use_query_params

use_query_params is a hook that returns all URL query parameters as a dictionary. Keys are parameter names and values are list[str].

Note

Deephaven and all custom components share query parameters. Avoid using query parameters in shared components to prevent conflicts. Deephaven reserves the following parameters for internal use:

envoyPrefix

authProvider

name

psk

theme

preloadTransparentTheme

isSamlRedirect

algorithm

encodedStr

Any parameter starting with _ or dh

Example

from deephaven import ui
import deephaven.plot.express as dx

# Table containing stock data with "Sym" and "Side" columns
_stocks = dx.data.stocks()

VALID_SIDES = {"buy", "sell"}


@ui.component
def filter_app():
    # Get all query parameters as a dictionary
    params = ui.use_query_params()
    # Get the "side" as a string
    side = params.get("side", [""])[0]
    # Get the "sym" as a list of strings
    syms = params.get("sym", [])

    # Validate parameters before use as they can be manipulated by the user
    validated_side = side if side in VALID_SIDES else None
    validated_syms = [s for s in syms if s.isalpha() and s.isupper()]

    # Filter the stocks table based on the query parameters
    filtered = _stocks
    if validated_side:
        filtered = filtered.where("Side = validated_side")
    if validated_syms:
        filtered = filtered.where("Sym in validated_syms")
    return filtered


app = filter_app()

Navigating to a URL with a query string such as ?sym=DOG&sym=CAT&side=buy will display the table pre-filtered to only show rows where Sym is DOG or CAT and Side is buy.

Recommendations

Multiple parameter access: Use use_query_params when you need access to all query parameters or custom parsing logic.
Single parameter access: If you only need a single parameter, consider use_query_param for a more concise API.
Validate parameters before use: Parameters can be manipulated by the user and may not be in the format you expect.

API reference

deephaven.ui.use_query_params()

Returns the current URL query parameters as a dictionary.

Return type: Dict[str, List[str]]
Returns: A dictionary mapping parameter names to lists of string values.