enh: handle missing network connection better

Author: paulmueller

.gitignore

@@ -115,3 +115,6 @@ _dev_*.py
 # QtCreator temporary files
 *.ui.autosave
 *.png~
+
+# line_profiler
+*.lprof

dcoraid/gui/dbview/filter_chain.py

@@ -145,7 +145,7 @@ def on_add_datasets_to_collection(self):
         """Add all datasets currently selected to a collection
 
         Displays a dialog where the user can choose a collection
-        she has write-access to.
+        they have write-access to.
         """
         # get current selection
         dataset_ids = self.fw_datasets.get_entry_identifiers(selected=True)

dcoraid/gui/main.py

@@ -49,6 +49,8 @@ def __init__(self, *args, **kwargs):
         self._update_thread = None
         self._update_worker = None
 
+        self.database = None
+
         # Settings are stored in the .ini file format. Even though
         # `self.settings` may return integer/bool in the same session,
         # in the next session, it will reliably return strings. Lists
@@ -152,7 +154,14 @@ def __init__(self, *args, **kwargs):
     @QtCore.pyqtSlot(bool)
     def check_update_database(self, reset=False, force=False):
         doit = False
-        if force:
+        if not self.database:
+            QtWidgets.QMessageBox.critical(
+                self,
+                "No connection",
+                "Database could not be initialized. Please make sure "
+                "your are connected to the network."
+            )
+        elif force:
             doit = True
         else:
             if (self.database.local_timestamp < time.time() - 24*3600

dcoraid/gui/panel_find_data/widget_find_data.py

@@ -37,13 +37,15 @@ def __init__(self, *args, **kwargs):
 
     @QtCore.pyqtSlot()
     def on_search(self):
-        self.find_main_window().check_update_database()
-        self.setCursor(QtCore.Qt.CursorShape.WaitCursor)
-        dbextract = self.database.search_dataset(
-            self.lineEdit_search.text(),
-            limit=self.spinBox_public_rows.value())
-        self.public_filter_chain.set_db_extract(dbextract)
-        self.setCursor(QtCore.Qt.CursorShape.ArrowCursor)
+        mv = self.find_main_window()
+        mv.check_update_database()
+        if mv.database:
+            self.setCursor(QtCore.Qt.CursorShape.WaitCursor)
+            dbextract = self.database.search_dataset(
+                self.lineEdit_search.text(),
+                limit=self.spinBox_public_rows.value())
+            self.public_filter_chain.set_db_extract(dbextract)
+            self.setCursor(QtCore.Qt.CursorShape.ArrowCursor)
 
     @QtCore.pyqtSlot()
     def on_update_db(self):