Module: Pgbus::Streams::Streamable

Defined in:
lib/pgbus/streams/streamable.rb

Overview

ActiveRecord concern that adds ‘short_id` and `to_stream_key` instance methods for producing pgbus-safe stream identifiers from records whose primary key is a UUID (or any other long string).

Intended for inclusion in ‘ApplicationRecord`:

class ApplicationRecord < ActiveRecord::Base
  primary_abstract_class
  include Pgbus::Streams::Streamable
end

Every subclass then gets:

chat.short_id
# => "3a4f9c21b7d20e18"

chat.to_stream_key
# => "ai_chat_3a4f9c21b7d20e18"

Pgbus.stream_key(chat, :messages)
# => "ai_chat_3a4f9c21b7d20e18:messages"

The mixin is intentionally thin: it delegates to ‘Pgbus::Streams::Key` so the digest policy lives in one place.

‘#to_stream_key` calls `Key.short_id(self)` directly rather than dispatching through `#short_id`. Ruby does NOT warn when a class defines an instance method and a later `include` adds a module with the same name — the class method silently wins. A host app that already defines its own `#short_id` (returning, say, a display-friendly abbreviation) would therefore hijack `to_stream_key` without any indication, producing stream keys the wire format never promised. Calling `Key.short_id(self)` explicitly bypasses instance-method lookup and guarantees the advertised digest regardless of what the host class does with the unqualified name.

Instance Method Summary collapse

Instance Method Details

#short_id(digest_bits: Key::DEFAULT_DIGEST_BITS) ⇒ Object

Returns a short SHA-256 prefix (64 bits / 16 hex chars by default) of this record’s primary key. See ‘Pgbus::Streams::Key.short_id` for the digest policy and collision horizon.



45
46
47
 
# File 'lib/pgbus/streams/streamable.rb', line 45

def short_id(digest_bits: Key::DEFAULT_DIGEST_BITS)
  Key.short_id(self, digest_bits: digest_bits)
end

#to_stream_key ⇒ Object

Returns a stable, pgbus-safe identifier of the form ‘<model_key>_<short_id>` suitable for passing directly to `Pgbus.stream(…)` or composing with `Pgbus.stream_key`.



52
53
54
 
# File 'lib/pgbus/streams/streamable.rb', line 52

def to_stream_key
  "#{self.class.model_name.param_key}_#{Key.short_id(self)}"
end