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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 warnings
import re
import logging
from functools import wraps
import flask
from flask import Flask, Response
from flask_compress import Compress
import plotly
import dash_renderer
from .dependencies import Input, Output, State
from .resources import Scripts, Css
from .development.base_component import Component
from . import exceptions
from ._utils import AttributeDict as _AttributeDict
from ._utils import interpolate_str as _interpolate
from ._utils import format_tag as _format_tag
from ._utils import generate_hash as _generate_hash
from . import _watch
from ._utils import get_asset_path as _get_asset_path
from . import _configs
_default_index = '''<!DOCTYPE html>
<html>
<head>
{%metas%}
<title>{%title%}</title>
{%favicon%}
{%css%}
</head>
<body>
{%app_entry%}
<footer>
{%config%}
{%scripts%}
</footer>
</body>
</html>'''
_app_entry = '''
<div id="react-entry-point">
<div class="_dash-loading">
Loading...
</div>
</div>
'''
_re_index_entry = re.compile(r'{%app_entry%}')
_re_index_config = re.compile(r'{%config%}')
_re_index_scripts = re.compile(r'{%scripts%}')
_re_index_entry_id = re.compile(r'id="react-entry-point"')
_re_index_config_id = re.compile(r'id="_dash-config"')
_re_index_scripts_id = re.compile(r'src=".*dash[-_]renderer.*"')
# pylint: disable=too-many-instance-attributes
# pylint: disable=too-many-arguments, too-many-locals
class Dash(object):
def __init__(
self,
name='__main__',
server=None,
static_folder='static',
assets_folder='assets',
assets_url_path='/assets',
assets_ignore='',
include_assets_files=True,
url_base_pathname=None,
assets_external_path=None,
requests_pathname_prefix=None,
routes_pathname_prefix=None,
compress=True,
meta_tags=None,
index_string=_default_index,
external_scripts=None,
external_stylesheets=None,
suppress_callback_exceptions=None,
components_cache_max_age=None,
**kwargs):
# pylint-disable: too-many-instance-attributes
if 'csrf_protect' in kwargs:
warnings.warn('''
`csrf_protect` is no longer used,
CSRF protection has been removed as it is no longer
necessary.
See https://github.com/plotly/dash/issues/141 for details.
''', DeprecationWarning)
self._assets_folder = os.path.join(
flask.helpers.get_root_path(name),
assets_folder,
)
self._assets_url_path = assets_url_path
# allow users to supply their own flask server
self.server = server or Flask(name, static_folder=static_folder)
env_configs = _configs.env_configs()
url_base_pathname, routes_pathname_prefix, requests_pathname_prefix = \
_configs.pathname_configs(
url_base_pathname,
routes_pathname_prefix,
requests_pathname_prefix,
environ_configs=env_configs)
self.url_base_pathname = url_base_pathname
self.config = _AttributeDict({
'suppress_callback_exceptions': _configs.get_config(
'suppress_callback_exceptions',
suppress_callback_exceptions, env_configs, False
),
'routes_pathname_prefix': routes_pathname_prefix,
'requests_pathname_prefix': requests_pathname_prefix,
'include_assets_files': _configs.get_config(
'include_assets_files',
include_assets_files,
env_configs,
True),
'assets_external_path': _configs.get_config(
'assets_external_path', assets_external_path, env_configs, ''),
'components_cache_max_age': int(_configs.get_config(
'components_cache_max_age', components_cache_max_age,
env_configs, 2678400))
})
assets_blueprint_name = '{}{}'.format(
self.config.routes_pathname_prefix.replace('/', '_'),
'dash_assets'
)
self.server.register_blueprint(
flask.Blueprint(
assets_blueprint_name, name,
static_folder=self._assets_folder,
static_url_path='{}{}'.format(
self.config.routes_pathname_prefix,
assets_url_path.lstrip('/')
)
)
)
# list of dependencies
self.callback_map = {}
self._index_string = ''
self.index_string = index_string
self._meta_tags = meta_tags or []
self._favicon = None
if compress:
# gzip
Compress(self.server)
@self.server.errorhandler(exceptions.PreventUpdate)
def _handle_error(_):
"""Handle a halted callback and return an empty 204 response"""
return '', 204
# static files from the packages
self.css = Css()
self.scripts = Scripts()
self._external_scripts = external_scripts or []
self._external_stylesheets = external_stylesheets or []
self.assets_ignore = assets_ignore
self.registered_paths = collections.defaultdict(set)
# urls
self.routes = []
self._add_url(
