Example #1
0
File: core.go Project: Gwill/go-R
func VariableExists(name string) bool {
	nameC := C.CString(name)
	defer C.free(unsafe.Pointer(nameC))
	return C.findVar(C.install(nameC), C.R_GlobalEnv) == C.R_UnboundValue
}
Example #2
0
File: rmq.go Project: go-binder/rmq
//export ListenAndServe
func ListenAndServe(addr_ C.SEXP, handler_ C.SEXP, rho_ C.SEXP) C.SEXP {

	if C.TYPEOF(addr_) != C.STRSXP {
		fmt.Printf("addr is not a string (STRXSP; instead it is: %d)! addr argument to ListenAndServe() must be a string of form 'ip:port'\n", C.TYPEOF(addr_))
		return C.R_NilValue
	}

	//msglen := 0
	if 0 == int(C.isFunction(handler_)) { // 0 is false
		C.ReportErrorToR_NoReturn(C.CString("‘handler’ must be a function"))
		return C.R_NilValue
	}

	if rho_ != nil && rho_ != C.R_NilValue {
		if 0 == int(C.isEnvironment(rho_)) { // 0 is false
			C.ReportErrorToR_NoReturn(C.CString("‘rho’ should be an environment"))
			return C.R_NilValue
		}
	}

	caddr := C.R_CHAR(C.STRING_ELT(addr_, 0))
	addr := C.GoString(caddr)
	fmt.Printf("ListenAndServe listening on address '%s'...\n", addr)

	webSockHandler := func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/" {
			http.Error(w, "Not found", 404)
			return
		}
		if r.Method != "GET" {
			http.Error(w, "Method not allowed, only GET allowed.", 405)
			return
		}
		c, err := upgrader.Upgrade(w, r, nil)
		if err != nil {
			fmt.Print("websocket handler upgrade error:", err)
			return
		}
		defer c.Close()

		mt, message, err := c.ReadMessage()
		if err != nil {
			fmt.Println("read error: ", err)
			return
		}

		// make the call, and get a response
		msglen := len(message)
		rawmsg := C.allocVector(C.RAWSXP, C.R_xlen_t(msglen))
		C.Rf_protect(rawmsg)
		C.memcpy(unsafe.Pointer(C.RAW(rawmsg)), unsafe.Pointer(&message[0]), C.size_t(msglen))

		// put msg into env that handler_ is called with.
		C.defineVar(C.install(C.CString("msg")), rawmsg, rho_)

		R_serialize_fun = C.findVar(C.install(C.CString("serialize")), C.R_GlobalEnv)

		// todo: callbacks to R functions here not working. don't really need them if R always acts as a client instead.

		// evaluate
		C.PrintToR(C.CString("listenAndServe: stuffed msg into env rho_.\n"))
		//R_fcall := C.lang3(handler_, rawmsg, C.R_NilValue)
		R_fcall := C.lang3(R_serialize_fun, rawmsg, C.R_NilValue)
		C.Rf_protect(R_fcall)
		C.PrintToR(C.CString("listenAndServe: got msg, just prior to eval.\n"))
		evalres := C.eval(R_fcall, rho_)
		C.Rf_protect(evalres)

		C.PrintToR(C.CString("listenAndServe: after eval.\n"))
		/*
			var s, t C.SEXP
			s = C.allocList(3)
			t = s
			C.Rf_protect(t)
			C.SetTypeToLANGSXP(&s)
			//C.SETCAR(t, R_fcall)
			C.SETCAR(t, handler_)
			t = C.CDR(t)
			C.SETCAR(t, rawmsg)

			evalres := C.eval(s, rho_)
			C.Rf_protect(evalres)
		*/
		C.PrintToR(C.CString("nnListenAndServe: done with eval.\n"))

		if C.TYPEOF(evalres) != C.RAWSXP {
			fmt.Printf("rats! handler result was not RAWSXP raw bytes!\n")
		} else {

			//fmt.Printf("recv: %s\n", message)
			err = c.WriteMessage(mt, message)
			if err != nil {
				fmt.Println("write error: ", err)
			}
		}
		C.Rf_unprotect(3)

	} // end handler func

	http.HandleFunc("/", webSockHandler)
	err := http.ListenAndServe(addr, nil)
	if err != nil {
		fmt.Println("ListenAndServe: ", err)
	}

	return C.R_NilValue
}