Topical (topical v0.1.8)
This module provides the high level interface for interacting with topics. Primarily for subscribing (and unsubscribing), but also for sending requests.
After subscribing, a client will initially receive a {:reset, ref, value} message, and then
subsequent {:updates, ref, updates} messages when the value of the topic changes, where
updates is a list with each item being one of:
{:set, path, value}: thevaluehas been set at thepath.{:unset, path, key}: thekeyhas been unset from the object at thepath.{:insert, path, index, values}: thevalueshave been inserted into the array at thepath.{:delete, path, index, count}:countvalues have been deleted from the array at thepath, from the positionindex.
A client can interact directly with a topic by executing actions (which returns a result), or
by notifying (without waiting for a result). These are analogous to GenServer.call/3 and
GenServer.cast/2. Be aware that a topic is blocked while processing a request.
Link to this section Summary
Functions
Captures the state of the topic (in the specified registry) without subscribing.
Returns a specification to start a Topical registry under a supervisor.
Executes an action in a topic.
Send a notification to a registry.
Subscribes to the specified topic (in the specified registry).
Unsubscribes from a topic (in the specified registry).
Link to this section Functions
capture(registry, topic, context \\ nil)
Captures the state of the topic (in the specified registry) without subscribing.
example
Example
Topical.capture(MyApp.Topical, "lists/foo")
# => {:ok, %{items: %{}, order: []}}child_spec(options)
Returns a specification to start a Topical registry under a supervisor.
execute(registry, topic, action, args \\ {}, context \\ nil)
Executes an action in a topic.
example
Example
Topical.execute(MyApp.Topical, "lists/foo", "add_item", {"Test", false})
#=> {:ok, "item123"}notify(registry, topic, action, args \\ {}, context \\ nil)
Send a notification to a registry.
This is similar to execute/4, except no result is waited for.
example
Example
Topical.notify(MyApp.Topical, "lists/foo", "update_done", {"item123", true})
#=> :oksubscribe(registry, topic, pid, context \\ nil)
Subscribes to the specified topic (in the specified registry).
Returns {:ok, ref}, where the ref is a reference to the subscription.
The pid will be send messages, as described above.
example
Example
Topical.subscribe(MyApp.Topical, "lists/foo", self())
#=> {:ok, #Reference<0.4021726225.4145020932.239110>}unsubscribe(registry, topic, ref)
Unsubscribes from a topic (in the specified registry).
example
Example
Topical.unsubscribe(MyApp.Topical, "lists/foo", ref)