handler: Create HTTP Handler

In nanonext: Lightweight Toolkit for Messaging, Concurrency and the Web

Create HTTP Handler

Description

Creates an HTTP route handler for use with http_server().

Usage

handler(path, callback, method = "GET", prefix = FALSE)

Arguments

path	URI path to match (e.g., "/api/data", "/users").
callback	Function to handle requests. Receives a list with: method - HTTP method (character) uri - Request URI (character) headers - Named character vector of headers body - Request body (raw vector) Should return a list with: status - HTTP status code (integer, default 200) headers - Response headers as a named character vector, e.g. c("Content-Type" = "application/json") (optional) body - Response body (character or raw)
method	[default "GET"] HTTP method to match (e.g., "GET", "POST", "PUT", "DELETE"). Use "*" to match any method.
prefix	[default FALSE] Logical, if TRUE matches path as a prefix (e.g., "/api" will match "/api/users", "/api/items", etc.).

Details

If the callback throws an error, a 500 Internal Server Error response is returned to the client.

Value

A handler object for use with http_server().

See Also

handler_ws() for WebSocket handlers. Static handlers: handler_file(), handler_directory(), handler_inline(), handler_redirect().

Examples

# Simple GET handler
h1 <- handler("/hello", function(req) {
  list(status = 200L, body = "Hello!")
})

# POST handler that echoes the request body
h2 <- handler("/echo", function(req) {
  list(status = 200L, body = req$body)
}, method = "POST")

# Catch-all handler for a path prefix
h3 <- handler("/static", function(req) {
  # Serve static files under /static/*
}, method = "*", prefix = TRUE)

nanonext documentation built on March 8, 2026, 9:06 a.m.