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RestClientApp

REST Client Application Configuration

The N2SVCD REST Client Application supports sending of REST requests over HTTP.

The REST Client Application does not initiate any user content itself. It exists only as an agent to send requests on behalf of another application.

Typical uses of the RestClientApp are:

As an outbound REST Gateway, the LogicApp Lua scripting logic can initiate outbound REST requests (via the RESTLuaAgent agent plugin).
As an outbound REST Gateway, a TesterApp script can use the rest.Request Test operation to request RestClientApp to initiate outbound REST requests.

This is done by internally sending and receiving REST-... messages over the n2svcd message bus.

See the N2SVCD Configuration Overview for more information on how the REST Application interacts with other components.

The following configuration is used to create a REST Application TCP Client instance.

<?xml version="1.0" encoding="utf-8"?>
<n2svcd>
  ...
  <applications>
    ...
    <application name="REST-CLIENT" module="RestClientApp">
      <include><lib>../apps/rest_c/lib</lib></include>
      <parameters>
        <parameter name="trace_level"            value="0"/>
        <parameter name="remote_host"            value="localhost"/>
        <parameter name="remote_port"            value="8118"/>
        <parameter name="path"                   value="/servlet/ABC"/>
        <parameter name="num_client_connections" value="3"/>
        <parameter name="server_timeout"         value="2"/>
        <parameter name="ping_interval"          value="3"/>
        <parameter name="ping_path"             value="/ping"/>
        <parameter name="ping_expected_code"     value="200"/>
      </parameters>
      <config>
        <http_headers>
          <http_header name="x-api-key" value="aaaaaa-bbbbbb-ccccc-dddddd"/>
        </http_headers>
      </config>
    </application>
    ...
  </application>
  ...
</n2svcd>

Configuration Details

The application element attributes for a REST Client Application instance may include the below.

For details of the various parameter types used, refer to Common Configuration.

Parameter Name	Type	XML Type	Description
See: Common Application configuration
See: TCP Application configuration
`module`	String	Attribute	[Required] `RestClientApp`
`include.lib`	String	Element	[Required] `../apps/rest_c/lib`
`parameters`	Array	Element	[Required] As per Common Configuration Application `parameters`.
`"edr_enabled"`	-	-	This value is ignored; the REST Client Application does not support writing EDRs.
`"socket_mode"`	String	Attribute	The REST Client Application supports only `connect` (TCP Client). (Default = `connect`)
`"remote_port"`	Integer	Attribute	As per common TCP configuration for `local_port`. (Default = `80`)
`"ping_supported"`	Boolean	Attribute	Whether or not the Rest Client App should perform ping checks against a configured rest path. (Default = False)
`"ping_path"`	String	Attribute	The path component of the Ping REST URL. (Default = No Default)
`"ping_expected_code"`	Integer	Attribute	The expected HTTP response code to check for when executing Ping checks against the configured `ping_path`. If the response code is not present or does not match the expected response code the application will be set as `OFFLINE`. (Default = 200)
`"path"`	String	Attribute	The default path component of the REST URL. This may be overridden for each request. (Default = No Default)
`"security"`	String	Attribute	The security for the HTTP Interaction, either `basic` or `none`. This may be overridden for each request. (Default = `none`)
`"username"`	String	Attribute	The HTTP Basic Access Authentication username to use for the HTTP Interaction. This may be overridden for each request. (Default = No Default)
`"password"`	String	Attribute	The HTTP Basic Access Authentication password to use for the HTTP Interaction. This may be overridden for each request. (Default = No Default)
`config`	Object	Element	Container for extended configuration for this Application instance.
`.http_headers`	Array	Element	Array of REST `http_header` elements for additional HTTP headers to send with each REST operation.

REST Headers

Each http_header Object in the config.http_headers Array is configured as follows.

Parameter Name	Type	XML Type	Description
`name`	String	Attribute	[Required] The HTTP Header key.
`value`	String	Attribute	[Required] The HTTP Header Value.

Each configured HTTP header will be appended to all outbound REST requests.

Application-defined static HTTP headers will be added first. Per-request HTTP headers will be added subsequently.

Message Handling

In addition to the common Application management messages, the REST Client Application uses the following messages:

REST-C Messages (REST-C-REQUEST inbound).