REST Client

REST Client

Description

The REST Client transform enables you to consume RESTfull services. Representational State Transfer (REST) is a key design idiom that embraces a stateless client-server architecture in which the web services are viewed as resources and can be identified by their URLs.

The REST client transform can use a pre-defined REST connection or use full URLs directly. When using a REST connection, the URL (hard-coded or accepted from a field) will be considered a path relative to the base URL defined in the REST connection. Header values that are specified in the Headers tab of the transform will overwrite any headers with the same name that were defined in the REST connection.

When used without a REST connection, the full URL needs to be specified.

Example

The REST client Transform returns a "result" field (can change the name), and the field is often used in the next transform. For example, it can be read in by a JSON input transform that extracts the fields specified on the Fields tab.

Hop Engine	✓
Spark	?
Flink	?
Dataflow	?

Options

General Tab

The General tab is where you enter basic connection information for accessing a resource.

Option	Description
Transform name	Name of this transform as it appears in the pipeline workspace
REST Connection	The (optional) REST connection to use for the base URL and authentication/authorization header name and value.
URL	Indicates the path to a resource
Accept URL from field	Designates the path to a resource is defined from a field
URL field name	Indicates the field from which the path to a resource is defined
HTTP method	Indicates how the transform interacts with a resource---options are either GET, PUT, DELETE, POST, HEAD, or OPTIONS
Get Method from field	Designates the GET method is defined from a field
Method fieldname	Indicates the field from which the GET method is defined
Body field	Contains the request body for POST, PUT, and DELETE methods. Body field only accepts a previous field, not a hard coded value.
Application type	Designates what type of application a resource is---options are either TEXT PLAIN, XML, JSON, OCTET STREAM, XHTML, FORM URLENCODED, ATOM XML, SVG XML, or TEXT XML
Connection timeout	Indicates the timeout until a connection is established (milliseconds)
Read timeout	Indicates the timeout for waiting for reading data (milliseconds)
Result fieldname	Designates the name of the result output field
HTTP status code fieldname	Designates the name of the HTTP status code field
Response time (milliseconds) fieldname	Designates the name of the response time field

Authentication Tab

If necessary, enter authentication details for a resource in the Authentication tab.

Tip: Hop allows using NULL parameters/variables for both the HTTP Login and HTTP Password.

Option	Description
HTTP Login	Indicates the username required to access a resource
HTTP Password	Indicates the password associated with the provided HTTP Login username
Preemptive	Option to send the authentication credentials before a server gives an unauthorized response. Currently always true, due to bug #4196.
Proxy Host	Indicates the name of a proxy host
Proxy Port	Indicates the port number of a proxy host

SSL Tab

The SSL tab is where you provide authentication details for accessing a resource that requires SSL certificate authentication.

Option	Description
Truststore file	Indicates the location of a truststore file
Truststore password	Indicates the password associated with the provided truststore file

Headers Tab

The Headers tab enables you to define the content of any HTTP headers using an existing field. Populate the list of fields by clicking the Get fields button.

Tip: To figure out what Headers are required, you can use Postman and remove as many headers as possible for the Request to still work. You should not need to use the Headers with value “<calculated when request is sent>” in Postman. You do not need to manually add an Authorization header if you used the Authentication tab.

Option	Description
Field	The field from incoming Hop stream that contains the header information. Add the header value field name to the Field column.
Name	The name of the outgoing Hop field from this transform. Add the header key field name to the Name column.

Parameters Tab

The Parameters tab enables you to define parameter values for POST, PUT, and DELETE requests. GET parameters should be part of the URL directly.

Option	Description
Parameter	The field from incoming Hop stream that contains the parameter information
Parameter	The name of the outgoing Hop field from this transform

Matrix Parameters tab

Use the Matrix Parameters tab to define matrix parameter values for POST, PUT, DELETE, and PATCH requests.

Option	Description
Parameter	The field from the incoming Hop stream that contains the matrix parameter information
Parameter	The name of the outgoing Hop field from this transform