DataBridge

DataBridge is an entity that provides temporary data storage that exists within a single application session (from startup to exit). It is designed for data exchange between handlers.

The main way to access DataBridge is through DI.

from argenta.di import FromDishka
from argenta import DataBridge, Response

# ... setting up router and other

def my_handler(response: Response, data_bridge: FromDishka[DataBridge]):
    # ... your code

Practical Example: Authentication

Let’s consider an example where the login command saves an authentication token, and the get-profile command uses it.

from argenta import Router, Response, Command, DataBridge
from argenta.command import Flag
from argenta.di import FromDishka

router = Router(title="Authentication")


def authenticate_user(username: str) -> str:
    return f"token_for_{username}"


@router.command(Command("login", flags=Flag("username")))
def login_handler(response: Response, data_bridge: FromDishka[DataBridge]):
    username_flag = response.input_flags.get_flag_by_name("username")
    if not username_flag or not username_flag.input_value:
        print("Error: username must be specified using the --username flag.")
        return

    username = username_flag.input_value
    token = authenticate_user(username)

    data_bridge.update({"auth_token": token})
    print(f"Login successful! User '{username}' authenticated.")


@router.command("get-profile")
def get_profile_handler(response: Response, data_bridge: FromDishka[DataBridge]):
    token = data_bridge.get_by_key("auth_token")

    if not token:
        print("Error: you are not authenticated. Please run the 'login' command first.")
        return

    print(f"Loading profile using token: [yellow]{token}[/yellow]")


@router.command("logout")
def logout_handler(response: Response, data_bridge: FromDishka[DataBridge]):
    try:
        data_bridge.delete_by_key("auth_token")
        print("Logout successful. Session data cleared.")
    except KeyError:
        print("You were not authenticated anyway.")

How it works:

1. When calling a handler, dishka automatically injects a DataBridge instance.

2. The login --username <name> command calls login_handler, which saves the token through the injected data_bridge.

3. The get-profile command calls get_profile_handler, which also receives data_bridge and extracts the token from it.

---

class DataBridge

__init__(self, initial_data: dict | None = None)

Initializes the storage. When used through DI, it is called automatically.

update(self, data: dict) → None

Updates the storage with data from a dictionary.

get_all(self) → dict

Returns all data from the storage.

get_by_key(self, key: str) → Any

Returns the value by key or None if the key is not found.

delete_by_key(self, key: str) → None

Deletes the value by key. Raises KeyError if the key is not found.

clear_all(self) → None

Completely clears the storage.