register_serializer: Register or fetch a serializer

In plumber2: Easy and Powerful Web Servers

Register or fetch a serializer

Description

plumber2 comes with many serializers that should cover almost all standard use cases. Still you might want to provide some of your own, which this function facilitates.

Usage

register_serializer(name, fun, mime_type, default = TRUE)

show_registered_serializers()

get_serializers(serializers = NULL)

Arguments

name	The name to register the serializer function to. If already present the current serializer will be overwritten by the one provided by you
fun	A function that, when called, returns a unary function that can serialize a response body to the mime type defined in mime_type
mime_type	The format this serializer creates. You should take care to ensure that the value provided is a standard mime type for the format
default	Should this serializer be part of the default set of serializers
serializers	Serializers to collect. This can either be a character vector of names of registered serializers or a list. If it is a list then the following expectations apply: Any unnamed elements containing a character vector will be considered as names of registered serializers constructed with default values. The special value "..." will fetch all the serializers that are otherwise not specified in the call. Any element containing a function are considered as a provided serializer and the element must be named by the mime type the serializer understands Any remaining named elements will be considered names of registered serializers that should be constructed with the arguments given in the element

Details

If you want to register your own serializer, then the function you register must be a factory function, i.e. a function returning a function. The returned function must accept a single argument which is the response body. All arguments to the factory function should be optional.

Value

For get_serializers a named list of serializer functions named by their mime type. The order given in serializers is preserved.

Note

Using the ... will provide remaining graphics serializers if a graphics serializer is explicitely requested elsewhere. Otherwise it will provide the remaining non-graphics serializers. A warning is thrown if a mix of graphics and non-graphics serializers are requested.

See Also

serializers

register_serializer()

Examples

# Add a serializer that deparses the value
register_serializer("deparse", function(...) {
  function(x) {
    deparse(x, ...)
  }
}, mime_type = "text/plain")

plumber2 documentation built on Jan. 20, 2026, 5:06 p.m.