Implement picking a random book

src/calibre/srv/code.py

@@ -4,7 +4,7 @@
 
 from __future__ import (unicode_literals, division, absolute_import,
                         print_function)
-import re, hashlib
+import re, hashlib, random
 from functools import partial
 from threading import Lock
 from json import load as load_json_file
@@ -216,17 +216,27 @@ def get_books(ctx, rd):
                 mdata[book_id] = data
     return ans
 
-@endpoint('/interface-data/book-metadata/{book_id}', postprocess=json, types={'book_id': int})
+@endpoint('/interface-data/book-metadata/{book_id=0}', postprocess=json)
 def book_metadata(ctx, rd, book_id):
     '''
-    Get metadata for the specified book
+    Get metadata for the specified book. If no book_id is specified, return metadata for a random book.
 
     Optional: ?library_id=<default library>
     '''
     library_id, db = get_basic_query_data(ctx, rd.query)[:2]
+    book_ids = ctx.allowed_book_ids(rd, db)
+    def notfound():
+        raise HTTPNotFound(_('No book with id: %d in library') % book_id)
+    if not book_ids:
+        notfound()
+    if not book_id:
+        book_id = random.choice(tuple(book_ids))
+    elif book_id not in book_ids:
+        notfound()
     data = book_as_json(db, book_id)
     if data is None:
-        raise HTTPNotFound('No book with id: %d in library' % book_id)
+        notfound()
+    data['id'] = book_id
     return data
 
 @endpoint('/interface-data/tag-browser')

src/pyj/book_list/book_details.pyj

@@ -58,9 +58,7 @@ class BookDetailsPanel:
     def fetch_metadata(self, book_id):
         if self.is_fetching:
             self.is_fetching.abort()
-        def fetched(end_type, xhr, ev):
+        self.is_fetching = ajax('interface-data/book-metadata/' + book_id, self.metadata_fetched.bind(self),
-            self.metadata_fetched(book_id, end_type, xhr, ev)
-        self.is_fetching = ajax('interface-data/book-metadata/' + book_id, fetched,
                                 query={'library_id':self.interface_data.library_id})
         self.is_fetching.send()
         self.container.appendChild(E.div(
@@ -68,7 +66,7 @@ class BookDetailsPanel:
             create_spinner(), '\xa0' + _('Fetching metadata for the book, please wait') + '…',
         ))
 
-    def metadata_fetched(self, book_id, end_type, xhr, event):
+    def metadata_fetched(self, end_type, xhr, event):
         if self.is_fetching is None or self.is_fetching is not xhr:
             return  # Fetching was aborted
         self.is_fetching = None
@@ -80,6 +78,7 @@ class BookDetailsPanel:
                 error_dialog(_('Could not fetch metadata for book'), _('Server returned an invalid response'), err.stack or err.toString())
                 return
             clear(c)
+            book_id = data['id']
             self.interface_data.metadata[book_id] = data
             self.render_book(book_id)
         elif end_type != 'abort':
@@ -98,12 +97,13 @@ class BookDetailsPanel:
         alt = str.format(_('{} by {}'), metadata['title'], metadata['authors'].join(' & '))
         img = E.img(
             src=cover_url, alt=alt, title=alt, data_title=metadata['title'], data_authors=metadata['authors'].join(' & '),
-            style='margin-left: 1em; max-width: 45vw; max-height: 95vh; display: block; width:auto; height:auto'
+            style='max-width: 45vw; max-height: 93vh; display: block; width:auto; height:auto'
         )
         img.onerror = self.on_img_err.bind(self)
         c = self.container
         c.appendChild(E.div(
-            E.div(),
+            style='display:flex; flex-wrap: wrap; align-items:flex-start; padding: 1ex 1em',
+            E.div(style='margin-right: 1em'),
             img
         ))
 

src/pyj/book_list/ui.pyj

@@ -67,6 +67,9 @@ def create_book_view_top_bar_state(books_view):
     ibs.add_button(icon_name='ellipsis-v', tooltip=_('More actions'), action=show_panel_action('more-actions-menu'))
     return ibs
 
+def random_book():
+    get_boss().ui.replace_panel('book-details', extra_query_data={'book-id':'0'})
+
 class UI:
 
     ROOT_PANEL = 'books'
@@ -85,6 +88,7 @@ class UI:
 
         self.panel_map['more-actions-menu'] = UIState(ClosePanelBar(_('More actions')), panel_data=[
             create_item(_('Book List Mode'), replace_panel_action('booklist-mode-menu'), _('Change how the list of books is displayed')),
+            create_item(_('A Random Book'), random_book, _('Choose a random book from your library')),
         ])
 
         self.panel_map['booklist-mode-menu'] = UIState(ClosePanelBar(_('Book List Mode')), panel_data=[])
@@ -132,11 +136,11 @@ class UI:
         else:
             self.show_panel(self.ROOT_PANEL)
 
-    def replace_panel(self, panel_name, force=False):
+    def replace_panel(self, panel_name, force=False, extra_query_data=None):
         action_needed = force or panel_name != self.current_panel
         if action_needed:
             self.current_panel = panel_name or self.ROOT_PANEL
-        get_boss().push_state(replace=True)
+        get_boss().push_state(replace=True, extra_query_data=extra_query_data)
         if action_needed:
             self.apply_state()