.. include:: /Includes.rst.txt
.. _configuration:
=============
Configuration
=============
The extension works out of the box with sensible defaults. All
three operating modes -- on-demand frontend processing, on-upload
compression, and bulk CLI -- activate automatically after
installation. This page documents the extension points that can
be tweaked.
.. _configuration-viewhelper:
SourceSetViewHelper
===================
The ``SourceSetViewHelper`` generates responsive ```` tags
with ``srcset`` attributes.
.. code-block:: html
:caption: Basic ViewHelper usage
{namespace nr=Netresearch\NrImageOptimize\ViewHelpers}
.. _configuration-parameters:
Parameters
----------
.. confval:: path
:name: confval-path
:type: string
:required: true
Public path to the source image (for example
``/fileadmin/foo.jpg``), typically generated via
``f:uri.image()``.
.. confval:: width
:name: confval-width
:type: int|float
:Default: 0
Base width in pixels for the rendered ````. ``0``
resolves automatically from the source file.
:ref:`Clamped by the processor ` to
1--8192 when baked into the variant URL.
.. confval:: height
:name: confval-height
:type: int|float
:Default: 0
Base height in pixels. ``0`` preserves aspect ratio
relative to :confval:`width `.
:ref:`Clamped by the processor `
to 1--8192.
.. confval:: set
:name: confval-set
:type: array
:Default: []
Responsive set in the form
``{maxWidth: {width: int, height: int}}``. Each entry
becomes a ````
tag.
.. confval:: alt
:name: confval-alt
:type: string
:Default: empty string
Alternative text for the image. Always rendered (even
when empty) to keep assistive-tech compatibility.
.. confval:: title
:name: confval-title
:type: string
:Default: empty string
HTML-escaped title attribute.
.. confval:: class
:name: confval-class
:type: string
:Default: empty string
CSS classes for the ```` tag. Include
``lazyload`` to switch from native to JS-based lazy
loading (see :ref:`configuration-lazy-loading`).
.. confval:: mode
:name: confval-mode
:type: string
:Default: cover
Render mode. ``cover`` resizes images to fully cover
the given dimensions (crop/fill). ``fit`` resizes images
to fit within the given dimensions.
.. confval:: lazyload
:name: confval-lazyload
:type: boolean
:Default: false
Add ``loading="lazy"`` (native lazy loading).
.. confval:: responsiveSrcset
:name: confval-responsive-srcset
:type: boolean
:Default: false
Enable width-based responsive ``srcset`` instead of the
density-based ``2x`` output (preserved for backward
compatibility).
.. confval:: widthVariants
:name: confval-width-variants
:type: string|array
:Default: 480, 576, 640, 768, 992, 1200, 1800
Width variants for responsive ``srcset``
(comma-separated string or array). Only honored when
:confval:`responsiveSrcset `
is enabled.
.. confval:: sizes
:name: confval-sizes
:type: string
:Default: auto, (min-width: 992px) 991px, 100vw
Responsive ``sizes`` attribute for the generated
```` tag.
.. confval:: fetchpriority
:name: confval-fetchpriority
:type: string
:Default: empty string
Native HTML ``fetchpriority`` attribute. Allowed
values: ``high``, ``low``, ``auto``. Omitted when
empty.
.. confval:: attributes
:name: confval-attributes
:type: array
:Default: []
Extra HTML attributes merged into the rendered tag.
.. note::
Quality and output format are not exposed as ViewHelper
arguments. Quality defaults to 75 and is baked into the
generated ``/processed/...q...`` URL; the variant's
file extension is inherited from the source image. Use
:ref:`the URL format ` and
:ref:`variant negotiation `
to influence the served format.
.. _configuration-source-sets:
Source set configuration
========================
Define source sets per media breakpoint via the ``set``
attribute:
.. code-block:: html
:caption: Source set with breakpoint-specific dimensions
.. _configuration-render-modes:
Render modes
============
``cover``
Default. Resizes images to fully cover the provided
width and height.
``fit``
Resizes images so they fit within the provided width
and height.
.. code-block:: html
:caption: Using fit mode
.. _configuration-lazy-loading:
Lazy loading
============
Both modes support lazy loading via the native
``loading="lazy"`` attribute. When using JS-based lazy
loading (``class="lazyload"``), the ``data-srcset``
attribute is added automatically.
.. _configuration-backward-compatibility:
Backward compatibility
======================
By default :confval:`responsiveSrcset `
is ``false``, preserving the existing 2x density-based
``srcset`` behavior. All existing templates continue to work
without modifications.
.. _configuration-url-format:
Variant URL format
==================
Processed variants are served from a dedicated URL path. The
ViewHelper generates these URLs automatically, but any markup
that writes a URL of this form will be intercepted by the
:ref:`ProcessingMiddleware `:
.. code-block:: text
:caption: URL template
/processed/..[?]
````
Public path of the source image, including the
``/fileadmin/`` (or other storage) prefix. Path traversal
sequences (``..``) are rejected at URL-parsing time.
