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

387 lines
13 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.
import io
from streamlit.scriptrunner import ScriptRunContext, get_script_run_ctx
from streamlit.type_util import Key, to_key
from typing import cast, Optional, Union, BinaryIO, TextIO
from textwrap import dedent
import streamlit
from streamlit.errors import StreamlitAPIException
from streamlit.proto.Button_pb2 import Button as ButtonProto
from streamlit.in_memory_file_manager import in_memory_file_manager
from streamlit.proto.DownloadButton_pb2 import DownloadButton as DownloadButtonProto
from streamlit.state import (
register_widget,
WidgetArgs,
WidgetCallback,
WidgetKwargs,
)
from .form import current_form_id, is_in_form
from .utils import check_callback_rules, check_session_state_rules
FORM_DOCS_INFO = """
For more information, refer to the
[documentation for forms](https://docs.streamlit.io/library/api-reference/control-flow/st.form).
"""
DownloadButtonDataType = Union[str, bytes, TextIO, BinaryIO]
class ButtonMixin:
def button(
self,
label: str,
key: Optional[Key] = None,
help: Optional[str] = None,
on_click: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
) -> bool:
"""Display a button widget.
Parameters
----------
label : str
A short label explaining to the user what this button is 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
An optional tooltip that gets displayed when the button is
hovered over.
on_click : callable
An optional callback invoked when this button is clicked.
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 button if set to True. The
default is False. This argument can only be supplied by keyword.
Returns
-------
bool
True if the button was clicked on the last run of the app,
False otherwise.
Example
-------
>>> if st.button('Say hello'):
... st.write('Why hello there')
... else:
... st.write('Goodbye')
.. output::
https://share.streamlit.io/streamlit/docs/main/python/api-examples-source/widget.button.py
height: 220px
"""
key = to_key(key)
ctx = get_script_run_ctx()
return self.dg._button(
label,
key,
help,
is_form_submitter=False,
on_click=on_click,
args=args,
kwargs=kwargs,
disabled=disabled,
ctx=ctx,
)
def download_button(
self,
label: str,
data: DownloadButtonDataType,
file_name: Optional[str] = None,
mime: Optional[str] = None,
key: Optional[Key] = None,
help: Optional[str] = None,
on_click: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
) -> bool:
"""Display a download button widget.
This is useful when you would like to provide a way for your users
to download a file directly from your app.
Note that the data to be downloaded is stored in-memory while the
user is connected, so it's a good idea to keep file sizes under a
couple hundred megabytes to conserve memory.
Parameters
----------
label : str
A short label explaining to the user what this button is for.
data : str or bytes or file
The contents of the file to be downloaded. See example below for
caching techniques to avoid recomputing this data unnecessarily.
file_name: str
An optional string to use as the name of the file to be downloaded,
such as 'my_file.csv'. If not specified, the name will be
automatically generated.
mime : str or None
The MIME type of the data. If None, defaults to "text/plain"
(if data is of type *str* or is a textual *file*) or
"application/octet-stream" (if data is of type *bytes* or is a
binary *file*).
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
An optional tooltip that gets displayed when the button is
hovered over.
on_click : callable
An optional callback invoked when this button is clicked.
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 download button if set to
True. The default is False. This argument can only be supplied by
keyword.
Returns
-------
bool
True if the button was clicked on the last run of the app,
False otherwise.
