textformatter Automatically link page titles

[MoritzLost 122]

This is a textformatter module that will automatically replace titles of other pages on your site with links to those pages. For example, if you have a template glossary-term, and mention the exact title of one page using that template in a textfield, the title will be automatically linked to that page (if the textfield uses that formatter). This is good for SEO, and saves you some manual labour. You can configure which templates should get automatically linked, and of course the formatter is only active for the fields you add this formatter to. Note that if you need more manual control over when and where titles are automatically linked, you're probably better of using Autolink from a Glossary by @mr-fan.

Features

• Allows you to limit the automatic links by template.
• Only includes published & visible pages by default, with an option to include hidden pages.
• Automatically excludes the current page, with an option to change that behaviour.
• Allows you to configure the minimum title length for linked pages.
• Doesn't overwrite existing links, and detects most edge cases (titles inside other tag's attributes, titles inside existing links et c.).
• Supports multi-language sites. Titles will only be linked if a title in the current language is set.
• Can add configurable attributes to all automatically created links.
  • Includes the ability to use page fields as replacement patterns for attributes. For example, you can create CSS classes that include the name of the template of the linked page.
• Prefer oldest or newest page in the case of duplicate titles.
• Queries the database directly for improved performance.
  • Only queries the database once per request & language.

Download & Documentation

The module is now available in the modules directory: https://modules.processwire.com/modules/textformatter-page-title-links/
You can download & install it through the backend using the classname TextformatterPageTitleLinks.

To install it manually, download or clone the module from the Github repository into your site/modules folder and install through the backend.

The complete documentation can be found in the README in the repository. Make sure to check out the module configuration page after installing the module.

Requirements

• PHP 7.1 or higher
• ProcessWire 3+ (it will probably work in older versions, I haven't tested those though).

This is my first module, I hope it may become useful to some of you

If you find any errors or have some other suggestions or feedback, let me know!

Edited February 3 by MoritzLost
Updated features section to include most recent additions

[MoritzLost 122]

Changelog

Version 2.1.0

• Feature: Prefer the oldest or the most recent page for automatic linking, in the case that two or more pages have the same title. Defaults to linking the oldest page. This is technically backwards-incompatible, as previously the selection of the linked page was pseudo-random in this case, but it's a pretty niche case.
• Feature: Set the minimum length for linkable pages. If you have pages with very short titles that appear commonly in different places, you might not want those linked every time. For example, if you set the minimum length to 5 characters, pages whose title is only four characters or shorter will never be linked.
  • Tiny caveat: The length detection doesn't work correctly with emoji (or probably any 4-byte UTF8 character in the title). No idea why, the query uses CHAR_LENGTH which is supposed to accurately report multi-byte string length. If you know more about this, let me know!
• Bugfix: Version 2.0.0 changed the query in a way that would cause errors on older versions of MySQL, this is now fixed. Previous version might have thrown errors depending on the MySQL configuration (specifically, if ONLY_FULL_GROUP_BY was active), this should also  not happen anymore.
• Miscellaneous
  • I expanded the README, it now has a section about how to use the formatter manually. There are a couples of gotchas to this, so it could be helpful to beginners.
  • The attribute settings are now parsed using preg_split instead of explode. This should prevent potential issues with windows-style CRLF linebreaks.

Version 2.0.0

• Backward incompatible changes
  • Version 2.0.0 changes how titles are selected from the database and matched in text fields (see below for details). This is why this gets a major version number bump.
  • The previous CSS classes setting has been removed in favour of the more general attributes setting (see below).
• Feature: Better HTML detection and edge case prevention
  • The module got much better at checking the surroundings of a title to make sure it doesn't produce invalid HTML. In particular, it will now detect the following scenarios leave those as-is:
    • If a page title is already inside anchor-tags.
    • If a page title is inside attributes of other tags (for example, the description in a title-attribute.
  • That said,  the module still uses regex to find and replace titles, so it will never be able to cover all scenarios. For example, it will not detect if a page title is inside other tags that are not anchor tags (e.g. spans) which are in turn inside another anchor. So this module shouldn't be used on text fields where you need lots of custom HTML and intricate HTML structures.
• Feature: Configure arbitrary attributes to include in the created links
  • You can now add attributes such as title, class, target, custom data-* attributes or anything you want to the links. This includes standalone attributes (without a value).
  • For the attribute values, you can use replacement patterns that are passed to $page->getText(). For example, you can annotate the links with descriptive titles for accessibility or generate a class absed on the template of the linked page. Check out the examples on the module settings page!
• Feature: Longer titles get linked preferrentially
  • If the title of one page is contained within the title of another page, the page with the longer title will get linked, not the shorter one. For example, if you have two pages titled "Content" and "Content Management System", the entire phrase "Content Management System" will be linked to the corresponding page. The page "Content" will not be linked in that instance. Of course, if in another part of the text you only have the word "Content", it will still be linked to the page as usual.
  • This change was made possible by the detection of the edge cases mentioned above. Previously, the module would create the shorter links first to avoid creating nested links.
  • The reason for this change is that longer titles tend to be more relevant for internal links. For example, in the previous case, the word "Content" could appear in many contexts not necessarily related to the page "Content", whereas the phrase "Content Management System" is much more specific. I may make this behaviour optional if there is a usecase for it. If you need this for some reason, let me know.
• Feature: Unicode support
  • Now works with diacritics and emoji in the titles. To be fair, it was mostly working already, but now the regex includes the u Flag to explicitly turn off UTF-8 compatible functionality.
  • There's still an edge case regarding diacritics (try creating two pages "Apfel" and "Äpfel" and you'll see it ...). I don't have a fix for it at this point, but it only occurs in very specific scenarios, so for now it'll do.
• Bug fixes
  • Correctly detects multilanguage sites. Previously it would fail on a multilanguage site that used a non-multilangue title field.
  • Adjusted the main database query to not produce warnings when fed directly to MySQL in certain configurations.

Edited February 3 by MoritzLost
Added version 2.1.0 information

[MoritzLost 122]

I just pushed version 2.1.0 to Github & the modules directory! Includes a minimum length settings for linkable titles, a preference to link the oldest or most recent page if multiple pages have the same title, and an important bugfix for older MySQL versions. Check out the full changelog above