# Copyright 2020 Karlsruhe Institute of Technology
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from pluggy import HookspecMarker
hookspec = HookspecMarker("kadi")
[docs]@hookspec
def kadi_get_about_templates():
"""Hook for collecting templates shown on the about page.
The contents collected by this hook will be shown below the existing content on the
about page.
"""
[docs]@hookspec
def kadi_get_blueprints():
"""Hook for collecting custom Flask blueprints.
Each plugin can return a single blueprint or a list of blueprints, which will be
registered in the application. The definition of a custom blueprint may look like
the following:
.. code-block:: python3
from flask import Blueprint
bp = Blueprint(
"my_plugin",
__name__,
url_prefix="/my_plugin",
template_folder="templates",
static_folder="static",
)
Next to the unique name of the blueprint, which should preferably correspond to the
plugin name, the optional parameters of this example blueprint specify a custom URL
prefix, which will also be used for the static URL, a folder for searching HTML
templates and a folder for static files, respectively.
Note that since API endpoints are handled a bit differently in the application, the
existing API blueprint, which uses ``api`` as name and ``/api`` as URL prefix,
should be preferred for custom API endpoints. An example on how to use it may look
like the following:
.. code-block:: python3
from kadi.plugins import api_bp
from kadi.plugins import json_response
@api_bp.get("/my_plugin/<my_endpoint>")
def my_endpoint():
return json_response(200)
"""
[docs]@hookspec
def kadi_get_capabilities():
"""Hook for collecting capabilities of the application.
A capability can for example be an installed external program or a database
extension, which may be a requirement for other internal functionality or plugins to
work.
Each plugin can return a single string or a list of strings, each string uniquely
representing the capability. If the requirements for none of the capabilities are
met, ``None`` can be returned instead.
"""
[docs]@hookspec
def kadi_get_content_security_policies():
"""Hook for collecting custom Content Security Policy configurations.
Each plugin has to return a single dictionary, mapping the resource type of each
policy to one or more corresponding CSP directives. If multiple plugins return the
same resource type, the directives will be merged. In cases where no policies should
be collected, ``None`` can be returned instead.
An example dictionary may look like the following:
.. code-block:: python3
{
"frame-src": "https://example.com",
"img-src": ["'self'", "https://example.com/images/"],
}
"""
[docs]@hookspec(firstresult=True)
def kadi_get_custom_mimetype(file, base_mimetype):
"""Hook for determining a custom MIME type of a file.
Each plugin has to check the given base MIME type and decide whether it should try
determining a custom MIME type or not. Otherwise, it has to return ``None``. The
returned MIME type should be based on the content a file actually contains.
Can be used together with :func:`kadi_get_preview_data`. Note that the hook chain
will stop after the first returned result that is not ``None``.
:param file: The :class:`.File` to get the custom MIME type of.
:param base_mimetype: The base MIME type of the file, based on the actual file
content, which a plugin can base its decision to return a custom MIME type on.
"""
[docs]@hookspec
def kadi_get_index_templates():
"""Hook for collecting templates shown on the index page.
The contents collected by this hook will be shown below the existing content on the
index page.
For simple content, consisting of an image and/or markdown text, the ``INDEX_IMAGE``
and ``INDEX_TEXT`` configuration values may also be used instead.
"""
[docs]@hookspec
def kadi_get_licenses():
"""Hook for collecting custom licenses.
All licenses have to be returned as a dictionary, mapping the unique name of a
license to another dictionary, containing the title of the license and an optional
URL further describing it.
An example dictionary may look like the following:
.. code-block:: python3
{
"my_license": {
"title": "My license",
# Specifying an URL is optional, but recommended.
"url": "https://example.com",
},
}
Before any custom licenses can be used, they have to be added to the database. This
can be done using the Kadi CLI, which also allows updating and/or deleting licenses
that have been added previously:
.. code-block:: bash
kadi db licenses --help
"""
[docs]@hookspec
def kadi_get_oauth2_providers():
"""Hook for collecting OAuth2 providers.
Each OAuth2 provider has to be returned as a dictionary containing all necessary
information about the provider. A provider must at least provide the unique name
that was also used to register it.
An example dictionary may look like the following:
.. code-block:: python3
{
"name": "my_plugin",
"title": "My Provider",
"website": "https://example.com",
"description": "The (HTML) description of the OAuth2 provider.",
}
Needs to be used together with :func:`kadi_register_oauth2_providers`.
"""
[docs]@hookspec
def kadi_get_preferences_config():
"""Hook for collecting configuration needed for plugin-specific preferences.
Plugin preferences are shown in a separate tab on the user's preferences page and
will be handled by the main application automatically. A plugin can retrieve them
later on using :func:`kadi.plugins.get_user_config()
<kadi.lib.config.core.get_user_config>`.
For adding a custom preferences tab, a plugin has to return a dictionary containing
a title, form and a callable returning a template (so it can be rendered at
runtime). The form needs to be an instance of a class derived from
:class:`.PluginConfigForm` containing the name of the plugin, while the template
returned by the callable should only contain the rendering of the form fields, since
the surrounding form element, including the CSRF input field and the submit button,
are added automatically.
