.. index:: single: http_websocket_service_registry
.. _http_websocket_service_registry/0:

.. rst-class:: right

**object**

``http_websocket_service_registry``
===================================

Session registry predicates for active WebSocket sessions and queued broadcast delivery.

| **Availability:** 
|    ``logtalk_load(http_websocket_service(loader))``

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-06-26

| **Compilation flags:**
|    ``static, context_switching_calls``


| **Uses:**
|    :ref:`http_websocket_messages <http_websocket_messages/0>`
|    :ref:`list <list/0>`

| **Remarks:**
|    (none)

| **Inherited public predicates:**
|    (none)

.. contents::
   :local:
   :backlinks: top

Public predicates
-----------------

.. index:: open/1
.. _http_websocket_service_registry/0::open/1:

``open/1``
^^^^^^^^^^

Opens a new empty WebSocket session registry.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``open(Registry)``
| **Mode and number of proofs:**
|    ``open(-compound)`` - ``one``


------------

.. index:: close/1
.. _http_websocket_service_registry/0::close/1:

``close/1``
^^^^^^^^^^^

Closes a session registry and removes all registered sessions and queued messages.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``close(Registry)``
| **Mode and number of proofs:**
|    ``close(+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is a variable:
|        ``instantiation_error``
|    ``Registry`` is neither a variable nor an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Registry`` refers to a closed WebSocket service registry handle:
|        ``existence_error(http_websocket_service_registry,session_registry(RegistryId))``


------------

.. index:: register/2
.. _http_websocket_service_registry/0::register/2:

``register/2``
^^^^^^^^^^^^^^

Registers a new active session in the given registry and returns its session identifier.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``register(Registry,Session)``
| **Mode and number of proofs:**
|    ``register(+compound,-compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is a variable:
|        ``instantiation_error``
|    ``Registry`` is neither a variable nor an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Registry`` refers to a closed WebSocket service registry handle:
|        ``existence_error(http_websocket_service_registry,session_registry(RegistryId))``


------------

.. index:: unregister/2
.. _http_websocket_service_registry/0::unregister/2:

``unregister/2``
^^^^^^^^^^^^^^^^

Removes a session from the given registry together with any queued outbound messages.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``unregister(Registry,Session)``
| **Mode and number of proofs:**
|    ``unregister(+compound,+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is a variable:
|        ``instantiation_error``
|    ``Registry`` is neither a variable nor an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Registry`` refers to a closed WebSocket service registry handle:
|        ``existence_error(http_websocket_service_registry,session_registry(RegistryId))``
|    ``Session`` is a variable or is not a session for ``Registry``:
|        ``instantiation_error``
|    ``Session`` is not a valid WebSocket service registry session handle:
|        ``domain_error(http_websocket_service_registry_session,Session)``
|    ``Session`` is not registered in ``Registry``:
|        ``existence_error(http_websocket_service_registry_session,websocket_session(RegistryId,SessionId))``


------------

.. index:: session/2
.. _http_websocket_service_registry/0::session/2:

``session/2``
^^^^^^^^^^^^^

Enumerates active session identifiers registered in the given registry.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``session(Registry,Session)``
| **Mode and number of proofs:**
|    ``session(+compound,?compound)`` - ``zero_or_more``


------------

.. index:: sessions/2
.. _http_websocket_service_registry/0::sessions/2:

``sessions/2``
^^^^^^^^^^^^^^

Returns the list of active session identifiers registered in the given registry.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``sessions(Registry,Sessions)``
| **Mode and number of proofs:**
|    ``sessions(+compound,-list(compound))`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is a variable:
|        ``instantiation_error``
|    ``Registry`` is neither a variable nor an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Registry`` refers to a closed WebSocket service registry handle:
|        ``existence_error(http_websocket_service_registry,session_registry(RegistryId))``


------------

.. index:: session_count/2
.. _http_websocket_service_registry/0::session_count/2:

``session_count/2``
^^^^^^^^^^^^^^^^^^^

Returns the number of active sessions currently registered in the given registry.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``session_count(Registry,Count)``
| **Mode and number of proofs:**
|    ``session_count(+compound,-integer)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is a variable:
|        ``instantiation_error``
|    ``Registry`` is neither a variable nor an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Registry`` refers to a closed WebSocket service registry handle:
|        ``existence_error(http_websocket_service_registry,session_registry(RegistryId))``


------------

.. index:: send/3
.. _http_websocket_service_registry/0::send/3:

