3-storage.py

"""
This example shows how to write, read and manipulate value in storage.

It is also a good example of using neo-python's `debugstorage`, which
allows you to test `Put` operations with `build .. test` commands.
Debugstorage is enabled by default, you can disable it with
`sc debugstorage off` and, more importantly, reset it with
`sc debugstorage reset`.

Test & Build:
neo> sc build_run 3-storage.py True False False 07 05

Invoke this multiple times to see an increasing value in storage. Reset with:

neo> sc debugstorage reset
"""
from boa.interop.Neo.Runtime import Log, Notify
from boa.interop.Neo.Storage import Get, Put, GetContext

def Main():
    context = GetContext()

    # This is the storage key we use in this example
    item_key = 'test-storage-key'

    # Try to get a value for this key from storage
    item_value = Get(context, item_key)
    msg = ["Value read from storage:", item_value]
    Notify(msg)

    if len(item_value) == 0:
        Notify("Storage key not yet set. Setting to 1")
        item_value = 1

    else:
        Notify("Storage key already set. Incrementing by 1")
        item_value += 1

    # Store the new value
    Put(context, item_key, item_value)
    msg = ["New value written into storage:", item_value]
    Notify(msg)

    return item_value