More work on the new viewer

src/calibre/gui2/viewer2/web_view.py

@@ -47,6 +47,7 @@ def get_data(name):
             return f.read(), guess_type(name)
     except EnvironmentError as err:
         prints('Failed to read from book file: {} with error: {}'.format(name, as_unicode(err)))
+    return None, None
 
 
 class UrlSchemeHandler(QWebEngineUrlSchemeHandler):

src/pyj/viewer-main.pyj

@@ -2,15 +2,21 @@
 # License: GPL v3 Copyright: 2018, Kovid Goyal <kovid at kovidgoyal.net>
 from __python__ import bound_methods, hash_literals
 
-
+import traceback
 from elementmaker import E
-from read_book.globals import runtime, ui_operations
+from gettext import gettext as _
+
+from ajax import ajax
+from modals import error_dialog
 from qt import from_python
+from read_book.globals import runtime, ui_operations
+
 
 def container_div(id):
     return E.div(id=id, style='margin: 0; padding: 0; display: none')
 
 runtime.is_standalone_viewer = True
+book_manifest = None
 
 
 def get_file(book, name, proceed):
@@ -29,9 +35,39 @@ def show_error(title, msg, details):
     pass  # TODO: Implement this
 
 
+def manifest_received(end_type, xhr, ev):
+    nonlocal book_manifest
+    if end_type is 'load':
+        book_manifest = xhr.response
+    else:
+        error_dialog(_('Could not open book'), _(
+            'Failed to load book manifest, click "Show details" for more info'),
+        xhr.error_html or None)
+
+
 @from_python
 def start_book_load():
-    print(111111111111111)
+    ajax('book/calibre-book-manifest.json', manifest_received, ok_code=0).send()
+
+
+def onerror(msg, script_url, line_number, column_number, error_object):
+    if error_object is None:
+        # This happens for cross-domain errors (probably javascript injected
+        # into the browser via extensions/ userscripts and the like). It also
+        # happens all the time when using Chrom on Safari, so ignore this
+        # type of error
+        console.log(f'Unhandled error from external javascript, ignoring: {msg} {script_url} {line_number}')
+        return
+    console.log(error_object)
+    try:
+        fname = script_url.rpartition('/')[-1] or script_url
+        msg = msg + '<br><span style="font-size:smaller">' + 'Error at {}:{}:{}'.format(fname, line_number, column_number or '') + '</span>'
+        details = ''
+        details = traceback.format_exception(error_object).join('')
+        error_dialog(_('Unhandled error'), msg, details)
+        return True
+    except:
+        console.log('There was an error in the unhandled exception handler')
 
 
 if window is window.top:
@@ -42,6 +78,7 @@ if window is window.top:
     ui_operations.show_error = show_error
     document.body.appendChild(E.div(id='loading'))
     document.body.appendChild(E.div(id='view'))
+    window.onerror = onerror
 else:
     # iframe
     pass