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.

Select the root model node in the tree on the left.
Enter a path prefix.
Configure the REST Server endpoint.

Enter the IP.
Enter the port.
Enter the Content-Type.

Check the webapp checkbox and provide the WAR-file if you want to host an application.
Select the Message encoding standard.
Check the box to Log data (E.g., the body of a request).
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.

Select the root model node in the tree on the left
Select the content type - defines the media type of the associated representation
Set the wait timeout

Select the Command node
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.
Headers (Optional) - Enable the checkbox Headers for the configuration of the following fields:
- Enter the name of the header
- Enter the value
Add multiple header entries by clicking the Add button
Delete a header by clicking the Delete button

Select the Authentication type
Select the Message encoding standard
Check the box to Log data (E.g., the body of a request).

URL Parameters (Optional) - Select a custom variable node
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`