node-cache-depend

A utility function to detect when you should invalidate your cached data

Installation

npm install --save cache-depend

Usage

CacheDepend can help you formalize on what sources you depend for you cached data and notify you when your data needs to be updated

var onETag = require('cache-depend')
               .etag('http://example.com/resource/with/ETag')

onETag.on('change', function (changeinfo) {
  changeinfo.changeId
  changeinfo.oldETag
  changeinfo.newETag
  // I should probably invalidate my cached data
})

var onDate = require('cache-depend')
               .date('2015-06-23 12:36:00')

onDate.on('change', function (changeinfo) {
  changeinfo.changeId
  changeinfo.startedAt
  changeinfo.endedAt
  // Same here
})

var onOthers = require('cache-depend')
                .others(onEtag, onDate) // any number of arguments

onOthers.on('change', function (changeinfo) {
  changeinfo.changeId // is the same as the one emitted by the first to change
  changeinfo.changed // reference to the changing dependency
})

You can also manually check your watchers

var onOthers = require('cache-depend')
                .others(onEtag, onDate1, onDate2)

onOthers.check(function (isGood) {
  // isGood is true if you should keep your cached data
})

Test

You can run the tests with npm test. You will need to know mocha

Contributing

Anyone is welcome to submit issues and pull requests

License

MIT

Copyright (c) 2014 Florent Jaby

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.