Initial Implementation (#1)

* initial commit

* test

* improve further

* exit early if header is not a string

.npmrc

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+package-lock=false

.nycrc

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+{
+  "all": true,
+  "check-coverage": true,
+  "reporter": [
+    "lcov",
+    "text"
+  ],
+  "include": [
+    "index.js"
+  ],
+  "branches": 100,
+  "lines": 100,
+  "functions": 100,
+  "statements": 100
+}

LICENSE

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+The MIT License
+
+Copyright (c) 2022 The Fastify Team
+
+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.

README.md

@@ -1,37 +1,52 @@
-# skeleton
-
-Template repository to create standardized Fastify plugins.
-
-# Getting started
-
-- Click on `Use this template` above to create a new repository based on this repository.
-
-# What's included?
-
-1. Github CI Actions for installing, testing your package.
-2. Github CI Actions to validate different package managers.
-3. Dependabot V2 config to automate dependency updates.
-4. Template for the GitHub App [Stale](https://github.com/apps/stale) to mark issues as stale. 
-5. Template for the GitHub App [tests-checker](https://github.com/apps/tests-checker) to check if a PR contains tests.
-
-# Repository structure
-
-```
-├── .github
-│   ├── workflows
-│   │   ├── ci.yml
-│   │   └── package-manager-ci.yml
-│   ├── .stale.yml
-│   ├── dependabot.yml
-│   └── tests_checker.yml
-│
-├── docs (Documentation)
-│   
-├── examples (Code examples)
-│
-├── test (Application tests)
-│   
-├── types (Typescript types)
-│  
-└── README.md
-```
+# @fastify/accept-negotiator
+
+
+![CI](https://github.com/fastify/fastify-accept-negotiator/workflows/CI/badge.svg)
+[![NPM version](https://img.shields.io/npm/v/@fastify/accept-negotiator.svg?style=flat)](https://www.npmjs.com/package/@fastify/accept-negotiator)
+[![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](https://standardjs.com/)
+
+A negotiator for the accept-headers
+
+### Install
+```
+npm i @fastify/accept-negotiator
+```
+
+### Usage
+
+The module exports a function that you can use for negotiating an accept-header, e.g. accept-encoding. It takes 2 parameters:
+
+```
+negotiate(header, supportedValues)
+```
+
+- `header` (`string`, required) - The accept-header, e.g. accept-encoding
+- `supportedValues` (`string[]`, required) - The values, which are supported
+
+```js
+const negotiate = require('@fastify/accept-encoding').negotiate
+const encoding = negotiate('gzip, deflate, br', ['br'])
+console.log(encoding) // 'br*
+```
+
+The module also exports a class that you can use for negotiating an accept-header, e.g. accept-encoding, and use caching for better performance.
+
+
+```
+Negotiate(supportedValues)
+```
+
+- `supportedValues` (`string[]`, required) - The values, which are supported
+- `cache` (`{ set: Function; get: Function; has: Function }`, optional) - A Cache-Store, e.g. ES6-Map or mnemonist LRUCache
+
+```js
+const Negotiator = require('@fastify/accept-encoding').Negotiator
+const encodingNegotiator = new Negotiator({ supportedValues: ['br'], cache: new Map() })
+
+const encoding = encodingNegotiator.negotiate('gzip, deflate, br')
+console.log(encoding) // 'br*
+```
+
+## License
+
+Licensed under [MIT](./LICENSE).

benchmarks/Negotiator.js

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+'use strict'
+
+const { Suite } = require('benchmark')
+const { Negotiator } = require('..')
+
+const benchCases = require('./benchCases')
+
+for (let i = 0; i < benchCases.length; ++i) {
+  const [header, supportedEncodings] = benchCases[i]
+  const suite = new Suite()
+  const negotiator = new Negotiator({ supportedValues: supportedEncodings })
+  suite
+    .add(`${header} and ${supportedEncodings}`, function () {
+      negotiator.negotiate(header)
+    })
+    .on('cycle', function (event) {
+      console.log(String(event.target))
+    })
+    .run()
+}

benchmarks/benchCases.js

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+module.exports = [
+  ['identity;q=1', ['gzip', 'identity'], 'identity'],
+  ['gzip;q=1, identity;q=0.5', ['gzip', 'deflate'], 'gzip'],
+  ['deflate;q=0.5,identity; q=0.5', ['gzip', 'deflate'], 'deflate'],
+  ['deflate;q=0.5, gzip;q=0.5', ['gzip', 'deflate'], 'gzip'],
+  ['deflate;q=0.5, gzip;q=0.5', ['deflate', 'gzip'], 'deflate'],
+  ['*', ['gzip', 'deflate'], 'gzip'],
+  ['deflate;q=1.0, *', ['gzip'], 'gzip'],
+  ['test,br', ['br'], 'br'],
+  ['gzip;q=0', [], null],
+  ['gzip;q=0', ['gzip', 'identity'], null],
+  ['white rabbit', ['gzip', 'identity'], null],
+  [undefined, ['gzip', 'identity'], undefined],
+  ['compress;q=0.5, gzip;q=1.0', ['gzip', 'compress'], 'gzip'],
+  ['gzip;q=1.0, compress;q=0.5', ['compress', 'gzip'], 'gzip'],
+  ['compress;q=0.5, gzip;q=1.0', ['compress'], 'compress'],
+  ['gzip, deflate, br', ['br', 'gzip', 'deflate'], 'br'],
+  ['*', ['br', 'gzip', 'deflate'], 'br'],
+  ['*;q=0, identity;q=1', ['gzip', 'identity'], 'identity'],
+  ['identity;q=0', ['identity'], null],
+  ['gzip, compress;q=0', ['compress', 'gzip'], 'gzip'],
+  ['gzip;q=0.8, deflate', ['gzip', 'deflate'], 'deflate'],
+  ['gzip;q=0.8, identity;q=0.5, *;q=0.3', ['deflate', 'gzip', 'br'], 'gzip']
+]

