# 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 collections.abc import Iterable, Iterator, Mapping, MutableMapping from dataclasses import dataclass, field from typing import TYPE_CHECKING, Final, cast from urllib import parse from streamlit.errors import StreamlitAPIException, StreamlitQueryParamDictValueError from streamlit.proto.ForwardMsg_pb2 import ForwardMsg from streamlit.runtime.scriptrunner_utils.script_run_context import get_script_run_ctx if TYPE_CHECKING: from _typeshed import SupportsKeysAndGetItem QueryParamValue = str | Iterable[str] QueryParamsInput = Mapping[str, QueryParamValue] | Iterable[tuple[str, QueryParamValue]] EMBED_QUERY_PARAM: Final[str] = "embed" EMBED_OPTIONS_QUERY_PARAM: Final[str] = "embed_options" EMBED_QUERY_PARAMS_KEYS: Final[list[str]] = [ EMBED_QUERY_PARAM, EMBED_OPTIONS_QUERY_PARAM, ] @dataclass class QueryParams(MutableMapping[str, str]): """A lightweight wrapper of a dict that sends forwardMsgs when state changes. It stores str keys with str and List[str] values. """ _query_params: dict[str, list[str] | str] = field(default_factory=dict) def __iter__(self) -> Iterator[str]: self._ensure_single_query_api_used() return iter( key for key in self._query_params if key.lower() not in EMBED_QUERY_PARAMS_KEYS ) def __getitem__(self, key: str) -> str: """Retrieves a value for a given key in query parameters. Returns the last item in a list or an empty string if empty. If the key is not present, raise KeyError. """ self._ensure_single_query_api_used() if key.lower() in EMBED_QUERY_PARAMS_KEYS: raise KeyError(missing_key_error_message(key)) try: value = self._query_params[key] if isinstance(value, list): if len(value) == 0: return "" # Return the last value to mimic Tornado's behavior # https://www.tornadoweb.org/en/stable/web.html#tornado.web.RequestHandler.get_query_argument return value[-1] return value except KeyError: raise KeyError(missing_key_error_message(key)) def __setitem__(self, key: str, value: str | Iterable[str]) -> None: self._ensure_single_query_api_used() self._set_item_internal(key, value) self._send_query_param_msg() def _set_item_internal(self, key: str, value: str | Iterable[str]) -> None: _set_item_in_dict(self._query_params, key, value) def __delitem__(self, key: str) -> None: self._ensure_single_query_api_used() if key.lower() in EMBED_QUERY_PARAMS_KEYS: raise KeyError(missing_key_error_message(key)) try: del self._query_params[key] self._send_query_param_msg() except KeyError: raise KeyError(missing_key_error_message(key)) def update( self, other: Iterable[tuple[str, str | Iterable[str]]] | SupportsKeysAndGetItem[str, str | Iterable[str]] = (), /, **kwds: str, ) -> None: # This overrides the `update` provided by MutableMapping # to ensure only one one ForwardMsg is sent. self._ensure_single_query_api_used() if hasattr(other, "keys") and hasattr(other, "__getitem__"): other = cast("SupportsKeysAndGetItem[str, str | Iterable[str]]", other) for key in other.keys(): # noqa: SIM118 self._set_item_internal(key, other[key]) else: for key, value in other: self._set_item_internal(key, value) for key, value in kwds.items(): self._set_item_internal(key, value) self._send_query_param_msg() def get_all(self, key: str) -> list[str]: self._ensure_single_query_api_used() if key not in self._query_params or key.lower() in EMBED_QUERY_PARAMS_KEYS: return [] value = self._query_params[key] return value if isinstance(value, list) else [value] def __len__(self) -> int: self._ensure_single_query_api_used() return len( { key for key in self._query_params if key.lower() not in EMBED_QUERY_PARAMS_KEYS } ) def __str__(self) -> str: self._ensure_single_query_api_used() return str(self._query_params) def _send_query_param_msg(self) -> None: ctx = get_script_run_ctx() if ctx is None: return self._ensure_single_query_api_used() msg = ForwardMsg() msg.page_info_changed.query_string = parse.urlencode( self._query_params, doseq=True ) ctx.query_string = msg.page_info_changed.query_string ctx.enqueue(msg) def clear(self) -> None: self._ensure_single_query_api_used() self.clear_with_no_forward_msg(preserve_embed=True) self._send_query_param_msg() def to_dict(self) -> dict[str, str]: self._ensure_single_query_api_used() # return the last query param if multiple values are set return { key: self[key] for key in self._query_params if key.lower() not in EMBED_QUERY_PARAMS_KEYS } def from_dict( self, _dict: Iterable[tuple[str, str | Iterable[str]]] | SupportsKeysAndGetItem[str, str | Iterable[str]], ) -> None: self._ensure_single_query_api_used() old_value = self._query_params.copy() self.clear_with_no_forward_msg(preserve_embed=True) try: self.update(_dict) except StreamlitAPIException: # restore the original from before we made any changes. self._query_params = old_value raise def set_with_no_forward_msg(self, key: str, val: list[str] | str) -> None: self._query_params[key] = val def clear_with_no_forward_msg(self, preserve_embed: bool = False) -> None: self._query_params = { key: value for key, value in self._query_params.items() if key.lower() in EMBED_QUERY_PARAMS_KEYS and preserve_embed } def _ensure_single_query_api_used(self) -> None: ctx = get_script_run_ctx() if ctx is None: return ctx.mark_production_query_params_used() def missing_key_error_message(key: str) -> str: return f'st.query_params has no key "{key}".' def _set_item_in_dict( target_dict: dict[str, list[str] | str], key: str, value: str | Iterable[str] ) -> None: """Set an item in a dictionary.""" if isinstance(value, dict): raise StreamlitQueryParamDictValueError(key) if key.lower() in EMBED_QUERY_PARAMS_KEYS: raise StreamlitAPIException( "Query param embed and embed_options (case-insensitive) cannot be set programmatically." ) # Type checking users should handle the string serialization themselves # We will accept any type for the list and serialize to str just in case if isinstance(value, Iterable) and not isinstance(value, str): target_dict[key] = [str(item) for item in value] else: target_dict[key] = str(value) def process_query_params( query_params: Iterable[tuple[str, str | Iterable[str]]] | SupportsKeysAndGetItem[str, str | Iterable[str]], ) -> str: """Convert query params into a URL-encoded query string.""" processed_params: dict[str, list[str] | str] = {} if hasattr(query_params, "keys") and hasattr(query_params, "__getitem__"): query_params = cast( "SupportsKeysAndGetItem[str, str | Iterable[str]]", query_params ) for key in query_params.keys(): # noqa: SIM118 value = query_params[key] _set_item_in_dict(processed_params, key, value) else: for key, value in query_params: if key in processed_params: # If the key already exists, we need to accumulate the values. if isinstance(value, dict): raise StreamlitQueryParamDictValueError(key) current_val = processed_params[key] if not isinstance(current_val, list): current_val = [current_val] if isinstance(value, Iterable) and not isinstance(value, str): current_val.extend([str(item) for item in value]) else: current_val.append(str(value)) processed_params[key] = current_val else: _set_item_in_dict(processed_params, key, value) return parse.urlencode(processed_params, doseq=True)