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"""An interface for publishing rich data to frontends.
There are two components of the display system:
* Display formatters, which take a Python object and compute the
representation of the object in various formats (text, HTML, SVG, etc.).
* The display publisher that is used to send the representation data to the
various frontends.
This module defines the logic display publishing. The display publisher uses
the ``display_data`` message type that is defined in the IPython messaging
# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.
import sys
from traitlets.config.configurable import Configurable
from traitlets import List
# This used to be defined here - it is imported for backwards compatibility
from .display import publish_display_data
# Main payload class
class DisplayPublisher(Configurable):
"""A traited class that publishes display data to frontends.
Instances of this class are created by the main IPython object and should
be accessed there.
def _validate_data(self, data, metadata=None):
"""Validate the display data.
data : dict
The formata data dictionary.
metadata : dict
Any metadata for the data.
if not isinstance(data, dict):
raise TypeError('data must be a dict, got: %r' % data)
if metadata is not None:
if not isinstance(metadata, dict):
raise TypeError('metadata must be a dict, got: %r' % data)
# use * to indicate transient, update are keyword-only
def publish(self, data, metadata=None, source=None, *, transient=None, update=False, **kwargs):
"""Publish data and metadata to all frontends.
See the ``display_data`` message in the messaging documentation for
more details about this message type.
The following MIME types are currently implemented:
* text/plain
* text/html
* text/markdown
* text/latex
* application/json
* application/javascript
* image/png
* image/jpeg
* image/svg+xml
data : dict
A dictionary having keys that are valid MIME types (like
'text/plain' or 'image/svg+xml') and values that are the data for
that MIME type. The data itself must be a JSON'able data
structure. Minimally all data should have the 'text/plain' data,
which can be displayed by all frontends. If more than the plain
text is given, it is up to the frontend to decide which
representation to use.
metadata : dict
A dictionary for metadata related to the data. This can contain
arbitrary key, value pairs that frontends can use to interpret
the data. Metadata specific to each mime-type can be specified
in the metadata dict with the same mime-type keys as
the data itself.
source : str, deprecated
transient: dict, keyword-only
A dictionary for transient data.
Data in this dictionary should not be persisted as part of saving this output.
Examples include 'display_id'.
update: bool, keyword-only, default: False
If True, only update existing outputs with the same display_id,
rather than creating a new output.
# The default is to simply write the plain text data using sys.stdout.
if 'text/plain' in data:
def clear_output(self, wait=False):
"""Clear the output of the cell receiving output."""
print('\033[2K\r', end='')
print('\033[2K\r', end='')
class CapturingDisplayPublisher(DisplayPublisher):
"""A DisplayPublisher that stores"""
outputs = List()
def publish(self, data, metadata=None, source=None):
self.outputs.append((data, metadata))
def clear_output(self, wait=False):
super(CapturingDisplayPublisher, self).clear_output(wait)
# empty the list, *do not* reassign a new list
del self.outputs[:]