LabVIEW Web services allow Web browsers and HTTP-capable clients to interact with LabVIEW applications. You use URLs and HTTP methods to transmit data to the Web service. The LabVIEW Datalogging and Supervisory Control (DSC) Module includes built-in Web services that expose DSC Module VIs functionality. The DSC Module includes the following Web services:
In a Web browser or other Web client, you use URLs and HTTP methods to exchange information with the Web service, as well as send values as post data using the POST HTTP method. Refer to the World Wide Web Consortium at www.w3.org for more information about HTTP method definitions, including the POST method.
The following figure shows an example URL that a Web client might use to exchange data with the Alarms & Events Web service, nialarm.
DSC Module Web services can return data as XML- or JSON-formatted responses. By default, the DSC Module Web services return XML-formatted responses.
After responding to a client request, the Web service displays a response message in the HTTP header. The HTTP header describes whether an operation succeeds or fails. If an operation succeeds, the Reason-Phrase field in the HTTP header is empty. If an operation fails, the Reason-Phrase field in the HTTP header contains information about the failure, such as the LabVIEW error code and explanation of the error.