"""
Defines the baseclasses that make a component render to a bokeh model
and become viewable including:
* Layoutable: Defines parameters concerned with layout and style
* ServableMixin: Mixin class that defines methods to serve object on server
* Renderable: Defines methods to render a component as a bokeh model
* Viewable: Defines methods to view the component in the
notebook, on the server or in static exports
"""
import datetime as dt
import logging
import sys
import traceback
import uuid
from functools import partial
import param
from bokeh.document.document import Document as _Document
from bokeh.io import curdoc as _curdoc
from pyviz_comms import JupyterCommManager
from .config import config, panel_extension
from .io import serve
from .io.document import init_doc
from .io.embed import embed_state
from .io.loading import start_loading_spinner, stop_loading_spinner
from .io.model import add_to_doc, patch_cds_msg
from .io.notebook import (
ipywidget, render_mimebundle, render_model, show_embed, show_server
)
from .io.save import save
from .io.state import state
from .util import escape, param_reprs
class Layoutable(param.Parameterized):
"""
Layoutable defines shared style and layout related parameters
for all Panel components with a visual representation.
"""
align = param.ClassSelector(default='start',
class_=(str, tuple), doc="""
Whether the object should be aligned with the start, end or
center of its container. If set as a tuple it will declare
(vertical, horizontal) alignment.""")
aspect_ratio = param.Parameter(default=None, doc="""
Describes the proportional relationship between component's
width and height. This works if any of component's dimensions
are flexible in size. If set to a number, ``width / height =
aspect_ratio`` relationship will be maintained. Otherwise, if
set to ``"auto"``, component's preferred width and height will
be used to determine the aspect (if not set, no aspect will be
preserved).""")
background = param.Parameter(default=None, doc="""
Background color of the component.""")
css_classes = param.List(default=None, doc="""
CSS classes to apply to the layout.""")
width = param.Integer(default=None, bounds=(0, None), doc="""
The width of the component (in pixels). This can be either
fixed or preferred width, depending on width sizing policy.""")
height = param.Integer(default=None, bounds=(0, None), doc="""
The height of the component (in pixels). This can be either
fixed or preferred height, depending on height sizing policy.""")
min_width = param.Integer(default=None, bounds=(0, None), doc="""
Minimal width of the component (in pixels) if width is adjustable.""")
min_height = param.Integer(default=None, bounds=(0, None), doc="""
Minimal height of the component (in pixels) if height is adjustable.""")
max_width = param.Integer(default=None, bounds=(0, None), doc="""
Minimal width of the component (in pixels) if width is adjustable.""")
max_height = param.Integer(default=None, bounds=(0, None), doc="""
Minimal height of the component (in pixels) if height is adjustable.""")
margin = param.Parameter(default=5, doc="""
Allows to create additional space around the component. May
be specified as a two-tuple of the form (vertical, horizontal)
or a four-tuple (top, right, bottom, left).""")
width_policy = param.ObjectSelector(
default="auto", objects=['auto', 'fixed', 'fit', 'min', 'max'], doc="""
Describes how the component should maintain its width.
``"auto"``
Use component's preferred sizing policy.
``"fixed"``
Use exactly ``width`` pixels. Component will overflow if
it can't fit in the available horizontal space.
``"fit"``
Use component's preferred width (if set) and allow it to
fit into the available horizontal space within the minimum
and maximum width bounds (if set). Component's width
neither will be aggressively minimized nor maximized.
``"min"``
Use as little horizontal space as possible, not less than
the minimum width (if set). The starting point is the
preferred width (if set). The width of the component may
shrink or grow depending on the parent layout, aspect
management and other factors.
``"max"``
Use as much horizontal space as possible, not more than
the maximum width (if set). The starting point is the
preferred width (if set). The width of the component may
shrink or grow depending on the parent layout, aspect
management and other factors.
""")
height_policy = param.ObjectSelector(
default="auto", objects=['auto', 'fixed', 'fit', 'min', 'max'], doc="""
Describes how the component should maintain its height.
