mach/lib/middleware/gzip.js

HTTP for JavaScript

"use strict";

var zlib = require("zlib");
var mach = require("../index");

mach.extend(require("../extensions/acceptEncoding"));

var GZIP_MATCHER = /text|javascript|json/i;

function shouldGzipContentType(contentType) {
  if (!contentType || contentType === "text/event-stream") {
    return false;
  }return GZIP_MATCHER.test(contentType);
}

/**
 * A middleware that gzip's the response content (see http://www.gzip.org/).
 * Options may be any of node's zlib options (see http://nodejs.org/api/zlib.html).
 */
function gzip(app, options) {
  return function (conn) {
    return conn.call(app).then(function () {
      var response = conn.response;
      var headers = response.headers;

      if (shouldGzipContentType(headers["Content-Type"]) && conn.acceptsEncoding("gzip")) {
        response.content = response.content.pipe(zlib.createGzip(options));

        delete headers["Content-Length"];
        headers["Content-Encoding"] = "gzip";
        headers.Vary = "Accept-Encoding";
      }
    });
  };
}

module.exports = gzip;