REST

Characteristics - REST

Representational state transfer (REST) is a software architectural style that describes a uniform interface between decoupled components in the Internet in a Client-Server architecture. To learn more about the standard visit the REST section in Wikipedia website.

Information Model Requirements

• The first Node after the root node can be of type Event , Command or Variable

• The following Node Types can be used under the Event Node:

  • Variables with a Simple Data Type represents the key-value pairs.

  • Variables with a Custom Data Type represent objects that can contain key-value pairs.

Configuration - REST Server

The following sample configuration shows how variables can be made accessible over a REST server.

1. Select the root model node in the tree on the left.

2. Enter a path prefix.

3. Configure the REST Server endpoint.

• Enter the IP.

• Enter the port.

• Enter the Content-Type.

4. Check the webapp checkbox and provide the WAR-file if you want to host an application.

5. Select the Message encoding standard.

6. Check the box to Log data (E.g., the body of a request).

7. Click the Apply button and save the Channel by clicking the Save button on the upper right corner.

Description of configuration properties:

Property	Description	Example
pathPrefix	Prefix for the URL	e.g., demo
Port	Port of the REST server	e.g., 9002, 9000, ...
IP	IP address of the REST server	http://localhost
DefaultContentType	Is used to indicate the media type of the resource	application/json, application/xml, text/html, text/csv
webapp	Possibility to host an application	true, false
Message encoding	Encoding standard for messages	ISO-8859-1, UTF-16

Configuration - REST Client

The following sample configuration shows a GET request using url parameters.

1. Select the root model node in the tree on the left

2. Select the content type - defines the media type of the associated representation

3. Set the wait timeout

4. Select the Command node

5. Enable the Command routes checkbox for the configuration of the following fields:

   • Enter the URL - If URL parameters are used then add each parameter in the following syntax ${id}

   • Select the HTTP method.

6. Headers (Optional) - Enable the checkbox Headers for the configuration of the following fields:

   • Enter the name of the header

   • Enter the value

7. Add multiple header entries by clicking the Add button

8. Delete a header by clicking the Delete button

9. Select the Authentication type

10. Select the Message encoding standard

11. Check the box to Log data (E.g., the body of a request).

12. URL Parameters (Optional) - Select a custom variable node

13. Enable the Command routes for the configuration of the following fields:

    • Select the Content Type

    • (Optional) Enter a Field Name in case the Information Model Node is not matching the REST API

Description of configuration properties:

Property	Description	Example
URL	URL of the REST API.	http://localhost:8081/api/v1/dataPoint/${id}
HttpMethod	HTTP method for the action performed by the Client.	GET, POST, PUT
HeaderName and Header Value	To provide server and client with additional information	Retry-After: 12
Default Content Type	Is used to indicate the media type of the resource.	application/json
RouteHeaderConfiguration	Headers represent the meta-data associated with the API request	Name, Value
Authentication Type	Type of the Authentication	Basic, Digest, Kerberos, NTLM, SPNEGO
Content Type of Parameter Nodes	Type of the Parameter	Parameters, Body, Header, None
Field Name	For non-matching Information Model nodes and API spelling	String
WaitTimeoutDuration	Timeout in seconds until request is failing	10
Message encoding	Encoding standard for messages	ISO-8859-1, UTF-16