benchmarks/negotiate.js

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+'use strict'
+
+const { Suite } = require('benchmark')
+const encodingNegotiator = require('..')
+
+const suite = new Suite()
+
+const benchCases = require('./benchCases')
+
+for (let i = 0; i < benchCases.length; ++i) {
+  const [header, supportedEncodings] = benchCases[i]
+  suite.add(`${header} and ${supportedEncodings}`, function () {
+    encodingNegotiator.negotiate(header, supportedEncodings)
+  })
+}
+suite
+  .on('cycle', function (event) {
+    console.log(String(event.target))
+  })
+  .on('complete', function () {
+    console.log('Fastest is ' + this.filter('fastest').map('name'))
+    console.log('Slowest is ' + this.filter('slowest').map('name'))
+  })
+  .run({ async: true })

index.js

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+'use strict'
+
+function Negotiator (options) {
+  if (!new.target) {
+    return new Negotiator(options)
+  }
+
+  const {
+    supportedValues = [],
+    cache
+  } = (options && typeof options === 'object' && options) || {}
+
+  this.supportedValues = supportedValues
+
+  this.cache = cache
+}
+
+Negotiator.prototype.negotiate = function (header) {
+  if (typeof header !== 'string') {
+    return null
+  }
+  if (!this.cache) {
+    return negotiate(header, this.supportedValues)
+  }
+  if (!this.cache.has(header)) {
+    this.cache.set(header, negotiate(header, this.supportedValues))
+  }
+  return this.cache.get(header)
+}
+
+function negotiate (header, supportedValues) {
+  if (
+    !header ||
+    !Array.isArray(supportedValues) ||
+    supportedValues.length === 0
+  ) {
+    return null
+  }
+
+  if (header === '*') {
+    return supportedValues[0]
+  }
+
+  let preferredEncoding = null
+  let preferredEncodingPriority = Infinity
+  let preferredEncodingQuality = 0
+
+  function processMatch (enc, quality) {
+    if (quality === 0 || preferredEncodingQuality > quality) {
+      return false
+    }
+
+    const encoding = (enc === '*' && supportedValues[0]) || enc
+    const priority = supportedValues.indexOf(encoding)
+    if (priority === -1) {
+      return false
+    }
+
+    if (priority === 0 && quality === 1) {
+      preferredEncoding = encoding
+      return true
+    } else if (preferredEncodingQuality < quality) {
+      preferredEncoding = encoding
+      preferredEncodingPriority = priority
+      preferredEncodingQuality = quality
+    } else if (preferredEncodingPriority > priority) {
+      preferredEncoding = encoding
+      preferredEncodingPriority = priority
+      preferredEncodingQuality = quality
+    }
+    return false
+  }
+
+  parse(header, processMatch)
+
+  return preferredEncoding
+}
+
+const BEGIN = 0
+const TOKEN = 1
+const QUALITY = 2
+const END = 3
+
+function parse (header, processMatch) {
+  let str = ''
+  let quality
+  let state = BEGIN
+  for (let i = 0, il = header.length; i < il; ++i) {
+    const char = header[i]
+
+    if (char === ' ' || char === '\t') {
+      continue
+    } else if (char === ';') {
+      if (state === TOKEN) {
+        state = QUALITY
+        quality = ''
+      }
+      continue
+    } else if (char === ',') {
+      if (state === TOKEN) {
+        if (processMatch(str, 1)) {
+          state = END
+          break
+        }
+        state = BEGIN
+        str = ''
+      } else if (state === QUALITY) {
+        if (processMatch(str, parseFloat(quality) || 0)) {
+          state = END
+          break
+        }
+        state = BEGIN
+        str = ''
+        quality = ''
+      }
+      continue
+    } else if (
+      state === QUALITY
+    ) {
+      if (char === 'q' || char === '=') {
+        continue
+      } else if (
+        char === '.' ||
+        char === '1' ||
+        char === '0' ||
+        char === '2' ||
+        char === '3' ||
+        char === '4' ||
+        char === '5' ||
+        char === '6' ||
+        char === '7' ||
+        char === '8' ||
+        char === '9'
+      ) {
+        quality += char
+        continue
+      }
+    } else if (state === BEGIN) {
+      state = TOKEN
+      str += char
+      continue
+    }
+    if (state === TOKEN) {
+      const prevChar = header[i - 1]
+      if (prevChar === ' ' || prevChar === '\t') {
+        str = ''
+      }
+      str += char
+      continue
+    }
+    if (processMatch(str, parseFloat(quality) || 0)) {
+      state = END
+      break
+    }
+    state = BEGIN
+    str = char
+    quality = ''
+  }
+
+  if (state === TOKEN) {
+    processMatch(str, 1)
+  } else if (state === QUALITY) {
+    processMatch(str, parseFloat(quality) || 0)
+  }
+}
+
+module.exports = negotiate
+module.exports.default = negotiate
+module.exports.negotiate = negotiate
+module.exports.Negotiator = Negotiator