An example may look like the following:
.. code-block:: python3
from flask import render_template
from kadi.plugins import PluginConfigForm
from kadi.plugins import StringField
class MyPluginForm(PluginConfigForm):
my_field = StringField("My field")
@hookimpl
def kadi_get_preferences_config():
form = MyPluginForm("my_plugin")
return {
"title": "My Plugin",
"form": form,
"get_template": lambda: render_template(
"my_plugin/preferences.html", form=form
),
}
"""
[docs]@hookspec(firstresult=True)
def kadi_get_preview_data(file):
"""Hook for obtaining preview data of a file to be passed to the frontend.
Each plugin has to check whether preview data should be returned for the given file,
based on e.g. its storage type, size or MIME types, otherwise it has to return
``None``. The preview data must consist of a tuple containing the preview type and
the actual preview data used for rendering the preview later on.
Should be used together with :func:`kadi_get_preview_templates` and
:func:`kadi_get_scripts`. Note that the hook chain will stop after the first
returned result that is not ``None``.
:param file: The :class:`.File` to get the preview data of.
"""
[docs]@hookspec
def kadi_get_preview_templates(file):
"""Hook for collecting templates for rendering preview data.
Each template should consist of an HTML snippet containing all necessary markup to
render the preview data. As currently all previews are rendered using Vue.js
components, the easiest way to include a custom preview is by using such a
component, which can automatically receive the preview data from the backend as
shown in the following example:
.. code-block:: html
<!-- Check the preview type first before rendering the component. -->
<div v-if="previewData.type === 'my_preview_type'">
<!-- Pass the preview data from the backend into the component. -->
<my-previewer-component :data="previewData.data"></my-previewer-component>
</div>
In order to actually register the custom component via JavaScript,
:func:`kadi_get_scripts` can to be used. Should also be used together with
:func:`kadi_get_preview_data`.
:param file: The :class:`.File` to get the preview of.
"""
[docs]@hookspec
def kadi_get_publication_providers(resource):
"""Hook for collecting publication providers.
Each publication provider has to be returned as a dictionary containing all
necessary information about the provider. A provider must at least provide the
unique name that was also used to register the OAuth2 provider that this provider
should use. The given resource can be used to adjust the returned information based
on the resource type.
An example dictionary may look like the following:
.. code-block:: python3
{
"name": "my_plugin",
"description": "The (HTML) description of the publication provider.",
}
Needs to be used together with :func:`kadi_register_oauth2_providers` and
:func:`kadi_get_oauth2_providers`.
:param resource: The :class:`.Record` or :class:`.Collection` to eventually publish.
"""
[docs]@hookspec
def kadi_get_resource_overview_templates(resource):
"""Hook for collecting templates shown on the overview pages of resources.
The contents collected by this hook will be shown below the existing actions and
links on the respective resource overview page. For resource types where no
templates should be collected, ``None`` can be returned instead.
:param resource: The resource which the overview page belongs to, either a
:class:`.Record`, :class:`.File`, :class:`.Collection`, :class:`.Template` or
:class:`.Group`.
"""
[docs]@hookspec
def kadi_get_scripts():
"""Hook for collecting JavaScript sources.
Each plugin can return a single string or a list of strings, each string
representing the full URL where the script can be loaded from. As only internal
scripts can currently be used, scripts should be loaded via a custom static route,
which a plugin can define by using :func:`kadi_get_blueprints`.
Note that by default, the scripts are inserted on every page. Plugins may limit each
script to certain pages based on e.g. the current endpoint (retrieved via the
``endpoint`` attribute of ``flask.request``) or other requirements. In cases where
no script should be inserted, the plugin has to return ``None``.
An example of using this hook could be the registration of custom (global) Vue.js
components, which can be used in combination with a template such as the one shown
in :func:`kadi_get_preview_templates`:
.. code-block:: js
Vue.component('my-previewer-component', {
// The data to preview. Its type depends on how the preview data is returned
// from the backend.
props: {
data: String,
},
// Note the custom delimiters, which are used so they can coexist with
// Jinja's templating syntax when not using single file components like in
// this case.
template: `
<div>{$ data $}</div>
`,
})
"""
[docs]@hookspec
def kadi_get_storage_providers():
"""Hook for collecting storage providers.
Either a single storage provider or a list of storage providers can be returned by
each plugin. Each storage provider must be an instance of a class derived from
:class:`.BaseStorage` with a unique storage type.
In cases where no storage provider should be collected, ``None`` can be returned
instead.
"""
[docs]@hookspec(firstresult=True)
def kadi_get_terms(query, page, per_page):
"""Hook for collecting term IRIs and related information from terminology services.
The terms have to be returned as a tuple, containing the total number of terms
corresponding to the given search query as well as the terms themselves. The latter
have to consist of a list of dictionaries, each dictionary containing at least the
term IRI and an optional HTML body.
