ckanext-traffic_light

The extension will add an image of a red, yellow or green traffic light to each metadata record that indicates the metadata provision for this record. With default settings, the evaluation resolves to a percentage value that represents the proportion of filled optional metadata fields. The image is furthermore attached to each dataset in the search results.

Configuration options of the extension allow to redefined the limits at which the traffic light switches color, define which metadata fields are included in the evaluation, to assign weights to the fields that are used for the evaluation, and to change the shown images.

The extensions also provides a reference page that is available at <your-ckan-domain>/traffic-light-reference. Clicking on a traffic light redirects to this page. The reference page gives information about whether or not weights are used in the calculation, at which breaking points the traffic light switches color, and which fields (and with which weights) are used in the evaluation.

Requirements

• Tested on CKAN 2.9 with Python 2.7
• Full functionality only provided with ckanext-scheming (required to find the labels of the metadata fields as shown on the reference page)

Config settings

Edit fields.json to define which metadata fields are used to evaluate the metadata provision for each record. Don't include any mandatory field here, since it obviously doesn't make sense.

It is assumed that this extension is used in conjunction with the scheming extension; therefore, fields can be defined for different metadata schemas (The file you download with the extension, defines fields for the three metadata schemas dataset, process and workflow.). The default metadata schema of CKAN is called dataset. If a metadata record has a schema that is not referenced in fields.json, it falls back to a default list of keys that is based on the default CKAN schema (see plugin.py). If you want to always use this fallback keys, just set the content of fields.json to {}. This ({}) is also the minimum content for the files fields.json and fields_weighted.json. If these files are empty or non-existent the extension might stop working.

The general schema of fields.json is:

{
    "<metadata_schema_name_1>": [
        "<key_1_of_metadata_schema_1>",
        "<key_2_of_metadata_schema_1>",
        "<key_3_of_metadata_schema_1>",
        ...
    ],
    "<metadata_schema_name_2>": [
        "<key_1_of_metadata_schema_2>",
        "<key_2_of_metadata_schema_2>",
        "<key_3_of_metadata_schema_2>",
        ...
    ],
    ...
}

The default content of the file (based on the GeoKur metadata schemas https://github.com/GeoinformationSystems/ckanext-scheming, https://zenodo.org/record/4916698) is:

{
    "dataset": [
        "license_title",
        "temporal_resolution",
        "spatial_resolution",
        "was_derived_from",
        "theme",
        "tags",
        "is_version_of",
        "is_part_of",
        "notes",
        "quality_metrics",
        "conforms_to",
        "temporal_start",
        "temporal_end",
        "documentation",
        "url"
    ],
    "process": [
        "documentation",
        "used",
        "generated",
        "category",
        "notes"
    ],
    "workflow": [
        "documentation",
        "source_code",
        "rel_processes",
        "rel_datasets",
        "notes"
    ]
}

Traffic Light Limits

The default limits for the switching of the traffic light (> 0.8: green, > 0.3: yellow) can be changed in the ckan.ini:

ckanext.traffic_light.green_limit = 0.9
ckanext.traffic_light.yellow_limit = 0.5

Weights

Users of the extension can specify weights for the metadata fields that are included in the evaluation. They therefore have to add ckanext.traffic_light.weights = true to the ckan.ini. If weights are applied, the extension uses fields_weighted.json rather than fields.json. Conclusively, in this case, the definition of the included fields and their weights has to be done in fields-weighted. The evaluation procedure normalizes the provided weights, so that the result is always a value between 0 and 1. The schema of fields_weighted is as follows:

{
    "<metadata_schema_name_1>": [
        {
            "field_name" : "<key_1_of_metadata_schema_1>",
            "weight": "<weight_of_key_1_of metadata_schema_1>"
        },
        {
            "field_name" : "<key_2_of_metadata_schema_1>",
            "weight": "<weight_of_key_2_of metadata_schema_1>"
        }
        ...
    ],
    "<metadata_schema_name_2>": [
        {
            "field_name" : "<key_1_of_metadata_schema_2>",
            "weight": "<weight_of_key_1_of metadata_schema_2>"
        },
        ...
    ],
    ...
}

Changing the Images

Traffic lights might not always be a feasible option to represent the metadata provision. Users can change the images by replacing the according PNG files in the public folder by files with identical names. If the new images turn out to be wider, users might need to adapt the bootstrap-column-with:

• Metadata record page: in package/read.html at line 13 and 18 (col-sm-<...>), keep the sum at 12.

• Search result list: in snippets/package_item.html at line 5 and 16 (col-sm-<...>), keep the sum at 12.

Installation

Currently, only developer installation is supported.

Developer installation

To install ckanext-traffic_light for development, activate your CKAN virtualenv (. /usr/lib/ckan/default/bin/activate) and do:

git clone https://github.com/rue-a/ckanext-traffic_light.git
cd ckanext-traffic_light
python setup.py develop
pip install -r dev-requirements.txt