File: C:/Users/fred/anaconda3/Lib/site-packages/panel/io/handlers.py
from __future__ import annotations
import ast
import html
import json
import logging
import os
import pathlib
import re
import sys
import traceback
import urllib.parse as urlparse
from contextlib import contextmanager
from types import ModuleType
from typing import IO, Any, Callable
import bokeh.command.util
from bokeh.application.handlers.code import CodeHandler
from bokeh.application.handlers.code_runner import CodeRunner
from bokeh.application.handlers.handler import Handler, handle_exception
from bokeh.core.types import PathLike
from bokeh.document import Document
from bokeh.io.doc import curdoc, patch_curdoc, set_curdoc as bk_set_curdoc
from bokeh.util.dependencies import import_required
from ..config import config
from .mime_render import MIME_RENDERERS
from .profile import profile_ctx
from .reload import record_modules
from .state import state
log = logging.getLogger('panel.io.handlers')
CELL_DISPLAY = []
@contextmanager
def _patch_ipython_display():
try:
import IPython
_orig_display = IPython.display
IPython.display.display = display
except Exception:
pass
yield
try:
IPython.display.display = _orig_display
except Exception:
pass
@contextmanager
def _monkeypatch_io(loggers: dict[str, Callable[..., None]]) -> dict[str, Any]:
import bokeh.io as io
old: dict[str, Any] = {}
for f in CodeHandler._io_functions:
old[f] = getattr(io, f)
setattr(io, f, loggers[f])
yield
for f in old:
setattr(io, f, old[f])
@contextmanager
def set_env_vars(**env_vars):
old = {var: os.environ.get(var) for var in env_vars}
os.environ.update(env_vars)
yield
for var, value in old.items():
if value is None:
del os.environ[var]
else:
os.environ[var] = value
def get_figure():
if 'matplotlib.pyplot' not in sys.modules:
return None
import matplotlib.pyplot as plt
fig = plt.gcf()
if fig.get_axes():
return fig
def display(*args, **kwargs):
if kwargs.get('raw'):
for arg in args:
for mime_type in arg:
if mime_type in MIME_RENDERERS:
out = MIME_RENDERERS[mime_type](arg[mime_type], {}, mime_type)
CELL_DISPLAY.append(out)
break
else:
CELL_DISPLAY.append(arg)
else:
CELL_DISPLAY.extend(args)
def extract_code(
filehandle: IO, supported_syntax: tuple[str, ...] = ('{pyodide}', 'python')
) -> str:
"""
Extracts Panel application code from a Markdown file.
"""
inblock = False
block_opener = None
title = None
markdown = []
out = []
while True:
line = filehandle.readline()
if not line:
# EOF
break
lsline = line.lstrip()
if inblock:
if lsline.startswith(block_opener):
inblock = False
else:
out.append(line)
elif lsline.startswith("```"):
num_leading_backticks = len(lsline) - len(lsline.lstrip("`"))
block_opener = '`'*num_leading_backticks
syntax = line.strip()[num_leading_backticks:]
if syntax in supported_syntax:
if markdown:
md = ''.join(markdown)
markdown.clear()
if any('pn.extension' in o for o in out):
out.append(f"pn.pane.Markdown({md!r}).servable()\n")
inblock = True
else:
markdown.append(line)
elif line.startswith('# '):
title = line[1:].lstrip()
else:
markdown.append(line)
if markdown:
md = ''.join(markdown)
if any('pn.extension' in o for o in out):
out.append(f"pn.pane.Markdown({md!r}).servable()\n")
if title and any('template=' in o for o in out if 'pn.extension' in o):
out.append(f'pn.state.template.title = {title.strip()!r}')
return '\n'.join(out)
def capture_code_cell(cell):
"""
Parses a code cell and generates wrapper code to capture the
return value of the cell and any other outputs published inside
the cell.
