Park and Ride is one of the solutions to tackle Helsinki regions growing population and traffic by encouraging citizens to leave their cars outside of the most congested areas and continuing their trip with public transportation. HSL Park and Ride application contains all the important information about parking facilities and their services near public transportation hubs. The application is used by HSL, parking operators, roadside displays and third party applications. All data is provided free of charge under the CC BY 4.0 license.
API follows REST conventions roughly. Resources are divided into collection and item URLs. Collection resources typically accept GET-parameters for filtering, paging and sorting items. Reading data uses GET-method and doesn’t require authorization - except for user management. Restricted modifications use either POST on collection-URL for creating new items and PUT on item URL for updates.
DELETE is not directly supported currently but the goal is achieved using e.g. a status field. However, if sometime in the future we need to delete something for reason or another, please prepare for 404 on a resource that has previously returned a result.
Somewhat contrary to strict REST ideology we provide all dependent (deep) information directly from item URLs. You need not get basic relations using nested calls. Shared resources are referenced using IDs (not URIs), and until HATEOAS-type links are implemented one needs to know and construct URIs using templates in order get details of such shared resources (e.g. operator or contacts). For most cases there exists an ID-based filtering parameter (ids) for collection URLs that allow getting basic information of all referred resources with single request.