Content server: When using user accounts on the homepage show recently read books from any device not just the current device. Fixes #1998557 [[feature request] Content-server viewer suggesting of book being read on other devices](https://bugs.launchpad.net/calibre/+bug/1998557)

src/calibre/srv/books.py

@@ -13,7 +13,9 @@ from threading import Lock, RLock
 
 from calibre.constants import cache_dir, iswindows
 from calibre.customize.ui import plugin_for_input_format
+from calibre.ebooks.metadata import authors_to_string
 from calibre.srv.errors import BookNotFound, HTTPNotFound
+from calibre.srv.last_read import last_read_cache
 from calibre.srv.metadata import book_as_json
 from calibre.srv.render_book import RENDER_VERSION
 from calibre.srv.routes import endpoint, json
@@ -220,8 +222,14 @@ def set_last_read_position(ctx, rd, library_id, book_id, fmt):
         device, cfi, pos_frac = data['device'], data['cfi'], data['pos_frac']
     except Exception:
         raise HTTPNotFound('Invalid data')
+    cfi = cfi or None
     db.set_last_read_position(
-        book_id, fmt, user=user, device=device, cfi=cfi or None, pos_frac=pos_frac)
+        book_id, fmt, user=user, device=device, cfi=cfi, pos_frac=pos_frac)
+    if user:
+        with db.safe_read_lock:
+            tt = db._field_for('title', book_id)
+            tt += ' ' + _('by') + ' ' + authors_to_string(db._field_for('authors', book_id))
+        last_read_cache().add_last_read_position(library_id, book_id, fmt, user, cfi, pos_frac, tt)
     rd.outheaders['Content-type'] = 'text/plain'
     return b''
 

src/calibre/srv/code.py

@@ -18,6 +18,7 @@ from calibre.srv.ajax import search_result
 from calibre.srv.errors import (
     BookNotFound, HTTPBadRequest, HTTPForbidden, HTTPNotFound, HTTPRedirect,
 )
+from calibre.srv.last_read import last_read_cache
 from calibre.srv.metadata import (
     book_as_json, categories_as_json, categories_settings, icon_map,
 )
@@ -167,6 +168,9 @@ def basic_interface_data(ctx, rd):
         'lang_code_for_user_manual': lang_code_for_user_manual(),
     }
     ans['library_map'], ans['default_library_id'] = ctx.library_info(rd)
+    if ans['username']:
+        lrc = last_read_cache()
+        ans['recently_read_by_user'] = lrc.get_recently_read(ans['username'])
     return ans
 
 

src/calibre/srv/last_read.py

@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+# vim:fileencoding=utf-8
+# License: GPL v3 Copyright: 2022, Kovid Goyal <kovid at kovidgoyal.net>
+
+import apsw
+import os
+from contextlib import suppress
+from threading import Lock
+from time import time_ns
+
+from calibre.constants import cache_dir
+
+creation_sql = '''
+CREATE TABLE IF NOT EXISTS last_read_positions ( id INTEGER PRIMARY KEY,
+    library_id TEXT NOT NULL,
+    book INTEGER NOT NULL,
+    format TEXT NOT NULL COLLATE NOCASE,
+    user TEXT NOT NULL,
+    cfi TEXT NOT NULL,
+    epoch INTEGER NOT NULL,
+    pos_frac REAL NOT NULL DEFAULT 0,
+    tooltip TEXT NOT NULL,
+    UNIQUE(user, library_id, book, format)
+);
+CREATE INDEX IF NOT EXISTS users_id ON last_read_positions (user);
+'''
+
+lock = Lock()
+
+
+class LastReadCache:
+
+    def __init__(self, path='', limit=5):
+        self.limit = limit
+        self.conn = apsw.Connection(path or os.path.join(cache_dir(), 'srv-last-read.sqlite'))
+        self.execute(creation_sql)
+
+    def get(self, *args, **kw):
+        ans = self.conn.cursor().execute(*args)
+        if kw.get('all', True):
+            return ans.fetchall()
+        with suppress(StopIteration, IndexError):
+            return next(ans)[0]
+
+    def execute(self, sql, bindings=None):
+        cursor = self.conn.cursor()
+        return cursor.execute(sql, bindings)
+
+    def add_last_read_position(self, library_id, book_id, fmt, user, cfi, pos_frac, tooltip):
+        with lock, self.conn:
+            if not cfi:
+                self.execute(
+                    'DELETE FROM last_read_positions WHERE library_id=? AND book=? AND format=? AND user=?',
+                    (library_id, book_id, fmt, user))
+            else:
+                epoch = time_ns()
+                self.execute(
+                    'INSERT OR REPLACE INTO last_read_positions(library_id,book,format,user,cfi,epoch,pos_frac,tooltip) VALUES (?,?,?,?,?,?,?,?)',
+                    (library_id, book_id, fmt, user, cfi, epoch, pos_frac, tooltip))
+                items = tuple(self.get('SELECT epoch FROM last_read_positions WHERE user=? ORDER BY epoch DESC', (user,), all=True))
+                if len(items) > self.limit:
+                    limit_epoch = items[self.limit][0]
+                    self.execute('DELETE FROM last_read_positions WHERE user=? AND epoch <= ?', (user, limit_epoch))
+                return epoch
+
+    def get_recently_read(self, user):
+        with lock:
+            ans = []
+            for library_id, book, fmt, cfi, epoch, pos_frac, tooltip in self.execute(
+                'SELECT library_id,book,format,cfi,epoch,pos_frac,tooltip FROM last_read_positions WHERE user=? ORDER BY epoch DESC', (user,)
+            ):
+                ans.append({
+                    'library_id': library_id, 'book_id': book, 'format': fmt,
+                    'cfi': cfi, 'epoch':epoch, 'pos_frac':pos_frac, 'tooltip': tooltip,
+                })
+            return ans
+
+
+path_cache = {}
+
+
+def last_read_cache(path=''):
+    with lock:
+        ans = path_cache.get(path)
+        if ans is None:
+            ans = path_cache[path] = LastReadCache(path)
+    return ans

