Add a BlackFriday option for rel="noreferrer" on external links

Add a configuration option "noreferrerLinks". When set to "true" the "HTML_NOREFERRER_LINKS" flag is being passed to Blackfriday. Thereby all *absolute* links will get a "noreferrer" value for their "rel" attribute.

See #4722
This commit is contained in:
Stefan Neuhaus 2018-05-27 23:20:39 +02:00 committed by Bjørn Erik Pedersen
parent a6e279362b
commit a41ad0254e

View File

@ -48,6 +48,11 @@
Blackfriday flag: **`HTML_NOFOLLOW_LINKS`** <br>
Purpose: `true` creates <s>external links</s> **absolute** links with `nofollow` being added to their `rel` attribute. Thereby crawlers are advised to not follow the link. While the `rel="nofollow"` attribute is typically used for external links, Blackfriday does that for _all_ absolute links. One needs to make note of this if they use absolute links throughout, for internal links too (for example, by setting `canonifyURLs` to `true` or via `absURL`).
`noreferrerLinks`
: default: **`false`** <br>
Blackfriday flag: **`HTML_NOREFERRER_LINKS`** <br>
Purpose: `true` creates <s>external links</s> **absolute** links with `noreferrer` being added to their `rel` attribute. Thus when following the link no referrer information will be leaked. While the `rel="noreferrer"` attribute is typically used for external links, Blackfriday does that for _all_ absolute links. One needs to make note of this if they use absolute links throughout, for internal links too (for example, by setting `canonifyURLs` to `true` or via `absURL`).
`plainIDAnchors`
: default **`true`** <br>
Blackfriday flag: **`FootnoteAnchorPrefix` and `HeaderIDSuffix`** <br>