How to connect to external context providers

Context Broker GE also implements a mechanism so part of the context information is not managed directly by the Context Broker, but by external Context Providers. Thus, in this way, Context Broker GE becomes the single access point  for all the context data , regardless the actual location of the context source. This approach has several advantages:

  • It’s easy for client applications to interact with just one API endpoint, instead of interacting with a different API endpoint for each source of context. Moreover, if the endpoint for a given source of context changes, the change is done at Context Broker GE in a way that is transparent for clients.
  • Scalability. When a single Context Broker GE is not enough to manage all the context information, several can be used. Each Context Broker GE (managing a subset of the context) is set as Context Provider in the Context Broker GE acting as single access point. This schema can be applied in a hierarchical way, which GE at different “level”, each level managing finer-grained context subsets.
  • Security. Clients may be not allowed to access directly to Context Providers for security reasons. In that case, the Context Broker GEs (which has the ability to authenticate and authorize requests) acts as security enforcement point.

Let’s illustrate with an example based on the NiceEating case. Let’s consider an external restaurant booking system that is able to provide in real time the occupancy level (as an absolute value). That system runs at and plays the role of a Context Provider.

First, the Context Provider is registered as provider of occupancyLevels for Elizalde restaurant which ID is 0115206c51f60b48b77e4c937835795c33bb953f:

POST <cb_host>:<cb_port>/v1/registry/contextEntities/type/Restaurant/id/0115206c51f60b48b77e4c937835795c33bb953f/attributes/occupancyLevels


    "Content-Type": "application/json",
    "Fiware-Service": "tourguide"


    "duration": "P1M",
    "providingApplication": ""

Thus, each time occupancyLevels is queried at Context Broker GE (e.g. from the user mobile phone application), that query is forwarded to From a Context Consumer perspective, all the process is transparent, as if the information were actually managed by Context Broker GE locally.