Examples
--------
Download a large DataFrame as a CSV:
>>> @st.cache
... def convert_df(df):
... # IMPORTANT: Cache the conversion to prevent computation on every rerun
... return df.to_csv().encode('utf-8')
>>>
>>> csv = convert_df(my_large_df)
>>>
>>> st.download_button(
... label="Download data as CSV",
... data=csv,
... file_name='large_df.csv',
... mime='text/csv',
... )
Download a string as a file:
>>> text_contents = '''This is some text'''
>>> st.download_button('Download some text', text_contents)
Download a binary file:
>>> binary_contents = b'example content'
>>> # Defaults to 'application/octet-stream'
>>> st.download_button('Download binary file', binary_contents)
Download an image:
>>> with open("flower.png", "rb") as file:
... btn = st.download_button(
... label="Download image",
... data=file,
... file_name="flower.png",
... mime="image/png"
... )
.. output::
https://share.streamlit.io/streamlit/docs/main/python/api-examples-source/widget.download_button.py
height: 335px
"""
ctx = get_script_run_ctx()
return self._download_button(
label=label,
data=data,
file_name=file_name,
mime=mime,
key=key,
help=help,
on_click=on_click,
args=args,
kwargs=kwargs,
disabled=disabled,
ctx=ctx,
)
def _download_button(
self,
label: str,
data: DownloadButtonDataType,
file_name: Optional[str] = None,
mime: Optional[str] = None,
key: Optional[Key] = None,
help: Optional[str] = None,
on_click: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
ctx: Optional[ScriptRunContext] = None,
) -> bool:
key = to_key(key)
check_session_state_rules(default_value=None, key=key, writes_allowed=False)
if is_in_form(self.dg):
raise StreamlitAPIException(
f"`st.download_button()` can't be used in an `st.form()`.{FORM_DOCS_INFO}"
)
download_button_proto = DownloadButtonProto()
download_button_proto.label = label
download_button_proto.default = False
marshall_file(
self.dg._get_delta_path_str(), data, download_button_proto, mime, file_name
)
if help is not None:
download_button_proto.help = dedent(help)
def deserialize_button(ui_value, widget_id=""):
return ui_value or False
current_value, _ = register_widget(
"download_button",
download_button_proto,
user_key=key,
on_change_handler=on_click,
args=args,
kwargs=kwargs,
deserializer=deserialize_button,
serializer=bool,
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.
download_button_proto.disabled = disabled
self.dg._enqueue("download_button", download_button_proto)
return cast(bool, current_value)
def _button(
self,
label: str,
key: Optional[str],
help: Optional[str],
is_form_submitter: bool,
on_click: Optional[WidgetCallback] = None,
args: Optional[WidgetArgs] = None,
kwargs: Optional[WidgetKwargs] = None,
*, # keyword-only arguments:
disabled: bool = False,
ctx: Optional[ScriptRunContext] = None,
) -> bool:
if not is_form_submitter:
check_callback_rules(self.dg, on_click)
check_session_state_rules(default_value=None, key=key, writes_allowed=False)
# It doesn't make sense to create a button inside a form (except
# for the "Form Submitter" button that's automatically created in
# every form). We throw an error to warn the user about this.
# We omit this check for scripts running outside streamlit, because
# they will have no script_run_ctx.
if streamlit._is_running_with_streamlit:
if is_in_form(self.dg) and not is_form_submitter:
raise StreamlitAPIException(
f"`st.button()` can't be used in an `st.form()`.{FORM_DOCS_INFO}"
)
elif not is_in_form(self.dg) and is_form_submitter:
raise StreamlitAPIException(
f"`st.form_submit_button()` must be used inside an `st.form()`.{FORM_DOCS_INFO}"
)
button_proto = ButtonProto()
button_proto.label = label
button_proto.default = False
button_proto.is_form_submitter = is_form_submitter
button_proto.form_id = current_form_id(self.dg)
if help is not None:
button_proto.help = dedent(help)
def deserialize_button(ui_value: bool, widget_id: str = "") -> bool:
return ui_value or False
current_value, _ = register_widget(
"button",
button_proto,
user_key=key,
on_change_handler=on_click,
args=args,
kwargs=kwargs,
deserializer=deserialize_button,
serializer=bool,
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.
button_proto.disabled = disabled
self.dg._enqueue("button", button_proto)
return cast(bool, current_value)
@property
def dg(self) -> "streamlit.delta_generator.DeltaGenerator":
"""Get our DeltaGenerator."""
return cast("streamlit.delta_generator.DeltaGenerator", self)
def marshall_file(coordinates, data, proto_download_button, mimetype, file_name=None):
if isinstance(data, str):
data = data.encode()
mimetype = mimetype or "text/plain"
elif isinstance(data, io.TextIOWrapper):
string_data = data.read()
data = string_data.encode()
mimetype = mimetype or "text/plain"
# Assume bytes; try methods until we run out.
elif isinstance(data, bytes):
mimetype = mimetype or "application/octet-stream"
elif isinstance(data, io.BytesIO):
data.seek(0)
data = data.getvalue()
mimetype = mimetype or "application/octet-stream"
elif isinstance(data, io.RawIOBase) or isinstance(data, io.BufferedReader):
data.seek(0)
data = data.read()
mimetype = mimetype or "application/octet-stream"
else:
raise RuntimeError("Invalid binary data format: %s" % type(data))
this_file = in_memory_file_manager.add(
data, mimetype, coordinates, file_name=file_name, is_for_static_download=True
)
proto_download_button.url = this_file.url