piston/api/main.go

195 lines
3.8 KiB
Go

package main
import (
"bytes"
"encoding/json"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"os/exec"
"regexp"
"strings"
"time"
)
type inbound struct {
Language string `json:"language"`
Source string `json:"source"`
Args []string `json:"args"`
}
type problem struct {
Code string `json:"code"`
Message string `json:"message"`
}
type outbound struct {
Ran bool `json:"ran"`
Output string `json:"output"`
}
type Language struct {
Name string `json:"name,omitempty"`
Version string `json:"version,omitempty"`
}
type Languages struct {
Languages []Language `json:"languages"`
}
var instance int
var versionRegex = regexp.MustCompile("([0-9]+\\.[0-9]+\\.[0-9]+)")
func main() {
port := "2000"
updateVersions()
fmt.Println("starting api on port", port)
http.HandleFunc("/execute", Execute)
http.ListenAndServe(":"+port, nil)
}
func Execute(res http.ResponseWriter, req *http.Request) {
res.Header().Set("Content-Type", "application/json")
// get json
inbound := inbound{}
message := json.NewDecoder(req.Body)
message.Decode(&inbound)
whitelist := []string{
"c",
"cpp", "c++",
"c#", "csharp", "cs",
"go",
"java",
"nasm", "asm",
"javascript", "js", "node",
"typescript", "ts",
"php",
"python", "python2", "python3",
"ruby",
"swift",
"rust",
"bash",
}
// check if the supplied language is supported
// now calls function and returns
for _, lang := range whitelist {
if lang == inbound.Language {
launch(inbound, res)
return
}
}
// now only called when the language is not supported
problem := problem{
Code: "unsupported_language",
Message: inbound.Language + " is not supported by Piston",
}
pres, _ := json.Marshal(problem)
res.Write(pres)
}
func launch(request inbound, res http.ResponseWriter) {
stamp := time.Now().UnixNano()
// write the code to temp dir
srcfile := fmt.Sprintf("/tmp/%d.code", stamp)
ioutil.WriteFile(srcfile, []byte(request.Source), 0644)
// set up the arguments to send to the execute command
var args []string
args = append(args, request.Language)
args = append(args, srcfile)
args = append(args, strings.Join(request.Args, "\n"))
// set up the execution
cmd := exec.Command("../lxc/execute", args...)
// capture out/err
var stdout, stderr bytes.Buffer
cmd.Stdout = &stdout
cmd.Stderr = &stderr
err := cmd.Run()
// prepare response
outbound := outbound{
Ran: err == nil,
Output: strings.TrimSpace(stdout.String()),
}
response, _ := json.Marshal(outbound)
res.Write(response)
}
func updateVersions() {
f, err := os.Create("versions.json")
if err != nil {
log.Println(err)
return
}
defer f.Close()
langs, err := getVersions()
if err != nil {
log.Println(err)
return
}
res, err := json.Marshal(langs)
if err != nil {
log.Println(err)
return
}
f.Write(res)
}
// get all the language and their current version
func getVersions() ([]Language, error) {
var languages []Language
res, err := execVersionScript()
if err != nil {
return nil, err
}
languageInfo := strings.Split(res, "---")
for _, v := range languageInfo {
if len(v) < 2 {
continue
}
name, version := getVersion(v)
languages = append(languages, Language{
Name: name,
Version: version,
})
}
return languages, nil
}
// run the script that retrieves all the language versions
func execVersionScript() (string, error) {
fmt.Println("running script")
output := bytes.Buffer{}
cmd := exec.Command("../lcx/versions")
cmd.Stdout = &output
err := cmd.Run()
return strings.ToLower(output.String()), err
}
// return the language and its version
// most of the time it is easy to get the name and version
// but for some languages helper functions are used
func getVersion(s string) (string, string) {
lines := strings.Split(s, "\n")
return lines[1], versionRegex.FindString(lines[2])
}