"""
code = []
if not len(cell['source']):
return code
source = cell['source'].split('\n')
for line in source[:-1]:
line = (line
.replace('get_ipython().run_line_magic', '')
.replace('get_ipython().magic', '')
)
code.append(line)
cell_out = source[-1]
# Expand last statement or expression until it can be parsed
parses = False
while not parses:
try:
if not cell_out.strip():
raise SyntaxError
ast.parse(cell_out)
parses = True
except SyntaxError:
if not code:
break
cell_out = f'{code.pop()}\n{cell_out}'
if not parses:
# Skip cell if it cannot be parsed
log.warn(
"The following cell did not contain valid Python syntax "
f"and was skipped:\n\n{cell['source']}"
)
return code
elif cell_out.rstrip().endswith(';'):
# Do not record output of cells ending in semi-colon
code.append(cell_out)
return code
# Remove code comments
if '#' in cell_out and not cell_out.count('\n'):
try:
# To not remove "#000000"
cell_tmp = cell_out[:cell_out.index('#')].rstrip()
ast.parse(cell_tmp)
cell_out = cell_tmp
except SyntaxError:
pass
# Use eval mode to check whether cell ends in a statement or an
# expression that will be rendered
try:
ast.parse(cell_out, mode='eval')
except SyntaxError:
code.append(cell_out)
return code
# Capture cell outputs
cell_id = cell['id']
code.append(f"""\
_pn__state._cell_outputs[{cell_id!r}].append(({cell_out}))
for _cell__out in _CELL__DISPLAY:
_pn__state._cell_outputs[{cell_id!r}].append(_cell__out)
_CELL__DISPLAY.clear()
_fig__out = _get__figure()
if _fig__out:
_pn__state._cell_outputs[{cell_id!r}].append(_fig__out)
""")
return code
def autoreload_handle_exception(handler, module, e):
if not config.autoreload:
handle_exception(handler, e)
return
from ..pane import Alert
# Clean up module
del sys.modules[module.__name__]
try:
state.curdoc.modules._modules.remove(module)
except ValueError:
pass
# Serve error
e_msg = str(e).replace('\033[1m', '<b>').replace('\033[0m', '</b>')
tb = html.escape(traceback.format_exc()).replace('\033[1m', '<b>').replace('\033[0m', '</b>')
Alert(
f'<b>{type(e).__name__}</b>: {e_msg}\n<pre style="overflow-y: auto">{tb}</pre>',
alert_type='danger', margin=5, sizing_mode='stretch_width'
).servable()
def run_app(handler, module, doc, post_run=None, allow_empty=False):
try:
old_doc = curdoc()
except RuntimeError:
old_doc = None
bk_set_curdoc(doc)
sessions = []
def post_check():
newdoc = curdoc()
# Do not let curdoc track modules when autoreload is enabled
# otherwise it will erroneously complain that there is
# a memory leak
if config.autoreload:
newdoc.modules._modules = []
# script is supposed to edit the doc not replace it
if newdoc is not doc:
raise RuntimeError(f"{handler._origin} at '{handler._runner.path}' replaced the output document")
try:
state._launching.append(doc)
with _monkeypatch_io(handler._loggers):
with patch_curdoc(doc):
with profile_ctx(config.profiler) as sessions:
with record_modules(handler=handler):
runner = handler._runner
if runner.error:
from ..pane import Alert
Alert(
f'<b>{runner.error}</b>\n<pre style="overflow-y: auto">{runner.error_detail}</pre>',
alert_type='danger', margin=5, sizing_mode='stretch_width'
).servable()
else:
handler._runner.run(module, post_check)
if post_run:
post_run()
if not doc.roots and not allow_empty and config.autoreload and doc not in state._templates:
from ..pane import Alert
Alert(
('<b>Application did not publish any contents</b>\n\n<span>'
'Ensure you have marked items as servable or added models to '
'the bokeh document manually.'),
alert_type='danger', margin=5, sizing_mode='stretch_width'
).servable()
finally:
if config.profiler:
try:
path = doc.session_context.request.path
state._profiles[(path, config.profiler)] += sessions
state.param.trigger('_profiles')
except Exception:
pass
state._launching.remove(doc)
if old_doc is not None:
bk_set_curdoc(old_doc)
def parse_notebook(filename: str | os.PathLike | IO, preamble: list[str] | None = None):
"""
Parses a notebook on disk and returns a script.
Arguments
---------
filename: str | os.PathLike
The notebook file to parse.
preamble: list[str]
Any lines of code to prepend to the parsed code output.
