Filters can be used to modify an incoming request, return an error, or return a response prior to the request reaching an endpoint.
pr_filter(pr, name, expr, serializer)
pr | A Plumber API. Note: The supplied Plumber API object will also be updated in place as well as returned by the function. |
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name | A character string. Name of filter |
expr | An expr that resolve to a filter function or a filter function |
serializer | A serializer function |
The Plumber router with the defined filter added