heya-io-node/node.js

Intelligent I/O for Node

'use strict';

const http = require('http');
const https = require('https');
// const http2 = require('http2');
const zlib = require('zlib');
const {Readable} = require('stream');

const io = require('heya-io/io');
const FauxXHR = require('heya-io/FauxXHR');

// This is a Node-only module.

const getCharset = /;\scharset=(.+)$/i;

const makeHeaders = (rawHeaders, mime) => {
  if (mime) {
    rawHeaders = rawHeaders.filter((_, index, array) => array[(index >> 1) << 1].toLowerCase() != 'content-type');
    rawHeaders.push('Content-Type', mime);
  }
  return rawHeaders.reduce((acc, value, index) => acc + (index % 2 ? ': ' : index ? '\r\n' : '') + value, '');
};

const returnOutputStream = (res, options) => {
  const encoding = res.headers['content-encoding'];
  const decoder = encoding && io.node.encoders[encoding] && io.node.encoders[encoding].decode && io.node.encoders[encoding].decode(options);
  return decoder ? res.pipe(decoder) : res;
};

const returnInputStream = (req, options) => {
  let encoding = req.getHeader('$-content-encoding');
  req.removeHeader('$-content-encoding');
  const encoder = io.node.encoders[encoding];
  if (!encoder) return req;
  req.setHeader('content-encoding', encoding);
  const stream = encoder.encode(options).pipe(req);
  if (stream === req) req.removeHeader('content-encoding');
  return stream;
};

const requestTransport = (options, prep) => {
  // create request options
  const urlObject = new URL(prep.url);
  const newOptions = {
    url: prep.url,
    protocol: urlObject.protocol,
    hostname: urlObject.hostname,
    port: urlObject.port,
    path: urlObject.pathname + urlObject.search + urlObject.hash,
    method: options.method,
    headers: Object.assign({}, options.headers)
  };
  if (urlObject.username) {
    newOptions.auth = urlObject.username;
    if (urlObject.password) {
      newOptions.auth += ':' + urlObject.password;
    }
  }
  if (options.timeout) newOptions.timeout = options.timeout;

  // create Accept-Encoding
  Object.keys(newOptions.headers)
    .filter(key => /^Accept\-Encoding$/i.test(key))
    .forEach(key => delete newOptions.headers[key]);
  if (io.node.acceptedEncoding) {
    newOptions.headers['Accept-Encoding'] = io.node.acceptedEncoding;
  }

  // prepare body
  newOptions.body = io.processData(
    {
      setRequestHeader(key, value) {
        newOptions.headers[key] = value;
      }
    },
    options,
    prep.data
  );

  return new Promise((resolve, reject) => {
    const opt = io.node.inspectRequest(newOptions);
    const proto = opt.protocol && opt.protocol.toLowerCase() === 'https:' ? https : http;
    const req = proto.request(opt, res => resolve(res));
    req.on('error', e => reject(e));
    if (opt.body instanceof Readable) {
      const stream = req.getHeader('content-type') && req.getHeader('$-content-encoding') ? returnInputStream(req, opt) : req;
      opt.body.pipe(stream);
    } else if (opt.body instanceof http.IncomingMessage) {
      const rawHeaders = opt.body.rawHeaders;
      for (let i = 0; i < rawHeaders.length; i += 2) {
        req.setHeader(rawHeaders[i], rawHeaders[i + 1]);
      }
      const stream = req.getHeader('content-type') && req.getHeader('$-content-encoding') ? returnInputStream(req, opt) : req;
      opt.body.pipe(stream);
    } else {
      const stream =
        opt.body &&
        req.getHeader('content-type') &&
        ((io.node.encodingThreshold && opt.body.length > io.node.encodingThreshold) || req.getHeader('$-content-encoding'))
          ? returnInputStream(req, opt)
          : req;
      stream.end(opt.body);
    }
  })
    .then(res => {
      if (options.responseType === '$tream') {
        const xhr = new FauxXHR({
          status: res.statusCode,
          statusText: res.statusMessage,
          headers: makeHeaders(res.rawHeaders, options.mime),
          responseType: options.responseType,
          responseText: ''
        });
        xhr.response = returnOutputStream(res, options);
        return xhr;
      }
      return new Promise(resolve => {
        const dataStream = returnOutputStream(res, options);
        let buffer = Buffer.alloc(0);
        dataStream.on('data', chunk => (buffer = Buffer.concat([buffer, chunk])));
        dataStream.on('end', () => resolve(buffer));
      }).then(buffer => {
        const contentType = res.headers['content-type'],
          charsetResult = contentType && getCharset.exec(contentType);
        let charset = charsetResult && charsetResult[1];
        charset = !charset || charset === 'utf8' || charset === 'utf-8' ? 'utf8' : 'latin1';
        return new FauxXHR({
          status: res.statusCode,
          statusText: res.statusMessage,
          headers: makeHeaders(res.rawHeaders, options.mime),
          responseType: options.responseType || '',
          responseText: buffer.toString(charset),
          response: buffer
        });
      });
    })
    .then(xhr => io.node.inspectResult(new io.Result(xhr, options)));
};

let oldTransport;

const attach = () => {
  if (io.defaultTransport !== requestTransport) {
    oldTransport = io.defaultTransport;
    io.defaultTransport = requestTransport;
    return true;
  }
  return false;
};

const detach = () => {
  if (oldTransport && io.defaultTransport === requestTransport) {
    io.defaultTransport = oldTransport;
    oldTransport = null;
    return true;
  }
  return false;
};

const identity = x => x;

const updateEncodingSettings = () => {
  const encoders = io.node.encoders,
    keys = Object.keys(encoders);
  io.node.acceptedEncoding = keys
    .filter(key => encoders[key].decode)
    .sort((a, b) => encoders[a].priority - encoders[b].priority)
    .join(', ');
  io.node.preferredEncoding = keys
    .filter(key => encoders[key].encode)
    .reduce((last, key) => (!last ? key : encoders[last].priority < encoders[key].priority ? last : key));
};

const addEncoder = (key, object) => {
  io.node.encoders[key] = object;
  updateEncodingSettings();
};

const removeEncoder = key => {
  delete io.node.encoders[key];
  updateEncodingSettings();
};

io.node = {
  attach: attach,
  detach: detach,
  inspectRequest: identity,
  inspectResult: identity,
  encodingThreshold: 0,
  encoders: {
    gzip: {
      priority: 10,
      encode: options => zlib.createGzip(options && options.compressor),
      decode: options => zlib.createGunzip(options && options.decompressor)
    },
    deflate: {
      priority: 20,
      encode: options => zlib.createDeflate(options && options.compressor),
      decode: options => zlib.createInflate(options && options.decompressor)
    }
  },
  preferredEncoding: '',
  acceptedEncoding: '',
  addEncoder: addEncoder,
  removeEncoder: removeEncoder
};

updateEncodingSettings();

if (zlib.createBrotliCompress && zlib.createBrotliDecompress) {
  io.node.addEncoder('br', {
    priority: 30,
    encode: options => zlib.createBrotliCompress(options && options.compressor),
    decode: options => zlib.createBrotliDecompress(options && options.decompressor)
  });
}

module.exports = io;