Awesome
hexo-renderer-marked
Add support for Markdown. This plugin uses marked as its render engine.
Important note on security
By default, this plugin contains a potential security issue: It is possible to inject Markdown containing Unsafe HTML that will not be sanitized
This issue might not affect you because you checked the content of the markdown before using this plugin, but it's still a risk
There are two solutions to avoid those issues:
- First solution is to enable option
dompurify: true
, which will sanitize the rendered HTML. The side effect of this solution is that it will break any tag plugin (aka{% codeblock %}
). This explains why the safer option has not been enabled by default - Second solution is to migrate to hexo-renderer-markdown-it which is safe by default and does not suffer from the same limitations
Installation
$ npm install hexo-renderer-marked --save
- Hexo 4: >= 2.0
- Hexo 3: >= 0.2
- Hexo 2: 0.1.x
Options
You can configure this plugin in _config.yml
.
marked:
gfm: true
pedantic: false
breaks: true
smartLists: true
smartypants: true
quotes: '“”‘’'
modifyAnchors: 0
anchorAlias: false
autolink: true
mangle: true
sanitizeUrl: false
dompurify: false
headerIds: true
lazyload: false
figcaption: false
prependRoot: true
postAsset: false
external_link:
enable: false
exclude: []
nofollow: false
disableNunjucks: false
descriptionLists: true
- gfm - Enables GitHub flavored markdown
- pedantic - Conform to obscure parts of
markdown.pl
as much as possible. Don't fix any of the original markdown bugs or poor behavior. - breaks - Enable GFM line breaks. This option requires the
gfm
option to be true. - smartLists - Use smarter list behavior than the original markdown.
- smartypants - Use "smart" typographic punctuation for things like quotes and dashes.
- quotes - Defines the double and single quotes used for substituting regular quotes if smartypants is enabled.
- Example: '«»“”'
- "double" will be turned into «double»
- 'single' will be turned into “single”
- Both double and single quotes substitution must be specified, otherwise it will be silently ignored.
- Example: '«»“”'
- modifyAnchors - Transform the anchorIds into lower case (
1
) or upper case (2
). - autolink - Enable autolink for URLs. E.g.
https://hexo.io
will become<a href="https://hexo.io">https://hexo.io</a>
. - mangle - Escape autolinked email address with HTML character references.
- This is to obscure email address from basic crawler used by spam bot, while still readable to web browsers.
- sanitizeUrl - Remove URLs that start with
javascript:
,vbscript:
anddata:
. - dompurify - Enable DOMPurify to be run on the rendered Markdown. See below for configuration
- headerIds - Insert header id, e.g.
<h1 id="value">text</h1>
. Useful for inserting anchor link to each paragraph with a heading. - anchorAlias - Enables custom header id
- Example:
## [foo](#bar)
, id will be set as "bar". - Requires headerIds to be enabled.
- Example:
- lazyload - Lazy loading images via
loading="lazy"
attribute. - figcaption - Append
figcaption
element after each image. - prependRoot - Prepend root value to (internal) image path.
- Example
_config.yml
:
root: /blog/
![text](/path/to/image.jpg)
becomes<img src="/blog/path/to/image.jpg" alt="text">
- Example
- postAsset - Resolve post asset's image path to relative path and prepend root value when
post_asset_folder
is enabled.- "image.jpg" is located at "/2020/01/02/foo/image.jpg", which is a post asset of "/2020/01/02/foo/".
![](image.jpg)
becomes<img src="/2020/01/02/foo/image.jpg">
- Requires prependRoot to be enabled.
- external_link
- enable - Open external links in a new tab.
- exclude - Exclude hostname. Specify subdomain when applicable, including
www
.- Example:
[foo](https://example.com)
becomes<a href="https://example.com" target="_blank" rel="noopener">foo</a>
- Example:
- nofollow - Add
rel="noopener external nofollow noreferrer"
to all external links for security, privacy and SEO. Read more. This can be enabled regardless ofexternal_link.enable
- Example:
[foo](https://example.com)
becomes<a href="https://example.com" rel="noopener external nofollow noreferrer">foo</a>
- Example:
- disableNunjucks: If true, Nunjucks tags
{{ }}
or{% %}
(usually used by tag plugins) will not be rendered. - descriptionLists: Enable support for description lists syntax.
- Currently description lists syntax is not in neither CommonMark or GFM,
hexo-renderer-marked
only provides the option for backward compatibility. - By disabling the
descriptionLists
, markdown rendering performance will be improved by a lot.
