Content server: Add an option to control the timeout for making AJAX queries to the server. Fixes #1722016 [Private bug](https://bugs.launchpad.net/calibre/+bug/1722016)

src/calibre/srv/code.py

@@ -48,16 +48,14 @@ def robots(ctx, rd):
     return b'User-agent: *\nDisallow: /'
 
 
-@endpoint('/auto-reload-port', auth_required=False, cache_control='no-cache')
-def auto_reload(ctx, rd):
+@endpoint('/ajax-setup', auth_required=False, cache_control='no-cache', postprocess=json)
+def ajax_setup(ctx, rd):
     auto_reload_port = getattr(rd.opts, 'auto_reload_port', 0)
-    rd.outheaders.set('Content-Type', 'text/plain')
-    return str(max(0, auto_reload_port))
-
-
-@endpoint('/allow-console-print', cache_control='no-cache', auth_required=False)
-def allow_console_print(ctx, rd):
-    return 'y' if getattr(rd.opts, 'allow_console_print', False) else 'n'
+    return {
+        'auto_reload_port': max(0, auto_reload_port),
+        'allow_console_print': bool(getattr(rd.opts, 'allow_console_print', False)),
+        'ajax_timeout': rd.opts.ajax_timeout,
+    }
 
 
 print_lock = Lock()

src/calibre/srv/opts.py

@@ -40,6 +40,10 @@ raw_options = (
     'timeout', 120.0,
     None,
 
+    _('Time (in seconds) to wait for a response from the server when making queries'),
+    'ajax_timeout',  60.0,
+    None,
+
     _('Total time in seconds to wait for clean shutdown'),
     'shutdown_timeout', 5.0,
     None,

src/pyj/ajax.pyj

@@ -4,6 +4,15 @@ from __python__ import hash_literals
 
 from gettext import gettext as _
 
+
+default_timeout = 60
+
+
+def set_default_timeout(val):
+    nonlocal default_timeout
+    default_timeout = val
+
+
 def encode_query_component(x):
     ans = encodeURIComponent(x)
     # The following exceptions are to make epubcfi() look better
@@ -38,7 +47,7 @@ def absolute_path(path):
     return path
 
 
-def ajax(path, on_complete, on_progress=None, bypass_cache=True, method='GET', query=None, timeout=30*1000, ok_code=200, progress_totals_needed=True):
+def ajax(path, on_complete, on_progress=None, bypass_cache=True, method='GET', query=None, timeout=None, ok_code=200, progress_totals_needed=True):
     # Run an AJAX request. on_complete must be a function that accepts three
     # arguments: end_type, xhr, ev where end_type is one of 'abort', 'error',
     # 'load', 'timeout'. In case end_type is anything other than 'load' you can
@@ -47,6 +56,8 @@ def ajax(path, on_complete, on_progress=None, bypass_cache=True, method='GET', q
     # where loaded is the number of bytes received, total is the total size.
     #
     # Returns the xhr object, call xhr.send() to start the request.
+    if timeout is None:
+        timeout = default_timeout
     query = query or {}
     xhr = XMLHttpRequest()
     eq = encode_query(query)
@@ -62,7 +73,7 @@ def ajax(path, on_complete, on_progress=None, bypass_cache=True, method='GET', q
         if is_network_error:
             xhr.error_html = str.format(_('Failed to communicate with "{}", network error, is the server running and accessible?'), xhr.request_path)
         elif event is 'timeout':
-            xhr.error_html = str.format(_('Failed to communicate with "{}", timed out after: {} seconds'), xhr.request_path, timeout/1000)
+            xhr.error_html = str.format(_('Failed to communicate with "{}", timed out after: {} seconds'), xhr.request_path, timeout)
         elif event is 'abort':
             xhr.error_html = str.format(_('Failed to communicate with "{}", aborted'), xhr.request_path)
         else:
@@ -99,7 +110,7 @@ def ajax(path, on_complete, on_progress=None, bypass_cache=True, method='GET', q
     xhr.addEventListener('load', def(ev): complete_callback('load', ev);)
     xhr.addEventListener('timeout', def(ev): complete_callback('timeout', ev);)
     xhr.open(method, path)
-    xhr.timeout = timeout  # IE requires timeout to be set after open
+    xhr.timeout = timeout * 1000 # IE requires timeout to be set after open
     return xhr
 
 def ajax_send(path, data, on_complete, on_progress=None, query=None, timeout=30*1000, ok_code=200):

src/pyj/srv.pyj

@@ -5,7 +5,7 @@ from __python__ import hash_literals
 from gettext import gettext as _
 
 import initialize  # noqa: unused-import
-from ajax import ajax, console_print
+from ajax import ajax, console_print, set_default_timeout
 from autoreload import create_auto_reload_watcher
 from book_list.globals import main_js
 from book_list.main import main
@@ -50,17 +50,20 @@ else:
     # we know are going to be needed immediately.
     window.addEventListener('load', main)
 
-    ajax('auto-reload-port', def(end_type, xhr, event):
-        nonlocal autoreload_enabled
+    ajax('ajax-setup', def(end_type, xhr, event):
+        nonlocal autoreload_enabled, print
         if end_type is 'load':
-            port = parseInt(xhr.responseText)
+            try:
+                data = JSON.parse(xhr.responseText)
+            except:
+                return
+            tim = data.ajax_timeout
+            if not isNaN(tim) and tim > 0:
+                set_default_timeout(tim)
+            port = data.auto_reload_port
             if not isNaN(port) and port > 0:
                 autoreload_enabled = True
                 create_auto_reload_watcher(port)
-    ).send()  # We must bypass cache as otherwise we could get stale port info
-    ajax('allow-console-print', def(end_type, xhr, event):
-         nonlocal print
-         if end_type is 'load':
-            if xhr.responseText == 'y':
+            if data.allow_console_print:
                 print = console_print
-    ).send()
+    ).send()  # We must bypass cache as otherwise we could get stale info