Creates a server that can handle HTTP requests and WebSocket connections.
Usage
http_server(url, handlers = list(), tls = NULL)Arguments
- url
URL to listen on (e.g., "http://127.0.0.1:8080").
- handlers
A handler or list of handlers created with
handler(),handler_ws(), etc.- tls
TLS configuration for HTTPS/WSS, created via
tls_config().
Value
A nanoServer object with methods:
$start()- Start accepting connections$close()- Stop and release all resources$url- The server URL
Details
This function leverages NNG's shared HTTP server architecture. When both HTTP handlers and WebSocket handlers are provided, they share the same underlying server and port. WebSocket handlers automatically handle the HTTP upgrade handshake and all WebSocket framing (RFC 6455).
WebSocket callbacks are executed on R's main thread via the 'later' package.
To process callbacks, you must run the event loop (e.g., using
later::run_now() in a loop).
Examples
if (FALSE) { # interactive() && requireNamespace("later", quietly = TRUE)
# Simple HTTP server
server <- http_server(
url = "http://127.0.0.1:8080",
handlers = list(
handler("/", function(req) {
list(status = 200L, body = "Hello, World!")
}),
handler("/api/data", function(req) {
list(
status = 200L,
headers = c("Content-Type" = "application/json"),
body = '{"value": 42}'
)
})
)
)
server$start()
# Run event loop: repeat later::run_now(Inf)
server$close()
# HTTP + WebSocket server
server <- http_server(
url = "http://127.0.0.1:8080",
handlers = list(
handler("/", function(req) {
list(status = 200L, body = "<html>...</html>")
}),
handler_ws("/ws", function(ws, data) {
ws$send(data) # Echo
}, textframes = TRUE)
)
)
# Multiple WebSocket endpoints
server <- http_server(
url = "http://127.0.0.1:8080",
handlers = list(
handler_ws("/echo", function(ws, data) ws$send(data)),
handler_ws("/upper", function(ws, data) ws$send(toupper(data)), textframes = TRUE)
)
)
# HTTPS server with self-signed certificate
cert <- write_cert(cn = "127.0.0.1")
cfg <- tls_config(server = cert$server)
server <- http_server(
url = "https://127.0.0.1:8443",
handlers = list(
handler("/", function(req) list(status = 200L, body = "Secure!"))
),
tls = cfg
)
server$start()
# Send async request and run event loop
aio <- ncurl_aio(
"https://127.0.0.1:8443/",
tls = tls_config(client = cert$client),
timeout = 2000
)
while (unresolved(aio)) later::run_now(0.1)
aio$status
aio$data
server$close()
}