``"auto"``
Use component's preferred sizing policy.
``"fixed"``
Use exactly ``height`` pixels. Component will overflow if
it can't fit in the available vertical space.
``"fit"``
Use component's preferred height (if set) and allow to fit
into the available vertical space within the minimum and
maximum height bounds (if set). Component's height neither
will be aggressively minimized nor maximized.
``"min"``
Use as little vertical space as possible, not less than
the minimum height (if set). The starting point is the
preferred height (if set). The height of the component may
shrink or grow depending on the parent layout, aspect
management and other factors.
``"max"``
Use as much vertical space as possible, not more than the
maximum height (if set). The starting point is the
preferred height (if set). The height of the component may
shrink or grow depending on the parent layout, aspect
management and other factors.
""")
sizing_mode = param.ObjectSelector(default=None, objects=[
'fixed', 'stretch_width', 'stretch_height', 'stretch_both',
'scale_width', 'scale_height', 'scale_both', None], doc="""
How the component should size itself.
This is a high-level setting for maintaining width and height
of the component. To gain more fine grained control over
sizing, use ``width_policy``, ``height_policy`` and
``aspect_ratio`` instead (those take precedence over
``sizing_mode``).
``"fixed"``
Component is not responsive. It will retain its original
width and height regardless of any subsequent browser
window resize events.
``"stretch_width"``
Component will responsively resize to stretch to the
available width, without maintaining any aspect ratio. The
height of the component depends on the type of the
component and may be fixed or fit to component's contents.
``"stretch_height"``
Component will responsively resize to stretch to the
available height, without maintaining any aspect
ratio. The width of the component depends on the type of
the component and may be fixed or fit to component's
contents.
``"stretch_both"``
Component is completely responsive, independently in width
and height, and will occupy all the available horizontal
and vertical space, even if this changes the aspect ratio
of the component.
``"scale_width"``
Component will responsively resize to stretch to the
available width, while maintaining the original or
provided aspect ratio.
``"scale_height"``
Component will responsively resize to stretch to the
available height, while maintaining the original or
provided aspect ratio.
``"scale_both"``
Component will responsively resize to both the available
width and height, while maintaining the original or
provided aspect ratio.
""")
visible = param.Boolean(default=True, doc="""
Whether the component is visible. Setting visible to false will
hide the component entirely.""")
__abstract = True
def __init__(self, **params):
if (params.get('width') is not None and
params.get('height') is not None and
params.get('width_policy') is None and
params.get('height_policy') is None and
'sizing_mode' not in params):
params['sizing_mode'] = 'fixed'
elif (not (self.param.sizing_mode.constant or self.param.sizing_mode.readonly) and
type(self).sizing_mode is None and 'sizing_mode' not in params):
if config.sizing_mode == 'stretch_both':
if params.get('height') is not None:
params['sizing_mode'] = 'stretch_width'
elif params.get('width') is not None:
params['sizing_mode'] = 'stretch_height'
else:
params['sizing_mode'] = config.sizing_mode
else:
params['sizing_mode'] = config.sizing_mode
super().__init__(**params)
class ServableMixin(object):
"""
Mixin to define methods shared by objects which can served.
"""
def _modify_doc(self, server_id, title, doc, location):
"""
Callback to handle FunctionHandler document creation.
"""
if server_id:
state._servers[server_id][2].append(doc)
return self.server_doc(doc, title, location)
def _add_location(self, doc, location, root=None):
from .io.location import Location
if isinstance(location, Location):
loc = location
elif doc in state._locations:
loc = state._locations[doc]
else:
loc = Location()
state._locations[doc] = loc
if root is None:
loc_model = loc._get_root(doc)
else:
loc_model = loc._get_model(doc, root)
loc_model.name = 'location'
doc.add_root(loc_model)
return loc
def _on_msg(self, ref, manager, msg):
"""
Handles Protocol messages arriving from the client comm.
