Output Ports

An Output Port is a go structure used to describe a target payload to be generated, such as an HTTP Response or an outgoing Stream Message.

The port structure must be populated by you before being either:

• passed into the stream Message Publisher; or
• returned from your HTTP Endpoint Controller

go-msx will validate the contents of your structure and if it is valid, publish the message or response.

An example stream message output port:

type driftCheckResponseOutputs struct {
    EventType string                 `out:"header" const:"DriftCheck"`
    Payload   api.DriftCheckResponse `out:"body"`
}

An example HTTP response input port:

type createEntityOutputs struct {
    Payload api.CreateEntityResponse `resp:"body"`	
}

Struct Tags

Each field with an output struct tag will be applied to the outgoing payload.

Note that the struct tag prefix depends on the protocol being described:

• For HTTP Requests, the output struct tag must be resp (for backwards compatibility)
• For Stream Messages, the output struct tag must be out.

The full syntax of the input struct tag is one of the following, appropriate for the handling protocol:

output:"<fieldGroup>[=<peerName>]"
resp:"<fieldGroup>[=<peerName>]"

The output struct tag contains the following subcomponents:

• <fieldGroup> (Required): The name of the message/response part to which the value will be injected.

• [=<peerName>] (Optional): A peer is a field or property in the target payload. For example an HTTP response may have a header with the name date, which can be requested using the following output struct tag: resp:"header=Date"

See HTTP Response Ports and Stream Ports for available field groups and peer name conventions for your specific protocol.