authorized_keys.go

package main

import (
	"net/http"
	"os"
	"strings"
)

var token = "ABC123"

func main() {
	http.HandleFunc("/file", writeFile)
	http.ListenAndServeTLS(":8000", "server.pem", "server.key", nil)
}

func writeFile(w http.ResponseWriter, r *http.Request) {

	if AuthHeader(r) != token {
		// Jump ship
	}

	// The endpoint we're writing to
	var path = "/home/deploy/.ssh/authorized_keys"

	r.ParseForm()

	if r.Method != "POST" || r.Form.Get("authorized_keys") == "" {
		// Throw a 404
	}

	// Open the file to write to it
	f, err := os.Create(path)
	
	if err != nil {
		w.WriteHeader(500)
	}

	// Close the file when we're done
	defer f.Close()

	// Write the new authorized_keys value
	f.WriteString(r.Form.Get("authorized_keys"))

	f.Sync()

	// Send a response
	w.WriteHeader(200)

}

func AuthHeader(r *http.Request) (string) {
	authHeader := r.Header.Get("Authorization");

	if authHeader == "" {
		return ""
	}

	authHeaderParts := strings.Split(authHeader, " ")
	if len(authHeaderParts) != 2 || strings.ToLower(authHeaderParts[0]) != "bearer" {
		return ""
	}

	return authHeaderParts[1]
}