index.js

'use strict';

module.exports = noCache;

function setNoCacheHeaders(ctx) {
  if (ctx.skipNoCache) {
    return;
  }
  ctx.set('Cache-Control', 'no-store, no-cache, must-revalidate');
  ctx.set('Pragma', 'no-cache');
  ctx.set('Expires', 0);
}

function noCache(options) {
  options = options || {};
  options.global = !!options.global;

  var paths = options.paths || [];
  var types = options.types || [];
  var config = options.config || {
    sensitive: true,
    strict: true
  };

  if (options.global) {
    return function * noCache(next) {
      yield * next;
      setNoCacheHeaders(this);
    };
  } else {
    // only load modules if needed
    var pathToRegExp = require('path-to-regexp');
    var typeis = require('type-is').is;

    return function * noCache(next) {
      yield * next;

      if (typeis(this.type, types) || match(this.path)) {
        setNoCacheHeaders(this);
      }
    };
  }

  function match(path) {
    for (var i = 0; i < paths.length; i++) {
      if (pathToRegExp(paths[i], [], config).exec(path)) return true;
    }
  }
}