[refactor] typification of SearXNG (initial) / result items (part 1)

Typification of SearXNG
=======================

This patch introduces the typing of the results.  The why and how is described
in the documentation, please generate the documentation ..

    $ make docs.clean docs.live

and read the following articles in the "Developer documentation":

- result types --> http://0.0.0.0:8000/dev/result_types/index.html

The result types are available from the `searx.result_types` module.  The
following have been implemented so far:

- base result type: `searx.result_type.Result`
  --> http://0.0.0.0:8000/dev/result_types/base_result.html

- answer results
  --> http://0.0.0.0:8000/dev/result_types/answer.html

including the type for translations (inspired by #3925).  For all other
types (which still need to be set up in subsequent PRs), template documentation
has been created for the transition period.

Doc of the fields used in Templates
===================================

The template documentation is the basis for the typing and is the first complete
documentation of the results (needed for engine development).  It is the
"working paper" (the plan) with which further typifications can be implemented
in subsequent PRs.

- https://github.com/searxng/searxng/issues/357

Answer Templates
================

With the new (sub) types for `Answer`, the templates for the answers have also
been revised, `Translation` are now displayed with collapsible entries (inspired
by #3925).

    !en-de dog

Plugins & Answerer
==================

The implementation for `Plugin` and `Answer` has been revised, see
documentation:

- Plugin: http://0.0.0.0:8000/dev/plugins/index.html
- Answerer: http://0.0.0.0:8000/dev/answerers/index.html

With `AnswerStorage` and `AnswerStorage` to manage those items (in follow up
PRs, `ArticleStorage`, `InfoStorage` and .. will be implemented)

Autocomplete
============

The autocompletion had a bug where the results from `Answer` had not been shown
in the past.  To test activate autocompletion and try search terms for which we
have answerers

- statistics: type `min 1 2 3` .. in the completion list you should find an
  entry like `[de] min(1, 2, 3) = 1`

- random: type `random uuid` .. in the completion list, the first item is a
  random UUID

Extended Types
==============

SearXNG extends e.g. the request and response types of flask and httpx, a module
has been set up for type extensions:

- Extended Types
  --> http://0.0.0.0:8000/dev/extended_types.html

Unit-Tests
==========

The unit tests have been completely revised.  In the previous implementation,
the runtime (the global variables such as `searx.settings`) was not initialized
before each test, so the runtime environment with which a test ran was always
determined by the tests that ran before it.  This was also the reason why we
sometimes had to observe non-deterministic errors in the tests in the past:

- https://github.com/searxng/searxng/issues/2988 is one example for the Runtime
  issues, with non-deterministic behavior ..

- https://github.com/searxng/searxng/pull/3650
- https://github.com/searxng/searxng/pull/3654
- https://github.com/searxng/searxng/pull/3642#issuecomment-2226884469
- https://github.com/searxng/searxng/pull/3746#issuecomment-2300965005

Why msgspec.Struct
==================

We have already discussed typing based on e.g. `TypeDict` or `dataclass` in the past:

- https://github.com/searxng/searxng/pull/1562/files
- https://gist.github.com/dalf/972eb05e7a9bee161487132a7de244d2
- https://github.com/searxng/searxng/pull/1412/files
- https://github.com/searxng/searxng/pull/1356

In my opinion, TypeDict is unsuitable because the objects are still dictionaries
and not instances of classes / the `dataclass` are classes but ...

The `msgspec.Struct` combine the advantages of typing, runtime behaviour and
also offer the option of (fast) serializing (incl. type check) the objects.

Currently not possible but conceivable with `msgspec`: Outsourcing the engines
into separate processes, what possibilities this opens up in the future is left
to the imagination!

Internally, we have already defined that it is desirable to decouple the
development of the engines from the development of the SearXNG core / The
serialization of the `Result` objects is a prerequisite for this.

HINT: The threads listed above were the template for this PR, even though the
implementation here is based on msgspec.  They should also be an inspiration for
the following PRs of typification, as the models and implementations can provide
a good direction.

Why just one commit?
====================

I tried to create several (thematically separated) commits, but gave up at some
point ... there are too many things to tackle at once / The comprehensibility of
the commits would not be improved by a thematic separation. On the contrary, we
would have to make multiple changes at the same places and the goal of a change
would be vaguely recognizable in the fog of the commits.

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

1 files changed, 0 insertions, 106 deletions

diff --git a/docs/dev/plugins.rst b/docs/dev/plugins.rst
deleted file mode 100644
index fb3201e66..000000000
--- a/docs/dev/plugins.rst
+++ /dev/null
@@ -1,106 +0,0 @@
-.. _dev plugin:
-
-=======
-Plugins
-=======
-
-.. sidebar:: Further reading ..
-
-   - :ref:`plugins generic`
-
-Plugins can extend or replace functionality of various components of searx.
-
-Example plugin
-==============
-
-.. code:: python
-
-   name = 'Example plugin'
-   description = 'This plugin extends the suggestions with the word "example"'
-   default_on = False  # disabled by default
-
-   # attach callback to the post search hook
-   #  request: flask request object
-   #  ctx: the whole local context of the post search hook
-   def post_search(request, search):
-       search.result_container.suggestions.add('example')
-       return True
-
-External plugins
-================
-
-SearXNG supports *external plugins* / there is no need to install one, SearXNG
-runs out of the box.  But to demonstrate; in the example below we install the
-SearXNG plugins from *The Green Web Foundation* `[ref]
-<https://www.thegreenwebfoundation.org/news/searching-the-green-web-with-searx/>`__:
-
-.. code:: bash
-
-   $ sudo utils/searxng.sh instance cmd bash -c
-   (searxng-pyenv)$ pip install git+https://github.com/return42/tgwf-searx-plugins
-
-In the :ref:`settings.yml` activate the ``plugins:`` section and add module
-``only_show_green_results`` from ``tgwf-searx-plugins``.
-
-.. code:: yaml
-
-   plugins:
-     ...
-     - only_show_green_results
-     ...
-
-
-Plugin entry points
-===================
-
-Entry points (hooks) define when a plugin runs. Right now only three hooks are
-implemented. So feel free to implement a hook if it fits the behaviour of your
-plugin. A plugin doesn't need to implement all the hooks.
-
-
-.. py:function:: pre_search(request, search) -> bool
-
-   Runs BEFORE the search request.
-
-   `search.result_container` can be changed.
-
-   Return a boolean:
-
-   * True to continue the search
-   * False to stop the search
-
-   :param flask.request request:
-   :param searx.search.SearchWithPlugins search:
-   :return: False to stop the search
-   :rtype: bool
-
-
-.. py:function:: post_search(request, search) -> None
-
-   Runs AFTER the search request.
-
-   :param flask.request request: Flask request.
-   :param searx.search.SearchWithPlugins search: Context.
-
-
-.. py:function:: on_result(request, search, result) -> bool
-
-   Runs for each result of each engine.
-
-   `result` can be changed.
-
-   If `result["url"]` is defined, then `result["parsed_url"] = urlparse(result['url'])`
-
-   .. warning::
-      `result["url"]` can be changed, but `result["parsed_url"]` must be updated too.
-
-   Return a boolean:
-
-   * True to keep the result
-   * False to remove the result
-
-   :param flask.request request:
-   :param searx.search.SearchWithPlugins search:
-   :param typing.Dict result: Result, see - :ref:`engine results`
-   :return: True to keep the result
-   :rtype: bool