Re-running a Script Filter

New in version 1.23.

Alfred 3.2 introduced an new “rerun” feature. Emitting a rerun value from a Script Filter tells Alfred to run that script again after the specified number of seconds. Alfred will also pass back any variables set at the top-level of your feedback, i.e. via the Workflow3.setvar() method.

Set Workflow3.rerun to instruct Alfred to re-run your Script Filter.

This could be used, for example, to provide a seamless (to the user) status update in a workflow that reports on the status of a download client like aria2 via its API.

The refresh is invisible to the user, as Alfred doesn’t update its UI unless the Script Filter output changes.

In terms of Alfred-Workflow more generally, you might use this feature to re-run your Script Filter if its data are still being updated in the background. For example:

from workflow import Workflow3
from workflow.background import is_running, run_in_background

wf = Workflow3()

# Unconditionally load data from cache
data = wf.cached_data('data', ..., max_age=0)

# Update cached data if they're stale
if not wf.cached_data_fresh('data', max_age=30):
    run_in_background('update_cache', ...)

# Tell Alfred to re-run the Script Filter if the cache is
# currently being updated.
if is_running('update_cache'):
    wf.rerun = 1

# Show (stale) cached data
for d in data:
    wf.add_item(**d)

wf.send_feedback()

In this way, the results shown to the user will be updated only if the background update changes the cached data.