"""
root, doc, comm = state._views[ref][1:]
patch_cds_msg(root, msg)
held = doc.callbacks.hold_value
patch = manager.assemble(msg)
doc.hold()
patch.apply_to_document(doc, comm.id)
doc.unhold()
if held:
doc.hold(held)
def _on_error(self, ref, error):
if ref not in state._handles or config.console_output in [None, 'disable']:
return
handle, accumulator = state._handles[ref]
formatted = '\n'+escape(traceback.format_exc())+'
\n'
if config.console_output == 'accumulate':
accumulator.append(formatted)
elif config.console_output == 'replace':
accumulator[:] = [formatted]
if accumulator:
handle.update({'text/html': '\n'.join(accumulator)}, raw=True)
def _on_stdout(self, ref, stdout):
if ref not in state._handles or config.console_output is [None, 'disable']:
return
handle, accumulator = state._handles[ref]
formatted = ["%s" % o for o in stdout]
if config.console_output == 'accumulate':
accumulator.extend(formatted)
elif config.console_output == 'replace':
accumulator[:] = formatted
if accumulator:
handle.update({'text/html': '\n'.join(accumulator)}, raw=True)
#----------------------------------------------------------------
# Public API
#----------------------------------------------------------------
def servable(self, title=None, location=True, area='main'):
"""
Serves the object if in a `panel serve` context and returns
the Panel object to allow it to display itself in a notebook
context.
Arguments
---------
title : str
A string title to give the Document (if served as an app)
location : boolean or panel.io.location.Location
Whether to create a Location component to observe and
set the URL location.
area: str
The area of a template to add the component too. Only has an
effect if pn.config.template has been set.
Returns
-------
The Panel object itself
"""
if _curdoc().session_context:
logger = logging.getLogger('bokeh')
for handler in logger.handlers:
if isinstance(handler, logging.StreamHandler):
handler.setLevel(logging.WARN)
if config.template:
template = state.template
if template.title == template.param.title.default and title:
template.title = title
if area == 'main':
template.main.append(self)
elif area == 'sidebar':
template.sidebar.append(self)
elif area == 'modal':
template.modal.append(self)
elif area == 'header':
template.header.append(self)
else:
self.server_doc(title=title, location=location)
return self
def show(self, title=None, port=0, address=None, websocket_origin=None,
threaded=False, verbose=True, open=True, location=True, **kwargs):
"""
Starts a Bokeh server and displays the Viewable in a new tab.
Arguments
---------
title : str
A string title to give the Document (if served as an app)
port: int (optional, default=0)
Allows specifying a specific port
address : str
The address the server should listen on for HTTP requests.
websocket_origin: str or list(str) (optional)
A list of hosts that can connect to the websocket.
This is typically required when embedding a server app in
an external web site.
If None, "localhost" is used.
threaded: boolean (optional, default=False)
Whether to launch the Server on a separate thread, allowing
interactive use.
verbose: boolean (optional, default=True)
Whether to print the address and port
open : boolean (optional, default=True)
Whether to open the server in a new browser tab
location : boolean or panel.io.location.Location
Whether to create a Location component to observe and
set the URL location.
Returns
-------
server: bokeh.server.Server or threading.Thread
Returns the Bokeh server instance or the thread the server
was launched on (if threaded=True)
"""
return serve(
self, port=port, address=address, websocket_origin=websocket_origin,
show=open, start=True, title=title, verbose=verbose,
location=location, threaded=threaded, **kwargs
)
class Renderable(param.Parameterized):
"""
Baseclass for objects which can be rendered to a Bokeh model.
It therefore declare APIs for initializing the models from
parameter values.
