Plugin specs

This section contains an API reference of the kadi.plugins.spec Python module, which contains the hook specifications that currently exist for use in plugins. For implementing any of the plugin hooks, see also how to develop plugins.

kadi.plugins.spec.kadi_get_about_templates()[source]

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.

kadi.plugins.spec.kadi_get_blueprints()[source]

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. Each blueprint needs to be an instance of a class derived from PluginBlueprint, which works like a regular Flask blueprint. The actual blueprint definition may look like the following:

from kadi.lib.plugins.core import PluginBlueprint

bp = PluginBlueprint(
    "my_plugin",
    __name__,
    url_prefix="/my_plugin",
    template_folder="templates",
    static_folder="static",
)

Next to the unique name of the blueprint, which may e.g. correspond to the name of the plugin, 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:

from kadi.lib.api.blueprint import bp
from kadi.lib.api.core import json_response

@bp.get("/my_plugin/<my_endpoint>")
def my_endpoint():
    return json_response(200)

kadi.plugins.spec.kadi_get_capabilities()[source]

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 representing the respective capability. If the requirements for none of the capabilities are met, None can be returned instead.

kadi.plugins.spec.kadi_get_content_security_policies()[source]

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:

{
    "frame-src": "https://example.com",
    "img-src": ["'self'", "https://example.com/images/"],
}

kadi.plugins.spec.kadi_get_custom_mimetype(file, base_mimetype)[source]

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 must be based on the content a file actually contains.

Can be used together with kadi_get_preview_data(). Note that the hook chain will stop after the first returned result that is not None.

Parameters:

file – The File to get the custom MIME type of.
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.

kadi.plugins.spec.kadi_get_index_templates()[source]

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.

kadi.plugins.spec.kadi_get_licenses()[source]

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:

{
    "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:

kadi db licenses --help

kadi.plugins.spec.kadi_get_nav_footer_items()[source]

Hook for collecting templates for navigation items shown in the footer.

The contents collected by this hook will be shown on all pages in the footer next to the existing navigation items.

For simple navigation items, without the need for custom styling or translations, the NAV_FOOTER_ITEMS configuration value may also be used instead.

kadi.plugins.spec.kadi_get_oauth2_providers()[source]

Hook for collecting OAuth2 providers.

Either a single OAuth2 provider or a list of providers can be returned by each plugin. Each provider has to be specified as a dictionary containing all necessary information about it, but at least the unique name that was also used to register it via kadi_register_oauth2_providers().

An example dictionary may look like the following:

{
    "name": "my_plugin",
    "title": "My Provider",
    "website": "https://example.com",
    "description": "The description of the OAuth2 provider.",
}

Needs to be used together with kadi_register_oauth2_providers().

kadi.plugins.spec.kadi_get_preferences_config()[source]

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 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 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:

from flask import render_template
from kadi.lib.forms import StringField
from kadi.lib.plugins.core import PluginConfigForm

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
        ),
    }

kadi.plugins.spec.kadi_get_preview_data(file)[source]

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 kadi_get_preview_templates() and kadi_get_scripts(). Note that the hook chain will stop after the first returned result that is not None.

Parameters:: file – The File to get the preview data of.

kadi.plugins.spec.kadi_get_preview_templates(file)[source]

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:

<!-- 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-preview-component :data="previewData.data"></my-preview-component>
</div>

In order to actually register the custom component via JavaScript, kadi_get_scripts() can be used. Should also be used together with kadi_get_preview_data().

Parameters:: file – The File to get the preview of.

kadi.plugins.spec.kadi_get_publication_form(provider, resource)[source]

Hook for collecting a publication form of a specific provider.

Each plugin has to check the given provider and type of the given resource to decide whether it should return a form or not, otherwise it has to return None. The returned form should be be an instance of a class derived from BaseForm.

After successful validation, the data obtained via the form will be passed into the kadi_publish_resource() hook as form_data, where it may be used to further customize the publication process.

Needs to be used together with kadi_get_publication_form_template() and kadi_publish_resource(). Note that the hook chain will stop after the first returned result that is not None.

Parameters:

provider – The unique name of the publication provider.
resource – The Record or Collection that will be published.

kadi.plugins.spec.kadi_get_publication_form_template(provider, resource, form)[source]

Hook for collecting a publication form template of a specific provider.

