1. Optimize Callback Performance (+3)
1. Optimize Callback Performance
# Use prevent_initial_call when appropriate
@callback(
Output("output", "children"),
Input("button", "n_clicks"),
prevent_initial_call=True
)
def handle_click(n_clicks):
return f"Clicked {n_clicks} times"
# Use State for non-triggering inputs
@callback(
Output("output", "children"),
Input("submit-btn", "n_clicks"),
State("input-field", "value") # Doesn't trigger callback
)
def submit_form(n_clicks, value):
return f"Submitted: {value}"
2. Efficient Data Loading
# Cache expensive computations
from flask_caching import Cache
cache = Cache(app.server, config={"CACHE_TYPE": "simple"})
@cache.memoize(timeout=300)
def load_data():
return pd.read_parquet("large_file.parquet")
3. Modular Callbacks
# Separate callbacks into modules
# callbacks/analytics.py
from dash import callback, Output, Input
def register_callbacks(app):
@callback(
Output("chart", "figure"),
Input("dropdown", "value")
)
def update_chart(value):
return create_figure(value)
4. Error Handling
from dash import callback, Output, Input
from dash.exceptions import PreventUpdate
@callback(
Output("output", "children"),
Input("input", "value")
)
def safe_callback(value):
if value is None:
raise PreventUpdate
try:
result = process(value)
return result
except Exception as e:
return html.Div(f"Error: {str(e)}", className="text-danger")
vamseeachanta