logo CKAN Extensions

CKAN extension providing right time context support through FIWARE NGSI
by CoNWeT Lab. Universidad Politécnica de Madrid

CKAN ckanext-right_time_context

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CKAN extension that will give you the ability to manage right-time resources provided by a FIWARE Context Broker. This extension also provides a basic view to provide a data preview to user browsing context broker resources, altough it can be combined with other plugins (e.g. the ckanext-wirecloud_view one) to provide a more advanced visualization of the data provided using CKAN.

Note: This extension is being tested using CKAN 2.5, 2.6, 2.7 and 2.8. These are therefore considered as the supported versions

Requirements

  • resource_proxy. This extension is required to be able to make requests to the Context Broker and thus is required for the raw view (ngsi-view) provided by this plugin.
  • OAuth2 CKAN Extension. This extension is required to make request to secured Context Broker instances. The autentication token will be taken from the current user session, so the accessed context broker must be connected to the same IdM server as the one used to login into CKAN, if not, the token will not work.

Installation

To install ckanext-right_time_context:

  1. Activate your CKAN virtual environment, for example:

    . /usr/lib/ckan/default/bin/activate

  2. Install the ckanext-right_time_context python package into your virtual environment:

    pip install ckanext-right_time_context

  3. Add right_time_context to the ckan.plugins setting in your CKAN config file (e.g. /etc/ckan/default/production.ini). If you want to make use of the raw view provided by this plugin, you will have to ensure the resource_proxy is also enabled (comes directly with CKAN, but it is not enabled by default)

  4. Restart CKAN. For example if you’ve deployed CKAN with Apache:

    sudo service apache2 graceful

Please take a look into the ckanext-oauth2 installation guide if you are interested on linking secured context brokers.

Development Installation

To install ckanext-right_time_context for development, activate your CKAN virtualenv and do:

git clone https://github.com/conwetlab/ckanext-right_time_context.git
cd ckanext-right_time_context
python setup.py develop

How it works

How to create a fiware-ngsi resource

The way to create a NGSI resource is fairly simple:

  1. Firstly you have to access to the form for creating a new resource.

    Create resource form

  2. Use fiware-ngsi to fill the Format field, this will make the form change adding some extra fields required when using the fiware-ngsi format.

    Create resource after switching to the fiware-ngsi format

  3. Fill the URL field with a Context Broker query. It is recommended to use a NGSIv2 query, but it is possible to use also a v1 convenience query context url. Examples are:

    • http://orion.lab.fiware.org:1026/v2/entities?type=AirQualityObserved
    • http://orion.lab.fiware.org:1026/v1/contextEntities/MeteoLo
  4. Finally, check if you have to use some of the extra options:
    • Set Auth Type to the appropiate value if the Context Broker server requires authentication.
    • Fill the FIWARE-Service field if the data is not provided by the default tenant.
    • And finally, fill the FIWARE-ServicePath field if the data should be filtered using a service path.
  5. Once you provide all the requested information, click on the Add button.

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