Register a Serializer — register_serializer • plumber

A serializer is responsible for translating a generated R value into output that a remote user can understand. For instance, the serializer_json serializes R objects into JSON before returning them to the user. The list of available serializers in plumber is global.

Usage

register_serializer(name, serializer, verbose = TRUE)

registered_serializers()

Arguments

name: The name of the serializer (character string)
serializer: The serializer function to be added. This function should accept arguments that can be supplied when plumb()ing a file. This function should return a function that accepts four arguments: value, req, res, and errorHandler. See print(serializer_json) for an example.
verbose: Logical value which determines if a message should be printed when overwriting serializers

Details

There are three main building-block serializers:

serializer_headers: the base building-block serializer that is required to have as_attachment() work
serializer_content_type(): for setting the content type. (Calls serializer_headers())
serializer_device(): add endpoint hooks to turn a graphics device on and off in addition to setting the content type. (Uses serializer_content_type())

Functions

register_serializer(): Register a serializer with a name
registered_serializers(): Return a list of all registered serializers

Examples

# `serializer_json()` calls `serializer_content_type()` and supplies a serialization function
print(serializer_json)
#> function (..., type = "application/json") 
#> {
#>     serializer_content_type(type, function(val) {
#>         toJSON(val, ...)
#>     })
#> }
#> <bytecode: 0x55e9366d6fa8>
#> <environment: namespace:plumber>
# serializer_content_type() calls `serializer_headers()` and supplies a serialization function
print(serializer_content_type)
#> function (type, serialize_fn = identity) 
#> {
#>     if (missing(type)) {
#>         stop("You must provide the custom content type to the serializer_content_type")
#>     }
#>     stopifnot(length(type) == 1)
#>     stopifnot(is.character(type))
#>     stopifnot(nchar(type) > 0)
#>     serializer_headers(list(`Content-Type` = type), serialize_fn)
#> }
#> <bytecode: 0x55e9366ce390>
#> <environment: namespace:plumber>