Extending guide

The following sections will teach you how to customize and extend CKAN’s features by developing your own CKAN extensions.

See also

Some core extensions come packaged with CKAN. Core extensions don’t need to be installed before you can use them as they’re installed when you install CKAN, they can simply be enabled by following the setup instructions in each extension’s documentation (some core extensions are already enabled by default). For example, the datastore extension, multilingual extension, and stats extension are all core extensions, and the data viewer also uses core extensions to enable data previews for different file formats.

See also

External extensions are CKAN extensions that don’t come packaged with CKAN, but must be downloaded and installed separately. Find external extensions at https://extensions.ckan.org/. Again, follow each extension’s own documentation to install, setup, and use the extension.

• Writing extensions tutorial
  • Installing CKAN
  • Creating a new extension
  • Creating a plugin class
  • Adding the plugin to setup.py
  • Installing the extension
  • Enabling the plugin
  • Troubleshooting
  • Implementing the IAuthFunctions plugin interface
  • Using the plugins toolkit
  • Exception handling
  • We’re done!
  • Troubleshooting
• Using custom config settings in extensions
• Making configuration options runtime-editable
• Testing extensions
• Best practices for writing extensions
  • Follow CKAN’s coding standards
  • Use the plugins toolkit instead of importing CKAN
  • Don’t edit CKAN’s database tables
  • Use migrations when introducing new models
  • Declare models using shared metadata
  • Implement each plugin class in a separate Python module
  • Avoid name clashes
  • Internationalize user-visible strings
  • Add third party libraries to requirements.txt
  • Do not automatically modify the database structure
  • Implementing CSRF protection
• Customizing dataset and resource metadata fields using IDatasetForm
  • CKAN schemas and validation
  • Custom validators
  • Tag vocabularies
  • Adding custom fields to resources
  • Sorting by custom fields on the dataset search page
• Plugin interfaces reference
• Plugins toolkit reference
• Validator functions reference
  • Built-in validators
• Internationalizing strings in extensions
  • Extract strings
  • Manually create translations
  • Translations with Transifex
  • Compiling the catalog
  • The ITranslation interface
• Migration from Pylons to Flask
  • Always import methods and objects from the plugins toolkit if available
• Signals