title: Web Server Running Shell Script
tags: golang net web shell

My first attempt at writing anything in golang.

Obviously this is not for something visible to the world. This is just for
quick and dirty stuff on a LAN. This takes the path of a request and sends
it as the sole argument to a script called `bobbins` in the current directory
where the program is run. Usefully one can edit this script without restarting
the server. It returns the stdout and stderr.

```golang
package main

import (
  "fmt"
  "log"
  "net/http"
  "strings"
  "encoding/json"
  "os/exec"
  "bytes"
)

func myfunc(w http.ResponseWriter, r *http.Request) {
  a := strings.Trim(r.URL.Path,"/")
  log.Printf("bobbins called with path %s", a)
  w.Header().Set("Content-Type", "application/json; charset=utf-8")
  
  data := map[string]interface{} {}
  data["bobbins"] = a

  command := "./bobbins"
  args := []string{a}
  var stdout bytes.Buffer
  var stderr bytes.Buffer
  cmd := exec.Command(command, args...)
  cmd.Stdout = &stdout
  cmd.Stderr = &stderr
  err := cmd.Run()
  data["output"] = string(stdout.Bytes())
  data["stderr"] = string(stderr.Bytes())
  data["err"] = err

  j, _ := json.Marshal(data)
  w.Write(j)
}

func main() {
  router := http.NewServeMux()
  router.HandleFunc("/", myfunc)

  server := http.Server{
    Addr: ":8901",
    Handler: router,
  }

  fmt.Println("Server listening on port :8901")
  server.ListenAndServe()
}
```