.. index:: single: http_message_helpers
.. _http_message_helpers/0:

.. rst-class:: right

**category**

``http_message_helpers``
========================

Internal shared helpers for HTTP transport persistence rules, connection token normalization, and chunk-size line parsing.

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

| **Author:** Paulo Moura
| **Version:** 1:0:0
| **Date:** 2026-05-23

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


| **Extends:**
|    ``public`` :ref:`http_text_helpers <http_text_helpers/0>`
| **Uses:**
|    :ref:`http_core <http_core/0>`
|    :ref:`list <list/0>`

| **Remarks:**
|    (none)

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

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

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

(no local declarations; see entity ancestors if any)

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

.. index:: connection_persistent/2
.. _http_message_helpers/0::connection_persistent/2:

``connection_persistent/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Succeeds when a request-response exchange can continue on the same connection according to HTTP persistence semantics.

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

| **Template:**
|    ``connection_persistent(Request,Response)``
| **Mode and number of proofs:**
|    ``connection_persistent(+compound,+compound)`` - ``zero_or_one``


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

.. index:: request_persistent/1
.. _http_message_helpers/0::request_persistent/1:

``request_persistent/1``
^^^^^^^^^^^^^^^^^^^^^^^^

Succeeds when a normalized HTTP request keeps the connection persistent.

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

| **Template:**
|    ``request_persistent(Request)``
| **Mode and number of proofs:**
|    ``request_persistent(+compound)`` - ``zero_or_one``


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

.. index:: response_persistent/1
.. _http_message_helpers/0::response_persistent/1:

``response_persistent/1``
^^^^^^^^^^^^^^^^^^^^^^^^^

Succeeds when a normalized HTTP response keeps the connection persistent.

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

| **Template:**
|    ``response_persistent(Response)``
| **Mode and number of proofs:**
|    ``response_persistent(+compound)`` - ``zero_or_one``


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

.. index:: version_persistent_by_default/1
.. _http_message_helpers/0::version_persistent_by_default/1:

``version_persistent_by_default/1``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Succeeds when the given HTTP version uses persistent connections by default.

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

| **Template:**
|    ``version_persistent_by_default(Version)``
| **Mode and number of proofs:**
|    ``version_persistent_by_default(+compound)`` - ``zero_or_one``


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

.. index:: message_has_connection_token/2
.. _http_message_helpers/0::message_has_connection_token/2:

``message_has_connection_token/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Succeeds when a normalized HTTP message exposes the given normalized Connection token through either headers or derived properties.

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

| **Template:**
|    ``message_has_connection_token(Message,Token)``
| **Mode and number of proofs:**
|    ``message_has_connection_token(+compound,+atom)`` - ``zero_or_one``


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

.. index:: message_connection_tokens/2
.. _http_message_helpers/0::message_connection_tokens/2:

``message_connection_tokens/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the de-duplicated normalized Connection tokens exposed by a normalized HTTP message.

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

| **Template:**
|    ``message_connection_tokens(Message,Tokens)``
| **Mode and number of proofs:**
|    ``message_connection_tokens(+compound,-list(atom))`` - ``one``


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

.. index:: message_header_values/3
.. _http_message_helpers/0::message_header_values/3:

``message_header_values/3``
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Returns the stored header values for the given header name in message order.

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

| **Template:**
|    ``message_header_values(Message,Name,Values)``
| **Mode and number of proofs:**
|    ``message_header_values(+compound,+atom,-list)`` - ``one``


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

.. index:: chunk_size_line_size/2
.. _http_message_helpers/0::chunk_size_line_size/2:

``chunk_size_line_size/2``
^^^^^^^^^^^^^^^^^^^^^^^^^^

Parses a chunk-size line into its hexadecimal size, ignoring optional whitespace and chunk extensions.

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

| **Template:**
|    ``chunk_size_line_size(LineBytes,Size)``
| **Mode and number of proofs:**
|    ``chunk_size_line_size(+list(integer),-integer)`` - ``one``


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

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

(no local declarations; see entity ancestors if any)

Operators
---------

(none)