# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2025) # # 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 __future__ import annotations from dataclasses import dataclass from textwrap import dedent from typing import TYPE_CHECKING, Literal, Union, cast, overload from typing_extensions import TypeAlias from streamlit import config from streamlit.elements.lib.file_uploader_utils import ( enforce_filename_restriction, normalize_upload_file_type, ) from streamlit.elements.lib.form_utils import current_form_id from streamlit.elements.lib.layout_utils import ( LayoutConfig, WidthWithoutContent, validate_width, ) from streamlit.elements.lib.policies import ( check_widget_policies, maybe_raise_label_warnings, ) from streamlit.elements.lib.utils import ( Key, LabelVisibility, compute_and_register_element_id, get_label_visibility_proto_value, to_key, ) from streamlit.proto.Common_pb2 import FileUploaderState as FileUploaderStateProto from streamlit.proto.Common_pb2 import UploadedFileInfo as UploadedFileInfoProto from streamlit.proto.FileUploader_pb2 import FileUploader as FileUploaderProto from streamlit.runtime.metrics_util import gather_metrics from streamlit.runtime.scriptrunner import ScriptRunContext, get_script_run_ctx from streamlit.runtime.state import ( WidgetArgs, WidgetCallback, WidgetKwargs, register_widget, ) from streamlit.runtime.uploaded_file_manager import DeletedFile, UploadedFile if TYPE_CHECKING: from collections.abc import Sequence from streamlit.delta_generator import DeltaGenerator SomeUploadedFiles: TypeAlias = Union[ UploadedFile, DeletedFile, list[Union[UploadedFile, DeletedFile]], None, ] def _get_upload_files( widget_value: FileUploaderStateProto | None, ) -> list[UploadedFile | DeletedFile]: 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 [] file_recs_list = ctx.uploaded_file_mgr.get_files( session_id=ctx.session_id, file_ids=[f.file_id for f in uploaded_file_info], ) file_recs = {f.file_id: f for f in file_recs_list} collected_files: list[UploadedFile | DeletedFile] = [] for f in uploaded_file_info: maybe_file_rec = file_recs.get(f.file_id) if maybe_file_rec is not None: uploaded_file = UploadedFile(maybe_file_rec, f.file_urls) collected_files.append(uploaded_file) else: collected_files.append(DeletedFile(f.file_id)) return collected_files @dataclass class FileUploaderSerde: accept_multiple_files: bool allowed_types: Sequence[str] | None = None def deserialize(self, ui_value: FileUploaderStateProto | None) -> SomeUploadedFiles: upload_files = _get_upload_files(ui_value) for file in upload_files: if isinstance(file, DeletedFile): continue if self.allowed_types: enforce_filename_restriction(file.name, self.allowed_types) if len(upload_files) == 0: return_value: SomeUploadedFiles = [] if self.accept_multiple_files else None else: return_value = ( upload_files if self.accept_multiple_files else upload_files[0] ) return return_value def serialize(self, files: SomeUploadedFiles) -> FileUploaderStateProto: state_proto = FileUploaderStateProto() if not files: return state_proto if not isinstance(files, list): files = [files] for f in files: if isinstance(f, DeletedFile): continue file_info: UploadedFileInfoProto = state_proto.uploaded_file_info.add() file_info.file_id = f.file_id file_info.name = f.name file_info.size = f.size file_info.file_urls.CopyFrom(f._file_urls) return state_proto class FileUploaderMixin: # Multiple overloads are defined on `file_uploader()` below to represent # the different return types of `file_uploader()`. # These return types differ according to the value of the `accept_multiple_files` argument. # There are 2 associated variables, each with 2 options. # 1. The `accept_multiple_files` argument is set as `True`, # or it is set as `False` or omitted, in which case the default value `False`. # 2. The `type` argument may or may not be provided as a keyword-only argument. # There must be 2x2=4 overloads to cover all the possible arguments, # as these overloads must be mutually exclusive for mypy. # 1. type is given as not a keyword-only argument # 2. accept_multiple_files = True @overload def file_uploader( self, label: str, type: str | Sequence[str] | None, accept_multiple_files: Literal[True], key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, *, disabled: bool = False, label_visibility: LabelVisibility = "visible", width: WidthWithoutContent = "stretch", ) -> list[UploadedFile]: ... # 1. type is given as not a keyword-only argument # 2. accept_multiple_files = False or omitted @overload def file_uploader( self, label: str, type: str | Sequence[str] | None, accept_multiple_files: Literal[False] = False, key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, *, disabled: bool = False, label_visibility: LabelVisibility = "visible", width: WidthWithoutContent = "stretch", ) -> UploadedFile | None: ... # The following 2 overloads represent the cases where # the `type` argument is a keyword-only argument. # See https://github.com/python/mypy/issues/4020#issuecomment-737600893 # for the related discussions and examples. # 1. type is skipped or a keyword argument # 2. accept_multiple_files = True @overload def file_uploader( self, label: str, *, accept_multiple_files: Literal[True], type: str | Sequence[str] | None = None, key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, disabled: bool = False, label_visibility: LabelVisibility = "visible", width: WidthWithoutContent = "stretch", ) -> list[UploadedFile]: ... # 1. type is skipped or a keyword argument # 2. accept_multiple_files = False or omitted @overload def file_uploader( self, label: str, *, accept_multiple_files: Literal[False] = False, type: str | Sequence[str] | None = None, key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, disabled: bool = False, label_visibility: LabelVisibility = "visible", width: WidthWithoutContent = "stretch", ) -> UploadedFile | None: ... @gather_metrics("file_uploader") def file_uploader( self, label: str, type: str | Sequence[str] | None = None, accept_multiple_files: bool = False, key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, *, # keyword-only arguments: disabled: bool = False, label_visibility: LabelVisibility = "visible", width: WidthWithoutContent = "stretch", ) -> UploadedFile | list[UploadedFile] | None: r"""Display a file uploader widget. By default, uploaded files are limited to 200 MB each. You can configure this using the ``server.maxUploadSize`` config option. For more information on how to set config options, see |config.toml|_. .. |config.toml| replace:: ``config.toml`` .. _config.toml: https://docs.streamlit.io/develop/api-reference/configuration/config.toml Parameters ---------- label : str A short label explaining to the user what this file uploader is for. The label can optionally contain GitHub-flavored Markdown of the following types: Bold, Italics, Strikethroughs, Inline Code, Links, and Images. Images display like icons, with a max height equal to the font height. Unsupported Markdown elements are unwrapped so only their children (text contents) render. Display unsupported elements as literal characters by backslash-escaping them. E.g., ``"1\. Not an ordered list"``. See the ``body`` parameter of |st.markdown|_ for additional, supported Markdown directives. For accessibility reasons, you should never set an empty label, but you can hide it with ``label_visibility`` if needed. In the future, we may disallow empty labels by raising an exception. .. |st.markdown| replace:: ``st.markdown`` .. _st.markdown: https://docs.streamlit.io/develop/api-reference/text/st.markdown type : str or list of str or None The allowed file extension(s) for uploaded files. This can be one of the following types: - ``None`` (default): All file extensions are allowed. - A string: A single file extension is allowed. For example, to only accept CSV files, use ``"csv"``. - A sequence of strings: Multiple file extensions are allowed. For example, to only accept JPG/JPEG and PNG files, use ``["jpg", "jpeg", "png"]``. accept_multiple_files : bool Whether to accept more than one file in a submission. If this is ``False`` (default), the user can only submit one file at a time. If this is ``True``, the user can upload multiple files at the same time, in which case the return value will be a list of files. 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. No two widgets may have the same key. help : str or None A tooltip that gets displayed next to the widget label. Streamlit only displays the tooltip when ``label_visibility="visible"``. If this is ``None`` (default), no tooltip is displayed. The tooltip can optionally contain GitHub-flavored Markdown, including the Markdown directives described in the ``body`` parameter of ``st.markdown``. on_change : callable An optional callback invoked when this file_uploader'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 that disables the file uploader if set to ``True``. The default is ``False``. label_visibility : "visible", "hidden", or "collapsed" The visibility of the label. The default is ``"visible"``. If this is ``"hidden"``, Streamlit displays an empty spacer instead of the label, which can help keep the widget aligned with other widgets. If this is ``"collapsed"``, Streamlit displays no label or spacer. width : "stretch" or