'{}_dash-layout'.format(self.config['routes_pathname_prefix']),
self.serve_layout)
self._add_url(
'{}_dash-dependencies'.format(
self.config['routes_pathname_prefix']),
self.dependencies)
self._add_url(
'{}_dash-update-component'.format(
self.config['routes_pathname_prefix']),
self.dispatch,
['POST'])
self._add_url((
'{}_dash-component-suites'
'/<string:package_name>'
'/<path:path_in_package_dist>').format(
self.config['routes_pathname_prefix']),
self.serve_component_suites)
self._add_url(
'{}_dash-routes'.format(self.config['routes_pathname_prefix']),
self.serve_routes)
self._add_url(
self.config['routes_pathname_prefix'],
self.index)
self._add_url(
'{}_reload-hash'.format(self.config['routes_pathname_prefix']),
self.serve_reload_hash)
# catch-all for front-end routes, used by dcc.Location
self._add_url(
'{}<path:path>'.format(self.config['routes_pathname_prefix']),
self.index)
self._add_url(
'{}_favicon.ico'.format(self.config['routes_pathname_prefix']),
self._serve_default_favicon)
self.server.before_first_request(self._setup_server)
self._layout = None
self._cached_layout = None
self._dev_tools = _AttributeDict({
'serve_dev_bundles': False,
'hot_reload': False,
'hot_reload_interval': 3000,
'hot_reload_watch_interval': 0.5,
'hot_reload_max_retry': 8
})
# add a handler for components suites errors to return 404
self.server.errorhandler(exceptions.InvalidResourceError)(
self._invalid_resources_handler)
self._assets_files = []
# hot reload
self._reload_hash = None
self._hard_reload = False
self._lock = threading.RLock()
self._watch_thread = None
self._changed_assets = []
self.logger = logging.getLogger(name)
self.logger.addHandler(logging.StreamHandler(stream=sys.stdout))
def _add_url(self, name, view_func, methods=('GET',)):
self.server.add_url_rule(
name,
view_func=view_func,
endpoint=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(name)
@property
def layout(self):
return self._layout
def _layout_value(self):
if isinstance(self._layout, collections.Callable):
self._cached_layout = self._layout()
else:
self._cached_layout = self._layout
return self._cached_layout
@layout.setter
def layout(self, value):
if (not isinstance(value, Component) and
not isinstance(value, collections.Callable)):
raise exceptions.NoLayoutException(
''
'Layout must be a dash component '
'or a function that returns '
'a dash component.')
self._layout = value
layout_value = self._layout_value()
# pylint: disable=protected-access
self.css._update_layout(layout_value)
self.scripts._update_layout(layout_value)
@property
def index_string(self):
return self._index_string
@index_string.setter
def index_string(self, value):
checks = (
(_re_index_entry.search(value), 'app_entry'),
(_re_index_config.search(value), 'config',),
(_re_index_scripts.search(value), 'scripts'),
)
missing = [missing for check, missing in checks if not check]
if missing:
raise exceptions.InvalidIndexException(
'Did you forget to include {} in your index string ?'.format(
', '.join('{%' + x + '%}' for x in missing)
)
)
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):
config = {
'url_base_pathname': self.url_base_pathname,
'requests_pathname_prefix': self.config['requests_pathname_prefix']
}
if self._dev_tools.hot_reload:
config['hot_reload'] = {
'interval': self._dev_tools.hot_reload_interval,
'max_retry': self._dev_tools.hot_reload_max_retry
}
return config
def serve_reload_hash(self):
hard = self._hard_reload
changed = self._changed_assets
self._lock.acquire()
self._hard_reload = False
self._changed_assets = []
self._lock.release()
return flask.jsonify({
'reloadHash': self._reload_hash,
'hard': hard,
'packages': list(self.registered_paths.keys()),
'files': list(changed)
})
def serve_routes(self):
return flask.Response(
json.dumps(self.routes,
cls=plotly.utils.PlotlyJSONEncoder),
mimetype='application/json'
)
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/{}/{}?v={}&m={}'.format(
self.config['requests_pathname_prefix'],
namespace,
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:
for url in resource['external_url']:
srcs.append(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 bust query param
static_url += '?m={}'.format(resource['ts'])
srcs.append(static_url)
return srcs
def _generate_css_dist_html(self):
links = self._external_stylesheets + \
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 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
