prevent_initial_call`` in their definitions, or set it
``True`` here in which case you must explicitly set it ``False`` for
those callbacks you wish to have an initial call. This setting has no
effect on triggering callbacks when their inputs change later on.
: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 extra_hot_reload_paths: A list of paths to watch for changes, in
addition to assets and known Python and JS code, if hot reloading is
enabled.
:type extra_hot_reload_paths: list of strings
: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
:param title: Default ``Dash``. Configures the document.title
(the text that appears in a browser tab).
:param update_title: Default ``Updating...``. Configures the document.title
(the text that appears in a browser tab) text when a callback is being run.
Set to None or '' if you don't want the document.title to change or if you
want to control the document.title through a separate component or
clientside callback.
:param long_callback_manager: Deprecated, use ``background_callback_manager``
instead.
:param background_callback_manager: Background callback manager instance
to support the ``@callback(..., background=True)`` decorator.
One of ``DiskcacheManager`` or ``CeleryManager`` currently supported.
"""
def __init__( # pylint: disable=too-many-statements
self,
name=None,
server=True,
assets_folder="assets",
pages_folder="pages",
use_pages=False,
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,
prevent_initial_callbacks=False,
show_undo_redo=False,
extra_hot_reload_paths=None,
plugins=None,
title="Dash",
update_title="Updating...",
long_callback_manager=None,
background_callback_manager=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")
if (
self.server is not None
and not hasattr(self.server.config, "COMPRESS_ALGORITHM")
and _flask_compress_version >= parse_version("1.6.0")
):
# flask-compress==1.6.0 changed default to ['br', 'gzip']
# and non-overridable default compression with Brotli is
# causing performance issues
self.server.config["COMPRESS_ALGORITHM"] = ["gzip"]
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, ""
),
pages_folder=pages_folder_config(name, pages_folder, use_pages),
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, False),
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
),
prevent_initial_callbacks=prevent_initial_callbacks,
show_undo_redo=show_undo_redo,
extra_hot_reload_paths=extra_hot_reload_paths or [],
title=title,
update_title=update_title,
)
self.config.set_read_only(
[
"name",
"assets_folder",
"assets_url_path",
"eager_loading",
"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"
)
_get_paths.CONFIG = self.config
_pages.CONFIG = self.config
self.pages_folder = pages_folder
self.use_pages = True if pages_folder != "pages" else use_pages
# keep title as a class property for backwards compatibility
self.title = title
# 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._layout_is_function = False
self.validation_layout = None
self._extra_components = []
self._setup_dev_tools()
self._hot_reload = AttributeDict(
hash=None,
hard=False,
lock=threading.RLock(),
watch_thread=None,
changed_assets=[],
)
self._assets_files = []
self._long_callback_count = 0
self._background_manager = background_callback_manager or long_callback_manager
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()
self.logger.setLevel(logging.INFO)
def init_app(self, app=None, **kwargs):
"""Initialize the parts of Dash that require a flask app."""
config = self.config
config.update(kwargs)
config.set_read_only(
[
"url_base_pathname",
"routes_pathname_prefix",
"requests_pathname_prefix",
],
"Read-only: can only be set in the Dash constructor or during init_app()",
)
if app is not None:
self.server = app
bp_prefix = config.routes_pathname_prefix.replace("/", "_").replace(".", "_")
assets_blueprint_name = f"{bp_prefix}dash_assets"
self.server.register_blueprint(
flask.Blueprint(
assets_blueprint_name,
config.name,
static_folder=self.config.assets_folder,
static_url_path=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)
_get_app.APP = self
self.enable_pages()
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):
layout = self._layout() if self._layout_is_function else self._layout
# Add any extra components
if self._extra_components:
layout = html.Div(children=[layout] + self._extra_components)
return layout
@layout.setter
def layout(self, value):
_validate.validate_layout_type(value)
self._layout_is_function = callable(value)
self._layout = value
# for using flask.has_request_context() to deliver a full layout for
# validation inside a layout function - track if a user might be doing this.
if (
self._layout_is_function
and not self.validation_layout
and not self.config.suppress_callback_exceptions
):
def simple_clone(c, children=None):
cls = type(c)
