Deno repl server

repl-server.ts

import { serve } from "https://deno.land/std@0.50.0/http/server.ts";
const s = serve({ port: 8000 });
console.log('Server online at http://localhost:8000');
for await (const req of s) {
  switch(req.url) {
    case '/run': {
      const {headers, method} = req;
      const contentType = headers.get('Content-Type');
      if (method === 'POST' && contentType == 'application/javascript') {
        const textDecoder = new TextDecoder();
        const bodyEncoded = await Deno.readAll(req.body);
        const body = textDecoder.decode(bodyEncoded);
        const executor = Deno.run({
          cmd: ['deno', 'eval', body],
          stdout: 'piped',
          stderr: 'piped',
        });
        const {code} = await executor.status();
        let output;
        let outputString;
        if (code === 0) {
          output = await executor.output();
        } else {
          output = await executor.stderrOutput();
        }
        outputString = textDecoder.decode(output);
        const headers = new Headers();
        headers.set('Content-Type', 'text/plain');
        req.respond({status: 200, headers, body: outputString});
        break;
      } else {
        req.respond({status: 500, body: 'Not available'});
        break;
      }
    }
    case '/':
    default:
      // TODO: editor
      req.respond({body: 'Editor'});
      break;
  }
}

$ deno run --allow-net --allow-run repl-server.ts
# feed it with deno source code
$ curl --location --request POST 'localhost:8000/run' \
> --header 'Content-Type: application/javascript' \
> --data-raw 'console.log('\''Hi deno!'\'');'
# and get the output:
Hi deno!