ssz-views

Generate Views

Views are pre-generated based on the exported JSON files. A command line tool is provided for this step. The tool must be called like this:

./bin/ssz-views.js generate --endpoint=http://ld.zazuko.com/query --base=http://localhost:8080/ config.json views

The endpoint argument is used to lookup hierarchies on the SPARQL endpoint. The given base will be used as base URL for the views. It must match the URL that will be used for the server. config.json is the input file and views the output folder.

Generate Views to a Triplestore

Generating the view triples into a triplestore is almost the same as into a file. The filename must be replaced by the SPARQL Graph Store URL of the target store. Additional you can give a target named graph and user + password, if required:

./bin/ssz-views.js generate2store --endpoint=http://ld.zazuko.com/query --base=http://localhost:8080/ config.json http://localhost:3030/ssz/data

View Server

The view server hosts the generated views and runs them on the fly. Content negotiation can be used to fetch the results in RDF serializations or CSV.
The following URL patterns are used:

• GET /: Returns an index of all views pointing to the views using hydra:member.
• GET /:viewId: Returns the triples of the generated view. The viewId matches the Veröffentlichung/VeröffentlichungID from the json config.
• GET /:viewId/observation/: Returns the on the fly generated observations based on the view definition with the given viewId.

Examples

To run server locally, create a .env.dev.local file with values for environment to configure. For example:

BASE_URL=https://ld.stadt-zuerich.ch/statistics/view/
ENDPOINT_URL=https://ld.integ.stadt-zuerich.ch/query
VIEW_ENDPOINT_URL=https://ld.integ.stadt-zuerich.ch/query

Then, execute npm start to run the server.

The following curl request will fetch the view V000001 as CSV and store it in test.csv:

curl -v -H 'accept: text/csv' http://localhost:8080/V000001/observation/ > test.csv

The following curl request will fetch the view V000001 as N-Triples and store it in test.nt:

curl -v -H 'accept: application/n-triples' http://localhost:8080/V000001/observation/ > test.nt