72 lines
2.4 KiB
Python
72 lines
2.4 KiB
Python
# Copyright (c) Streamlit Inc. (2018-2022) Snowflake Inc. (2022-2025)
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from __future__ import annotations
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import os
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from typing import TYPE_CHECKING
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from streamlit.errors import StreamlitAPIException
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if TYPE_CHECKING:
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from collections.abc import Sequence
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TYPE_PAIRS = [
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(".jpg", ".jpeg"),
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(".mpg", ".mpeg"),
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(".mp4", ".mpeg4"),
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(".tif", ".tiff"),
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(".htm", ".html"),
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]
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def normalize_upload_file_type(file_type: str | Sequence[str]) -> Sequence[str]:
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if isinstance(file_type, str):
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file_type = [file_type]
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# May need a regex or a library to validate file types are valid
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# extensions.
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file_type = [
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file_type_entry if file_type_entry[0] == "." else f".{file_type_entry}"
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for file_type_entry in file_type
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]
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file_type = [t.lower() for t in file_type]
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for x, y in TYPE_PAIRS:
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if x in file_type and y not in file_type:
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file_type.append(y)
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if y in file_type and x not in file_type:
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file_type.append(x)
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return file_type
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def enforce_filename_restriction(filename: str, allowed_types: Sequence[str]) -> None:
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"""Ensure the uploaded file's extension matches the allowed
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types set by the app developer. In theory, this should never happen, since we
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enforce file type check by extension on the frontend, but we check it on backend
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before returning file to the user to protect ourselves.
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"""
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normalized_filename = filename.lower()
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base_name, extension = os.path.splitext(normalized_filename)
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normalized_allowed_types = [allowed_type.lower() for allowed_type in allowed_types]
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if not any(
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normalized_filename.endswith(allowed_type)
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for allowed_type in normalized_allowed_types
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):
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raise StreamlitAPIException(
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f"Invalid file extension: `{extension}`. Allowed: {allowed_types}"
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)
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