Equivalent to dispatch(Topic, Message, []).

Equivalent to dispatch(server(), Topic, Message, Opts).

-spec dispatch(atom(), topic(), term(), dispatch_opts()) -> ok.

Sends a message only to one subscriber handler of the Topic.

• Server: The registered server name or pid.
• Topic: The string topic, for example <<"users:123">>.
• Message: Any erlang term.
• Opts: The optional list of options. See below.

• {scope, local | global}: define if the message must be delivered to a local or global (any) process. Default is local.
• {dispatch_fun, dispatch_fun()}: allows to pass a function to choose a subscriber from the current subscribers handlers to a topic.

Examples:

  > ebus:dispatch("bar", #{topic => "foo", payload => "hi"}).
  ok
  > ebus:dispatch("bar", #{topic => "foo", payload => "hi"}, []).
  ok
  > ebus:dispatch(ebus_ps, "bar", "my message",
      [{scope, global}, {dispatch_fun, fun([H | _]) -> H end}]).
  ok

Equivalent to local_subscribers(server(), Topic).

-spec local_subscribers(atom(), topic()) -> [pid()].

Same as subscribers/2 but only local subscribers handlers for the given Topic are returned.

Example:

  > ebus:local_subscribers(ebus_ps, <<"foo">>).
  [<0.48.0>, <0.49.0>]

Equivalent to local_topics(server()).

-spec local_topics(atom()) -> [binary()].

Same as topics/1 but only local topics are returned.

Example:

  > ebus:local_topics().
  [<<"foo">>, <<"bar">>]
  > ebus:local_topics(ebus_ps).
  [<<"foo">>, <<"bar">>]

Equivalent to pub(server(), Topic, Message).

-spec pub(atom(), topic(), term()) -> ok | {error, term()}.

Sends a message to all subscribers of a topic.

• Server: The registered server name or pid.
• Topic: The string topic, for example <<"users:123">>.
• Message: Any erlang term.

Examples:

  > ebus:pub("bar", #{topic => "foo", payload => "hi"}).
  ok
  > ebus:pub(ebus_ps, "bar", #{topic => "foo", payload => "hi"}).
  ok

Equivalent to pub_from(server(), From, Topic, Message).

-spec pub_from(atom(), handler(), topic(), term()) -> ok | {error, term()}.

Same as pub/3 but message is not sent to FromHandler.

Examples:

  > ebus:pub_from(self(), "foo", <<"message">>).
  ok
  > ebus:pub_from(ebus_ps, self(), "foo", <<"message">>).
  ok

Equivalent to sub(server(), Handler, Topic).

Equivalent to sub(Server, Handler, Topic, []).

-spec sub(atom(), handler(), topic(), options()) -> ok | {error, term()}.

Subscribes the Handler given Topic.

• Server: The Pid registered name of the server.
• Handler: The subscriber pid to receive pubsub messages.
• Topic: The topic to subscribe to, ie: "users:123".
• Opts: The optional list of options. See below.

• {link, _}: links the subscriber to the pubsub adapter.
• {fastlane, ebus_ps_local:fastlane()}: Provides a fastlane path for the broadcasts for broadcast() events. The fastlane process is notified of a cached message instead of the normal subscriber. Fastlane handlers must implement fastlane/1 callbacks which accepts a broadcast() struct and returns a fastlaned format for the handler.

Examples:

  > ebus:sub(self(), <<"foo">>).
  ok
  > ebus:sub(ebus_ps, self(), <<"foo">>).
  ok
  > ebus:sub(ebus_ps, self(), <<"foo">>, []).
  ok
  > ebus:sub(ebus_ps, self(), <<"foo">>,
      [{fastlane, {FastPid, my_serializer, [<<"event1">>]}]).
  ok

Equivalent to subscribers(server(), Topic).

-spec subscribers(atom(), topic()) -> [pid()].

Returns a set of all subscribers handlers (local and global) for the given Topic.

• Server: The registered server name or pid.
• Topic: The string topic, for example <<"users:123">>.

Example:

  > ebus:subscribers(ebus_ps, <<"foo">>).
  [<0.48.0>, <0.49.0>]

Equivalent to topics(server()).

-spec topics(atom()) -> [binary()].

Returns the list of all topics (local and global) in use. This is an expensive and private operation.

This is an expensive operation. DO NOT USE IT IN PROD

Example:

  > ebus:topics().
  [<<"foo">>, <<"bar">>]
  > ebus:topics(ebus_ps).
  [<<"foo">>, <<"bar">>]

Equivalent to unsub(server(), Handler, Topic).

-spec unsub(atom(), handler(), topic()) -> ok | {error, term()}.

Unsubscribes the given Handler from the Topic.

• Server: The registered server name or pid.
• Handler: The subscriber pid.
• Topic: The string topic, for example <<"users:123">>.

Example:

  > ebus:unsub(self(), <<"foo">>).
  ok
  > ebus:unsub(ebus_ps, self(), <<"foo">>).
  ok