feat(cache): plain object cache (#162)

* feat(cache): plain object cache
* feat(cache): bring up Cache()
* refactor(cache): utilize Cache()
* feat(cache): add cache.del()
* docs(README): add Cache()
* refactor(url_for): reduce lines
* feat(cache): make null cacheable

Author: SukkaW

README.md

@@ -12,6 +12,7 @@ Utilities for [Hexo].
 
 - [Installation](#installation)
 - [Usage](#usage)
+- [Cache](#cache)
 - [CacheStream](#cachestream)
 - [camelCaseKeys](#camelcasekeysobj-options)
 - [createSha1Hash](#createsha1hash)
@@ -53,6 +54,47 @@ $ npm install hexo-util --save
 var util = require('hexo-util');
 ```
 
+### Cache()
+
+A simple plain object cache
+
+``` js
+const cache = new Cache();
+
+// set(key, value)
+cache.set('foo', 'bar');
+
+// get(key) => value
+cache.get('foo');
+// 'bar'
+
+// has(key) => Boolean
+cache.has('foo');
+// true
+cache.has('bar');
+// false
+
+// apply(key. value)
+cache.apply('baz', () => 123);
+// 123
+cache.apply('baz', () => 456);
+// 123
+cache.apply('qux', 456);
+// 456
+cache.apply('qux', '789');
+// 456
+
+// del(key)
+cache.del('baz');
+cache.has('baz');
+// false
+
+// flush()
+cache.flush();
+cache.has('foo');
+// false
+```
+
 ### CacheStream()
 
 Caches contents piped to the stream.

lib/cache.js

@@ -0,0 +1,36 @@
+'use strict';
+
+module.exports = class Cache {
+  constructor() {
+    this.cache = {};
+  }
+
+  set(id, value) {
+    this.cache[id] = value;
+  }
+
+  has(id) {
+    return typeof this.cache[id] !== 'undefined';
+  }
+
+  get(id) {
+    return this.cache[id];
+  }
+
+  del(id) {
+    delete this.cache[id];
+  }
+
+  apply(id, value) {
+    if (this.has(id)) return this.get(id);
+
+    if (typeof value === 'function') value = value();
+
+    this.set(id, value);
+    return value;
+  }
+
+  flush() {
+    this.cache = {};
+  }
+};

lib/full_url_for.js

@@ -4,27 +4,32 @@ const { parse, URL } = require('url');
 const encodeURL = require('./encode_url');
 const prettyUrls = require('./pretty_urls');
 
+const Cache = require('./cache');
+const cache = new Cache();
+
 function fullUrlForHelper(path = '/') {
   const pathRegex = /^(\/\/|http(s)?:)/;
   if (pathRegex.test(path)) return path;
 
   const { config } = this;
-  const sitehost = parse(config.url).hostname || config.url;
-  const data = new URL(path, `http://${sitehost}`);
-
-  // Exit if input is an external link or a data url
-  if (data.hostname !== sitehost || data.origin === 'null') return path;
-
-  path = encodeURL(config.url + `/${path}`.replace(/\/{2,}/g, '/'));
-
   const prettyUrlsOptions = Object.assign({
     trailing_index: true,
     trailing_html: true
   }, config.pretty_urls);
 
-  path = prettyUrls(path, prettyUrlsOptions);
+  // cacheId is designed to works across different hexo.config & options
+  return cache.apply(`${config.url}-${prettyUrlsOptions.trailing_index}-${prettyUrlsOptions.trailing_html}-${path}`, () => {
+    const sitehost = parse(config.url).hostname || config.url;
+    const data = new URL(path, `http://${sitehost}`);
+
+    // Exit if input is an external link or a data url
+    if (data.hostname !== sitehost || data.origin === 'null') return path;
+
+    path = encodeURL(config.url + `/${path}`.replace(/\/{2,}/g, '/'));
+    path = prettyUrls(path, prettyUrlsOptions);
 
-  return path;
+    return path;
+  });
 }
 
 module.exports = fullUrlForHelper;

lib/gravatar.js

@@ -3,6 +3,9 @@
 const { createHash } = require('crypto');
 const { stringify } = require('querystring');
 
+const Cache = require('./cache');