Each plugin has to check the given provider and type of the given resource to decide whether it should return a form template or not, otherwise it has to return None. The template should only contain the rendering of the form fields, since the surrounding form element, including the CSRF input field and the submit button, will be added automatically.

Needs to be used together with kadi_get_publication_form_template() and kadi_publish_resource(). Note that the hook chain will stop after the first returned result that is not None.

Parameters:

provider – The unique name of the publication provider.
resource – The Record or Collection that will be published.
form – The form object as returned by kadi_get_publication_form().

kadi.plugins.spec.kadi_get_publication_providers(resource)[source]

Hook for collecting publication providers.

Either a single publication provider or a list of providers can be returned by each plugin. Each provider has to be specified as a dictionary containing all necessary information about it, but at least the unique name that was also used to register the OAuth2 provider that this publication 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:

{
    "name": "my_plugin",
    "description": "The (HTML) description of the publication provider.",
}

Needs to be used together with kadi_register_oauth2_providers() and kadi_get_oauth2_providers().

Parameters:: resource – The Record or Collection that is targeted for publication.

kadi.plugins.spec.kadi_get_default_rate_limit()[source]

Hook for determining a custom default rate limit.

The returned rate limit must be a string according to the specification of the Flask-Limiter library. Different limits may be returned depending on e.g. the current endpoint (retrieved via the endpoint attribute of flask.request) or other requirements. Returning an empty string will disable the rate limit altogether.

Note that this hook will not be called for the static file endpoint and for endpoints that already have a fixed rate limit applied. Also note that the hook chain will stop after the first returned result that is not None. If no plugin returns a valid result, the configured default rate limits will be used instead.

kadi.plugins.spec.kadi_get_resource_overview_templates(resource)[source]

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.

Parameters:: resource – The resource which the overview page belongs to, either a Record, File, Collection, Template or Group.

kadi.plugins.spec.kadi_get_scripts()[source]

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 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 a custom, global Vue.js 3 component (using the options API), which can be used in combination with a template such as the one shown in kadi_get_preview_templates():

// Register the component in the main app.
kadi.app.component('my-preview-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>
    `,
})

kadi.plugins.spec.kadi_get_storage_providers()[source]

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 BaseStorage with a unique storage type.

In cases where no storage provider should be collected, None can be returned instead.

kadi.plugins.spec.kadi_get_terms(query, page, per_page)[source]

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:

{
    "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 kadi_get_capabilities().

Note that the hook chain will stop after the first returned result that is not None.

Parameters:

query – The search query, which may be an empty string.
page – The current result page used for pagination, starting at 1.
per_page – The number of results per page used for pagination.

kadi.plugins.spec.kadi_get_translations_bundles(locale)[source]

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 e.g. 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:

const translatedText = $t('My translated text');

This can be combined with custom scripts registered via kadi_get_scripts(), including the use within 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 kadi_get_translations_paths().

Parameters:: locale – The locale for which translations are collected, currently one of "en" or "de".

kadi.plugins.spec.kadi_get_translations_paths()[source]

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 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:

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 kadi_get_translations_bundles().

kadi.plugins.spec.kadi_post_resource_change(revision)[source]

Hook to run operations after a resource was created or changed.

This 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 respective resource. The given revision can be used to react to specific changes, e.g. based on the revisioned resource (revision.object), the user that triggered the revision (revision.user) or whether a parent revision (revision.parent) exists, i.e. whether the resources was newly created or changed instead.

Parameters:: revision – The revision that was created after a resource was created or changed. Supported resources are instances of Record, File, Collection, Template or Group.

kadi.plugins.spec.kadi_publish_resource(provider, resource, form_data, user, client, token, task)[source]

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 kadi_get_publication_providers(). Note that the hook chain will stop after the first returned result that is not None.

Parameters:

provider – The unique name of the publication provider.
resource – The Record or Collection to publish.
form_data – Form data as dictionary to customize the publication process, see kadi_get_publication_form(). Note that the dictionary will be empty if a plugin does not specify a custom form.
user – The User who started the publication process.
client – The OAuth2 client to use for authenticated requests together with the token.
token – The OAuth2 client token in a format usable by the client.
task – A 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.

kadi.plugins.spec.kadi_register_oauth2_providers(registry)[source]

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 library using a unique name, e.g. corresponding to the name of the plugin.

Needs to be used together with kadi_get_oauth2_providers().

Parameters:: registry – The OAuth2 provider registry, which is used to register the provider via its register method.