/**
 * Context prototype.
 */
const proto = module.exports = {
  // ...
}

const delegate = require('delegates');
/**
 * Response delegation.
 */
delegate(proto, 'response')
  .method('attachment')
  .method('redirect')
  .method('remove')
  .method('vary')
  .method('set')
  .method('append')
  .method('flushHeaders')
  .access('status')
  .access('message')
  .access('body')
  .access('length')
  .access('type')
  .access('lastModified')
  .access('etag')
  .getter('headerSent')
  .getter('writable');
/**
 * Request delegation.
 */
delegate(proto, 'request')
  .method('acceptsLanguages')
  .method('acceptsEncodings')
  .method('acceptsCharsets')
  .method('accepts')
  .method('get')
  .method('is')
  .access('querystring')
  .access('idempotent')
  .access('socket')
  .access('search')
  .access('method')
  .access('query')
  .access('path')
  .access('url')
  .access('accept')
  .getter('origin')
  .getter('href')
  .getter('subdomains')
  .getter('protocol')
  .getter('host')
  .getter('hostname')
  .getter('URL')
  .getter('header')
  .getter('headers')
  .getter('secure')
  .getter('stale')
  .getter('fresh')
  .getter('ips')
  .getter('ip');

const createError = require('http-errors');
const httpAssert = require('http-assert');
//...
const proto = module.exports = {
  //...
  /**
   * Similar to .throw(), adds assertion.
   *
   *    this.assert(this.user, 401, 'Please login!');
   *
   * See: https://github.com/jshttp/http-assert
   *
   * @param {Mixed} test
   * @param {Number} status
   * @param {String} message
   * @api public
   */
  assert: httpAssert,
  /**
   * Throw an error with `msg` and optional `status`
   * defaulting to 500. Note that these are user-level
   * errors, and the message may be exposed to the client.
   *
   *    this.throw(403)
   *    this.throw('name required', 400)
   *    this.throw(400, 'name required')
   *    this.throw('something exploded')
   *    this.throw(new Error('invalid'), 400);
   *    this.throw(400, new Error('invalid'));
   *
   * See: https://github.com/jshttp/http-errors
   *
   * @param {String|Number|Error} err, msg or status
   * @param {String|Number|Error} [err, msg or status]
   * @param {Object} [props]
   * @api public
   */
  throw(...args) {
    throw createError(...args);
  },
  //...
}

handleRequest(ctx, fnMiddleware) {
  const res = ctx.res;
  res.statusCode = 404;
  const onerror = err => ctx.onerror(err);
  const handleResponse = () => respond(ctx);
  onFinished(res, onerror);
  return fnMiddleware(ctx).then(handleResponse).catch(onerror);
}

const statuses = require('statuses');
//...
const proto = module.exports = {
  //...
  /**
   * Default error handling.
   *
   * @param {Error} err
   * @api private
   */
  onerror(err) {
    // don't do anything if there is no error.
    // this allows you to pass `this.onerror`
    // to node-style callbacks.
    if (null == err) return;
    if (!(err instanceof Error)) err = new Error(util.format('non-error thrown: %j', err));
    let headerSent = false;
    if (this.headerSent || !this.writable) {
      headerSent = err.headerSent = true;
    }
    // delegate
    this.app.emit('error', err, this);
    // nothing we can do here other
    // than delegate to the app-level
    // handler and log.
    if (headerSent) {
      return;
    }
    const { res } = this;
    // first unset all headers
    /* istanbul ignore else */
    if (typeof res.getHeaderNames === 'function') {
      res.getHeaderNames().forEach(name => res.removeHeader(name));
    } else {
      res._headers = {}; // Node < 7.7
    }
    // then set those specified
    this.set(err.headers);
    // force text/plain
    this.type = 'text';
    // ENOENT support
    if ('ENOENT' == err.code) err.status = 404;
    // default to 500
    if ('number' != typeof err.status || !statuses[err.status]) err.status = 500;
    // respond
    const code = statuses[err.status];
    const msg = err.expose ? err.message : code;
    this.status = err.status;
    this.length = Buffer.byteLength(msg);
    this.res.end(msg);
  },
  //...
}

const Cookies = require('cookies');
const COOKIES = Symbol('context#cookies');
//...
const proto = module.exports = {
  //...
  get cookies() {
    if (!this[COOKIES]) {
      this[COOKIES] = new Cookies(this.req, this.res, {
        keys: this.app.keys,
        secure: this.request.secure
      });
    }
    return this[COOKIES];
  },
  set cookies(_cookies) {
    this[COOKIES] = _cookies;
  }
};

const util = require('util');
//...
const proto = module.exports = {
  //...
  /**
   * util.inspect() implementation, which
   * just returns the JSON output.
   *
   * @return {Object}
   * @api public
   */
  inspect() {
    if (this === proto) return this;
    return this.toJSON();
  },
  /**
   * Return JSON representation.
   *
   * Here we explicitly invoke .toJSON() on each
   * object, as iteration will otherwise fail due
   * to the getters and cause utilities such as
   * clone() to fail.
   *
   * @return {Object}
   * @api public
   */
  toJSON() {
    return {
      request: this.request.toJSON(),
      response: this.response.toJSON(),
      app: this.app.toJSON(),
      originalUrl: this.originalUrl,
      req: '<original node req>',
      res: '<original node res>',
      socket: '<original node socket>'
    };
  },
  //...
}
/**
 * Custom inspection implementation for newer Node.js versions.
 *
 * @return {Object}
 * @api public
 */
/* istanbul ignore else */
if (util.inspect.custom) {
  module.exports[util.inspect.custom] = module.exports.inspect;
}