rest server concept

Author: shikokuchuo

NAMESPACE

@@ -91,6 +91,7 @@ export(request)
 export(send)
 export(send_aio)
 export(serial_config)
+export(server)
 export(set_promise_context)
 export(socket)
 export(stat)

NEWS.md

@@ -4,6 +4,7 @@
 
 * Adds support for threaded dispatcher in `mirai`.
 * Adds 'recvAio' method for `promises::as.promise()` and `promises::is.promising()` to enable 'recvAio' promises.
+* Adds `server()`, an HTTP REST server for evaluation of R expressions (experimental).
 
 #### Updates
 

R/ncurl.R

@@ -271,3 +271,46 @@ as.promise.ncurlAio <- function(x) {
 #' @exportS3Method promises::is.promising
 #'
 is.promising.ncurlAio <- function(x) TRUE
+
+#' Start REST Server
+#'
+#' Creates an instance of an HTTP REST server which evaluates R expressions sent
+#'     to it [EXPERIMENTAL]. As arbitrary R expressions are evaluated, this
+#'     should only be deployed on the local machine (using the 127.0.0.1
+#'     loopback address) in a trusted environment.
+#'
+#' @param url full http address including hostname, port and path at which to
+#'     host the server.
+#'
+#' @details Query the API with an HTTP client using the \sQuote{POST} method,
+#'     with the request data being the R expression as a text string. The
+#'     received response body will consist of the serialized evaluation result.
+#'     Unserialize to return an R object.
+#'
+#'     Use only in a new session. Use \sQuote{ctrl + \\} to forcibly quit
+#'     when finished as the function blocks with no means of interruption.
+#'
+#'     Currently still experimental as the server lacks error handling. Sending
+#'     an invalid R expression will cause the server to exit.
+#'
+#' @return This function never returns.
+#'
+#' @examples
+#' if (interactive()) {
+#'
+#' # run in a new session:
+#' # nanonext::server()
+#'
+#' res <- ncurl("http://127.0.0.1:5555/api/rest",
+#'              convert = FALSE,
+#'              method = "POST",
+#'              data = "Sys.time()")
+#'
+#' if (!is_error_value(res$data)) unserialize(res$data)
+#'
+#' }
+#'
+#' @export
+#'
+server <- function(url = "http://127.0.0.1:5555/api/rest")
+  .Call(rnng_rest_server, url)

man/server.Rd

@@ -166,6 +166,7 @@ static const R_CallMethodDef callMethods[] = {
   {"rnng_recv", (DL_FUNC) &rnng_recv, 4},
   {"rnng_recv_aio", (DL_FUNC) &rnng_recv_aio, 6},
   {"rnng_request", (DL_FUNC) &rnng_request, 7},
+  {"rnng_rest_server", (DL_FUNC) &rnng_rest_server, 1},
   {"rnng_send", (DL_FUNC) &rnng_send, 4},
   {"rnng_send_aio", (DL_FUNC) &rnng_send_aio, 5},
   {"rnng_serial_config", (DL_FUNC) &rnng_serial_config, 4},

src/init.c

@@ -270,6 +270,7 @@ int nano_matchargs(const SEXP);
 
 void nano_REprintf(const char *);
 void pipe_cb_signal(nng_pipe, nng_pipe_ev, void *);
+void nano_printf(const int, const char *, ...);
 
 SEXP rnng_advance_rng_state(void);
 SEXP rnng_aio_call(SEXP);
@@ -322,6 +323,7 @@ SEXP rnng_reap(SEXP);
 SEXP rnng_recv(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_recv_aio(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_request(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
+SEXP rnng_rest_server(SEXP);
 SEXP rnng_send(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send_aio(SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_serial_config(SEXP, SEXP, SEXP, SEXP);