support multiple languages

python initially, because @KLINGTdotNET.

go/linguaevalia/linguaevalia.go

)
type Language interface {
	Eval(code string) (result []byte, err error)
	RunFile(f *os.File) (result []byte, err error)
	Extension() string
}
type LanguageGo struct{}
type LanguagePython struct{}
var Go = LanguageGo{}
var Python = LanguagePython{}
func (g LanguageGo) Eval(code string) ([]byte, error) {
	// write code to temp file
	f, err := writeCode(code)
	defer f.Close()
	if err != nil {
		return nil, err
	}
	// `go run` it
	res, err := runCode(f)
	if err != nil {
		return res, err
	}
	// remove the file
	os.Remove(f.Name())
	// return output
	return res, nil
var languageMappings = map[string]Language{
	"go":     Go,
	"python": Python,
}
func writeCode(code string) (*os.File, error) {
func writeCode(code string, extension string) (*os.File, error) {
	// create tmp file
	f, err := os.Create("/tmp/linguaevalia-go.go") // FIXME: actually create a tmpfile
	f, err := os.Create(fmt.Sprintf("/tmp/linguaevalia-%s.%s", extension, extension)) // FIXME: actually create a tmpfile
	if err != nil {
		return f, err
	}
	return f, nil
}
func runCode(f *os.File) ([]byte, error) {
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
	}
	//fmt.Println(string(code))
	res, err := Go.Eval(string(code))
	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)
}