diff options
Diffstat (limited to 'middleware/node_modules/fresh/README.md')
-rw-r--r-- | middleware/node_modules/fresh/README.md | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/middleware/node_modules/fresh/README.md b/middleware/node_modules/fresh/README.md new file mode 100644 index 0000000..1c1c680 --- /dev/null +++ b/middleware/node_modules/fresh/README.md @@ -0,0 +1,119 @@ +# 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 + +<!-- eslint-disable no-unused-vars --> + +```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 + +<!-- eslint-disable no-redeclare, no-undef --> + +```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 |