"""
__abstract = True
def __init__(self, **params):
super().__init__(**params)
self._callbacks = []
self._documents = {}
self._models = {}
self._comms = {}
self._kernels = {}
self._found_links = set()
self._logger = logging.getLogger(f'{__name__}.{type(self).__name__}')
def _log(self, msg, *args, level='debug'):
getattr(self._logger, level)(f'Session %s {msg}', id(state.curdoc), *args)
def _get_model(self, doc, root=None, parent=None, comm=None):
"""
Converts the objects being wrapped by the viewable into a
bokeh model that can be composed in a bokeh layout.
Arguments
----------
doc: bokeh.Document
Bokeh document the bokeh model will be attached to.
root: bokeh.Model
The root layout the viewable will become part of.
parent: bokeh.Model
The parent layout the viewable will become part of.
comm: pyviz_comms.Comm
Optional pyviz_comms when working in notebook
Returns
-------
model: bokeh.Model
"""
raise NotImplementedError
def _cleanup(self, root):
"""
Clean up method which is called when a Viewable is destroyed.
Arguments
---------
root: bokeh.model.Model
Bokeh model for the view being cleaned up
"""
ref = root.ref['id']
if ref in state._handles:
del state._handles[ref]
def _preprocess(self, root):
"""
Applies preprocessing hooks to the model.
"""
hooks = self._preprocessing_hooks+self._hooks
for hook in hooks:
hook(self, root)
def _render_model(self, doc=None, comm=None):
if doc is None:
doc = _Document()
if comm is None:
comm = state._comm_manager.get_server_comm()
model = self.get_root(doc, comm)
if config.embed:
embed_state(self, model, doc,
json=config.embed_json,
json_prefix=config.embed_json_prefix,
save_path=config.embed_save_path,
load_path=config.embed_load_path,
progress=False)
else:
add_to_doc(model, doc)
return model
def _init_params(self):
return {k: v for k, v in self.param.values().items() if v is not None}
def _server_destroy(self, session_context):
"""
Server lifecycle hook triggered when session is destroyed.
"""
session_id = session_context.id
sessions = state.session_info['sessions']
if session_id in sessions and sessions[session_id]['ended'] is None:
session = sessions[session_id]
if session['rendered'] is not None:
state.session_info['live'] -= 1
session['ended'] = dt.datetime.now().timestamp()
state.param.trigger('session_info')
doc = session_context._document
root = self._documents[doc]
ref = root.ref['id']
self._cleanup(root)
del self._documents[doc]
if ref in state._views:
del state._views[ref]
if doc in state._locations:
loc = state._locations[doc]
loc._cleanup(root)
del state._locations[doc]
def get_root(self, doc=None, comm=None, preprocess=True):
"""
Returns the root model and applies pre-processing hooks
Arguments
---------
doc: bokeh.Document
Bokeh document the bokeh model will be attached to.
comm: pyviz_comms.Comm
Optional pyviz_comms when working in notebook
preprocess: boolean (default=True)
Whether to run preprocessing hooks
Returns
-------
Returns the bokeh model corresponding to this panel object
"""
doc = init_doc(doc)
root = self._get_model(doc, comm=comm)
if preprocess:
self._preprocess(root)
ref = root.ref['id']
state._views[ref] = (self, root, doc, comm)
return root
class Viewable(Renderable, Layoutable, ServableMixin):
"""
Viewable is the baseclass all visual components in the panel
library are built on. It defines the interface for declaring any
object that displays itself by transforming the object(s) being
wrapped into models that can be served using bokeh's layout
engine. The class also defines various methods that allow Viewable
objects to be displayed in the notebook and on bokeh server.
"""
loading = param.Boolean(doc="""
Whether or not the Viewable is loading. If True a loading spinner
is shown on top of the Viewable.""")
