Render url in reference

Fully agree with lolcode (#5). Any plans on this?

Individual sites could also potentially rewrite such URLs as actual hyperlinks by implementing HOOK__preprocess_bibcite_citation(), which provides access to the already-rendered citation. Presumably you could use regular expressions to find/replace specific markup with hyperlinks. This would not be as elegant a solution as using Lambda functions to modify the citation processor itself, as described in https://github.com/seboettg/citeproc-php#use-lambda-functions-to-setup-c... , but might be more straightforward for some developers.

Thanks. Yes, that should be possible but because I also want to put the title into a span, I would have to rerender the whole citation in HOOK__preprocess_bibcite_citation().
This can be avoided by overriding the BibCiteProcessor plugin (citeproc-php) with HOOK_bibcite_bibcite_processor_info_alter() and passing the lambda functions to CiteProc() in render() there.

Okay, changing this to a "Support request." Let's try to add some documentation that shows example usage of both HOOK__preprocess_bibcite_citation() and HOOK_bibcite_bibcite_processor_info_alter()

This is the first time I am posting; unsure how to proceed. If appropriate I can supply some code snippets related to the info_alter option.

This is the first time I am posting; unsure how to proceed. If appropriate I can supply some code snippets related to the info_alter option.

Code snippets in a comment would be a great start. I can then move them into a new page under the documentation at https://www.drupal.org/docs/contributed-modules/bibliography-citation →

In MYMODULE.module:

/**
 * Overwrite the plugin Drupal\bibcite\Plugin\BibCiteProcessor\CiteprocPhp.
 * We want to be able to use the Lambda functions of seboettg/citeproc-php.
 * See \vendor\seboettg\citeproc-php\README.md.
 *
 * (If it is not clear whether this function gets called, flush
 * the plugins cache...)
 */
function MYMODULE_bibcite_bibcite_processor_info_alter(array &$definitions) {
  $definitions['citeproc-php']['class'] =
  'Drupal\MYMODULE\Plugin\BibCiteProcessor\CiteprocPhpFOOBAR';
}

MYMODULE\src\Plugin\BibCiteProcessor\CiteprocPhpFOOBAR.php:

<?php

namespace Drupal\MYMODULE\Plugin\BibCiteProcessor;

use Seboettg\CiteProc\CiteProc;
use Drupal\bibcite\Plugin\BibCiteProcessor\CiteprocPhp;

/**
 * Defines a style provider based on citeproc-php library.
 * This class extends the original class 
 * \vendor\seboettg\citeproc-php\src\CiteProc.php.
 *
 * @BibCiteProcessor(
 *   id = "citeproc-php-FOOBAR",
 *   label = @Translation("Citeproc PHP (FOOBAR)"),
 * )
 */
class CiteprocPhpFOOBAR extends CiteprocPhp {

  /**
   * {@inheritdoc}
   *
   * WARNING: This function is an example only. Your mileage *will* vary
   * depending on several factors; e.g. the CSL you are using.
   */
  public function render($data, $csl, $lang) {
    //
    // The following are Lambda functions for seboettg/citeproc-php.
    // See \vendor\seboettg\citeproc-php\README.md.
    $title_function = function($cslItem, $renderedText) {
      //
      // Add some classes to the title
      $title = '<span class="citeproc-title-and-descriptions">';
      $title .= '<span class="citeproc-title">';
      $title .= $renderedText;
      $title .= '</span></span>';
      return $title;
    };
    $doi_function = function($cslItem, $renderedText) {
      //
      // Pack the URL in an anchor
      //
      // WARNING: The situation here is quite complicated
      // and what can be done here probably depends on the
      // active CSL and on the contents of the DOI field 
      // in your bibcite records.
      // (See also the comment below.)
      $doi_link = '<span class="citeproc-access">';
      $doi_link .= '<a href="';
      if (!str_starts_with($renderedText, 'http')) {
        $doi_link .= 'https://doi.org/';
      }
      $doi_link .= $renderedText . '" target="_blank">';
      $doi_link .= '(abstract)</a></span>';
      return $doi_link;
    };
    $additionalMarkup = [
      'title' => $title_function,
      'DOI' => $doi_function
    ];
    
    $cite_proc = new CiteProc($csl, $lang, $additionalMarkup);
    if (!$data instanceof \stdClass) {
      $data = json_decode(json_encode($data));
    }
    $res = preg_replace('/(\\n|\r)( *)/', '', $cite_proc->render([$data]));
    //
    // CSLs can contain prefixes and suffixes. They are added  
    // only *after* the lambda functions above have run. As an 
    // alternative to the code below we could of course craft 
    // our own CSLs...
    //
    // We have to remove the prefix ('https://doi.org/') of the 
    // access field here because it has been added *after* we have 
    // already added a span around our anchor tag in $doi_function.
    $res = str_replace('https://doi.org/<span class="citeproc-access">',
                       '<span class="citeproc-access">', $res);
    //
    // Remove some unwanted <i>-Tags
    $res = str_replace(array('<i>', '</i>'), '', $res);
    return $res;
  }
}

After thinking about this further, I think that this is a common, reasonable request that should not require a developer in order to accomplish. I therefore propose adding a new, global setting to Bibcite for "Convert URLs into hyperlinks".

When enabled, this will pass the already-processed citation through Drupal core's _filter_url() function, which is robust and designed to handled a wide range of HTML content.

This approach does not give sites the ability to have some URLs be hyperlinks and others not be hyperlinks -- that, I feel, still should be the purlieu of developers and custom code.

As this is an opt-feature, I feel comfortable merging this in; should there need to be refinements, we can work those out subsequently.