rpcfu.go

package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"os/exec"
	"runtime"
	"strconv"
	"time"
)

type Response struct {
	Output string `json:"output"`
}

var g_temp_path string
var g_progress_path string

func timeString() string {
	// return epoch in nanoseconds prefixed by "abl_", intended for temporary file names
	now := time.Now().UnixNano()
	x := strconv.FormatInt(now, 10)
	return "abl_" + x
}

func runHandler(w http.ResponseWriter, r *http.Request) {
	_ = "breakpoint"
	//extract db from URL, and body from request
	querystring_args := r.URL.Query()
	db, exists := querystring_args["db"]
	if exists == false {
		http.Error(w, "Missing 'db' variable from in URL", 406)
		return
	}
	db_name := db[0]
	body, _ := ioutil.ReadAll(r.Body)

	// store 4gl query in temporary file
	file_path := g_temp_path + timeString() + ".4gl"
	f, _ := os.Create(file_path)
	f.Write(body)
	f.Close()

	// setup ENV and shell out to progress
	ext := exec.Command(g_progress_path)
	ext.Args = []string{db_name, "-b", "-p", file_path}
	ext.Env = []string{"TERM=xterm"}
	output, err := ext.CombinedOutput()
	os.Remove(file_path) // remove temporary file
	if err != nil {
		http.Error(w, err.Error(), 500)
		return
	}

	// encode output to JSON
	var m Response
	m.Output = string(output)
	msg, err := json.Marshal(m)
	if err != nil {
		http.Error(w, err.Error(), 500)
	}

	// return JSON
	fmt.Fprintf(w, string(msg))
}

func main() {
	concurrency := flag.Int("cpus", 1, "Concurrency factor for multiple CPUs")
	temp_path := flag.String("temp_path", "/tmp/", "Path prefix for temporary query storage")
	progress_path := flag.String("progress_binary", "_progres", "Explicit path to _progres(eg /foo/bin/_progres)")
	flag.Parse()

	g_temp_path = *temp_path
	g_progress_path = *progress_path
	runtime.GOMAXPROCS(*concurrency)

	http.HandleFunc("/query/", queryHandler)
	http.HandleFunc("/run/", runHandler)
	http.ListenAndServe(":8080", nil)
}