_preprocessing_hooks = []
def __init__(self, **params):
hooks = params.pop('hooks', [])
super().__init__(**params)
self._hooks = hooks
self._update_loading()
watcher = self.param.watch(self._update_loading, 'loading')
self._callbacks.append(watcher)
def _update_loading(self, *_):
if self.loading:
start_loading_spinner(self)
else:
stop_loading_spinner(self)
def __repr__(self, depth=0):
return '{cls}({params})'.format(cls=type(self).__name__,
params=', '.join(param_reprs(self)))
def __str__(self):
return self.__repr__()
def _repr_mimebundle_(self, include=None, exclude=None):
loaded = panel_extension._loaded
if not loaded and 'holoviews' in sys.modules:
import holoviews as hv
loaded = hv.extension._loaded
if config.comms in ('vscode', 'ipywidgets'):
widget = ipywidget(self)
if hasattr(widget, '_repr_mimebundle_'):
return widget._repr_mimebundle_(include, exclude)
plaintext = repr(widget)
if len(plaintext) > 110:
plaintext = plaintext[:110] + '…'
data = {
'text/plain': plaintext,
}
if widget._view_name is not None:
data['application/vnd.jupyter.widget-view+json'] = {
'version_major': 2,
'version_minor': 0,
'model_id': widget._model_id
}
if config.comms == 'vscode':
from IPython.display import display
display(data, raw=True)
return {'text/html': ''}, {}
return data, {}
if not loaded:
self.param.warning('Displaying Panel objects in the notebook '
'requires the panel extension to be loaded. '
'Ensure you run pn.extension() before '
'displaying objects in the notebook.')
return None
if config.comms == 'colab':
from .io.notebook import load_notebook
load_notebook(config.inline)
try:
from IPython import get_ipython
assert get_ipython().kernel is not None
state._comm_manager = JupyterCommManager
except Exception:
pass
if not state._views:
# Initialize the global Location
from .io.location import Location
state._location = location = Location()
else:
location = None
from IPython.display import display
from .models.comm_manager import CommManager
doc = _Document()
comm = state._comm_manager.get_server_comm()
model = self._render_model(doc, comm)
ref = model.ref['id']
manager = CommManager(comm_id=comm.id, plot_id=ref)
client_comm = state._comm_manager.get_client_comm(
on_msg=partial(self._on_msg, ref, manager),
on_error=partial(self._on_error, ref),
on_stdout=partial(self._on_stdout, ref)
)
self._comms[ref] = (comm, client_comm)
manager.client_comm_id = client_comm.id
if config.console_output != 'disable':
handle = display(display_id=uuid.uuid4().hex)
state._handles[ref] = (handle, [])
if config.embed:
return render_model(model)
return render_mimebundle(model, doc, comm, manager, location)
#----------------------------------------------------------------
# Public API
#----------------------------------------------------------------
def clone(self, **params):
"""
Makes a copy of the object sharing the same parameters.
Arguments
---------
params: Keyword arguments override the parameters on the clone.
Returns
-------
Cloned Viewable object
"""
inherited = {p: v for p, v in self.param.values().items()
if not self.param[p].readonly}
return type(self)(**dict(inherited, **params))
def pprint(self):
"""
Prints a compositional repr of the class.
"""
print(self)
def select(self, selector=None):
"""
Iterates over the Viewable and any potential children in the
applying the Selector.
Arguments
---------
selector: type or callable or None
The selector allows selecting a subset of Viewables by
declaring a type or callable function to filter by.
Returns
-------
viewables: list(Viewable)
"""
if (selector is None or
(isinstance(selector, type) and isinstance(self, selector)) or
(callable(selector) and not isinstance(selector, type) and selector(self))):
return [self]
else:
return []
def app(self, notebook_url="localhost:8888", port=0):
"""
Displays a bokeh server app inline in the notebook.
Arguments
---------
notebook_url: str
URL to the notebook server
port: int (optional, default=0)
Allows specifying a specific port
"""
return show_server(self, notebook_url, port)
def embed(self, max_states=1000, max_opts=3, json=False, json_prefix='',
save_path='./', load_path=None, progress=False, states={}):
"""
Renders a static version of a panel in a notebook by evaluating
the set of states defined by the widgets in the model. Note
this will only work well for simple apps with a relatively
small state space.
