replit-identity/index.js

A simple package to interact with the Replit CLI's identity command.

const { exec } = require('child_process');
const util = require('node:util');

const execAsync = util.promisify(exec); 

const { REPLIT_CLI, REPLIT_DEPLOYMENT, REPL_IDENTITY } = process.env;
if (!REPLIT_CLI || !REPL_IDENTITY) {
  const deployment = REPLIT_DEPLOYMENT === '1';
  if (deployment) {
    throw 'Replit Identity is not yet available in deployments.';
  } else {
    throw 'Replit Identity is not available in this environment.';
  }
}

/** 
 * @typedef {Object} Runtime
 * @property {Object} [interactive]
 * This is set if the Repl is running interactively and not when the Repl is running in hosting.
 * @property {string} interactive.cluster - The cluster in which this Repl is running.
 * @property {string} interactive.subcluster - The subcluster in which this Repl is running.
 * @property {Object} [hosting]
 * This is set if the Repl is running in a hosting subcluster.
 * @property {string} hosting.cluster - The cluster in which this Repl is running.
 * @property {string} hosting.subcluster - The subcluster in which this Repl is running.
 * @property {boolean} [deployment]
 * This is set if the Repl is running in a Deployment.
 */

/**
 * @typedef {Object} Info
 * @property {string} username - The name of the user who created the token.
 * @property {string} slug - The slug of the repl where the token was created.
 * @property {number} userId - The id of the user who created the token.
 * @property {string} replId - The id of the repl where the token was created.
 * @property {string} [originReplId] - The id of the original repl despite the running environment being a fork.
 * @property {string} audience - The audience for which the token was created.
 * @property {Runtime|null} runtime - Runtime information about the Repl.
 */

/**
 * Executes Replit CLI's identity command with specified command and arguments.
 * @function
 * @param {'create'|'verify'} cmd - The command to execute.
 * @param {Object} [flags] - An object containing the options for the command.
 * @param {string} flags.audience - The audience for which the token will be/was created.
 * @param {string} flags.token - The token to verify. (Used with verify command)
 * @param {string} flags.json - Returns object.
 * @returns {Promise<object|string|null>} - Resolves with the result, or rejects on error.
 */
async function identity(cmd = '', flags = {}) {
  try {
    let args = '';
    const keys = Object.keys(flags);
    for (let i = 0; i < keys.length; i++) {
      const flag = keys[i];
      const value = flags[flag];
      if (!value) throw `${flag} is required.`;
      if (typeof value !== 'string') throw `${flag} must be a string.`;
      args += ` -${flag}="${value.replaceAll('"', '\\"')}"`
    }

    const command = `${REPLIT_CLI} identity ${cmd}` + args;
    const result = await execAsync(command);
    const output = result.stdout.trim();

    return flags.json ? JSON.parse(output) : output;
  } catch (err) {
    if (typeof err === 'string') {
      throw `[Replit Identity] ${cmd}() -> ${err}`;
    } else {
      return null; // error is identity mismatch or invalid token
    }
  }
}

/**
 * Creates a new identity token.
 * @function
 * @param {string} audience - The audience for which the token will be created.
 * @returns {Promise<string|null>} - Resolves with the token, or rejects on error.
 */
async function create(audience) {
  return identity('create', { audience });
}

/**
 * Verifies an existing identity token against an audience.
 * @function
 * @param {string} token - The identity token to verify.
 * @param {string} audience - The audience for which the token was created.
 * @returns {Promise<Info|null>} - Resolves with the Info object, or rejects on error.
 */
async function verify(token, audience) {
  const info = await identity('verify', {
    token, audience, json: 'true'
  });
  return info ? camelize(info) : null;
}

module.exports = { create, verify };

function camelize(obj) {
  rename(obj, {
    replId: 'replid',
    originReplId: 'originReplid',
    username: 'user',
    userId: 'user_id',
    audience: 'aud',
    runtime: 'Runtime'
  });
  rename(obj.runtime, {
    interactive: 'Interactive',
    hosting: 'Hosting',
    deployment: 'Deployment',
  });
  return obj;
}

// supposedly the fastest way to do this
function rename(object, keys) {
  for (const [newKey, oldKey] of Object.entries(keys)) {
    if (oldKey in object)
      delete Object.assign(object, { [newKey]: object[oldKey] })[oldKey];
  }
}