int The width of the file uploader widget. This can be one of the following: - ``"stretch"`` (default): The width of the widget matches the width of the parent container. - An integer specifying the width in pixels: The widget has a fixed width. If the specified width is greater than the width of the parent container, the width of the widget matches the width of the parent container. Returns ------- None, UploadedFile, or list of UploadedFile - If accept_multiple_files is False, returns either None or an UploadedFile object. - If accept_multiple_files is True, returns a list with the uploaded files as UploadedFile objects. If no files were uploaded, returns an empty list. The UploadedFile class is a subclass of BytesIO, and therefore is "file-like". This means you can pass an instance of it anywhere a file is expected. Examples -------- Insert a file uploader that accepts a single file at a time: >>> import streamlit as st >>> import pandas as pd >>> from io import StringIO >>> >>> uploaded_file = st.file_uploader("Choose a file") >>> if uploaded_file is not None: ... # To read file as bytes: ... bytes_data = uploaded_file.getvalue() ... st.write(bytes_data) >>> ... # To convert to a string based IO: ... stringio = StringIO(uploaded_file.getvalue().decode("utf-8")) ... st.write(stringio) >>> ... # To read file as string: ... string_data = stringio.read() ... st.write(string_data) >>> ... # Can be used wherever a "file-like" object is accepted: ... dataframe = pd.read_csv(uploaded_file) ... st.write(dataframe) Insert a file uploader that accepts multiple files at a time: >>> import streamlit as st >>> >>> uploaded_files = st.file_uploader( ... "Choose a CSV file", accept_multiple_files=True ... ) >>> for uploaded_file in uploaded_files: ... bytes_data = uploaded_file.read() ... st.write("filename:", uploaded_file.name) ... st.write(bytes_data) .. output:: https://doc-file-uploader.streamlit.app/ height: 375px """ ctx = get_script_run_ctx() return self._file_uploader( label=label, type=type, accept_multiple_files=accept_multiple_files, key=key, help=help, on_change=on_change, args=args, kwargs=kwargs, disabled=disabled, label_visibility=label_visibility, width=width, ctx=ctx, ) def _file_uploader( self, label: str, type: str | Sequence[str] | None = None, accept_multiple_files: bool = False, key: Key | None = None, help: str | None = None, on_change: WidgetCallback | None = None, args: WidgetArgs | None = None, kwargs: WidgetKwargs | None = None, *, # keyword-only arguments: label_visibility: LabelVisibility = "visible", disabled: bool = False, ctx: ScriptRunContext | None = None, width: WidthWithoutContent = "stretch", ) -> UploadedFile | list[UploadedFile] | None: key = to_key(key) check_widget_policies( self.dg, key, on_change, default_value=None, writes_allowed=False, ) maybe_raise_label_warnings(label, label_visibility) element_id = compute_and_register_element_id( "file_uploader", user_key=key, form_id=current_form_id(self.dg), dg=self.dg, label=label, type=type, accept_multiple_files=accept_multiple_files, help=help, width=width, ) normalized_type = normalize_upload_file_type(type) if type else None file_uploader_proto = FileUploaderProto() file_uploader_proto.id = element_id file_uploader_proto.label = label file_uploader_proto.type[:] = ( normalized_type if normalized_type is not None else [] ) file_uploader_proto.max_upload_size_mb = config.get_option( "server.maxUploadSize" ) file_uploader_proto.multiple_files = accept_multiple_files file_uploader_proto.form_id = current_form_id(self.dg) file_uploader_proto.disabled = disabled file_uploader_proto.label_visibility.value = get_label_visibility_proto_value( label_visibility ) if help is not None: file_uploader_proto.help = dedent(help) serde = FileUploaderSerde(accept_multiple_files, allowed_types=normalized_type) # FileUploader's widget value is a list of file IDs # representing the current set of files that this uploader should # know about. widget_state = register_widget( file_uploader_proto.id, on_change_handler=on_change, args=args, kwargs=kwargs, deserializer=serde.deserialize, serializer=serde.serialize, ctx=ctx, value_type="file_uploader_state_value", ) validate_width(width) layout_config = LayoutConfig(width=width) self.dg._enqueue( "file_uploader", file_uploader_proto, layout_config=layout_config ) if isinstance(widget_state.value, DeletedFile): return None if isinstance(widget_state.value, list): return [f for f in widget_state.value if not isinstance(f, DeletedFile)] return widget_state.value @property def dg(self) -> DeltaGenerator: """Get our DeltaGenerator.""" return cast("DeltaGenerator", self)