src/calibre/srv/tests/content.py

@@ -262,3 +262,18 @@ class ContentTest(LibraryBaseTest):
         text = 'a' * (127 * 1024)
         t('<p>{0}<p>{0}'.format(text), [{"n":"p","x":text}, {'n':'p','x':text}])
     # }}}
+
+    def test_last_read_cache(self):  # {{{
+        from calibre.srv.last_read import last_read_cache, path_cache
+        path_cache.clear()
+        lrc = last_read_cache(':memory:')
+        epoch = lrc.add_last_read_position('lib', 1, 'FMT', 'user', 'epubcfi(/)', 0.1, 'tt')
+        expected = {'library_id': 'lib', 'book_id': 1, 'format': 'FMT', 'cfi': 'epubcfi(/)', 'epoch': epoch, 'pos_frac': 0.1, 'tooltip': 'tt'}
+        self.ae(lrc.get_recently_read('user'), [expected])
+        epoch = lrc.add_last_read_position('lib', 1, 'FMT', 'user', 'epubcfi(/)', 0.2, 'tt')
+        expected['epoch'], expected['pos_frac'] = epoch, 0.2
+        self.ae(lrc.get_recently_read('user'), [expected])
+        for book_id in range(2, 7):
+            lrc.add_last_read_position('lib', book_id, 'FMT', 'user', 'epubcfi(/)', 0.1, 'tt')
+        self.ae(len(lrc.get_recently_read('user')), lrc.limit)
+    # }}}

src/pyj/book_list/home.pyj

@@ -3,16 +3,18 @@
 from __python__ import bound_methods, hash_literals
 
 from elementmaker import E
-from gettext import gettext as _
 
-from ajax import ajax_send
+from ajax import absolute_path, ajax_send
 from book_list.cover_grid import BORDER_RADIUS
 from book_list.globals import get_db
-from book_list.library_data import last_virtual_library_for, sync_library_books, all_libraries
-from book_list.router import open_book, update_window_title
+from book_list.library_data import (
+    all_libraries, last_virtual_library_for, sync_library_books
+)
+from book_list.router import open_book, open_book_url, update_window_title
 from book_list.top_bar import add_button, create_top_bar
 from book_list.ui import set_default_panel_handler, show_panel
 from dom import add_extra_css, build_rule, clear, ensure_id, set_css, unique_id
+from gettext import gettext as _
 from modals import create_custom_dialog
 from session import get_device_uuid, get_interface_data
 from utils import conditional_timeout, safe_set_inner_html, username_key
@@ -98,17 +100,44 @@ def start_sync(to_sync):
         sync_library_books(lid, libraries[lid], sync_data_received)
 
 
-def show_recent_stage2(books):
-    container = document.getElementById(this)
-    if not container or not books.length:
-        return
+def prepare_recent_container(container):
     container.style.display = 'block'
     container.style.borderBottom = 'solid 1px currentColor'
     container.style.paddingBottom = '1em'
     container.appendChild(E.h2(_(
         'Continue reading…')))
     container.appendChild(E.div(style='display:flex'))
-    images = container.lastChild
+    cover_container = container.lastChild
+    container.appendChild(E.div(style='margin: 1rem 1rem',
+        create_button(
+            _('Browse all downloaded books…'),
+            action=def():
+                show_panel('local_books')
+    )))
+    return cover_container
+
+
+def show_recent_for_user(container_id, interface_data):
+    container = document.getElementById(container_id)
+    images = prepare_recent_container(container)
+    for item in interface_data.recently_read_by_user[:3]:
+        q = {'library_id': item.library_id}
+        if item.cfi:
+            q.bookpos = item.cfi
+        url_to_read = open_book_url(item.book_id, item.format, q)
+        images.appendChild(E.div(style='margin: 0 1em',
+            E.a(
+                title=item.tooltip,
+                href=url_to_read,
+                E.img(alt=item.tooltip, src=absolute_path(f'get/cover/{item.book_id}/{item.library_id}'))
+        )))
+
+
+def show_recent_stage2(books):
+    container = document.getElementById(this)
+    if not container or not books.length:
+        return
+    images = prepare_recent_container(container)
     db = get_db()
     to_sync = v'[]'
     username = get_interface_data().username
@@ -129,12 +158,6 @@ def show_recent_stage2(books):
         if book.cover_name:
             db.get_file(book, book.cover_name, show_cover.bind(img_id))
     start_sync(to_sync)
-    container.appendChild(E.div(style='margin: 1rem 1rem',
-        create_button(
-            _('Browse all downloaded books…'),
-            action=def():
-                show_panel('local_books')
-    )))
 
 
 def show_recent():
@@ -242,6 +265,9 @@ def init(container_id):
     recent = E.div(style='display:none', class_='recently-read')
     recent_container_id = ensure_id(recent)
     container.appendChild(recent)
+    if interface_data.username and interface_data.recently_read_by_user and interface_data.recently_read_by_user.length > 0:
+        show_recent_for_user(recent_container_id, interface_data)
+    else:
         conditional_timeout(recent_container_id, 5, show_recent)
 
     # Choose library

src/pyj/session.pyj

@@ -243,6 +243,7 @@ default_interface_data = {
     'custom_list_template': None,
     'num_per_page': 50,
     'lang_code_for_user_manual': '',
+    'recently_read_by_user': v'[]',
 }
 
 def get_interface_data():