Validates a graphql query from stdin against a schema from http or file

gql-validate.js

#!/usr/bin/env node
/* Author: Pedro H L Campos <https://keybase.io/pedrohlc>
   License: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
*/
const { Source, buildSchema, buildClientSchema, getIntrospectionQuery, printSchema, validate, parse } = require('graphql');
const fs = require('fs');

async function main(stdin, argv) {
  // Remove interpreter and script
  argv.shift();
  argv.shift();
  if (argv.length != 1) {
    console.error('Expeting a single argument with an URL or path to the schema, e.g.: ./gql-validate "http://localhost:5000/api"');
    return 2;
  }

  if (stdin.isTTY) {
    console.error('TTY in STDIN. Pipe a GQL Query instead!');
    return 3;
  }

  // Doing it the hard way, for that timeout hack
  const inputChunks = [];
  stdin.setTimeout(100);
  stdin.resume();
  stdin.setEncoding('utf8');
  stdin.on('data', (chunk) => inputChunks.push(chunk));
  const inputDataPromise = new Promise((resolve, reject) => {
    stdin.on('end', () => resolve(inputChunks.join()));
    stdin.on('error', () => resolve(''));
    stdin.on('timeout', () => resolve(inputChunks.join())); // It's really hard to close stdin in Elixir's Port, let it timeout instead!
  }).catch((_reason) => "");
  const stdinData = await inputDataPromise;

  if (stdinData.length < 1) {
    console.error('Incomplete file in STDIN');
    return 4;
  }

  // Two interesting ways to have the schema: URL or File
  const schema =
    argv[0].includes(":") ?
      await fetch(argv[0], {
        method: 'POST',
        headers: { 'content-type': 'application/json' },
        body: JSON.stringify({ query: getIntrospectionQuery() }),
      })
        .then((response) => response.json())
        .then(({ data }) => buildClientSchema(data))
        .catch((reason) => {
          console.warn(reason);
          return null;
        })
      : buildSchema(fs.readFileSync(argv[0], 'utf-8'));

  if (!schema) {
    console.error('Couldn\'t fetch or find schema');
    return 4;
  }
  //console.debug(printSchema(schema));

  const errors = validate(schema, parse(new Source(stdinData, 'Query.graphql', { line: 1, column: 1 })));
  console.log(errors);
  return errors.length > 0 ? 1 : 0;
}

main(process.stdin, process.argv).then(process.exit);