notmodified

set and validate http cache headers

Installation

npm install notmodified

Example

var notmodified = require('notmodified');
var http = require('http');
 
var startTime = new Date();
 
http.createServer(function (req, res) {
  var valid = notmodified(req, res, {
    'hash': 'string-value',
    'mtime': startTime
  });
 
  if (valid) return res.end();
 
  res.end('Big chunk of data there should be cached');
}).listen();

API documentation

var notmodified = requrie('notmodified');
var valid = notmodified(req, res, cache);

requrie('notmodified') returns a function where the first two arguments are the http req and res object. The next argument (cache) is an object containing the cache validation data.

The notmodified function returns a valid boolean. If valid is true the client cache is valid and res.statusCode has been set to 304. However res.end() should stil be called.

The cache object can have three optional properties:

• hash this is the ETag value and must be a string. If its not set no ETag header will be send. If the client sends a if-none-match but no hash value is given valid will be false.

• mtime is the Last-Modified value and must be Date object. Just as with the ETag the header will only be send if mtime is specified and valid will be false if the client send If-Modified-Since but no mtime was set.

• weak this is an extension to the ETag header and must be a boolean. If its not set it defaults to false. This indicated if the ETag is byte-by-byte valid and if a Range request makes sence. Specifically if and only if true ETag will be prefixed with W/.

License

The software is license under "MIT"

Copyright (c) 2013 Andreas Madsen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.