Returns
-------
nb: nbformat.NotebookNode
nbformat dictionary-like representation of the notebook
code: str
The parsed and converted script
cell_layouts: dict
Dictionary containing the layout and positioning of cells.
"""
nbconvert = import_required('nbconvert', 'The Panel notebook application handler requires nbconvert to be installed.')
nbformat = import_required('nbformat', 'The Panel notebook application handler requires Jupyter Notebook to be installed.')
class StripMagicsProcessor(nbconvert.preprocessors.Preprocessor):
"""
Preprocessor to convert notebooks to Python source while stripping
out all magics (i.e IPython specific syntax).
"""
_magic_pattern = re.compile(r'^\s*(?P<magic>%%\w\w+)($|(\s+))')
def strip_magics(self, source: str) -> str:
"""
Given the source of a cell, filter out all cell and line magics.
"""
filtered: list[str] = []
for line in source.splitlines():
match = self._magic_pattern.match(line)
if match is None:
filtered.append(line)
else:
msg = 'Stripping out IPython magic {magic} in code cell {cell}'
message = msg.format(cell=self._cell_counter, magic=match.group('magic'))
log.warning(message)
return '\n'.join(filtered)
def preprocess_cell(self, cell, resources, index):
if cell['cell_type'] == 'code':
self._cell_counter += 1
cell['source'] = self.strip_magics(cell['source'])
return cell, resources
def __call__(self, nb, resources):
self._cell_counter = 0
return self.preprocess(nb,resources)
preprocessors = [StripMagicsProcessor()]
nb = nbformat.read(filename, nbformat.NO_CONVERT)
exporter = nbconvert.NotebookExporter()
for preprocessor in preprocessors:
exporter.register_preprocessor(preprocessor)
nb_string, _ = exporter.from_notebook_node(nb)
nb = nbformat.reads(nb_string, 4)
nb = nbformat.v4.upgrade(nb)
cell_layouts = {}
code = list(preamble or [])
for cell in nb['cells']:
cell_id = cell['id']
cell_layouts[cell_id] = cell['metadata'].get('panel-layout', {})
if cell['cell_type'] == 'code':
cell_code = capture_code_cell(cell)
code += cell_code
elif cell['cell_type'] == 'markdown':
md = ''.join(cell['source']).replace('"', r'\"')
code.append(f'_pn__state._cell_outputs[{cell_id!r}].append("""{md}""")')
code = '\n'.join(code)
return nb, code, cell_layouts
#---------------------------------------------------------------------
# Handler classes
#---------------------------------------------------------------------
class PanelCodeRunner(CodeRunner):
def run(self, module: ModuleType, post_check: Callable[[], None] | None = None) -> None:
"""
Execute the configured source code in a module and run any post
checks.
See bokeh.application.handlers.code_runner for original implementation.
"""
_cwd = os.getcwd()
_sys_path = list(sys.path)
_sys_argv = list(sys.argv)
sys.path.insert(0, os.path.dirname(self._path))
sys.argv = [os.path.basename(self._path), *self._argv]
# XXX: self._code shouldn't be None at this point but types don't reflect this
assert self._code is not None
try:
exec(self._code, module.__dict__)
if post_check:
post_check()
except Exception as e:
autoreload_handle_exception(self, module, e)
finally:
# undo sys.path, CWD fixups
os.chdir(_cwd)
sys.path = _sys_path
sys.argv = _sys_argv
self.ran = True
class PanelCodeHandler(CodeHandler):
"""Modify Bokeh documents by creating Dashboard from code.
Additionally this subclass adds support for the ability to:
- Log session launch, load and destruction
- Capture document_ready events to track when app is loaded.
