Support handling events by monitoring an events folder for changes

onionshare_gui/event_handler.py

@@ -0,0 +1,89 @@
+# -*- coding: utf-8 -*-
+"""
+OnionShare | https://onionshare.org/
+
+Copyright (C) 2014-2018 Micah Lee <micah@micahflee.com>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+import json
+import os
+from watchdog.observers import Observer
+from watchdog.events import FileSystemEventHandler, FileModifiedEvent
+from PyQt5 import QtCore
+
+
+class EventHandler(FileSystemEventHandler, QtCore.QObject):
+    """
+    To trigger an event, write a JSON line to the events file. When that file changes, 
+    each line will be handled as an event. Valid events are:
+    {"type": "new_tab"}
+    {"type": "new_share_tab", "filenames": ["file1", "file2"]}
+    """
+
+    new_tab = QtCore.pyqtSignal()
+    new_share_tab = QtCore.pyqtSignal(list)
+
+    def __init__(self, common):
+        super(EventHandler, self).__init__()
+        self.common = common
+
+    def on_modified(self, event):
+        if (
+            type(event) == FileModifiedEvent
+            and event.src_path == self.common.gui.events_filename
+        ):
+            # Read all the lines in the events, then delete it
+            with open(self.common.gui.events_filename, "r") as f:
+                lines = f.readlines()
+            os.remove(self.common.gui.events_filename)
+
+            self.common.log(
+                "EventHandler", "on_modified", f"processing {len(lines)} lines"
+            )
+            for line in lines:
+                try:
+                    obj = json.loads(line)
+                    if "type" not in obj:
+                        self.common.log(
+                            "EventHandler",
+                            "on_modified",
+                            f"event does not have a type: {obj}",
+                        )
+                        continue
+                except json.decoder.JSONDecodeError:
+                    self.common.log(
+                        "EventHandler", "on_modified", f"ignoring invalid line: {line}"
+                    )
+                    continue
+
+                if obj["type"] == "new_tab":
+                    self.common.log("EventHandler", "on_modified", "new_tab event")
+                    self.new_tab.emit()
+
+                elif obj["type"] == "new_share_tab":
+                    if "filenames" in obj and type(obj["filenames"]) is list:
+                        self.new_share_tab.emit(obj["filenames"])
+                    else:
+                        self.common.log(
+                            "EventHandler",
+                            "on_modified",
+                            f"invalid new_share_tab event: {obj}",
+                        )
+
+                else:
+                    self.common.log(
+                        "EventHandler", "on_modified", f"invalid event type: {obj}"
+                    )
+