cloudtrigger

Watch a Scratch project's cloud variables and set cloud variables when something changes.

pip install cloudtrigger          # or from this folder: pip install .

Heads up: Scratch has changed its cloud server so outside programs can no longer read cloud variables on scratch.mit.edu. The bot can still log in and connect, but it won't see any changes there. Use TurboWarp mode (below) and have people play your project at turbowarp.org/<project id>.

Python

from cloudtrigger import CloudWatcher

cloud = CloudWatcher(1234567890, "blockblock2", password="...")

# rule: when door becomes 1, set light to 1
cloud.when("door", equals=1, set={"light": 1})

# rule with a number check, copying the new value
cloud.when("score", above=100, set={"winner": lambda c: c.value})

# copy one variable into another every time it changes
cloud.mirror("score", "echo")

# full control with a handler
@cloud.on_change("request")
def answer(change):
    print(change.name, change.old, "->", change.value)
    change.set("response", change.number * 2)

cloud.run()          # blocks; or cloud.start() to run in the background

Variable names are written without the ☁ — it's added for you.

What a handler gets (change): .name, .value (string), .old, .number, .set(name, value). You can also call cloud.get("name") and cloud.set("name", value) anywhere.

Text

Cloud variables only hold numbers (max 256 digits). encode("hi") → "0809", decode("0809") → "hi". Each character is two digits: its position in cloudtrigger.encoding.CHARS plus 1 — use the same character list in your Scratch project to decode.

Command line

# just print changes
cloudtrigger watch 1234567890 -u blockblock2

# rules
cloudtrigger run 1234567890 -u blockblock2 \
  --rule "door=1 -> light=1" \
  --rule "score>100 -> winner=\$value, flash=1" \
  --rule "ping=* -> pong=1"

Ops: = != > <, * = any change, $value = the value that just changed. Rules can also go in a JSON file (--rules rules.json):

[{"var": "door", "op": "=", "value": "1", "set": {"light": "1"}}]

Password comes from a prompt or SCRATCH_PASSWORD; you can pass --session-id / SCRATCH_SESSION_ID instead.

TurboWarp (works even when Scratch's cloud is down)

Run your project at turbowarp.org/<project id> and point the bot at TurboWarp's cloud server. No password or Scratcher status needed:

cloud = CloudWatcher(1394305521, "blockblock2", server="turbowarp")

cloudtrigger watch 1394305521 -u blockblock2 --server turbowarp

The username is just a display name there. TurboWarp may reject names that look rude or impersonate someone. You can also pass any wss:// URL as server for other cloud servers.

Good to know

• The account needs to be a Scratcher (not "New Scratcher") to use cloud variables.
• Values Scratch sends right when you connect are stored but don't fire handlers (pass fire_on_initial=True to change that).
• Sets are spaced ~0.11 s apart because Scratch drops faster ones.
• It reconnects automatically if the connection drops.
• One handler throwing an error doesn't stop the others.