Signals

Describing Signals

• Signals are used for decoupling applications
• They do this by sending notifications when actions occur
• Essentially, signals allow certain senders to notify subscribers that something happened
• Signals are intended to notify subscribers
• They aren't intended for subscribers to modify data
• We can subscribe to signals safely
• Moreover, we can achieve this in a split second
• These temporary subscriptions are helpful for unit testing
• This is the benefit of using signals over handlers

Subscribing to Signals

• The connect method can be used to subscribe to signals
• The first argument is a function
• This function is called when the signal is emitted
• There is an optional second argument that specifies a sender
• The disconnect method can be used to unsubscribe
• A sender is the application that issued the signal

References

• Basics of Signals in Flask