Arguments
---------
max_states: int
The maximum number of states to embed
max_opts: int
The maximum number of states for a single widget
json: boolean (default=True)
Whether to export the data to json files
json_prefix: str (default='')
Prefix for JSON filename
save_path: str (default='./')
The path to save json files to
load_path: str (default=None)
The path or URL the json files will be loaded from.
progress: boolean (default=False)
Whether to report progress
states: dict (default={})
A dictionary specifying the widget values to embed for each widget
"""
show_embed(
self, max_states, max_opts, json, json_prefix, save_path,
load_path, progress, states
)
def save(self, filename, title=None, resources=None, template=None,
template_variables=None, embed=False, max_states=1000,
max_opts=3, embed_json=False, json_prefix='', save_path='./',
load_path=None, progress=True, embed_states={}, as_png=None,
**kwargs):
"""
Saves Panel objects to file.
Arguments
---------
filename: string or file-like object
Filename to save the plot to
title: string
Optional title for the plot
resources: bokeh resources
One of the valid bokeh.resources (e.g. CDN or INLINE)
template:
passed to underlying io.save
template_variables:
passed to underlying io.save
embed: bool
Whether the state space should be embedded in the saved file.
max_states: int
The maximum number of states to embed
max_opts: int
The maximum number of states for a single widget
embed_json: boolean (default=True)
Whether to export the data to json files
json_prefix: str (default='')
Prefix for the auto-generated json directory
save_path: str (default='./')
The path to save json files to
load_path: str (default=None)
The path or URL the json files will be loaded from.
progress: boolean (default=True)
Whether to report progress
embed_states: dict (default={})
A dictionary specifying the widget values to embed for each widget
save_png: boolean (default=None)
To save as a .png. If None save_png will be true if filename is
string and ends with png.
"""
return save(self, filename, title, resources, template,
template_variables, embed, max_states, max_opts,
embed_json, json_prefix, save_path, load_path,
progress, embed_states, as_png, **kwargs)
def server_doc(self, doc=None, title=None, location=True):
"""
Returns a serveable bokeh Document with the panel attached
Arguments
---------
doc : bokeh.Document (optional)
The bokeh Document to attach the panel to as a root,
defaults to bokeh.io.curdoc()
title : str
A string title to give the Document
location : boolean or panel.io.location.Location
Whether to create a Location component to observe and
set the URL location.
Returns
-------
doc : bokeh.Document
The bokeh document the panel was attached to
"""
doc = init_doc(doc)
if title or doc.title == 'Bokeh Application':
title = title or 'Panel Application'
doc.title = title
model = self.get_root(doc)
if hasattr(doc, 'on_session_destroyed'):
doc.on_session_destroyed(self._server_destroy)
self._documents[doc] = model
add_to_doc(model, doc)
if location: self._add_location(doc, location, model)
return doc
class Viewer(param.Parameterized):
"""
A baseclass for custom components that behave like a Panel object.
By implementing __panel__ method an instance of this class will
behave like the returned Panel component when placed in a layout,
render itself in a notebook and provide show and servable methods.
"""
def __panel__(self):
"""
Subclasses should return a Panel component to be rendered.
"""
raise NotImplementedError
def _create_view(self):
from .param import ParamMethod
if hasattr(self.__panel__, "_dinfo"):
view = ParamMethod(self.__panel__)
else:
view = self.__panel__()
return view
def servable(self, title=None, location=True):
return self._create_view().servable(title, location)
servable.__doc__ = ServableMixin.servable.__doc__
def show(self, title=None, port=0, address=None, websocket_origin=None,
threaded=False, verbose=True, open=True, location=True, **kwargs):
return self._create_view().show(
title, port, address, websocket_origin, threaded,
verbose, open, location, **kwargs
)
show.__doc__ = ServableMixin.show.__doc__
def _repr_mimebundle_(self, include=None, exclude=None):
return self._create_view()._repr_mimebundle_(include, exclude)