CKAN is an open-source data management solution for open data. It provides a platform for publishing and exposing metadata through an API and front-end interface. Major governments and communities use CKAN to organize large numbers of datasets. While it has advantages like organizing data in a structured way and providing APIs, its data model does not work for all use cases and there are no strict guidelines for dataset publishing. Extensions allow additional functionality and it can be deployed in various ways.

1. CKAN
an open-source data management solution
for open data
Ivan Ermilov

2. AKSW Research Group
http://aksw.org

3. My experience with CKAN
● PublicData.eu portal
o Crowd-sourcing CSV2RDF mappings
● LODStats
o Version 1: crawling datahub.io (CKAN)
o Version 2: CKAN aggregator for data.gov,
publicdata.eu and datahub.io
o Version 2: Crawled all three portals and published
the data on datahub.io

4. CKAN IS NOT
a file storage!

5. Why CKAN?
● An open source platform
o Relatively easy to deploy
o Provides a rich set of features for free
● Data management
● Community involvement

6. Who use CKAN?
● All major open governments
o Canada (open.canada.ca): 244,238 datasets
o The U.S. (data.gov): 131,348 datasets
o Europe (publicdata.eu): 47,863 datasets
● And some other communities:
o Semantic Web community (datahub.io): 9,509
datasets

7. CKAN architecture

8. CKAN Pros/Cons
● Pros
o Organizes your data in structured way
o Have an extension to support DCAT (only for
datasets)
o Provides API to digest your data
● Cons
o The data model does not work for all use cases
(DBpedia)
o No strict guidelines for dataset publishing

9. CKAN functionality
● Publishing metadata
● Exposing metadata (API/front-end)
● Access control for users/organizations
● Additional functionality via plugins

10. CKAN extensions/plugins
● Data preview and visualization
● CKAN + DCAT
● Extension that adds the Disqus commenting
system to CKAN
● Simple API dataset hits counter
Full list is available at: http://extensions.ckan.org/

11. CKAN deployment
● From source
● OS package (e.g. as debian package)
● Docker image
Official guide: http://docs.ckan.org/en/latest/maintaining/installing/index.html

12. CKAN Multi-Tier Deployment

13. CKAN API
● Well documented
● Covers everything you can do with the web
interface
o You can write your own web interface
● Various API clients
o ckanclient (python) - official
o Ruby, PHP, Java, Nodejs, Perl, R
https://github.com/ckan/ckan/wiki/CKAN-API-Clients

14. CKAN API methods
● Retrieving data
● Creating new data
● Update existing data
● Delete existing data
● Data is: packages, resources, groups, tags,
users etc.
http://docs.ckan.org/en/latest/api/index.html

15. CKAN API: Examples
● Get package list
o http://demo.ckan.org/api/3/action/package_list
o Disabled for data.gov
● Get one package
o http://demo.ckan.org/api/3/action/package_show?id=
adur_district_spending
● ckan.logic.action.get.organization_show
o api/3/action/organization_show?id=...

16. Use Case: LODStats
● Aggregate CKAN
instances via API
● Filter out only related
datasets
● Build an application on top
of it

17. Use Case: CSV2RDF
● Integrated with a particular CKAN instance
● Aggregates all CSV files from the instance
● Provides an interface for CSV2RDF conversion

18. Thank you for your attention!
Presented by Ivan Ermilov.
LinkedIn: https://www.linkedin.com/in/iermilov
Email: iermilov@informatik.uni-leipzig.de
Skype: earthquakesan