Sagents.PubSub (Sagents v0.7.0)
Copy MarkdownHelper functions for idempotent PubSub subscriptions.
This module provides utilities for managing PubSub subscriptions with automatic deduplication using the Process dictionary. Subscriptions are tracked per-process, supporting multiple subscriptions to different topics from a single process.
Examples
# Subscribe to a topic (idempotent)
Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "topic:123")
Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "topic:123") # No-op
# Subscribe to multiple topics from same process
Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "topic:123")
Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "topic:456")
# Unsubscribe
Sagents.PubSub.unsubscribe(Phoenix.PubSub, MyApp.PubSub, "topic:123")Summary
Functions
Subscribe to a PubSub topic without deduplication.
Unsubscribe from a PubSub topic without clearing Process dictionary tracking.
Subscribe the current process to a PubSub topic with automatic deduplication.
Check if the current process is subscribed to a topic (according to Process dictionary).
Unsubscribe the current process from a PubSub topic with proper cleanup.
Functions
Subscribe to a PubSub topic without deduplication.
This performs a raw subscription without tracking in the Process dictionary.
Most code should use subscribe/3 instead for automatic deduplication.
Only use this function when you explicitly need to bypass deduplication, such as testing or special cases where multiple subscriptions are acceptable.
Unsubscribe from a PubSub topic without clearing Process dictionary tracking.
This performs a raw unsubscription without clearing the tracking state.
Most code should use unsubscribe/3 instead for proper cleanup.
Only use this function when you explicitly need to bypass cleanup, such as testing or special cases.
Subscribe the current process to a PubSub topic with automatic deduplication.
This function is idempotent - safe to call multiple times with the same topic. It uses the Process dictionary to track subscriptions and prevent duplicates.
Multiple topics can be subscribed to from the same process - each topic is tracked independently.
Parameters
pubsub_module- The PubSub module (e.g., Phoenix.PubSub)pubsub_name- The PubSub server name (e.g., MyApp.PubSub)topic- The topic string to subscribe to
Returns
:okon success (whether newly subscribed or already subscribed)
Examples
# Single subscription
:ok = Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "agent:123")
# Multiple calls - no duplicate subscription
:ok = Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "agent:123")
# Multiple topics from same process
:ok = Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "agent:123")
:ok = Sagents.PubSub.subscribe(Phoenix.PubSub, MyApp.PubSub, "agent:456")Check if the current process is subscribed to a topic (according to Process dictionary).
Note: This only checks the Process dictionary tracking, not the actual PubSub state.
Unsubscribe the current process from a PubSub topic with proper cleanup.
This clears the subscription tracking in the Process dictionary and performs the actual unsubscription. This is the standard way to unsubscribe.
Parameters
pubsub_module- The PubSub module (e.g., Phoenix.PubSub)pubsub_name- The PubSub server name (e.g., MyApp.PubSub)topic- The topic string to unsubscribe from
Returns
:okon success