``send/3``
^^^^^^^^^^

Queues a normalized outbound message for the specified registered session.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``send(Registry,Session,Message)``
| **Mode and number of proofs:**
|    ``send(+compound,+compound,+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is not an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Session`` is not a valid WebSocket service registry session handle:
|        ``domain_error(http_websocket_service_registry_session,Session)``
|    ``Session`` is not registered in ``Registry``:
|        ``existence_error(http_websocket_service_registry_session,websocket_session(RegistryId,SessionId))``
|    ``Message`` is not a valid normalized WebSocket message term:
|        ``domain_error(http_websocket_service_registry_message,Message)``


------------

.. index:: broadcast/2
.. _http_websocket_service_registry/0::broadcast/2:

``broadcast/2``
^^^^^^^^^^^^^^^

Queues a normalized outbound message for all currently registered sessions.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``broadcast(Registry,Message)``
| **Mode and number of proofs:**
|    ``broadcast(+compound,+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is not an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Message`` is not a valid normalized WebSocket message term:
|        ``domain_error(http_websocket_service_registry_message,Message)``


------------

.. index:: broadcast_except/3
.. _http_websocket_service_registry/0::broadcast_except/3:

``broadcast_except/3``
^^^^^^^^^^^^^^^^^^^^^^

Queues a normalized outbound message for all currently registered sessions except the specified session.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``broadcast_except(Registry,Session,Message)``
| **Mode and number of proofs:**
|    ``broadcast_except(+compound,+compound,+compound)`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is not an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Session`` is not a valid WebSocket service registry session handle:
|        ``domain_error(http_websocket_service_registry_session,Session)``
|    ``Session`` is not registered in ``Registry``:
|        ``existence_error(http_websocket_service_registry_session,websocket_session(RegistryId,SessionId))``
|    ``Message`` is not a valid normalized WebSocket message term:
|        ``domain_error(http_websocket_service_registry_message,Message)``


------------

.. index:: take_pending/3
.. _http_websocket_service_registry/0::take_pending/3:

``take_pending/3``
^^^^^^^^^^^^^^^^^^

Removes and returns the queued outbound messages for the specified registered session.

| **Compilation flags:**
|    ``static``

| **Template:**
|    ``take_pending(Registry,Session,Messages)``
| **Mode and number of proofs:**
|    ``take_pending(+compound,+compound,-list(compound))`` - ``one_or_error``

| **Exceptions:**
|    ``Registry`` is not an open WebSocket service registry handle:
|        ``domain_error(http_websocket_service_registry,Registry)``
|    ``Session`` is not a valid WebSocket service registry session handle:
|        ``domain_error(http_websocket_service_registry_session,Session)``
|    ``Session`` is not registered in ``Registry``:
|        ``existence_error(http_websocket_service_registry_session,websocket_session(RegistryId,SessionId))``


------------

Protected predicates
--------------------

(no local declarations; see entity ancestors if any)

Private predicates
------------------

.. index:: registry_seed_/1
.. _http_websocket_service_registry/0::registry_seed_/1:

``registry_seed_/1``
^^^^^^^^^^^^^^^^^^^^

Last allocated registry identifier.

| **Compilation flags:**
|    ``dynamic``

| **Template:**
|    ``registry_seed_(RegistryId)``
| **Mode and number of proofs:**
|    ``registry_seed_(?positive_integer)`` - ``zero_or_one``


------------

.. index:: registry_state_/2
.. _http_websocket_service_registry/0::registry_state_/2:

``registry_state_/2``
^^^^^^^^^^^^^^^^^^^^^

Per-registry next session identifier state.

| **Compilation flags:**
|    ``dynamic``

| **Template:**
|    ``registry_state_(RegistryId,NextSessionId)``
| **Mode and number of proofs:**
|    ``registry_state_(?positive_integer,?non_negative_integer)`` - ``zero_or_more``


------------

.. index:: registry_session_/3
.. _http_websocket_service_registry/0::registry_session_/3:

``registry_session_/3``
^^^^^^^^^^^^^^^^^^^^^^^

Registered sessions and their queued outbound messages indexed by registry identifier. Messages are stored in reverse order to make enqueue operations constant time.

| **Compilation flags:**
|    ``dynamic``

| **Template:**
|    ``registry_session_(RegistryId,SessionId,QueuedMessagesReversed)``
| **Mode and number of proofs:**
|    ``registry_session_(?positive_integer,?positive_integer,?list(compound))`` - ``zero_or_more``


------------

Operators
---------

(none)