srcs = self._collect_and_register_resources(
self.scripts._resources._filter_resources(
dash_renderer._js_dist_dependencies,
dev_bundles=self._dev_tools.serve_dev_bundles
)) + self._external_scripts + self._collect_and_register_resources(
self.scripts.get_all_scripts(
dev_bundles=self._dev_tools.serve_dev_bundles) +
self.scripts._resources._filter_resources(
dash_renderer._js_dist,
dev_bundles=self._dev_tools.serve_dev_bundles
))
return '\n'.join([
_format_tag('script', src)
if isinstance(src, dict)
else '<script src="{}"></script>'.format(src)
for src in srcs
])
def _generate_config_html(self):
return (
'<script id="_dash-config" type="application/json">'
'{}'
'</script>'
).format(json.dumps(self._config()))
def _generate_meta_html(self):
has_ie_compat = any(
x.get('http-equiv', '') == 'X-UA-Compatible'
for x in self._meta_tags)
has_charset = any('charset' in x for x in self._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 = tags + [
_format_tag('meta', x, opened=True) for x in self._meta_tags
]
return '\n '.join(tags)
# Serve the JS bundles for each package
def serve_component_suites(self, package_name, path_in_package_dist):
if package_name not in self.registered_paths:
raise exceptions.DependencyException(
'Error loading dependency.\n'
'"{}" is not a registered library.\n'
'Registered libraries are: {}'
.format(package_name, list(self.registered_paths.keys())))
elif path_in_package_dist not in self.registered_paths[package_name]:
raise exceptions.DependencyException(
'"{}" is registered but the path requested is not valid.\n'
'The path requested: "{}"\n'
'List of registered paths: {}'
.format(
package_name,
path_in_package_dist,
self.registered_paths
)
)
mimetype = ({
'js': 'application/JavaScript',
'css': 'text/css',
'map': 'application/json'
})[path_in_package_dist.split('.')[-1]]
headers = {
'Cache-Control': 'public, max-age={}'.format(
self.config.components_cache_max_age)
}
return Response(
pkgutil.get_data(package_name, path_in_package_dist),
mimetype=mimetype,
headers=headers
)
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()
title = getattr(self, 'title', 'Dash')
if self._favicon:
favicon_mod_time = os.path.getmtime(
os.path.join(self._assets_folder, self._favicon))
favicon_url = self.get_asset_url(self._favicon) + '?m={}'.format(
favicon_mod_time
)
else:
favicon_url = '{}_favicon.ico'.format(
self.config.requests_pathname_prefix)
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)
checks = (
(_re_index_entry_id.search(index), '#react-entry-point'),
(_re_index_config_id.search(index), '#_dash-configs'),
(_re_index_scripts_id.search(index), 'dash-renderer'),
)
missing = [missing for check, missing in checks if not check]
if missing:
plural = 's' if len(missing) > 1 else ''
raise exceptions.InvalidIndexException(
'Missing element{pl} {ids} in index.'.format(
ids=', '.join(missing),
pl=plural
)
)
return index
def interpolate_index(self,
metas='', title='', css='', config='',
scripts='', app_entry='', favicon=''):
"""
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}
<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'))
: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 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(self.index_string,
metas=metas,
title=title,
css=css,
config=config,
scripts=scripts,
favicon=favicon,
app_entry=app_entry)
def dependencies(self):
return flask.jsonify([
{
'output': {
'id': k.split('.')[0],
'property': k.split('.')[1]
},
'inputs': v['inputs'],
'state': v['state'],
} for k, v in self.callback_map.items()
])
# pylint: disable=unused-argument, no-self-use
def react(self, *args, **kwargs):
raise exceptions.DashException(
'Yo! `react` is no longer used. \n'
'Use `callback` instead. `callback` has a new syntax too, '
'so make sure to call `help(app.callback)` to learn more.')
def _validate_callback(self, output, inputs, state):
# pylint: disable=too-many-branches
layout = self._cached_layout or self._layout_value()
if (layout is None and
not self.config.first('suppress_callback_exceptions',
'supress_callback_exceptions')):
# Without a layout, we can't do validation on the IDs and
# properties of the elements in the callback.
raise exceptions.LayoutIsNotDefined('''
Attempting to assign a callback to the application but
the `layout` property has not been assigned.
Assign the `layout` property before assigning callbacks.
