v1.4.516

Changes

PR #2261 by ksylvan: fix: harden REST server, template engine and plugins

• Reworked the template engine to resolve each token exactly once in a single linear scan, preventing variable values from being re-expanded into plugin or extension calls and eliminating quadratic processing time on long brace runs.
• Added loopback security middleware and JSON content-type enforcement to the REST and Ollama-compatible servers, so that, when no API key is set, these servers accept only loopback or configured CORS hosts and origins.
• Confined the file plugin to a root directory with os.Root, rejecting absolute, ~, .., and escaping symlink paths, and enforcing read size limits on special files such as /dev/zero.
• Restricted the fetch plugin and the Ollama image loader to public network addresses through a shared HTTP client with DNS-level address checks, a 30-second timeout, a 5-redirect limit, and no API key sent to image hosts.
• Added per-session locking with atomic writes, request body size limits (50 MiB), merged .env updates, and DOMPurify sanitization plus a Content-Security-Policy in the web UI to prevent data loss, memory exhaustion, and unsafe HTML in rendered output.
• Breaking: With no API key, the server gives 403 to a request whose Host is not loopback. To use a LAN address or another host name, add its origin with --cors-origins.
• Breaking: JSON endpoints need Content-Type: application/json. Other requests get 415. This includes the Ollama-compatible /api/chat: add -H 'Content-Type: application/json' to a curl -d call.
• Breaking: The file plugin reads only relative paths.
• Breaking: The template engine does not expand a variable value again. With x = "{{name}}", {{x}} gives {{name}}.
• Breaking: The fetch plugin and the Ollama image loader ignore HTTP_PROXY, and they refuse loopback, private and other non-public addresses. This also applies to the CLI. An Ollama image URL on a LAN host now gives an error.
• Breaking: Fabric removes terminal control sequences (other than colors) from the CLI output. GET /config shows a fixed mask in place of each API key. After the upgrade, get the configuration again before you send it to POST /config/update. The server keeps an old mask, such as ****abcd, as a new key value.
• Breaking: The Streamlit UI binds to 127.0.0.1. To open it from a different computer, start it with --server.address 0.0.0.0 and set FABRIC_UI_TOKEN.
• Breaking: In a workflow, --input-has-vars applies only to the first input and to each input from the workflow file. The output of a step goes to the next step as literal text.
• code2context and the pattern update (-U) skip symbolic links.
• New session and context files get mode 0600, and new storage folders get mode 0700. Existing files and folders keep their mode.
• --notification-command gets the title and the message with no ", no ' and no \. POST /config/update merges into .env and answers 400 for CR, LF or NUL. A strategy name must obey the storage name rules, which refuse Windows device names such as con and aux on all platforms.
• Breaking: The REST server runs only the text and datetime template plugins in a pattern. A sys, file or fetch plugin token or an extension token in a pattern gives an error on /patterns/:name/apply and /chat. The CLI runs all plugins.
• Breaking: With no API key, the server accepts a POST, PUT, DELETE or PATCH request with an Origin header only from the same origin (host and port), a --cors-origins entry or a JSON request from the web UI on port 5173 or 4173 (vite preview). Before, it accepted each loopback origin on any port.