nicegui/website/more_documentation/storage_documentation.py

from collections import Counter
from datetime import datetime

from nicegui import ui

from ..documentation_tools import text_demo


def main_demo() -> None:
    """Storage

    NiceGUI offers a straightforward method for data persistence within your application. 
    It features three built-in storage types:

    - `app.storage.user`:
        Stored server-side, each dictionary is associated with a unique identifier held in a browser session cookie.
        Unique to each user, this storage is accessible across all their browser tabs.
        `app.storage.browser['id']` is used to identify the user.
    - `app.storage.general`:
        Also stored server-side, this dictionary provides a shared storage space accessible to all users.
    - `app.storage.browser`:
        Unlike the previous types, this dictionary is stored directly as the browser session cookie, shared among all browser tabs for the same user.
        However, `app.storage.user` is generally preferred due to its advantages in reducing data payload, enhancing security, and offering larger storage capacity.
        By default, NiceGUI holds a unique identifier for the browser session in `app.storage.browser['id']`.

    The user storage and browser storage are only available within `page builder functions </documentation/page>`_
    because they are accessing the underlying `Request` object from FastAPI.
    Additionally these two types require the `storage_secret` parameter in`ui.run()` to encrypt the browser session cookie.
    """
    from nicegui import app

    # @ui.page('/')
    # def index():
    #     app.storage.user['count'] = app.storage.user.get('count', 0) + 1
    #     with ui.row():
    #        ui.label('your own page visits:')
    #        ui.label().bind_text_from(app.storage.user, 'count')
    #
    # ui.run(storage_secret='private key to secure the browser session cookie')
    # END OF DEMO
    app.storage.user['count'] = app.storage.user.get('count', 0) + 1
    with ui.row():
        ui.label('your own page visits:')
        ui.label().bind_text_from(app.storage.user, 'count')


counter = Counter()
start = datetime.now().strftime('%H:%M, %d %B %Y')


def more() -> None:
    @text_demo('Counting page visits', '''
        Here we are using the automatically available browser-stored session ID to count the number of unique page visits.
    ''')
    def page_visits():
        from collections import Counter
        from datetime import datetime

        from nicegui import app

        # counter = Counter()
        # start = datetime.now().strftime('%H:%M, %d %B %Y')
        #
        # @ui.page('/')
        # def index():
        #     counter[app.storage.browser['id']] += 1
        #     ui.label(f'{len(counter)} unique views ({sum(counter.values())} overall) since {start}')
        #
        # ui.run(storage_secret='private key to secure the browser session cookie')
        # END OF DEMO
        counter[app.storage.browser['id']] += 1
        ui.label(f'{len(counter)} unique views ({sum(counter.values())} overall) since {start}')

    @text_demo('Storing UI state', '''
        Storage can also be used in combination with [`bindings`](/documentation/bindings).
        Here we are storing the value of a textarea between visits.
        The note is also shared between all tabs of the same user.
    ''')
    def ui_state():
        from nicegui import app

        # @ui.page('/')
        # def index():
        #     ui.textarea('This note is kept between visits') \
        #         .classes('w-full').bind_value(app.storage.user, 'note')
        # END OF DEMO
        ui.textarea('This note is kept between visits').classes('w-full').bind_value(app.storage.user, 'note')