+const cache = new Cache();
+
 function md5(str) {
   return createHash('md5').update(str).digest('hex');
 }
@@ -12,11 +15,15 @@ function gravatarHelper(email, options) {
     options = {s: options};
   }
 
-  let str = `https://www.gravatar.com/avatar/${md5(email.toLowerCase())}`;
+  const hash = cache.has(email) ? cache.get(email) : md5(email.toLowerCase());
+  let str = `https://www.gravatar.com/avatar/${hash}`;
+
   const qs = stringify(options);
 
   if (qs) str += `?${qs}`;
 
+  cache.set('email', hash);
+
   return str;
 }
 

lib/index.js

@@ -2,6 +2,7 @@
 
 const hash = require('./hash');
 
+exports.Cache = require('./cache');
 exports.CacheStream = require('./cache_stream');
 exports.camelCaseKeys = require('./camel_case_keys');
 exports.Color = require('./color');

lib/is_external_link.js

@@ -2,6 +2,9 @@
 
 const { parse, URL } = require('url');
 
+const Cache = require('./cache');
+const cache = new Cache();
+
 /**
  * Check whether the link is external
  * @param {String} input The url to check
@@ -13,27 +16,29 @@ function isExternalLink(input, sitehost, exclude) {
 
   if (!sitehost) return false;
 
-  // handle relative url
-  const data = new URL(input, `http://${sitehost}`);
+  return cache.apply(`${input}-${sitehost}-${exclude}`, () => {
+    // handle relative url
+    const data = new URL(input, `http://${sitehost}`);
 
-  // handle mailto: javascript: vbscript: and so on
-  if (data.origin === 'null') return false;
+    // handle mailto: javascript: vbscript: and so on
+    if (data.origin === 'null') return false;
 
-  const host = data.hostname;
+    const host = data.hostname;
 
-  if (exclude) {
-    exclude = Array.isArray(exclude) ? exclude : [exclude];
+    if (exclude) {
+      exclude = Array.isArray(exclude) ? exclude : [exclude];
 
-    if (exclude && exclude.length) {
-      for (const i of exclude) {
-        if (host === i) return false;
+      if (exclude && exclude.length) {
+        for (const i of exclude) {
+          if (host === i) return false;
+        }
       }
     }
-  }
 
-  if (host !== sitehost) return true;
+    if (host !== sitehost) return true;
 
-  return false;
+    return false;
+  });
 }
 
 module.exports = isExternalLink;

lib/relative_url.js

@@ -2,30 +2,35 @@
 
 const encodeURL = require('./encode_url');
 
+const Cache = require('./cache');
+const cache = new Cache();
+
 function relativeUrlHelper(from = '', to = '') {
-  const fromParts = from.split('/');
-  const toParts = to.split('/');
-  const length = Math.min(fromParts.length, toParts.length);
-  let i = 0;
+  return cache.apply(`${from}-${to}`, () => {
+    const fromParts = from.split('/');
+    const toParts = to.split('/');
+    const length = Math.min(fromParts.length, toParts.length);
+    let i = 0;
 
-  for (; i < length; i++) {
-    if (fromParts[i] !== toParts[i]) break;
-  }
+    for (; i < length; i++) {
+      if (fromParts[i] !== toParts[i]) break;
+    }
 
-  let out = toParts.slice(i);
+    let out = toParts.slice(i);
 
-  for (let j = fromParts.length - i - 1; j > 0; j--) {
-    out.unshift('..');
-  }
+    for (let j = fromParts.length - i - 1; j > 0; j--) {
+      out.unshift('..');
+    }
 
-  const outLength = out.length;
+    const outLength = out.length;
 
-  // If the last 2 elements of `out` is empty strings, replace them with `index.html`.
-  if (outLength > 1 && !out[outLength - 1] && !out[outLength - 2]) {
-    out = out.slice(0, outLength - 2).concat('index.html');
-  }
+    // If the last 2 elements of `out` is empty strings, replace them with `index.html`.