Alternatively, suppress this warning by setting
`app.config['suppress_callback_exceptions']=True`
'''.replace(' ', ''))
for args, obj, name in [([output], Output, 'Output'),
(inputs, Input, 'Input'),
(state, State, 'State')]:
if not isinstance(args, list):
raise exceptions.IncorrectTypeException(
'The {} argument `{}` is '
'not a list of `dash.dependencies.{}`s.'.format(
name.lower(), str(args), name
))
for arg in args:
if not isinstance(arg, obj):
raise exceptions.IncorrectTypeException(
'The {} argument `{}` is '
'not of type `dash.{}`.'.format(
name.lower(), str(arg), name
))
if (not self.config.first('suppress_callback_exceptions',
'supress_callback_exceptions') and
arg.component_id not in layout and
arg.component_id != getattr(layout, 'id', None)):
raise exceptions.NonExistentIdException('''
Attempting to assign a callback to the
component with the id "{}" but no
components with id "{}" exist in the
app\'s layout.\n\n
Here is a list of IDs in layout:\n{}\n\n
If you are assigning callbacks to components
that are generated by other callbacks
(and therefore not in the initial layout), then
you can suppress this exception by setting
`app.config['suppress_callback_exceptions']=True`.
'''.format(
arg.component_id,
arg.component_id,
list(layout.keys()) + (
[] if not hasattr(layout, 'id') else
[layout.id]
)
).replace(' ', ''))
if not self.config.first('suppress_callback_exceptions',
'supress_callback_exceptions'):
if getattr(layout, 'id', None) == arg.component_id:
component = layout
else:
component = layout[arg.component_id]
if (hasattr(arg, 'component_property') and
arg.component_property not in
component.available_properties and not
any(arg.component_property.startswith(w) for w in
component.available_wildcard_properties)):
raise exceptions.NonExistentPropException('''
Attempting to assign a callback with
the property "{}" but the component
"{}" doesn't have "{}" as a property.\n
Here is a list of the available properties in "{}":
{}
'''.format(
arg.component_property,
arg.component_id,
arg.component_property,
arg.component_id,
component.available_properties).replace(
' ', ''))
if hasattr(arg, 'component_event'):
raise exceptions.NonExistentEventException('''
Events have been removed.
Use the associated property instead.
''')
if state and not inputs:
raise exceptions.MissingInputsException('''
This callback has {} `State` {}
but no `Input` elements.\n
Without `Input` elements, this callback
will never get called.\n
(Subscribing to input components will cause the
callback to be called whenever their values change.)
'''.format(
len(state),
'elements' if len(state) > 1 else 'element'
).replace(' ', ''))
if '.' in output.component_id:
raise exceptions.IDsCantContainPeriods('''The Output element
`{}` contains a period in its ID.
Periods are not allowed in IDs right now.'''.format(
output.component_id
))
callback_id = '{}.{}'.format(
output.component_id, output.component_property)
if callback_id in self.callback_map:
raise exceptions.CantHaveMultipleOutputs('''
You have already assigned a callback to the output
with ID "{}" and property "{}". An output can only have
a single callback function. Try combining your inputs and
callback functions together into one function.
'''.format(
output.component_id,
output.component_property).replace(' ', ''))
def _validate_callback_output(self, output_value, output):
valid = [str, dict, int, float, type(None), Component]
def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
toplevel=False):
outer_id = "(id={:s})".format(outer_val.id) \
if getattr(outer_val, 'id', False) else ''
outer_type = type(outer_val).__name__
raise exceptions.InvalidCallbackReturnValue('''
The callback for property `{property:s}` of component `{id:s}`
returned a {object:s} having type `{type:s}`
which is not JSON serializable.
{location_header:s}{location:s}
and has string representation
`{bad_val}`
In general, Dash properties can only be
dash components, strings, dictionaries, numbers, None,
or lists of those.
