Suggestions needed for building R server REST API's that I can call from external app?

问题

I've seen lots of articles about consuming data in R from other RESTful API services, but I have really struggled to find any articles about the reverse. I'm interested in R being the server, and not the client. I'd like a Node.js app to call a RESTful API of an R-server so I can leverage specific analytical functions such as multi-seasonality forecasting. Anyone have any ideas?

回答1:

You can use httpuv to fire up a basic server then handle the GET/POST requests. The following isn't "REST" per se, but it should provide the basic framework:

library(httpuv)
library(RCurl)
library(httr)

app <- list(call=function(req) {

  query <- req$QUERY_STRING
  qs <- httr:::parse_query(gsub("^\\?", "", query))

  status <- 200L
  headers <- list('Content-Type' = 'text/html')

  if (!is.character(query) || identical(query, "")) {
    body <- "\r\n<html><body></body></html>"
  } else {
    body <- sprintf("\r\n<html><body>a=%s</body></html>", qs$a)
  }

  ret <- list(status=status,
              headers=headers,
              body=body)

  return(ret)

})

message("Starting server...")

server <- startServer("127.0.0.1", 8000, app=app)
on.exit(stopServer(server))

while(TRUE) {
  service()
  Sys.sleep(0.001)
}

stopServer(server)

I have the httr and RCurl packages in there since you'll probably end up needing to use some bits of both to parse/format/etc requests & responses.

回答2:

node-rio provides a way to talk to rserve (a TCP/IP server that allows the use of R functions) from node.js.

Here is an example of use (from the documentation):

var rio = require('rio');
rio.evaluate("as.character('Hello World')");

来源：https://stackoverflow.com/questions/22179512/suggestions-needed-for-building-r-server-rest-apis-that-i-can-call-from-externa

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