Refactor book details web search link generating code to make it re-useable in server

src/calibre/ebooks/metadata/book/render.py

@@ -67,16 +67,21 @@ def search_action_with_data(search_term, value, book_id, field=None, **k):
     return search_action(search_term, value, field=field, book_id=book_id, **k)
 
 
+def web_search_link(template, mi, value):
+    formatter = SafeFormat()
+    mi.set('item_value', value)
+    u = formatter.safe_format(template, mi, 'BOOK DETAILS WEB LINK', mi)
+    if u:
+        return u, prepare_string_for_xml(_('Click to browse to: {}').format(u), attribute=True)
+    return '', ''
+
+
 def cc_search_action_with_data(search_term, value, book_id, fm, mi, field=None,  **k):
     if mi is not None and fm is not None:
         if template := fm.get('display', {}).get('web_search_template'):
             try:
-                formatter = SafeFormat()
-                mi.set('item_value', value)
-                u = formatter.safe_format(template, mi, 'BOOK DETAILS WEB LINK', mi)
-                if u:
-                    v = prepare_string_for_xml(_('Click to browse to {}').format(u), attribute=True)
-                    return action('cc_url', url=u), v
+                u, v = web_search_link(template, mi, value)
+                return action('cc_url', url=u), v
             except Exception:
                 import traceback
                 traceback.print_exc()
@@ -91,6 +96,13 @@ def notes_action(**keys):
 DEFAULT_AUTHOR_LINK = f'search-{DEFAULT_AUTHOR_SOURCE}'
 
 
+def resolve_default_author_link(ans: str | None = None) -> str:
+    if ans == 'https://en.wikipedia.org/w/index.php?search={author}':
+        # The old default value for this setting
+        ans = ''
+    return ans or DEFAULT_AUTHOR_LINK
+
+
 def author_search_href(which, title=None, author=None):
     if which == 'calibre':
         return 'calibre', _('Search the calibre library for books by %s') % author

src/calibre/gui2/__init__.py

@@ -630,12 +630,8 @@ QSettings.setDefaultFormat(QSettings.Format.IniFormat)
 
 
 def default_author_link():
-    from calibre.ebooks.metadata.book.render import DEFAULT_AUTHOR_LINK
-    ans = gprefs.get('default_author_link')
-    if ans == 'https://en.wikipedia.org/w/index.php?search={author}':
-        # The old default value for this setting
-        ans = DEFAULT_AUTHOR_LINK
-    return ans or DEFAULT_AUTHOR_LINK
+    from calibre.ebooks.metadata.book.render import resolve_default_author_link
+    return resolve_default_author_link(gprefs.get('default_author_link'))
 
 
 def available_heights():

src/calibre/srv/metadata.py

@@ -165,6 +165,22 @@ def get_gpref(name: str, defval=None):
     return gprefs.get(name, defval)
 
 
+def web_search_link(db, book_id: int, field: str, item_val: str) -> tuple[str, str]:
+    from calibre.ebooks.metadata.book.render import render_author_link, resolve_default_author_link, web_search_link
+    if field == 'authors':
+        default_author_link = resolve_default_author_link(get_gpref('default_author_link'))
+        author_sort = db.author_sort_from_authors((item_val,))
+        url, tooltip = render_author_link(default_author_link, item_val, author_sort, db.field_for('title', book_id))
+    else:
+        metadata = db.field_metadata.get(field)
+        if metadata is None or not (template := metadata.get('display', {}).get('web_search_template')):
+            return '', ''
+        url, tooltip = web_search_link(template, db.get_metadata(book_id), item_val)
+    if url.partition(':')[0].lower() in ('http', 'https'):
+        return url, tooltip
+    return '', ''
+
+
 def get_icon_for_node(node, parent, node_to_tag_map, tag_map, eval_formatter, db):
     category = node['category']
     if category in ('search', 'formats') or category.startswith('@'):