searxng/searx/plugins/ai_summary.py

# SPDX-License-Identifier: AGPL-3.0-or-later
"""Plugin that displays an AI generated summary of the search query at the top
of the result page.  The summary is generated by a (local) `Ollama`_ server.

The Ollama server URL and the model are configured by the user in the *AI
Summary* tab of the preferences (``ai_summary_server``, ``ai_summary_model``);
the administrator can configure instance wide defaults in the ``ai_summary:``
section and lock the preferences via :ref:`settings preferences`.

.. attention::

   A user configurable server URL allows any user of the instance to make the
   SearXNG server send requests to a URL of their choice (`SSRF`_), and each
   summary is real LLM work.  This plugin is intended for private instances --
   on a public instance, lock the ``ai_summary_server``, ``ai_summary_model``
   and ``ai_summary_grounding`` preferences and configure the ``ai_summary:``
   section instead.

The result page is never delayed by this plugin: it only places an empty
placeholder (:py:obj:`searx.result_types.AiSummary`) in the answer area, which
is filled asynchronously by the client (``client/simple/src/js/plugin/
AiSummary.ts``) from the ``/ai_summary`` endpoint (registered in
:py:obj:`searx.webapp`).  The endpoint streams the tokens from Ollama's
``/api/chat`` to the client as `NDJSON`_.

A summary is only generated on the first page of a *general* search and only
if no engine has contributed an infobox (e.g. wikipedia / wikidata) or an
instant answer (e.g. ddg definitions) -- in these cases the query is most
likely a lookup of a well known term that is already answered.

The requests to the Ollama server are sent directly (not via
:py:obj:`searx.network`), an outgoing proxy configuration is deliberately not
applied to reach an Ollama server in the local network.

Configuration of the defaults (:py:obj:`searx.ai_summary.SettingsAISummary`):

.. code:: yaml

   ai_summary:
     base_url: "http://127.0.0.1:11434"
     model: "llama3.2:3b"

.. code:: yaml

   plugins:
     searx.plugins.ai_summary.SXNGPlugin:
       active: false

.. _Ollama: https://ollama.com/
.. _NDJSON: https://github.com/ndjson/ndjson-spec
.. _SSRF: https://owasp.org/www-community/attacks/Server_Side_Request_Forgery
"""

import typing as t

import json
import logging
import re
import time
from urllib.parse import urlparse

import flask
import httpx
from flask_babel import gettext

from searx import get_setting
from searx.ai_summary import SettingsAISummary, build_ollama_messages
from searx.extended_types import sxng_request
from searx.result_types import EngineResults
import searx.ai_summary

from . import Plugin, PluginInfo

if t.TYPE_CHECKING:
    from searx.search import SearchWithPlugins
    from searx.extended_types import SXNG_Request
    from . import PluginCfg

VALID_ROLES = ("user", "assistant")
MODEL_NAME_REGEXP = re.compile(r"[A-Za-z0-9._:/-]{1,128}")


def _get_client(base_url: str, cfg: SettingsAISummary) -> httpx.Client:
    """HTTP client for one request to the Ollama server at ``base_url``."""
    return httpx.Client(
        base_url=base_url,
        timeout=httpx.Timeout(connect=cfg.connect_timeout, read=cfg.read_timeout, write=10.0, pool=10.0),
    )


def _valid_server(url: str) -> bool:
    try:
        parsed = urlparse(url)
    except ValueError:
        return False
    return parsed.scheme in ("http", "https") and bool(parsed.netloc) and len(url) <= 256


def _user_server(request: "SXNG_Request", cfg: SettingsAISummary) -> str:
    """The Ollama server URL for this request: the user's ``ai_summary_server``
    preference, or the administrator's default."""
    return str(request.preferences.get_value("ai_summary_server") or "").strip() or cfg.base_url


class SXNGPlugin(Plugin):
    """Plugin that adds the AI summary placeholder to the result page, the
    ``/ai_summary`` endpoint itself is registered in :py:obj:`searx.webapp`."""

    id = "ai_summary"

    def __init__(self, plg_cfg: "PluginCfg"):
        super().__init__(plg_cfg)

        self.info = PluginInfo(
            id=self.id,
            name=gettext("AI summary"),
            description=gettext(
                "Show an AI generated summary of the search query on top of the"
                " result page (uses an Ollama server, see the settings below)."
            ),
            preference_section="ai",
        )

    def init(self, app: "flask.Flask") -> bool:
        cfg: SettingsAISummary = get_setting("ai_summary")

        if cfg.base_url:
            searx.ai_summary.MODELS = list(cfg.models) or self._probe_models(cfg)
            if not cfg.model and searx.ai_summary.MODELS:
                cfg.model = searx.ai_summary.MODELS[0]
            if cfg.model and cfg.model not in searx.ai_summary.MODELS:
                searx.ai_summary.MODELS.insert(0, cfg.model)

        return True

    def _probe_models(self, cfg: SettingsAISummary) -> list[str]:
        """Request the list of models from the Ollama server (``GET
        /api/tags``).  The server might not be up when SearXNG starts, a
        failing probe only leaves the model suggestion list empty."""
        try:
            with _get_client(cfg.base_url, cfg) as client:
                resp = client.get("/api/tags")
                resp.raise_for_status()
                models = [model["name"] for model in resp.json().get("models", [])]
        except (httpx.HTTPError, ValueError, KeyError) as exc:
            self.log.warning("can't request model list from %s: %s", cfg.base_url, exc)
            models = []
        return models or ([cfg.model] if cfg.model else [])

    def post_search(self, request: "SXNG_Request", search: "SearchWithPlugins") -> EngineResults | None:
        results = EngineResults()
        sq = search.search_query
        cfg: SettingsAISummary = get_setting("ai_summary")