- Add profiling support
- Ensure that state.curdoc is set
- Reload the application module if autoreload is enabled
- Track modules loaded during app execution to enable autoreloading
"""
def __init__(self, *, source: str, filename: PathLike, argv: list[str] = [], package: ModuleType | None = None) -> None:
Handler.__init__(self)
self._runner = PanelCodeRunner(source, filename, argv, package=package)
self._loggers = {}
for f in PanelCodeHandler._io_functions:
self._loggers[f] = self._make_io_logger(f)
def url_path(self) -> str | None:
if self.failed and not config.autoreload:
return None
# TODO should fix invalid URL characters
return '/' + os.path.splitext(os.path.basename(self._runner.path))[0]
def modify_document(self, doc: 'Document'):
if config.autoreload:
path = self._runner.path
argv = self._runner._argv
handler = type(self)(filename=path, argv=argv)
self._runner = handler._runner
module = self._runner.new_module()
# If no module was returned it means the code runner has some permanent
# unfixable problem, e.g. the configured source code has a syntax error
if module is None and not config.autoreload:
return
# One reason modules are stored is to prevent the module from being gc'd
# before the document is. A symptom of a gc'd module is that its globals
# become None. Additionally stored modules are used to provide correct
# paths to custom models resolver.
if module is not None:
doc.modules.add(module)
run_app(self, module, doc)
CodeHandler.modify_document = PanelCodeHandler.modify_document
class ScriptHandler(PanelCodeHandler):
"""Modify Bokeh documents by creating Dashboard from a Python script.
"""
_logger_text = "%s: call to %s() ignored when running scripts with the 'bokeh' command."
_origin = "Script"
def __init__(self, *, filename: PathLike, argv: list[str] = [], package: ModuleType | None = None) -> None:
'''
Keywords:
filename (str) : a path to a Python source (".py") file
'''
with open(filename, encoding='utf-8') as f:
source = f.read()
super().__init__(source=source, filename=filename, argv=argv, package=package)
bokeh.application.handlers.directory.ScriptHandler = ScriptHandler
class MarkdownHandler(PanelCodeHandler):
"""Modify Bokeh documents by creating Dashboard from a Markdown file.
"""
_logger_text = "%s: call to %s() ignored when running Markdown files with the 'panel' command."
_origin = "Markdown"
def __init__(self, *args, **kwargs):
'''
Keywords:
filename (str) : a path to a Markdown (".md") file
'''
if 'filename' not in kwargs:
raise ValueError('Must pass a filename to Handler')
filename = os.path.abspath(kwargs['filename'])
with open(filename, encoding='utf-8') as f:
code = extract_code(f)
kwargs['source'] = code
super().__init__(*args, **kwargs)
class NotebookHandler(PanelCodeHandler):
"""Modify Bokeh documents by creating Dashboard from a notebook file.
"""
_imports = [
'from panel import state as _pn__state',
'from panel.io.handlers import CELL_DISPLAY as _CELL__DISPLAY, display, get_figure as _get__figure\n'
]
_logger_text = "%s: call to %s() ignored when running notebooks with the 'panel' command."
_origin = "Notebook"
def __init__(self, *, filename: PathLike, argv: list[str] = [], package: ModuleType | None = None) -> None:
'''
Keywords:
filename (str) : a path to a Jupyter notebook (".ipynb") file
'''
self._load_layout(filename)
super().__init__(source=self._parse(filename), filename=filename)
self._stale = False
def _parse(self, filename):
nb, code, cell_layouts = parse_notebook(filename, preamble=self._imports)
state._cell_layouts[self] = cell_layouts
for cell_id, layout in self._layout.get('cells', {}).items():
state._cell_layouts[self][cell_id] = layout
self._nb = nb
return code
def _load_layout(self, filename):
nb_path = pathlib.Path(filename)
layout_path = nb_path.parent / f'.{nb_path.name}.layout'
if layout_path.is_file():
with open(layout_path) as f:
self._layout = json.load(f)
else:
self._layout = {}
return self._layout
def _compute_layout(self, spec, panels):
from ..pane import Plotly
params = {}
if 'width' in spec and 'height' in spec:
params['sizing_mode'] = 'stretch_both'
else:
params['sizing_mode'] = 'stretch_width'
if len(panels) == 1 and isinstance(panels[0], Plotly):
params['min_height'] = 300
return params
def _render_template(self, doc, path):
"""Renders template containing cell outputs.
Creates an EditableTemplate containing all cell outputs
found in the notebook and lays them out according to the
cell metadata (if present).
Arguments
----------
doc (Document)
A ``Document`` to render the template into
path (str):
The path to the application code.
