OPC UA Adds Standardized REST Interface

With the addition of HTTP REST, applications outside the OPC UA ecosystem can now access OPC UA information. The OPC Foundation notes that the OPC UA specification includes “the transfer of meta-information such as server timestamp, source timestamp, value and quality of the individual information. The expansion of OPC UA with REST is less likely to be adopted at the field level, but in gateways and cloud services. Cloud companies can now access standardized information and use it efficiently to optimize the business processes of their customers and unlock new use cases.”

Stefan Hoppe, president and executive director of the OPC Foundation, says, "This extension of OPC UA with a standardized mapping to a RESTful interface is a significant step forward in ensuring the interoperability of industrial automation and IoT systems. By enabling access to information provided by implementations of over 90 OPC UA domain specific information models through standardized RESTful APIs, we are making it easier for developers to create OPC UA-enabled applications that can communicate with other web-based systems and applications."

The REST group, as a sub-group of the OPC Foundation UA Working Group, will meet to discuss use cases for OPC UA in edge and cloud computing environments using the proposed HTTP REST interface. Examples for work items include:

• Generic REST interface definition for common OPC UA services (e.g., read, write, call).
• Standardized mapping of OPC UA service parameters to datatypes commonly used in RESTful APIs.
• How the existing session-less OPC UA service can be used with a REST interface.
• Define a concept to provide REST interfaces for companion specification use cases.
• Define requirements for security.