�PNG  IHDR��;���IDATx��ܻn�0���K�� �)(�pA��� ���7�LeG{�� �§㻢|��ذaÆ 6lذaÆ 6lذaÆ 6lom��$^�y���ذag�5bÆ 6lذaÆ 6lذa{���� 6lذaÆ �`����}H�Fkm�,�m����Ӫ���ô�ô!� �x�|'ܢ˟;�E:���9�&ᶒ�}�{�v]�n&�6� �h��_��t�ڠ͵-ҫ���Z;��Z$�.�P���k�ž)�!��o���>}l�eQfJ�T��u і���چ��\��X=8��Rن4`Vw�l�>����n�G�^��i�s��"ms�$�u��i��?w�bs[m�6�K4���O���.�4��%����/����b�C%��t ��M�ז� �-l�G6�mrz2���s�%�9��s@���-�k�9�=���)������k�B5����\��+͂�Zsٲ ��Rn��~G���R���C����� �wIcI��n7jJ���hۛNCS|���j0��8y�iHKֶۛ�k�Ɉ+;Sz������L/��F�*\��Ԕ�#"5��m�2��[S��������=�g��n�a�P�e�ғ�L�� lذaÆ 6l�^k��̱aÆ 6lذaÆ 6lذa;���� �_��ذaÆ 6lذaÆ 6lذaÆ ���R���IEND�B` # fresh [![NPM Version][npm-image]][npm-url] [![NPM Downloads][downloads-image]][downloads-url] [![Node.js Version][node-version-image]][node-version-url] [![Build Status][travis-image]][travis-url] [![Test Coverage][coveralls-image]][coveralls-url] HTTP response freshness testing ## Installation This is a [Node.js](https://nodejs.org/en/) module available through the [npm registry](https://www.npmjs.com/). Installation is done using the [`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally): ``` $ npm install fresh ``` ## API ```js var fresh = require('fresh') ``` ### fresh(reqHeaders, resHeaders) Check freshness of the response using request and response headers. When the response is still "fresh" in the client's cache `true` is returned, otherwise `false` is returned to indicate that the client cache is now stale and the full response should be sent. When a client sends the `Cache-Control: no-cache` request header to indicate an end-to-end reload request, this module will return `false` to make handling these requests transparent. ## Known Issues This module is designed to only follow the HTTP specifications, not to work-around all kinda of client bugs (especially since this module typically does not recieve enough information to understand what the client actually is). There is a known issue that in certain versions of Safari, Safari will incorrectly make a request that allows this module to validate freshness of the resource even when Safari does not have a representation of the resource in the cache. The module [jumanji](https://www.npmjs.com/package/jumanji) can be used in an Express application to work-around this issue and also provides links to further reading on this Safari bug. ## Example ### API usage ```js var reqHeaders = { 'if-none-match': '"foo"' } var resHeaders = { 'etag': '"bar"' } fresh(reqHeaders, resHeaders) // => false var reqHeaders = { 'if-none-match': '"foo"' } var resHeaders = { 'etag': '"foo"' } fresh(reqHeaders, resHeaders) // => true ``` ### Using with Node.js http server ```js var fresh = require('fresh') var http = require('http') var server = http.createServer(function (req, res) { // perform server logic // ... including adding ETag / Last-Modified response headers if (isFresh(req, res)) { // client has a fresh copy of resource res.statusCode = 304 res.end() return } // send the resource res.statusCode = 200 res.end('hello, world!') }) function isFresh (req, res) { return fresh(req.headers, { 'etag': res.getHeader('ETag'), 'last-modified': res.getHeader('Last-Modified') }) } server.listen(3000) ``` ## License [MIT](LICENSE) [npm-image]: https://img.shields.io/npm/v/fresh.svg [npm-url]: https://npmjs.org/package/fresh [node-version-image]: https://img.shields.io/node/v/fresh.svg [node-version-url]: https://nodejs.org/en/ [travis-image]: https://img.shields.io/travis/jshttp/fresh/master.svg [travis-url]: https://travis-ci.org/jshttp/fresh [coveralls-image]: https://img.shields.io/coveralls/jshttp/fresh/master.svg [coveralls-url]: https://coveralls.io/r/jshttp/fresh?branch=master [downloads-image]: https://img.shields.io/npm/dm/fresh.svg [downloads-url]: https://npmjs.org/package/fresh