        skip = (
            sq.pageno > 1
            # post_search is also called for the json, csv and rss formats,
            # the placeholder is only useful on the HTML result page
            or request.form.get("format", "html") != "html"
            or "general" not in sq.categories
            # an infobox (e.g. wikipedia / wikidata) or an instant answer
            # (e.g. ddg definitions) most likely already answers the query
            or bool(search.result_container.infoboxes)
            or bool(search.result_container.answers)
            or not sq.query.strip()
            # without an Ollama server (user preference or admin default)
            # there is nothing to show
            or not _user_server(request, cfg)
        )
        if skip:
            return None

        grounding = bool(request.preferences.get_value("ai_summary_grounding"))
        results.add(results.types.AiSummary(query=sq.query, grounding=grounding))
        return results


def _bad_request(msg: str) -> flask.Response:
    return flask.Response(json.dumps({"error": msg}), status=400, mimetype="application/json")


def _validate_messages(messages: t.Any, cfg: SettingsAISummary) -> list[dict[str, str]]:
    if not isinstance(messages, list) or not messages or len(messages) > cfg.max_history_messages:
        raise ValueError("invalid messages")
    for msg in messages:
        if not isinstance(msg, dict) or msg.keys() != {"role", "content"}:
            raise ValueError("invalid message")
        if msg["role"] not in VALID_ROLES or not isinstance(msg["content"], str):
            raise ValueError("invalid message")
        if not msg["content"].strip() or len(msg["content"]) > cfg.max_message_length:
            raise ValueError("invalid message")
    if messages[-1]["role"] != "user":
        raise ValueError("last message is not a user message")
    return messages


def _validate_context(context: t.Any, cfg: SettingsAISummary) -> list[dict[str, str]]:
    if not isinstance(context, list) or len(context) > cfg.max_context_items:
        raise ValueError("invalid context")
    for item in context:
        if not isinstance(item, dict) or not item.keys() <= {"title", "url", "snippet"}:
            raise ValueError("invalid context item")
        for val in item.values():
            if not isinstance(val, str) or len(val) > cfg.max_message_length:
                raise ValueError("invalid context item")
    return context


def _validate_payload(payload: t.Any, cfg: SettingsAISummary) -> tuple[list[dict[str, str]], list[dict[str, str]]]:
    """Validate the request body of the ``/ai_summary`` endpoint and return
    the ``messages`` and ``context`` lists.  Raises a :py:obj:`ValueError` for
    any malformed payload."""

    if not isinstance(payload, dict):
        raise ValueError("payload is not an object")
    return _validate_messages(payload.get("messages"), cfg), _validate_context(payload.get("context", []), cfg)


def ai_summary_view() -> flask.Response:
    """Stream an AI generated answer for the messages in the request body,
    response is NDJSON: ``{"delta": ..}`` lines followed by one final
    ``{"done": true, ..}`` line."""

    cfg: SettingsAISummary = get_setting("ai_summary")

    if SXNGPlugin.id not in sxng_request.user_plugins:
        return flask.Response(json.dumps({"error": "plugin is not enabled"}), status=403, mimetype="application/json")

    try:
        messages, context = _validate_payload(sxng_request.get_json(force=True, silent=True), cfg)
    except ValueError as exc:
        return _bad_request(str(exc))

    server = _user_server(sxng_request, cfg)
    if not _valid_server(server):
        return _bad_request("no valid Ollama server configured")

    model = str(sxng_request.preferences.get_value("ai_summary_model") or "").strip() or cfg.model
    if not MODEL_NAME_REGEXP.fullmatch(model):
        return _bad_request("no valid model configured")

    ollama_payload = {
        "model": model,
        "messages": build_ollama_messages(cfg, messages, context),
        "stream": True,
        "keep_alive": cfg.keep_alive,
    }

    # open the upstream connection before streaming, a connection error is
    # reported as HTTP 502 instead of a line in an already started stream
    client = _get_client(server, cfg)
    stream_ctx = client.stream("POST", "/api/chat", json=ollama_payload)
    upstream = None
    try:
        upstream = stream_ctx.__enter__()  # pylint: disable=unnecessary-dunder-call
        if upstream.status_code != 200:
            stream_ctx.__exit__(None, None, None)
            upstream = None
    except httpx.HTTPError:
        upstream = None
    if upstream is None:
        client.close()
        return flask.Response(json.dumps({"error": "upstream error"}), status=502, mimetype="application/json")

    # from here on nothing must be read from the request context, the
    # generator runs after the request context has been torn down
    log = logging.getLogger("searx.plugins.ai_summary")

    def ndjson(obj: dict[str, t.Any]) -> bytes:
        # the generator bypasses flask's response encoding (direct_passthrough)
        return (json.dumps(obj) + "\n").encode()

    def generate():
        start = time.monotonic()
        try:
            for line in upstream.iter_lines():
                if time.monotonic() - start > cfg.stream_timeout:
                    yield ndjson({"done": True, "error": "timeout"})
                    return
                if not line.strip():
                    continue
                data = json.loads(line)
                if data.get("done"):
                    yield ndjson({"done": True, "model": model})
                    return
                delta = data.get("message", {}).get("content", "")
                if delta:
                    yield ndjson({"delta": delta})
            yield ndjson({"done": True, "model": model})
        except (httpx.HTTPError, ValueError) as exc:
            log.warning("error while streaming from Ollama: %s", exc)
            yield ndjson({"done": True, "error": "upstream error"})
        finally:
            stream_ctx.__exit__(None, None, None)
            client.close()

    return flask.Response(
        generate(),
        mimetype="application/x-ndjson",
        headers={"Cache-Control": "no-store", "X-Accel-Buffering": "no"},
        direct_passthrough=True,
    )