'''.format(
property=output.component_property,
id=output.component_id,
object='tree with one value' if not toplevel else 'value',
type=bad_type,
location_header=(
'The value in question is located at'
if not toplevel else
'''The value in question is either the only value returned,
or is in the top level of the returned list,'''
),
location=(
"\n" +
("[{:d}] {:s} {:s}".format(index, outer_type, outer_id)
if index is not None
else ('[*] ' + outer_type + ' ' + outer_id))
+ "\n" + path + "\n"
) if not toplevel else '',
bad_val=bad_val).replace(' ', ''))
def _value_is_valid(val):
return (
# pylint: disable=unused-variable
any([isinstance(val, x) for x in valid]) or
type(val).__name__ == 'unicode'
)
def _validate_value(val, index=None):
# val is a Component
if isinstance(val, Component):
for p, j in val.traverse_with_paths():
# check each component value in the tree
if not _value_is_valid(j):
_raise_invalid(
bad_val=j,
outer_val=val,
bad_type=type(j).__name__,
path=p,
index=index
)
# Children that are not of type Component or
# list/tuple not returned by traverse
child = getattr(j, 'children', None)
if not isinstance(child, (tuple,
collections.MutableSequence)):
if child and not _value_is_valid(child):
_raise_invalid(
bad_val=child,
outer_val=val,
bad_type=type(child).__name__,
path=p + "\n" + "[*] " + type(child).__name__,
index=index
)
# Also check the child of val, as it will not be returned
child = getattr(val, 'children', None)
if not isinstance(child, (tuple, collections.MutableSequence)):
if child and not _value_is_valid(child):
_raise_invalid(
bad_val=child,
outer_val=val,
bad_type=type(child).__name__,
path=type(child).__name__,
index=index
)
# val is not a Component, but is at the top level of tree
else:
if not _value_is_valid(val):
_raise_invalid(
bad_val=val,
outer_val=type(val).__name__,
bad_type=type(val).__name__,
path='',
index=index,
toplevel=True
)
if isinstance(output_value, list):
for i, val in enumerate(output_value):
_validate_value(val, index=i)
else:
_validate_value(output_value)
# TODO - Update nomenclature.
# "Parents" and "Children" should refer to the DOM tree
# and not the dependency tree.
# The dependency tree should use the nomenclature
# "observer" and "controller".
# "observers" listen for changes from their "controllers". For example,
# if a graph depends on a dropdown, the graph is the "observer" and the
# dropdown is a "controller". In this case the graph's "dependency" is
# the dropdown.
# TODO - Check this map for recursive or other ill-defined non-tree
# relationships
# pylint: disable=dangerous-default-value
def callback(self, output, inputs=[], state=[]):
self._validate_callback(output, inputs, state)
callback_id = '{}.{}'.format(
output.component_id, output.component_property
)
self.callback_map[callback_id] = {
'inputs': [
{'id': c.component_id, 'property': c.component_property}
for c in inputs
],
'state': [
{'id': c.component_id, 'property': c.component_property}
for c in state
]
}
def wrap_func(func):
@wraps(func)
def add_context(*args, **kwargs):
output_value = func(*args, **kwargs)
response = {
'response': {
'props': {
output.component_property: output_value
}
}
}
try:
jsonResponse = json.dumps(
response,
cls=plotly.utils.PlotlyJSONEncoder
)
except TypeError:
self._validate_callback_output(output_value, output)
raise exceptions.InvalidCallbackReturnValue('''
The callback for property `{property:s}`
of component `{id:s}` returned a value
which is not JSON serializable.
In general, Dash properties can only be
dash components, strings, dictionaries, numbers, None,
or lists of those.
'''.format(property=output.component_property,
id=output.component_id))
return flask.Response(
jsonResponse,
mimetype='application/json'
)
self.callback_map[callback_id]['callback'] = add_context
return add_context
return wrap_func
def dispatch(self):
body = flask.request.get_json()
inputs = body.get('inputs', [])
state = body.get('state', [])
output = body['output']
target_id = '{}.{}'.format(output['id'], output['property'])
args = []
for component_registration in self.callback_map[target_id]['inputs']:
args.append([
c.get('value', None) for c in inputs if
c['property'] == component_registration['property'] and
c['id'] == component_registration['id']
][0])
for component_registration in self.callback_map[target_id]['state']:
args.append([
c.get('value', None) for c in state if
c['property'] == component_registration['property'] and
c['id'] == component_registration['id']
][0])
return self.callback_map[target_id]['callback'](*args)
def _validate_layout(self):
if self.layout is None:
raise exceptions.NoLayoutException(
''
'The layout was `None` '
'at the time that `run_server` was called. '
'Make sure to set the `layout` attribute of your application '
'before running the server.')
to_validate = self._layout_value()
layout_id = getattr(self.layout, 'id', None)
component_ids = {layout_id} if layout_id else set()
for component in to_validate.traverse():
component_id = getattr(component, 'id', None)
if component_id and component_id in component_ids:
raise exceptions.DuplicateIdError(
'Duplicate component id found'
' in the initial layout: `{}`'.format(component_id))
component_ids.add(component_id)
def _setup_server(self):
if self.config.include_assets_files:
self._walk_assets_directory()
self._validate_layout()
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):