An example dictionary may look like the following:
.. code-block:: python3
{
"term": "https://example.org#example_term",
# If no body is specified, the term will be used as default content.
"body": '<a href="https://example.org#example_term">Example Term</a>',
}
In order to inform the main application about a term search being provided by a
plugin, the ``"term_search"`` capability has to be returned using
:func:`kadi_get_capabilities`.
Note that the hook chain will stop after the first returned result that is not
``None``.
:param query: The search query, which may be an empty string.
:param page: The current result page used for pagination, starting at ``1``.
:param per_page: The number of results per page used for pagination.
"""
[docs]@hookspec
def kadi_get_translations_bundles(locale):
"""Hook for collecting translation bundles used for frontend translations.
Each plugin has to return a single translation bundle consisting of a dictionary
that maps the strings to translate to their corresponding translated values
according to the given locale. This dictionary may also be constructed by loading an
external JSON file, containing the actual translations.
If a certain locale should be ignored, ``None`` can be returned instead. The same
can be done to limit the translations to certain pages based on e.g. the current
endpoint (retrieved via the ``endpoint`` attribute of ``flask.request``) or other
requirements.
The translations can then be used in the frontend by calling the globally available
``$t`` function with the corresponding text to translate:
.. code-block:: js
const translatedText = $t('My translated text');
This can be combined with custom scripts registered via
:func:`kadi_get_scripts`, including the use in custom Vue.js components.
Note that the texts to translate will themselves be used as a fallback if no
corresponding translation can be found. Therefore, it is recommended to keep these
texts in english, like in the example above, as english is used as the default
locale in the application and will therefore need no further handling. Also note
that translations of the main application always take precedence.
For adding custom backend translations, please see
:func:`kadi_get_translations_paths`.
:param locale: The locale for which translations are collected, currently one of
``"en"`` or ``"de"``.
"""
[docs]@hookspec
def kadi_get_translations_paths():
"""Hook for collecting translations paths used for backend translations.
Each plugin has to return a single translations path, which must be absolute and
needs to contain a configuration file called ``babel.cfg``, as required by the
`Flask-Babel <https://python-babel.github.io/flask-babel>`__ Python library in order
to find and extract strings to translate. Afterwards, the Kadi CLI can be used to
initialize or update all message catalogs for the desired languages, for example:
.. code-block:: bash
kadi i18n --help
As this process is similar to how translations in the main application are handled,
please see the developer documentation for more information. Note that translations
of the main application currently always take precedence.
For adding custom frontend translations, please see
:func:`kadi_get_translations_bundles`.
"""
[docs]@hookspec
def kadi_post_resource_change(resource, user, created):
"""Hook to run operations after a resource was created or changed.
Note that the hook is only executed after all changes have been persisted in the
database and if the creation or change triggered the creation of a new revision of
the given resource. The type of the given resource can be used to react to specific
changes, while the latest revision of the resource can be retrieved via
``resource.ordered_revisions.first()``.
:param resource: The resource that was created or changed, either a
:class:`.Record`, :class:`.File`, :class:`.Collection`, :class:`.Template` or
:class:`.Group`.
:param user: The :class:`.User` who triggered the revision. May be ``None`` in some
cases, see :attr:`.Revision.user_id`.
:param created: Flag indicating if the resource was newly created.
"""
[docs]@hookspec(firstresult=True)
def kadi_publish_resource(provider, resource, form_data, user, client, token, task):
"""Hook for publishing a resource using a specific provider.
Each plugin has to check the given provider and decide whether it should start the
publishing process, otherwise it has to return ``None``. After finishing the
publishing process, the plugin has to return a tuple consisting of a flag indicating
whether the operation succeeded and a (HTML) template further describing the result
in a user-readable manner, e.g. containing a link to view the published result if
the operation was successful.
Needs to be used together with :func:`kadi_get_publication_providers`. Note that the
hook chain will stop after the first returned result that is not ``None``.
:param provider: The unique name of the publication provider.
:param resource: The :class:`.Record` or :class:`.Collection` to publish.
:param form_data: Form data as dictionary to customize the publication process, see
:func:`kadi_get_publication_form`.
:param user: The :class:`.User` who started the publication process.
:param client: The OAuth2 client to use for authenticated requests together with the
token.
:param token: The OAuth2 client token in a format usable by the client.
:param task: A :class:`.Task` object that may be provided if this hook is executed
in a background task. Can be used to check whether the publishing operation was
canceled and to update the current progress of the operation via the task.
"""
[docs]@hookspec
def kadi_register_oauth2_providers(registry):
"""Hook for registering OAuth2 providers.
Currently, only the authorization code grant type is supported. Each provider needs
to register itself to the given registry provided by the `Authlib
<https://docs.authlib.org>`__ Python library using a unique name, preferably by
using the name of the plugin.
Needs to be used together with :func:`kadi_get_oauth2_providers`.
:param registry: The OAuth2 provider registry, which is used to register the
provider via its ``register`` method.
"""