- Currently description lists syntax is not in neither CommonMark or GFM,
For more options, see Marked. Due to the customizations implemented by this plugin, some of the Marked's options may not work as expected. Feel free to raise an issue to us for clarification.
Extras
Sanitize HTML with DOMPurify
DOMPurify can be enabled to sanitize the rendered HTML.
To enable it, pass an object containing the DOMPurify options:
dompurify: true
Or you can enable specific DOMPurify options (but according to DOMPurify authors, the default options are safe):
dompurify:
FORBID_TAGS:
- "style"
See https://github.com/cure53/DOMPurify#can-i-configure-dompurify for a full reference of available options
Definition/Description Lists
hexo-renderer-marked
also implements description/definition lists using the same syntax as PHP Markdown Extra.
This Markdown:
Definition Term
: This is the definition for the term
will generate this HTML:
<dl>
<dt>Definition Term</dt>
<dd>This is the definition for the term</dd>
</dl>
Note: There is currently a limitation in this implementation. If multiple definitions are provided, the rendered HTML will be incorrect.
For example, this Markdown:
Definition Term
: Definition 1
: Definition 2
will generate this HTML:
<dl>
<dt>Definition Term<br>: Definition 1</dt>
<dd>Definition 2</dd>
</dl>
If you've got ideas on how to support multiple definitions, please provide a pull request. We'd love to support it.
Extensibility
This plugin overrides some default behaviours of how marked plugin renders the markdown into html, to integrate with the Hexo ecosystem. It is possible to override this plugin too, without resorting to forking the whole thing.
For example, to override how heading like # heading text
is rendered:
hexo.extend.filter.register('marked:renderer', function(renderer) {
const { config } = this; // Skip this line if you don't need user config from _config.yml
renderer.heading = function(text, level) {
// Default behaviour
// return `<h${level}>${text}</h${level}>`;
// outputs <h1>heading text</h1>
// If you want to insert custom class name
return `<h${level} class="headerlink">${text}</h${level}>`;
// outputs <h1 class="headerlink">heading text</h1>
}
})
Save the file in "scripts/" folder and run Hexo as usual.
Notice renderer.heading = function (text, level) {
corresponds to this line. Refer to renderer.js on how this plugin overrides the default methods. For other methods not covered by this plugin, refer to marked's documentation.
Tokenizer
It is also possible to customize the tokenizer.
const { escapeHTML: escape } = require('hexo-util');
// https://github.com/markedjs/marked/blob/b6773fca412c339e0cedd56b63f9fa1583cfd372/src/Lexer.js#L8-L24
// Replace dashes only
const smartypants = (str) => {
return str
// em-dashes
.replace(/---/g, '\u2014')
// en-dashes
.replace(/--/g, '\u2013')
};
hexo.extend.filter.register('marked:tokenizer', function(tokenizer) {
const { smartypants: isSmarty } = this.config.marked;
tokenizer.inlineText = function(src, inRawBlock) {
const { rules } = this;
// https://github.com/markedjs/marked/blob/b6773fca412c339e0cedd56b63f9fa1583cfd372/src/Tokenizer.js#L643-L658
const cap = rules.inline.text.exec(src);
if (cap) {
let text;
if (inRawBlock) {
text = cap[0];
} else {
text = escape(isSmarty ? smartypants(cap[0]) : cap[0]);
}
return {
// `type` value is a corresponding renderer method
// https://marked.js.org/using_pro#inline-level-renderer-methods
type: 'text',
raw: cap[0],
text
};
}
}
});
Extensions
It is also possible to customize the extensions. For example, use KaTeX to render block-level math:
const katex = require('katex');
hexo.extend.filter.register('marked:extensions', function(extensions) {
// Info: `extensions` is an array.
extensions.push({
name: 'blockMath',
level: 'block',
tokenizer(src) {
const cap = /^\s{0,3}\$\$((?:[^\n]|\n[^\n])+?)\n{0,1}\$\$/.exec(src);
if (cap !== null) {
return {
type: 'blockMath',
raw: cap[0],
math: cap[1]
};
}
return undefined;
},
renderer(token) {
return `<p>${katex.renderToString(token.math, {displayMode: true})}</p>\n`;
}
});
});
You may also get access to marked.use
function.
For example to use the marked-alert extention wich also provides a walkTokens
functions:
const markedAlert = require('marked-alert');
hexo.extend.filter.register('marked:use', function (markedUse) {
markedUse(markedAlert());
});