Add configuration for markdown processing (#1601)

config/vufind/markdown.ini

+; This file could be used to define configuration of markdown to HTML converter.
+; More detailed configuration documentation could be found here:
+; https://github.com/thephpleague/commonmark/blob/master/docs/1.0/configuration.md
+[Markdown]
+; How to handle HTML input. Options are: strip, allow, escape. Defaults to strip
+;html_input = allow
+; Remove risky link and image URLs by setting this to false. Defaults to false
+;allow_unsafe_links = true
+; String to use for separating renderer block elements
+;renderer[block_separator] = "\n"
+; String to use for separating inner block contents
+;renderer[inner_separator] = "\n"
+; String to use for rendering soft breaks
+;renderer[inner_separator] = "\n"
+; Enable or disable <em> parsing. Enabled by default
+;enable_em = false
+; Enable or disable <strong> parsing. Enabled by default
+;enable_strong = false
+; Enable or disable parsing of '*' for emphasis. Enabled by default
+;use_asterisk = false
+; Enable or disable parsing of '_' for emphasis. Enabled by default
+;use_underscore = false
+; Array of characters that can be used to indicated a bulleted list (default:
+; ["-", "*", "+"])
+;unordered_list_markers[] = "-"
+;unordered_list_markers[] = "*"
+;unordered_list_markers[] = "+"
+; The maximum nesting level for blocks (default: infinite). Setting this to a
+; positive integer can help protect against long parse times and/or segfaults if
+; blocks are too deeply-nested.
+;max_nesting_level = 10
+

module/VuFind/src/VuFind/Service/MarkdownFactory.php

@@ -63,10 +63,28 @@ class MarkdownFactory implements FactoryInterface
     public function __invoke(
         ContainerInterface $container, $requestedName, array $options = null
     ) {
+        $config = $container->get(\VuFind\Config\PluginManager::class)
+            ->get('markdown')->Markdown;
         return new GithubFlavoredMarkdownConverter(
             [
-            'html_input' => 'strip',
-            'allow_unsafe_links' => false,
+                'html_input' => $config->html_input ?? 'strip',
+                'allow_unsafe_links' => $config->allow_unsafe_links ?? false,
+                'enable_em' => $config->enable_em ?? true,
+                'enable_strong' => $config->enable_strong ?? true,
+                'use_asterisk' => $config->use_asterisk ?? true,
+                'use_underscore' => $config->use_underscore ?? true,
+                'unordered_list_markers' => isset($config->unordered_list_markers)
+                    && $config->unordered_list_markers instanceof \ArrayAccess
+                        ? $config->unordered_list_markers->toArray()
+                        : ['-', '*', '+'],
+                'max_nesting_level' => $config->max_nesting_level ?? \INF,
+                'renderer' => [
+                    'block_separator'
+                        => $config->renderer['block_separator'] ?? "\n",
+                    'inner_separator'
+                        => $config->renderer['inner_separator'] ?? "\n",
+                    'soft_break' => $config->renderer['soft_break'] ?? "\n",
+                ],
             ]
         );
     }