docs(office): document all env vars and add size limits guide

Document every environment variable supported by the Document Server
Docker image in the installation page. Previously only a subset was listed.

Add a 'Size limits' section with a 200 MB PPTX example showing how the
four size-gate variables interact at different stages (nginx upload, temp
file buffer, converter download, uncompressed XML size).

Assisted-by: OpenCode:qwen3.6-27b
Signed-off-by: Christoph Schaefer <christoph.schaefer@nextcloud.com>

Author: chrip

admin_manual/office/euro-office/installation_docker.rst

@@ -92,33 +92,161 @@ Environment variables
     * - ``JWT_HEADER``
       - ``Authorization``
       - HTTP header carrying the JWT
-    * - ``WOPI_ENABLED``
-      - ``false``
-      - Enable WOPI protocol support
-    * - ``ALLOW_PRIVATE_IP_ADDRESS``
+    * - ``JWT_HEADER_INBOX`` / ``JWT_HEADER_OUTBOX``
+      - ``JWT_HEADER``
+      - Separate headers per direction
+    * - ``JWT_IN_BODY``
       - ``false``
-      - Allow the Document Server to fetch files from private IP ranges
-    * - ``NGINX_WORKER_PROCESSES``
-      - ``1``
-      - Number of nginx worker processes
-    * - ``GENERATE_FONTS``
-      - ``true``
-      - Regenerate font cache on startup
+      - Accept the token in the request body
+    * - ``JWT_SECRET_INBOX`` / ``JWT_SECRET_OUTBOX``
+      - ``JWT_SECRET``
+      - Separate secrets per direction
+    * - ``JWT_ENABLED_INBOX`` / ``JWT_ENABLED_OUTBOX``
+      - ``JWT_ENABLED``
+      - Enable JWT per direction
+    * - ``DB_TYPE``
+      - ``postgres``
+      - Database engine (standalone image supports ``postgres`` only)
     * - ``DB_HOST``
       - ``localhost``
-      - PostgreSQL host (for external database)
+      - Database host
+    * - ``DB_PORT``
+      - ``5432``
+      - Database port
     * - ``DB_NAME``
       - ``eurooffice``
-      - PostgreSQL database name
+      - Database name
     * - ``DB_USER``
       - ``eurooffice``
-      - PostgreSQL user
+      - Database user
+    * - ``DB_PWD``
+      - —
+      - Database password
     * - ``REDIS_SERVER_HOST``
       - ``localhost``
       - Redis host (for external Redis)
+    * - ``REDIS_SERVER_PORT``
+      - ``6379``
+      - Redis port
+    * - ``REDIS_SERVER_PASS``
+      - —
+      - Redis password
     * - ``AMQP_HOST``
       - ``localhost``
       - RabbitMQ host (for external RabbitMQ)
+    * - ``AMQP_PORT``
+      - ``5672``
+      - RabbitMQ port
+    * - ``AMQP_USER`` / ``AMQP_PWD``
+      - ``guest``
+      - RabbitMQ credentials
+    * - ``WOPI_ENABLED``
+      - ``false``
+      - Enable WOPI protocol support
+    * - ``PLUGINS_ENABLED``
+      - ``true``
+      - Enable editor plugins
+    * - ``GENERATE_FONTS``
+      - ``true``
+      - Regenerate font cache on startup
+    * - ``METRICS_ENABLED``
+      - ``false``
+      - Enable StatsD metrics collection
+    * - ``ALLOW_PRIVATE_IP_ADDRESS``
+      - ``false``
+      - Allow the Document Server to fetch files from private IP ranges
+    * - ``ALLOW_META_IP_ADDRESS``
+      - ``false``
+      - Allow fetching documents from meta-private IPs (169.254.0.0/16)
+    * - ``USE_UNAUTHORIZED_STORAGE``
