Fix a race condition where the URL was sometimes getting copied to the clipboard before it was actually generated, causing a crash

onionshare/__init__.py

@@ -122,6 +122,7 @@ def main(cwd=None):
     try:
         app = OnionShare(common, onion, local_only, stay_open, shutdown_timeout)
         app.set_stealth(stealth)
+        app.choose_port()
         app.start_onion_service()
     except KeyboardInterrupt:
         print("")

onionshare/onionshare.py

@@ -38,6 +38,7 @@ class OnionShare(object):
 
         self.hidserv_dir = None
         self.onion_host = None
+        self.port = None
         self.stealth = None
 
         # files and dirs to delete on shutdown
@@ -59,6 +60,15 @@ class OnionShare(object):
 
         self.stealth = stealth
         self.onion.stealth = stealth
+    
+    def choose_port(self):
+        """
+        Choose a random port.
+        """
+        try:
+            self.port = self.common.get_available_port(17600, 17650)
+        except:
+            raise OSError(strings._('no_available_port'))
 
     def start_onion_service(self):
         """
@@ -66,11 +76,8 @@ class OnionShare(object):
         """
         self.common.log('OnionShare', 'start_onion_service')
 
-        # Choose a random port
-        try:
-            self.port = self.common.get_available_port(17600, 17650)
-        except:
-            raise OSError(strings._('no_available_port'))
+        if not self.port:
+            self.choose_port()
 
         if self.local_only:
             self.onion_host = '127.0.0.1:{0:d}'.format(self.port)

onionshare/web.py

@@ -419,11 +419,12 @@ class Web(object):
 
     def generate_slug(self, persistent_slug=None):
         self.common.log('Web', 'generate_slug', 'persistent_slug={}'.format(persistent_slug))
-        if persistent_slug != None:
+        if persistent_slug != None and persistent_slug != '':
             self.slug = persistent_slug
+            self.common.log('Web', 'generate_slug', 'persistent_slug sent, so slug is: "{}"'.format(self.slug))
         else:
             self.slug = self.common.build_slug()
-        self.common.log('Web', 'generate_slug', 'slug is set to {}'.format(self.slug))
+            self.common.log('Web', 'generate_slug', 'built random slug: "{}"'.format(self.slug))
 
     def debug_mode(self):
         """

onionshare_gui/mode.py

@@ -138,6 +138,19 @@ class Mode(QtWidgets.QWidget):
 
         # Start the onion service in a new thread
         def start_onion_service(self):
+            # Choose a port for the web app
+            self.app.choose_port()
+
+            # Start http service in new thread
+            t = threading.Thread(target=self.web.start, args=(self.app.port, self.app.stay_open, self.common.settings.get('slug')))
+            t.daemon = True
+            t.start()
+
+            # Wait for the web app slug to generate before continuing
+            while self.web.slug == None:
+                time.sleep(0.1)
+
+            # Now start the onion service
             try:
                 self.app.start_onion_service()
                 self.starting_server_step2.emit()
@@ -148,13 +161,6 @@ class Mode(QtWidgets.QWidget):
 
             self.app.stay_open = not self.common.settings.get('close_after_first_download')
 
-            # Start http service in new thread
-            t = threading.Thread(target=self.web.start, args=(self.app.port, self.app.stay_open, self.common.settings.get('slug')))
-            t.daemon = True
-            t.start()
-            # Wait for modules in thread to load, preventing a thread-related cx_Freeze crash
-            time.sleep(0.2)
-
         self.common.log('Mode', 'start_server', 'Starting an onion thread')
         self.t = OnionThread(self.common, function=start_onion_service, kwargs={'self': self})
         self.t.daemon = True