package main
// lingua evalia
//
// try it with `curl -i localhost:8000/run --data-binary @hello-world.go`
import (
"fmt"
"html/template"
"io/ioutil"
"log"
"net/http"
"os"
"os/exec"
)
type Language interface {
RunFile(f *os.File) (result []byte, err error)
Extension() string
}
type LanguageGo struct{}
type LanguagePython struct{}
var Go = LanguageGo{}
var Python = LanguagePython{}
var languageMappings = map[string]Language{
"go": Go,
"python": Python,
}
func writeCode(code string, extension string) (*os.File, error) {
// create tmp file
f, err := os.Create(fmt.Sprintf("/tmp/linguaevalia-%s.%s", extension, extension)) // FIXME: actually create a tmpfile
if err != nil {
return f, err
}
// write code to it
_, err = f.Write([]byte(code))
if err != nil {
return f, err
}
return f, nil
}
func (l LanguageGo) RunFile(f *os.File) ([]byte, error) {
cmd := exec.Command("go", "run", f.Name())
return cmd.CombinedOutput()
}
func (l LanguageGo) Extension() string { return "go" }
func (l LanguagePython) RunFile(f *os.File) ([]byte, error) {
cmd := exec.Command("python", f.Name())
return cmd.CombinedOutput()
}
func (l LanguagePython) Extension() string { return "py" }
func Eval(lang Language, code string) ([]byte, error) {
// write code to temp file
f, err := writeCode(code, lang.Extension())
defer f.Close()
if err != nil {
return nil, err
}
// `go run` it
res, err := lang.RunFile(f)
if err != nil {
return res, err
}
// remove the file
os.Remove(f.Name())
// return output
return res, nil
}
func runCodeHandler(w http.ResponseWriter, r *http.Request) {
code, err := ioutil.ReadAll(r.Body)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
lang := getLanguage(r)
res, err := Eval(lang, string(code))
if err != nil {
http.Error(w, string(res), http.StatusNotAcceptable)
return
}
w.Write(res)
}
func getLanguage(r *http.Request) Language {
langName := r.URL.Query().Get("language")
if langName != "" {
lang, ok := languageMappings[langName]
if ok {
return lang
}
}
return Go
}
func homePageHandler(w http.ResponseWriter, r *http.Request) {
homePageTemplate.Execute(w, nil)
}
var homePageTemplate = template.Must(template.New("homepage").Parse(homePageTemplateStr))
func main() {
addr, port := "localhost", 8000
fmt.Printf("running on %s:%d\n", addr, port)
http.HandleFunc("/run", runCodeHandler)
http.HandleFunc("/", homePageHandler)
err := http.ListenAndServe(fmt.Sprintf("%s:%d", addr, port), nil)
if err != nil {
log.Fatal(err)
}
}
const homePageTemplateStr = `
lingua evalia
`