xblock-utils: Various utilities for XBlocks

Purpose

These are a collection of utility functions, base test classes and documentation that are useful for any XBlocks.

⚠️ Deprecation Notice ⚠️

Effective Date: September 26, 2023

Repository Migration: This xblock-utils repository has been deprecated as of September 26, 2023, and the code and documentation have been migrated to the Xblock repository.

This decision was made to streamline and consolidate our codebase.

The migration process was completed through this Pull Request: PR #669

Archival: We are going to archive the xblock-utils repository. This means that it will become read-only, and no further updates or changes will be accepted.

We appreciate your understanding and cooperation during this transition. If you have any questions or concerns, please don't hesitate to reach out to us through the XBlock repository's issue tracker.

Thank you for your continued support and contributions to the Open edX community.

Getting Started

Developing

One Time Setup

# Clone the repository
git clone [email protected]:openedx/xblock-utils.git
cd xblock-utils

# Set up a virtualenv with the same name as the repo and activate it
# Here's how you might do that if you have virtualenvwrapper setup.
mkvirtualenv -p python3.8 xblock-utils

Every time you develop something in this repo

# Activate the virtualenv
# Here's how you might do that if you're using virtualenvwrapper.
workon xblock-utils

# Grab the latest code
git checkout master
git pull

# Install/update the dev requirements
make requirements

# Run the tests and quality checks (to verify the status before you make any changes)
make test

# Make a new branch for your changes
git checkout -b <your_github_username>/<short_description>

# Using your favorite editor, edit the code to make your change.
vim ...

# Temporary until https://github.com/openedx/xblock-utils/issues/199 is resolved
mkdir var
touch var/workbench.log

# Run your new tests
pytest ./path/to/new/tests

# Run all the tests and quality checks
make test

# Commit all your changes
git commit ...
git push

# Open a PR and ask for review.

Deploying

This component is automatically deployed to PyPI whenever new GitHub releases are made.

To deploy this library.

1. Update the version in xblockutils/__init__.py based on semantic versioning.
2. Create a new GitHub release with a tag matching the version.
3. Automation should build and deploy the version to PyPI

Getting Help

Documentation

Start by going through the documentation. If you need more help see below.

More Help

If you're having trouble, we have discussion forums at https://discuss.openedx.org where you can connect with others in the community.

Our real-time conversations are on Slack. You can request a Slack invitation, then join our community Slack workspace.

For anything non-trivial, the best path is to open an issue in this repository with as many details about the issue you are facing as you can provide.

https://github.com/openedx/xblock-utils/issues

For more information about these options, see the Project Getting Help page.

License

The code in this repository is licensed under the AGPLv3 unless otherwise noted.

Please see the LICENSE for details.

Contributing

Contributions are very welcome. Please read How To Contribute for details.

This project is currently accepting all types of contributions, bug fixes, security fixes, maintenance work, or new features. However, please make sure to have a discussion about your new feature idea with the maintainers prior to beginning development to maximize the chances of your change being accepted. You can start a conversation by creating a new issue on this repo summarizing your idea.

The Open edX Code of Conduct

All community members are expected to follow the Open edX Code of Conduct.

People

The assigned maintainers for this component and other project details may be found in Backstage. Backstage pulls this data from the catalog-info.yaml file in this repo.

Reporting Security Issues

Please do not report security issues in public. Please email [email protected].

More Documentation

StudioEditableXBlockMixin

from xblockutils.studio_editable import StudioEditableXBlockMixin

This mixin will automatically generate a working studio_view form that allows content authors to edit the fields of your XBlock. To use, simply add the class to your base class list, and add a new class field called editable_fields, set to a tuple of the names of the fields you want your user to be able to edit.

@XBlock.needs("i18n")
class ExampleBlock(StudioEditableXBlockMixin, XBlock):
    ...
    mode = String(
        display_name="Mode",
        help="Determines the behaviour of this component. Standard is recommended.",
        default='standard',
        scope=Scope.content,
        values=('standard', 'crazy')
    )
    editable_fields = ('mode', 'display_name')

That's all you need to do. The mixin will read the optional display_name, help, default, and values settings from the fields you mention and build the editor form as well as an AJAX save handler.

If you want to validate the data, you can override validate_field_data(self, validation, data) and/or clean_studio_edits(self, data) - see the source code for details.