+      - ``false``
+      - Allow fetching documents from HTTP (non-TLS) storage
+    * - ``SSL_VERIFY_CLIENT``
+      - ``off``
+      - Enable SSL client certificate verification
+    * - ``ONLYOFFICE_HTTPS_HSTS_ENABLED``
+      - ``true``
+      - Enable HSTS headers
+    * - ``ONLYOFFICE_HTTPS_HSTS_MAXAGE``
+      - ``31536000``
+      - HSTS max-age in seconds (default 1 year)
+    * - ``NGINX_WORKER_PROCESSES``
+      - ``1``
+      - Number of nginx worker processes
+    * - ``NGINX_ACCESS_LOG``
+      - ``false``
+      - Enable nginx access logging
+    * - ``NGINX_CLIENT_MAX_BODY_SIZE``
+      - ``100m``
+      - Nginx client max body size (upload limit for nginx)
+    * - ``MAX_FILE_SIZE``
+      - ``104857600``
+      - Max temp file upload size in bytes (default 100 MB)
+    * - ``FILECONVERTER_MAX_DOWNLOAD_BYTES``
+      - ``524288000``
+      - Max file download size for the FileConverter in bytes (default 500 MB)
+    * - ``FILECONVERTER_INPUT_LIMIT_UNCOMPRESSED``
+      - ``500MB``
+      - Max uncompressed zip size for office files (docx, xlsx, pptx, vsdx)
+
+Size limits
+-----------
+
+Each limit guards a different stage of the file lifecycle. Imagine a user tries to
+open a **200 MB** ``.pptx`` file:
+
+**1. Nginx accepts the upload** — ``NGINX_CLIENT_MAX_BODY_SIZE`` must be higher than
+the file. Default is ``100m``. With a 200 MB file the user gets
+``413 Request Entity Too Large``. Set it to ``250m``:
+
+.. code-block:: bash
+
+    -e NGINX_CLIENT_MAX_BODY_SIZE=250m
+
+**2. Document Server temp file** — ``MAX_FILE_SIZE`` gates the internal upload buffer
+(bytes). Default is ``104857600`` (100 MB). A 200 MB file fails here too. Set it to
+``268435456`` (256 MB):
+
+.. code-block:: bash
+
+    -e MAX_FILE_SIZE=268435456
+
+**3. FileConverter downloads the file** — ``FILECONVERTER_MAX_DOWNLOAD_BYTES`` is the
+max bytes the converter will fetch (default ``524288000`` = 500 MB). Already
+sufficient for a 200 MB file. No change needed.
+
+**4. FileConverter unzips the archive** — ``FILECONVERTER_INPUT_LIMIT_UNCOMPRESSED``
+checks the internal XML size. A **200 MB** ``.pptx`` on disk might contain 800 MB of
+uncompressed XML data (especially with embedded images, shapes, or animations).
+The 500 MB default may be too low. Set it to ``800MB``:
+
+.. code-block:: bash
+
+    -e FILECONVERTER_INPUT_LIMIT_UNCOMPRESSED=800MB
+
+.. list-table::
+    :header-rows: 1
+    :widths: 25 35 40
+
+    * - Stage
+      - Variable
+      - Value for 200 MB PPTX
+    * - Nginx upload
+      - ``NGINX_CLIENT_MAX_BODY_SIZE``
+      - ``250m``
+    * - Temp file buffer
+      - ``MAX_FILE_SIZE``
+      - ``268435456`` (bytes)
+    * - Converter download
+      - ``FILECONVERTER_MAX_DOWNLOAD_BYTES``
+      - ``524288000`` (default OK)
+    * - Uncompressed XML size
+      - ``FILECONVERTER_INPUT_LIMIT_UNCOMPRESSED``
+      - ``800MB`` (if needed)
+
+Office files are ZIP archives containing XML. The uncompressed limit protects
+against files that blow up the converter's memory when extracted. Adjust all four
+if your users work with large documents.
 
 Updating
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