# in Py3 we can use the __init__ signature to reduce to just
# required args and id; in Py2 this doesn't work so we just
# empty out children.
sig = getattr(cls.__init__, "__signature__", None)
props = {
p: getattr(c, p)
for p in c._prop_names # pylint: disable=protected-access
if hasattr(c, p)
and (
p == "id" or not sig or sig.parameters[p].default == c.REQUIRED
)
}
if props.get("children", children):
props["children"] = children or []
return cls(**props)
layout_value = self._layout_value()
_validate.validate_layout(value, layout_value)
self.validation_layout = simple_clone(
# pylint: disable=protected-access
layout_value,
[simple_clone(c) for c in layout_value._traverse_ids()],
)
@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(
to_json(layout),
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,
"update_title": self.config.update_title,
"children_props": ComponentRegistry.children_props,
}
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,
}
if self.validation_layout and not self.config.suppress_callback_exceptions:
validation_layout = self.validation_layout
# Add extra components
if self._extra_components:
validation_layout = html.Div(
children=[validation_layout] + self._extra_components
)
config["validation_layout"] = validation_layout
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=""):
if any(
relative_package_path.startswith(x + "/")
for x in ["dcc", "html", "dash_table"]
):
relative_package_path = relative_package_path.replace("dash.", "")
version = importlib.import_module(
f"{namespace}.{os.path.split(relative_package_path)[0]}"
).__version__
else:
version = importlib.import_module(namespace).__version__
module_path = os.path.join(
os.path.dirname(sys.modules[namespace].__file__), relative_package_path
)
modified = int(os.stat(module_path).st_mtime)
fingerprint = build_fingerprint(relative_package_path, version, modified)
return f"{self.config.requests_pathname_prefix}_dash-component-suites/{namespace}/{fingerprint}"
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:
if any(x in rel_path for x in ["dcc", "html", "dash_table"]):
rel_path = rel_path.replace("dash.", "")
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 += f"?m={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 f'<link rel="stylesheet" href="{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
)
+ self.scripts._resources._filter_resources(
dcc._js_dist, dev_bundles=dev
)
+ self.scripts._resources._filter_resources(
html._js_dist, dev_bundles=dev
)
+ self.scripts._resources._filter_resources(
dash_table._js_dist, dev_bundles=dev
)
)
)
self._inline_scripts.extend(_callback.GLOBAL_INLINE_SCRIPTS)
_callback.GLOBAL_INLINE_SCRIPTS.clear()
return "\n".join(
[
format_tag("script", src)
if isinstance(src, dict)
else f'<script src="{src}"></script>'
for src in srcs
]
+ [f"<script>{src}</script>" for src in self._inline_scripts]
)
def _generate_config_html(self):
return f'<script id="_dash-config" type="application/json">{to_json(self._config())}</script>'
def _generate_renderer(self):
return f'<script id="_dash-renderer" type="application/javascript">{self.renderer}</script>'
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)
has_viewport = any(x.get("name") == "viewport" 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">')
if not has_viewport:
tags.append(
'<meta name="viewport" content="width=device-width, initial-scale=1">'
)
tags += [format_tag("meta", x, opened=True) for x in meta_tags]
return "\n ".join(tags)
def _pages_meta_tags(self):
start_page, path_variables = self._path_to_page(flask.request.path.strip("/"))
# use the supplied image_url or create url based on image in the assets folder
image = start_page.get("image", "")
if image:
image = self.get_asset_url(image)
assets_image_url = (
"".join([flask.request.url_root, image.lstrip("/")]) if image else None
)
supplied_image_url = start_page.get("image_url")
image_url = supplied_image_url if supplied_image_url else assets_image_url
title = start_page.get("title", self.title)
if callable(title):
title = title(**path_variables) if path_variables else title()
description = start_page.get("description", "")
if callable(description):
description = (
description(**path_variables) if path_variables else description()
)
return dedent(
f"""
<meta name="description" content="{description}" />
<!-- Twitter Card data -->
<meta property="twitter:card" content="summary_large_image">
<meta property="twitter:url" content="{flask.request.url}">
<meta property="twitter:title" content="{title}">
<meta property="twitter:description" content="{description}">
<meta property="twitter:image" content="{image_url}">
<!-- Open Graph data -->
<meta property="og:title" content="{title}" />
<meta property="og:type" content="website" />
<meta property="og:description" content="{description}" />
<meta property="og:image" content="{image_url}">
"""
)
# 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)
extension = "." + path_in_pkg.split(".")[-1]
mimetype = mimetypes.types_map.get(extension, "application/octet-stream")
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 f'"{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()
# use self.title instead of app.config.title for backwards compatibility
title = self.title
pages_metas = ""
if self.use_pages:
pages_metas = self._pages_meta_tags()
if self._favicon:
favicon_mod_time = os.path.getmtime(
os.path.join(self.config.assets_folder, self._favicon)
)
favicon_url = f"{self.get_asset_url(self._favicon)}?m={favicon_mod_time}"
else:
prefix = self.config.requests_pathname_prefix
favicon_url = f"{prefix}_favicon.ico?v={__version__}"
favicon = format_tag(
"link",
{"rel": "icon", "type": "image/x-icon", "href": favicon_url},
opened=True,
)
index = self.interpolate_index(
metas=pages_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):