"""
from ..config import config
from ..layout import Column
from ..pane import panel
from .state import state
config.template = 'editable'
persist = state._jupyter_kernel_context
editable = 'editable' in state.session_args
reset = 'reset' in state.session_args
if not (editable or persist):
state.template.editable = False
state.template.title = os.path.splitext(os.path.basename(path))[0].replace('_', ' ').title()
layouts, outputs, cells = {}, {}, {}
for cell_id, objects in state._cell_outputs.items():
if reset:
spec = {}
elif cell_id in self._layout.get('cells', {}):
spec = self._layout['cells'][cell_id]
else:
spec = state._cell_layouts[self].get(cell_id, {})
panels = [panel(obj) for obj in objects if obj is not None]
pout = Column(*panels, **self._compute_layout(spec, panels))
for po in pout:
po.sizing_mode = pout.sizing_mode
outputs[cell_id] = pout
layouts[id(pout)] = spec
cells[cell_id] = id(pout)
pout.servable()
# Reorder outputs based on notebook metadata
import nbformat
nb = nbformat.read(self._runner._path, nbformat.NO_CONVERT)
if 'order' in self._layout:
cell_order = self._layout['order']
else:
cell_order = nb['metadata'].get('panel-cell-order', [])
ordered = {}
for cell_id in cell_order:
if cell_id not in cells or reset:
continue
obj_id = cells[cell_id]
ordered[obj_id] = layouts[obj_id]
for cell_id in self._layout.get('order', []):
if cell_id not in cells:
continue
obj_id = cells[cell_id]
ordered[obj_id] = layouts[obj_id]
for obj_id, spec in layouts.items():
if obj_id not in ordered:
ordered[obj_id] = spec
# Set up state
state.template.param.update(
layout=ordered,
local_save=not bool(state._jupyter_kernel_context)
)
if reset:
def unset_reset():
query = state.location.query_params
query.pop('reset', None)
search = urlparse.urlencode(query)
state.location.search = f'?{search}' if search else ''
state.onload(unset_reset)
if persist:
state.template.param.watch(self._update_position_metadata, 'layout')
state._session_outputs[doc] = outputs
def modify_document(self, doc: Document) -> None:
"""Run Bokeh application code to update a ``Document``
Arguments
----------
doc (Document) : a ``Document`` to update
"""
path = self._runner._path
if self._stale or config.autoreload:
self._load_layout(path)
source = self._parse(path)
nodes = ast.parse(source, os.fspath(path))
self._runner._code = compile(nodes, filename=path, mode='exec', dont_inherit=True)
self._stale = False
module = self._runner.new_module()
# If no module was returned it means the code runner has some permanent
# unfixable problem, e.g. the configured source code has a syntax error
if module is None and not config.autoreload:
return
# One reason modules are stored is to prevent the module from being gc'd
# before the document is. A symptom of a gc'd module is that its globals
# become None. Additionally stored modules are used to provide correct
# paths to custom models resolver.
if module is not None:
doc.modules.add(module)
def post_run():
if not (doc.roots or doc in state._templates or self._runner.error):
self._render_template(doc, path)
state._cell_outputs.clear()
with _patch_ipython_display():
with set_env_vars(MPLBACKEND='agg'):
run_app(self, module, doc, post_run, allow_empty=True)
def _update_position_metadata(self, event):
"""
Maps EditableTemplate update events to cells in the original
notebook and then overwrites notebook metadata with updated
layout information.
"""
nb = self._nb
doc = event.obj._documents[-1]
outputs = state._session_outputs[doc]
cell_data, cell_ids = {}, {}
for cell in nb['cells']:
if cell['id'] in outputs:
out = outputs[cell['id']]
cell_ids[id(out)] = cell['id']
spec = dict(event.new[id(out)])
del spec['id']
cell_data[cell['id']] = spec
order = [cell_ids[obj_id] for obj_id in event.new]
nb_layout = {
'cells': cell_data,
'order': order
}
nb_path = pathlib.Path(self._runner.path)
path = nb_path.parent / f'.{nb_path.name}.layout'
with open(path, 'w') as f:
json.dump(nb_layout, f)
self._stale = True
bokeh.application.handlers.directory.NotebookHandler = NotebookHandler