Streamlit - Settings page with session state

multipage_settings_app.py

import streamlit as st
from persist import persist, load_widget_state


def main():
    if "page" not in st.session_state:
        # Initialize session state.
        st.session_state.update({
            # Default page.
            "page": "home",

            # Radio, selectbox and multiselect options.
            "options": ["Hello", "Everyone", "Happy", "Streamlit-ing"],

            # Default widget values.
            "text": "",
            "slider": 0,
            "checkbox": False,
            "radio": "Hello",
            "selectbox": "Hello",
            "multiselect": ["Hello", "Everyone"],
        })

    page = st.sidebar.radio("Select your page", tuple(PAGES.keys()), format_func=str.capitalize)

    PAGES[page]()


def page_home():
    st.write(
        f"""
        Settings values
        ---------------

        - **Input**: {st.session_state.text}
        - **Slider**: `{st.session_state.slider}`
        - **Checkbox**: `{st.session_state.checkbox}`
        - **Radio**: {st.session_state.radio}
        - **Selectbox**: {st.session_state.selectbox}
        - **Multiselect**: {", ".join(st.session_state.multiselect)}
        """
    )


def page_settings():
    st.header("Change settings")

    st.text_input("Input", key=persist("text"))
    st.slider("Slider", 0, 10, key=persist("slider"))
    st.checkbox("Checkbox", key=persist("checkbox"))
    st.radio("Radio", st.session_state["options"], key=persist("radio"))
    st.selectbox("Selectbox", st.session_state["options"], key=persist("selectbox"))
    st.multiselect("Multiselect", st.session_state["options"], key=persist("multiselect"))


PAGES = {
    "home": page_home,
    "settings": page_settings,
}


if __name__ == "__main__":
    load_widget_state()
    main()

persist.py

from streamlit import session_state as _state

_PERSIST_STATE_KEY = f"{__name__}_PERSIST"


def persist(key: str) -> str:
    """Mark widget state as persistent."""
    if _PERSIST_STATE_KEY not in _state:
        _state[_PERSIST_STATE_KEY] = set()

    _state[_PERSIST_STATE_KEY].add(key)

    return key


def load_widget_state():
    """Load persistent widget state."""
    if _PERSIST_STATE_KEY in _state:
        _state.update({
            key: value
            for key, value in _state.items()
            if key in _state[_PERSIST_STATE_KEY]
        })

I'm not sure to understand under which circumstances the state is cleared. When and how do you use st.cache? Could you provide some code to reproduce the issue? It'd greatly help!

can I run this on my laptop? what would be the command?

if Streamlit is correctly installed on your laptop, executing streamlit run st_demo_settings.py should work.

Thanks. Could you help how this http://ml.madpowah.org:8501/ might have implemented navigation across pages.

If you want an example without my session state boilerplate code, you can try something like this:

import streamlit as st


def main():
    # Register your pages
    pages = {
        "First page": page_first,
        "Second page": page_second,
    }

    st.sidebar.title("App with pages")

    # Widget to select your page, you can choose between radio buttons or a selectbox
    page = st.sidebar.selectbox("Select your page", tuple(pages.keys()))
    #page = st.sidebar.radio("Select your page", tuple(pages.keys()))

    # Display the selected page with the session state
    pages[page]()


def page_first():
    st.title("This is my first page")
    # ...


def page_second():
    st.title("This is my second page")
    # ...


if __name__ == "__main__":
    main()

Hello, I just want to thank you. It worked great for me.

This is perfect. Thank you!

@Ghasel, could you suggest how to persist the session on page refresh and across duplicate tabs?
Can we use caching?
Any suggestions/possible workarounds will be appreciated.

Hi guys,
i try to let the code works as the one shows above, but in the for..loop cycle that i show below that doesn't work. It's seems that if the assignment with one "number_input" works, inside a loop not. Do you know why?
Thanks

Hello, this alternative code is working well? @okld

You are a champ ! It worked like a charm in my App , which is a multipage app , Thanks so much _/|_

hello is there any way to set session-timeout which close the session after certain period???

@bbokka123, you can initialize your session state with the current time, and then each time the script reruns, get the new current time and compare it with the one stored in your state. If it exceeds your period, you can use st.stop() to stop your script execution.

Streamlit 0.84.0 has introduced a brand new session state feature

Streamlit 0.84.0 has introduced a brand new session state feature

Hi! is there any code snippet similar to the current gist, which demonstrates detailed usage of st.session_state Thanks!

Hello @drupano, I updated this gist to use st.session_state intsead of the old custom implementation.

Thanks Synode!

@bbokka123, you can initialize your session state with the current time, and then each time the script reruns, get the new current time and compare it with the one stored in your state. If it exceeds your period, you can use st.stop() to stop your script execution.

thanks!! one more question ... is there any way to get event when the script reruns? just like notifications if the script reruns

Seems the new session state stuff has broken this. In fact I cannot see any way to have page persistence with multiple pages in Streamlit.

The code doesn't work in streamlit 1.4.0.
When I switch the first time from "Settings" to "Home" page it works, but then going back to "Settings" it resets all value to default.

Hello @steeley and @federicodecillia, I updated the gist to fix this issue.

Apparently if a widget bound to session state (with key param) is displayed in run #1, but not in run #2, the associated session state variable is cleared in run #3. Self-applying session state values seems to do the trick.

thanks will have a go and see how it works.

Thanks @okld ! Now it works!

Apparently if a widget bound to session state (with key param) is displayed in run #1, but not in run #2, the associated session state variable is cleared in run #3. Self-applying session state values seems to do the trick.

Session state behavior changed in Streamlit 0.89.0. Related issue: streamlit/streamlit#4338

Many thanks for this snippet, it helped me work around #4338.
When I try the code however, on first page load, the widgets are initialized to default values rather than the initial values in the session state.
Does the same happen fo you? Is there any workaround?

Hi All,

I am new to streamlit,trying to build multipage webapp.
In first page i will upload a file and click and button and it redirects to second page.
In second page i have side bar and radio buttons. Based on button selection the output need to be changed.
If i change radio button multiple times i am facing EOF ran of input error could you please help me

Thanks for this! Works great for me.

I'm trying to edit the code so that I can persist a session state of an editable dataframe while navigating between different pages of the app. I'm using AgGrid to make the df editable, but when refreshing or going to another page, the df defaults back to original values. Do you have any suggestions on how to implement this from your code above? I've been stuck on this for a week now

@okld Really nice work. However, I see that for refreshing is not working anymore. Do you have any idea of how to handle it?

Really neat concept! Does this only work if you have a main script registering and driving the different pages?

I tried this persist/load_widget_state() approach on a multi-page app using the current directory structure of implementing multipage apps, and it didn't work for me.

Hey man, many thanks for this snippet!