+    if (outLength > 1 && !out[outLength - 1] && !out[outLength - 2]) {
+      out = out.slice(0, outLength - 2).concat('index.html');
+    }
 
-  return encodeURL(out.join('/').replace(/\/{2,}/g, '/'));
+    return encodeURL(out.join('/').replace(/\/{2,}/g, '/'));
+  });
 }
 
 module.exports = relativeUrlHelper;

lib/url_for.js

@@ -5,17 +5,11 @@ const encodeURL = require('./encode_url');
 const relative_url = require('./relative_url');
 const prettyUrls = require('./pretty_urls');
 
-function urlForHelper(path = '/', options) {
-  const pathRegex = /^(#|\/\/|http(s)?:)/;
-  if (pathRegex.test(path)) return path;
+const Cache = require('./cache');
+const cache = new Cache();
 
+function urlForHelper(path = '/', options) {
   const { config } = this;
-  const { root } = config;
-  const sitehost = parse(config.url).hostname || config.url;
-  const data = new URL(path, `http://${sitehost}`);
-
-  // Exit if input is an external link or a data url
-  if (data.hostname !== sitehost || data.origin === 'null') return path;
 
   options = Object.assign({
     relative: config.relative_link
@@ -26,17 +20,34 @@ function urlForHelper(path = '/', options) {
     return relative_url(this.path, path);
   }
 
-  // Prepend root path
-  path = encodeURL((root + path).replace(/\/{2,}/g, '/'));
-
+  const { root } = config;
   const prettyUrlsOptions = Object.assign({
     trailing_index: true,
     trailing_html: true
   }, config.pretty_urls);
 
-  path = prettyUrls(path, prettyUrlsOptions);
+  // cacheId is designed to works across different hexo.config & options
+  return cache.apply(`${config.url}-${root}-${prettyUrlsOptions.trailing_index}-${prettyUrlsOptions.trailing_html}-${path}`, () => {
+    const pathRegex = /^(#|\/\/|http(s)?:)/;
+    if (pathRegex.test(path)) {
+      return path;
+    }
+
+    const sitehost = parse(config.url).hostname || config.url;
+    const data = new URL(path, `http://${sitehost}`);
+
+    // Exit if input is an external link or a data url
+    if (data.hostname !== sitehost || data.origin === 'null') {
+      return path;
+    }
+
+    // Prepend root path
+    path = encodeURL((root + path).replace(/\/{2,}/g, '/'));
+
+    path = prettyUrls(path, prettyUrlsOptions);
 
-  return path;
+    return path;
+  });
 }
 
 module.exports = urlForHelper;

test/cache.spec.js

@@ -0,0 +1,48 @@
+'use strict';
+
+require('chai').should();
+
+describe('Cache', () => {
+  const Cache = require('../lib/cache');
+  const cache = new Cache();
+
+  it('get & set', () => {
+    cache.set('foo', 123);
+    cache.get('foo').should.eql(123);
+  });
+
+  it('has', () => {
+    cache.has('foo').should.eql(true);
+    cache.has('bar').should.eql(false);
+  });
+
+  it('apply - non function', () => {
+    cache.apply('bar', 123).should.eql(123);
+    cache.apply('bar', 456).should.eql(123);
+
+    cache.apply('foo', 456).should.eql(123);
+  });
+
+  it('apply - function', () => {
+    cache.apply('baz', () => 123).should.eql(123);
+    cache.apply('baz', () => 456).should.eql(123);
+  });
+
+  it('del', () => {
+    cache.del('baz');
+    cache.has('foo').should.eql(true);
+    cache.has('baz').should.eql(false);
+  });
+
+  it('flush', () => {
+    cache.flush();
+    cache.has('foo').should.eql(false);
+    cache.has('bar').should.eql(false);
+    cache.has('baz').should.eql(false);
+  });
+
+  it('cache null', () => {
+    cache.apply('foo', null);
+    (cache.apply('foo', 123) === null).should.eql(true);
+  });
+});