feat(link): add external_link

README.md

@@ -32,6 +32,9 @@ marked:
   sanitizeUrl: false
   headerIds: true
   prependRoot: false
+  external_link:
+    enable: false
+    exclude: []
 ```
 
 - **gfm** - Enables [GitHub flavored markdown](https://help.github.com/articles/github-flavored-markdown)
@@ -50,6 +53,10 @@ marked:
   root: /blog/
   ```
   * `![text](/path/to/image.jpg)` becomes `<img src="/blog/path/to/image.jpg" alt="text">`
+- **external_link**
+  * **enable** - Open external links in a new tab.
+  * **exclude** - Exclude hostname. Specify subdomain when applicable, including `www`.
+  * Example: `[foo](http://bar.com)` becomes `<a href="http://bar.com" target="_blank" rel="noopener">foo</a>`
 
 ## Extras
 

index.js

@@ -15,7 +15,11 @@ hexo.config.marked = Object.assign({
   sanitizeUrl: false,
   headerIds: true,
   // TODO: enable prependRoot by default in v3
-  prependRoot: false
+  prependRoot: false,
+  external_link: {
+    enable: false,
+    exclude: []
+  }
 }, hexo.config.marked);
 
 hexo.extend.renderer.register('md', 'html', renderer, true);

lib/renderer.js

@@ -3,9 +3,46 @@
 const { inherits } = require('util');
 const marked = require('marked');
 const stripIndent = require('strip-indent');
-const { stripHTML, highlight, slugize, encodeURL, url_for } = require('hexo-util');
+const { encodeURL, highlight, slugize, stripHTML, url_for } = require('hexo-util');
 const MarkedRenderer = marked.Renderer;
-const { parse } = require('url');
+const { URL } = require('url');
+
+const urlObj = (str) => {
+  try {
+    return new URL(str);
+  } catch (err) {
+    return str;
+  }
+};
+
+/**
+ * Check whether the link is external
+ * @param {String} url The url to check
+ * @param {Object} config The site config
+ * @returns {Boolean} True if the link is an internal link or having the same host with config.url
+ */
+const isExternal = (url, siteCfg, exclude) => {
+  const data = urlObj(url);
+  const host = typeof data === 'object' ? data.hostname : '';
+  const sitehost = typeof urlObj(siteCfg.url) === 'object' ? urlObj(siteCfg.url).hostname
+    : siteCfg.url;
+
+  if (!sitehost || typeof data === 'string') return false;
+  if (data.origin === 'null') return false;
+
+
+  if (exclude) {
+    exclude = Array.isArray(exclude) ? exclude : [exclude];
+
+    for (const i of exclude) {
+      if (host === i) return false;
+    }
+  }
+
+  if (host !== sitehost) return true;
+
+  return false;
+};
 
 function Renderer() {
   MarkedRenderer.apply(this);
@@ -41,13 +78,16 @@ function anchorId(str, transformOption) {
 
 // Support AutoLink option
 Renderer.prototype.link = function(href, title, text) {
-  if (this.options.sanitizeUrl) {
+  const { options } = this;
+  const { external_link } = options;
+
+  if (options.sanitizeUrl) {
     if (href.startsWith('javascript:') || href.startsWith('vbscript:') || href.startsWith('data:')) {
       href = '';
     }
   }
 
-  if (!this.options.autolink && href === text && title == null) {
+  if (!options.autolink && href === text && title == null) {
     return href;
   }
 
@@ -57,6 +97,12 @@ Renderer.prototype.link = function(href, title, text) {
     out += ` title="${title}"`;
   }
 
+  if (external_link) {
+    if (external_link.enable && isExternal(href, options.config, external_link.exclude)) {
+      out += ' target="_blank" rel="noopener"';
+    }
+  }
+
   out += `>${text}</a>`;
   return out;
 };
@@ -76,9 +122,11 @@ Renderer.prototype.paragraph = text => {
 
 // Prepend root to image path
 Renderer.prototype.image = function(href, title, text) {
-  if (!parse(href).hostname && !this.options.config.relative_link
-    && this.options.prependRoot) {
-    href = url_for.call(this.options, href);
+  const { options } = this;
+
+  if (!isExternal(href, options.config) && !options.config.relative_link
+    && options.prependRoot) {
+    href = url_for.call(options, href);
   }
 
   return `<img src="${encodeURL(href)}" alt="${text}">`;
@@ -96,14 +144,15 @@ marked.setOptions({
 });
 
 module.exports = function(data, options) {
-  const url_forCfg = Object.assign({}, {
+  const siteCfg = Object.assign({}, {
     config: {
+      url: this.config.url,
       root: this.config.root,
       relative_link: this.config.relative_link
     }
   });
 
   return marked(data.text, Object.assign({
     renderer: new Renderer()
-  }, this.config.marked, options, url_forCfg));
+  }, this.config.marked, options, siteCfg));
 };

test/index.js

@@ -263,6 +263,84 @@ describe('Marked renderer', () => {
     });
   });
 
+  describe('external_link', () => {
+    const renderer = require('../lib/renderer');
+
+    const ctx = {
+      config: {
+        marked: {
+          external_link: {
+            enable: false
+          }
+        },
+        url: 'http://example.com'
+      }
+    };
+
+    it('disable', () => {
+      const body = '[foo](http://bar.com/)';
+
+      const r = renderer.bind(ctx);
+      const result = r({text: body});
+
+      result.should.eql('<p><a href="http://bar.com/">foo</a></p>\n');
+    });
+
+    it('enable', () => {
+      ctx.config.marked.external_link.enable = true;
+      const body = [
+        '[foo](http://bar.com/)',
+        '[text](http://example.com/)',
+        '[baz](/foo/bar)'
+      ].join('\n');
+
+      const r = renderer.bind(ctx);
+      const result = r({text: body});
+
+      result.should.eql([
+        '<p><a href="http://bar.com/" target="_blank" rel="noopener">foo</a>',
+        '<a href="http://example.com/">text</a>',
+        '<a href="/foo/bar">baz</a></p>\n'
+      ].join('\n'));
+    });
+
+    it('exclude - string', () => {
+      ctx.config.marked.external_link.exclude = 'bar.com';
+      const body = [
+        '[foo](http://foo.com/)',
+        '[bar](http://bar.com/)',
+        '[baz](http://baz.com/)'
+      ].join('\n');
+
+      const r = renderer.bind(ctx);
+      const result = r({text: body});
+
+      result.should.eql([
+        '<p><a href="http://foo.com/" target="_blank" rel="noopener">foo</a>',
+        '<a href="http://bar.com/">bar</a>',
+        '<a href="http://baz.com/" target="_blank" rel="noopener">baz</a></p>\n'
+      ].join('\n'));
+    });
+
+    it('exclude - array', () => {
+      ctx.config.marked.external_link.exclude = ['bar.com', 'baz.com'];
+      const body = [
+        '[foo](http://foo.com/)',
+        '[bar](http://bar.com/)',
+        '[baz](http://baz.com/)'
+      ].join('\n');
+
+      const r = renderer.bind(ctx);
+      const result = r({text: body});
+
+      result.should.eql([
+        '<p><a href="http://foo.com/" target="_blank" rel="noopener">foo</a>',
+        '<a href="http://bar.com/">bar</a>',
+        '<a href="http://baz.com/">baz</a></p>\n'
+      ].join('\n'));
+    });
+  });
+
   it('should encode image url', () => {
     const urlA = '/foo/bár.jpg';
     const urlB = 'http://fóo.com/bar.jpg';