````
Concatenation of one or more of:
``w``
Target width in pixels.
``h``
Target height in pixels.
``q``
Quality (1--100).
``m``
Processing mode (``0`` = cover, ``1`` = scale/fit).
````
Source image extension. The processor decides at
response time whether to serve the original, the
``.webp`` sidecar, or the ``.avif`` sidecar based on
the ``Accept`` header and the query flags below.
.. code-block:: text
:caption: Example URL
/processed/fileadmin/photos/hero.w1200h800m0q85.jpg
.. _configuration-variant-negotiation:
Variant negotiation
===================
When the processor generates a variant, it writes the original
file to disk and additionally produces a ``.webp`` and an
``.avif`` sidecar (same base name). On each request it inspects
the ``Accept`` header and returns the best match the client
supports, preferring AVIF over WebP over the original format.
Two query parameters let callers opt out of sidecar generation
for individual URLs:
``skipWebP=1``
Do not produce or serve a WebP variant for this URL. The
``Content-Type`` always matches the source extension.
``skipAvif=1``
Do not produce or serve an AVIF variant for this URL. If
WebP is still allowed and the client supports it, WebP is
served.
These flags are useful when specific consumers (for example
e-mail clients or legacy RSS renderers) cannot handle modern
formats.
.. _configuration-cache-headers:
Cache headers
=============
Processed variant URLs are effectively content-addressed -- any
change to dimensions, quality, or format produces a different
URL. The processor therefore responds with an immutable,
long-lived cache header:
.. code-block:: text
Cache-Control: public, max-age=31536000, immutable
This value is a compile-time constant and not user-configurable.
.. _configuration-image-driver:
Image driver selection
======================
Intervention Image is instantiated through
:php:class:`~Netresearch\\NrImageOptimize\\Service\\ImageManagerFactory`,
which selects the best available driver at runtime:
1. **Imagick** when the ``imagick`` PHP extension is loaded
(preferred -- supports AVIF natively if the underlying
ImageMagick build does).
2. **GD** when ``imagick`` is unavailable and the ``gd``
extension is loaded.
If neither extension is present, the factory throws a
``RuntimeException`` with a descriptive message. Use the
:ref:`backend maintenance module `
to verify driver availability on your host.
.. _configuration-middleware:
Middleware registration
=======================
:file:`Configuration/RequestMiddlewares.php` registers the
``ProcessingMiddleware`` on the frontend pipeline **before**
``typo3/cms-frontend/site``. This ordering is required so the
middleware can intercept ``/processed/`` URLs before
TYPO3's frontend routing claims them. The registration has no
user-configurable options.
.. _configuration-limits:
Processor limits
================
The processor enforces the following bounds when parsing a URL:
``MAX_DIMENSION``
Width and height are clamped to 1--8192 pixels to prevent
denial-of-service via excessive memory allocation.
``MIN_QUALITY`` / ``MAX_QUALITY``
Quality is clamped to 1--100.
``LOCK_MAX_RETRIES``
Up to 10 attempts (at 100 ms intervals) to acquire the
per-variant processing lock before returning HTTP 503.
Prevents duplicate work when multiple clients hit the
same uncached variant simultaneously.
.. _configuration-trusted-storage-symlinks:
Trusted storage symlinks
=========================
.. versionadded:: 2.3.0
The ``additionalTrustedStorageSymlinks`` extension configuration
setting.
The processor validates that both the source image and the
target variant resolve (via ``realpath()``) to a location
inside an allowed root -- the public webroot, or a Local FAL
storage's own base path -- before reading or writing anything.
This rejects requests for images reached through a symlink that
escapes those roots (for example a symlink accidentally or
maliciously pointing at :file:`/etc`).
Some deployments relocate TYPO3 core's own
:file:`_processed_` image cache -- a subdirectory *inside* a FAL
storage's own directory, e.g. :file:`fileadmin/_processed_` --
onto local/ephemeral storage, to keep frequently-rewritten
derivative images off shared/NFS storage. That leaves only a
symlink behind inside the storage, which the FAL-storage
basePath lookup above does not see (it only resolves the
storage's own base path, never looks inside it), so variant
requests for such images are rejected even though the original
file is legitimately part of the deployed application.
The ``additionalTrustedStorageSymlinks`` extension configuration
setting closes this gap on an explicit, per-instance, opt-in
basis: a comma-separated list of directory names that, when
found as a symlink directly inside a Local FAL storage's base
path, are resolved and added to the allow-list too.
.. code-block:: php
:caption: config/system/additional.php
$GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']['nr_image_optimize']['additionalTrustedStorageSymlinks'] = '_processed_';
The setting can also be edited via the backend:
*Admin Tools > Settings > Extension Configuration >
nr_image_optimize*.
.. attention::
This widens the set of filesystem locations the processor
will read from and publicly serve variants of. Only add
well-known, infrastructure-managed names here -- never a
name an untrusted party (e.g. an FTP-only content account)
could create on their own. The default is empty, which
keeps today's behavior unchanged for every installation that
does not configure it.