Topical (topical v0.2.3)
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)