2022-05-23 00:16:32 +04:00

237 lines
7.7 KiB
Python

# Copyright 2018-2022 Streamlit Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from streamlit.type_util import Key, to_key
from textwrap import dedent
from typing import Optional, cast, List
import streamlit
from streamlit.proto.CameraInput_pb2 import (
CameraInput as CameraInputProto,
)
from streamlit.scriptrunner import ScriptRunContext, get_script_run_ctx
from streamlit.state import (
register_widget,
WidgetArgs,
WidgetCallback,
WidgetKwargs,
)
from ..proto.Common_pb2 import (
FileUploaderState as FileUploaderStateProto,
UploadedFileInfo as UploadedFileInfoProto,
)
from ..uploaded_file_manager import UploadedFile, UploadedFileRec
from .form import current_form_id
from .utils import check_callback_rules, check_session_state_rules
SomeUploadedSnapshotFile = Optional[UploadedFile]
class CameraInputMixin:
def camera_input(
self,
label: str,
key: Optional[Key] = None,
help: Optional[str] = None,
on_change: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
) -> SomeUploadedSnapshotFile:
"""Display a widget that returns pictures from the user's webcam.
Parameters
----------
label : str
A short label explaining to the user what this widget is used for.
key : str or int
An optional string or integer to use as the unique key for the widget.
If this is omitted, a key will be generated for the widget
based on its content. Multiple widgets of the same type may
not share the same key.
help : str
A tooltip that gets displayed next to the camera input.
on_change : callable
An optional callback invoked when this camera_input's value
changes.
args : tuple
An optional tuple of args to pass to the callback.
kwargs : dict
An optional dict of kwargs to pass to the callback.
disabled : bool
An optional boolean, which disables the camera input if set to
True. The default is False. This argument can only be supplied by
keyword.
Returns
-------
None or UploadedFile
The UploadedFile class is a subclass of BytesIO, and therefore
it is "file-like". This means you can pass them anywhere where
a file is expected.
Examples
--------
>>> import streamlit as st
>>>
>>> picture = st.camera_input("Take a picture")
>>>
>>> if picture:
... st.image(picture)
"""
ctx = get_script_run_ctx()
return self._camera_input(
label=label,
key=key,
help=help,
on_change=on_change,
args=args,
kwargs=kwargs,
disabled=disabled,
ctx=ctx,
)
def _camera_input(
self,
label: str,
key: Optional[Key] = None,
help: Optional[str] = None,
on_change: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
ctx: Optional[ScriptRunContext] = None,
) -> SomeUploadedSnapshotFile:
key = to_key(key)
check_callback_rules(self.dg, on_change)
check_session_state_rules(default_value=None, key=key, writes_allowed=False)
camera_input_proto = CameraInputProto()
camera_input_proto.label = label
camera_input_proto.form_id = current_form_id(self.dg)
if help is not None:
camera_input_proto.help = dedent(help)
def serialize_camera_image_input(
snapshot: SomeUploadedSnapshotFile,
) -> FileUploaderStateProto:
state_proto = FileUploaderStateProto()
ctx = get_script_run_ctx()
if ctx is None:
return state_proto
# ctx.uploaded_file_mgr._file_id_counter stores the id to use for
# the *next* uploaded file, so the current highest file id is the
# counter minus 1.
state_proto.max_file_id = ctx.uploaded_file_mgr._file_id_counter - 1
if not snapshot:
return state_proto
file_info: UploadedFileInfoProto = state_proto.uploaded_file_info.add()
file_info.id = snapshot.id
file_info.name = snapshot.name
file_info.size = snapshot.size
return state_proto
def deserialize_camera_image_input(
ui_value: Optional[FileUploaderStateProto], widget_id: str
) -> SomeUploadedSnapshotFile:
file_recs = self._get_file_recs_for_camera_input_widget(widget_id, ui_value)
if len(file_recs) == 0:
return_value = None
else:
return_value = UploadedFile(file_recs[0])
return return_value
widget_value, _ = register_widget(
"camera_input",
camera_input_proto,
user_key=key,
on_change_handler=on_change,
args=args,
kwargs=kwargs,
deserializer=deserialize_camera_image_input,
serializer=serialize_camera_image_input,
ctx=ctx,
)
# This needs to be done after register_widget because we don't want
# the following proto fields to affect a widget's ID.
camera_input_proto.disabled = disabled
ctx = get_script_run_ctx()
camera_image_input_state = serialize_camera_image_input(widget_value)
uploaded_shapshot_info = camera_image_input_state.uploaded_file_info
if ctx is not None and len(uploaded_shapshot_info) != 0:
newest_file_id = camera_image_input_state.max_file_id
active_file_ids = [f.id for f in uploaded_shapshot_info]
ctx.uploaded_file_mgr.remove_orphaned_files(
session_id=ctx.session_id,
widget_id=camera_input_proto.id,
newest_file_id=newest_file_id,
active_file_ids=active_file_ids,
)
self.dg._enqueue("camera_input", camera_input_proto)
return cast(SomeUploadedSnapshotFile, widget_value)
@property
def dg(self) -> "streamlit.delta_generator.DeltaGenerator":
"""Get our DeltaGenerator."""
return cast("streamlit.delta_generator.DeltaGenerator", self)
@staticmethod
def _get_file_recs_for_camera_input_widget(
widget_id: str, widget_value: Optional[FileUploaderStateProto]
) -> List[UploadedFileRec]:
if widget_value is None:
return []
ctx = get_script_run_ctx()
if ctx is None:
return []
uploaded_file_info = widget_value.uploaded_file_info
if len(uploaded_file_info) == 0:
return []
active_file_ids = [f.id for f in uploaded_file_info]
# Grab the files that correspond to our active file IDs.
return ctx.uploaded_file_mgr.get_files(
session_id=ctx.session_id,
widget_id=widget_id,
file_ids=active_file_ids,
)