Supported field types:

• Boolean: field_name = Boolean(display_name="Field Name")
• Float: field_name = Float(display_name="Field Name")
• Integer: field_name = Integer(display_name="Field Name")
• String: field_name = String(display_name="Field Name")
• String (multiline): field_name = String(multiline_editor=True, resettable_editor=False)
• String (html): field_name = String(multiline_editor='html', resettable_editor=False)

Any of the above will use a dropdown menu if they have a pre-defined list of possible values.

• List of unordered unique values (i.e. sets) drawn from a small set of possible values: field_name = List(list_style='set', list_values_provider=some_method)
  • The List declaration must include the property list_style='set' to indicate that the List field is being used with set semantics.
  • The List declaration must also define a list_values_provider method which will be called with the block as its only parameter and which must return a list of possible values.
• Rudimentary support for Dict, ordered List, and any other JSONField-derived field types
  • list_field = List(display_name="Ordered List", default=[])
  • dict_field = Dict(display_name="Normal Dict", default={})

Supported field options (all field types):

• values can define a list of possible options, changing the UI element to a select box. Values can be set to any of the formats defined in the XBlock source code:

  • A finite set of elements: [1, 2, 3]

  • A finite set of elements where the display names differ from the values:

    [
        {"display_name": "Always", "value": "always"},
        {"display_name": "Past Due", "value": "past_due"},
    ]
    

  • A range for floating point numbers with specific increments: {"min": 0 , "max": 10, "step": .1}

  • A callable that returns one of the above. (Note: the callable does not get passed the XBlock instance or runtime, so it cannot be a normal member function)

• values_provider can define a callable that accepts the XBlock instance as an argument, and returns a list of possible values in one of the formats listed above.

• resettable_editor - defaults to True. Set False to hide the "Reset" button used to return a field to its default value by removing the field's value from the XBlock instance.

Basic screenshot:

StudioContainerXBlockMixin

from xblockutils.studio_editable import StudioContainerXBlockMixin

This mixin helps to create XBlocks that allow content authors to add, remove, or reorder child blocks. By removing any existing author_view and adding this mixin, you'll get editable, re-orderable, and deletable child support in Studio. To enable authors to add arbitrary blocks as children, simply override author_edit_view and set can_add=True when calling render_children - see the source code. To restrict authors so they can add only specific types of child blocks or a limited number of children requires custom HTML.

An example is the mentoring XBlock:

SeleniumXBlockTest

from xblockutils.base_test import SeleniumXBlockTest

This is a base class that you can use for writing Selenium integration tests that are hosted in the XBlock SDK (Workbench).

Here is an example:

class TestStudentView(SeleniumXBlockTest):
    """
    Test the Student View of MyCoolXBlock
    """
    def setUp(self):
        super(TestStudentView, self).setUp()
        self.set_scenario_xml('<mycoolblock display_name="Test Demo Block" field2="hello" />')
        self.element = self.go_to_view("student_view")

    def test_shows_field_2(self):
        """
        The xblock should display the text value of field2.
        """
        self.assertIn("hello", self.element.text)

StudioEditableBaseTest

from xblockutils.studio_editable_test import StudioEditableBaseTest

This is a subclass of SeleniumXBlockTest that adds a few helper methods useful for testing the studio_view of any XBlock using StudioEditableXBlockMixin.

child_isinstance

from xblockutils.helpers import child_isinstance

If your XBlock needs to find children/descendants of a particular class/mixin, you should use

child_isinstance(self, child_usage_id, SomeXBlockClassOrMixin)

rather than calling

``isinstance(self.runtime.get_block(child_usage_id), SomeXBlockClassOrMixin)``.

On runtimes such as those in edx-platform, child_isinstance is orders of magnitude faster.

XBlockWithSettingsMixin

This mixin provides access to instance-wide XBlock-specific configuration settings. See [wiki page](https://github.com/openedx/xblock-utils/wiki/Settings-and-theme-support#accessing-xblock-specific-settings) for details

ThemableXBlockMixin

This mixin provides XBlock theming capabilities built on top of XBlock-specific settings. See [wiki page](https://github.com/openedx/xblock-utils/wiki/Settings-and-theme-support#theming-support) for details