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CKAN

App Overview​

CKAN (Comprehensive Knowledge Archive Network) is the world’s leading open-source data portal platform. CKAN makes it easy to publish, share and work with data. It's a data management system that provides a powerful platform for cataloging, storing and accessing datasets with a rich front-end, full API (for both data and catalog), visualization tools and more.

CKAN is a tool for making open data websites. It helps you manage and publish collections of data. It is used by national and local governments, research institutions, and other organizations who collect a lot of data. See the public documentation for more:

Helpful Features & Plug-ins​

See https://docs.ckan.org/en/2.9/extensions/index.html

Helpful features include:

  1. The CKAN DataStore extension provides an ad hoc database for storage of structured data from CKAN resources.
  2. Advanced geospatial features, covering data preview, search, and discovery.
  3. An intuitive web interface that allows you to easily register, update and refine datasets.
  4. Completely customizable with themes to match your brand.
  5. Creation of a federated network of data portals which share data between each other.
  6. Rich search experience which allows for quick ‘Google-style’ keyword search and filtering.
  7. Create data-visualisation views and expose data as line, bar and pie charts.
  8. Upload media and image files. Stores files either on the server or in the cloud using extensions.
  9. CKAN allows you to pick and choose which features you want to use for your data portal. Or, you can easily develop your own by following the extending guide!

Integration Use Cases​

CKAN has been adopted by enterprise organisations in sectors such as resources, energy, pharmaceuticals and finance to publish and manage internal data assets. In addition, CKAN is widely used, mainly in the field of open government data, where it has become a de facto standard software package. CKAN powers the national open data portals of the UK, the USA, Australia or the EU, to name only a few well-known examples.

Using the API you can do things like:

  • Access any bit of information in CKAN (if you are authorized!)
  • Edit any piece of information in CKAN
  • Create a whole new web front-end for CKAN (if you want!)

Example user stories:​

  • As a data collector, I want to create a data portal to easily publish and share datasets with my community/peers/hub, so that they can leverage my data for further research.

  • As a researcher, I want a way to search for datasets related to my research domain, so that I can run analyses and incorporate other datasets into my studies.

  • As a data hub, I want to create a web portal where researchers can easily browse, share, download, and discuss datasets and research activites, so that I can enhance communication, collaboration, and exchange across partners.

See https://docs.ckan.org/en/ckan-1.8/user-stories-list.html for more app-specific user stories.

APIs & Integration Options​

The APIs available depend on the CKAN version you're using. See API docs: https://docs.ckan.org/en/2.9/api/index.html

All of a CKAN website’s core functionality (everything you can do with the web interface and more) can be used by external code that calls the CKAN API. The CKAN API follows the RESTful (Representational State Transfer) style and uses JSON by default.

For example, using the CKAN API your app can:

Beyond using OpenFn to connect with the API, you can access the API using one the dedicated tools or libraries written specifically for CKAN. The following clients are available:

  • dpm (data package manager): command-line client and Python library (maintained by core CKAN team)
  • ckanclient - CKAN Python Client: Python client maintained by the core CKAN team
  • CKAN Ruby: Ruby Client
  • Ckan_client-PHP: PHP client
  • Ckan_client-J: Java client
  • net-ckan: PERL client
  • ckanjs: sophisticated Javascript client built on Backbone.
  • Google Refine CKAN Extension: Google Refine client which allows you to get and push data to and from a CKAN instance using Google Refine.

Webhook/webservice for CKAN​

See documentation on:

Getting Started with CKAN​

CKAN offers robust, public documentation. See the CKAN User Guide.

API Notes​

CKAN exposes all core features to its API. See the API guide: https://docs.ckan.org/en/2.9/api/

CKAN’s FileStore and DataStore have their own APIs, see:

Note that some API functions require authorization. The API uses the same authorization functions and configuration as the web interface, so if a user is authorized to do something in the web interface they’ll be authorized to do it via the API as well.

To call the CKAN API, post a JSON dictionary in an HTTP POST request to one of CKAN’s API URLs. The parameters for the API function should be given in the JSON dictionary. CKAN will also return its response in a JSON dictionary.

One way to post a JSON dictionary to a URL is using the command-line client Curl. For example, to get a list of the names of all the datasets in the data-explorer group on demo.ckan.org, install curl and then call the group_list API function by running this command in a terminal:

curl https://demo.ckan.org/api/3/action/group_list

The response from CKAN will look like this:

{
    "help": "...",
    "result": [
        "data-explorer",
        "department-of-ricky",
        "geo-examples",
        "geothermal-data",
        "reykjavik",
        "skeenawild-conservation-trust"
    ],
    "success": true
}

JSONP support​

To cater for scripts from other sites that wish to access the API, the data can be returned in JSONP format, where the JSON data is ‘padded’ with a function call. The function is named in the ‘callback’ parameter. For example:

http://demo.ckan.org/api/3/action/package_show?id=adur_district_spending&callback=myfunction

CKAN's source code can be found at github.

Example normal request:

GET /api/rest/dataset/pollution_stats

but now with the callback parameter:

GET /api/rest/dataset/pollution_stats?callback=name-of-callback-function
returns: jsoncallback({"name": "pollution_stats", ... });

This parameter can apply to all POST requests to the Action API and GET requests to the Search API and v1/v2/v3 APIs.

App Installation​

See the System Admin guide.

To provide your API token in an HTTP request, include it in either an Authorization or X-CKAN-API-Key header. (The name of the HTTP header can be configured with the apikey_header_name option in your CKAN configuration file.)

OpenFn Adaptor​

Currently no CKAN-specific adaptor exists, but language-http can be implemented to access the web API.

Implementation Examples​

CKAN has been implemented in catalog.data.gov, open.canada.ca/data, and data.humdata.org.