[iOS] Updated to Python 3.6.6, plus small tweaks

- Updated the 'make_ios_project' system to use Python 3.6+.  Python 3.5
is going to be phased out, but still unofficially works.

- iOS app has a much shorter reconnect interval on connection down; this
is necessary because mobile connections are quite spotty.

- iOS app has a hardcoded "preferred server only" setting internally for
now.  This is a security measure.  Users were getting intermittent
problems due to the phishers so we block them altogether on iOS.

- Refactored some stuff in network.py to allow iOS to specify its own
reconnect interval more easily.

- On iOS we always display the TOTAL balance (confirmed + unconfirmed
added together).  This is less confusing to newbie users and on BCH with
our reliable 0-conf, unconfirmed is not such a big deal.  Unconfirmed
balances are highlighted in BLUE to alert users that it's not confirmed
yet, but otherwise the UI shows the total balance (conf + unconf).

ios/ElectronCash/__main__.py

@@ -4,6 +4,11 @@
 #
 # MIT License
 #
+import os
+# Disable google protobuf C++ implementation since we don't have the .so files
+# anyway on iOS.  this call isn't strictly necessary but we may as well
+# do it just to be sure.
+os.environ['PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION'] = 'python'
 
 # The below line needs to be here becasue the iOS main.m evaluates this script and looks for a
 # Python class (that is bridged to ObjC) named "PythonAppDelegate", which gets the

ios/ElectronCash/app.py

@@ -8,9 +8,10 @@
 from electroncash_gui.ios_native.monkeypatches import MonkeyPatches
 from electroncash.util import set_verbosity
 from electroncash_gui.ios_native import ElectrumGui
-from electroncash_gui.ios_native.utils import call_later, get_user_dir, cleanup_tmp_dir, is_debug_build, NSLogSuppress
+from electroncash_gui.ios_native.utils import call_later, get_user_dir, cleanup_tmp_dir, is_debug_build, NSLogSuppress, NSLog
 from electroncash.simple_config import SimpleConfig
 
+# NB: This is called from appdelegate.py "application_didFinishLaunchingWithOptions_"
 def main():
     cleanup_tmp_dir()
 
@@ -19,19 +20,38 @@ def main():
             'cmd': 'gui',
             'gui': 'ios_native',
             'cwd': os.getcwd(),
+            'whitelist_servers_only' : True,  # on iOS we force only the whitelist ('preferred') servers only for now as a security measure
     }
 
     set_verbosity(config_options.get('verbose'), timestamps=False, thread_id=False)
     NSLogSuppress(not config_options.get('verbose'))
 
     MonkeyPatches.patch()
 
-    #for k,v in config_options.items():
-    #    print("config[%s] = %s"%(str(k),str(v)))
-
     config = SimpleConfig(config_options, read_user_dir_function = get_user_dir)
 
     gui = ElectrumGui(config)
     call_later(0.010, gui.main) # this is required for the activity indicator to actually animate. Switch to a direct call if not using activity indicator on Splash2
 
+    _printStats(config_options)  # Prints some startup/debug stats such as Python version and SSL version (this is done in another thread to hopefully not impact startup overhead too much, as importing ssl may be a bit heavy)
+
     return "Bitcoin Cash FTW!"
+
+def _printStats(config_options):
+    import threading
+    def thrdfunc(config_options):
+        # lazy init of SSL
+        import ssl, sys
+        from electroncash import version
+        NSLog("Electron Cash lib version: %s (using server protocol: %s)", version.PACKAGE_VERSION, version.PROTOCOL_VERSION)
+        NSLog("Python version: %s", ' '.join(sys.version.split('\n')))
+        NSLog("OpenSSL version: %s", ssl.OPENSSL_VERSION)
+        #NSLog("Environment Vars:")
+        #for k,v in os.environ.copy().items():
+        #    NSLog("%s=%s", str(k), str(v))
+        #NSLog("Config Vars:")
+        #for k,v in config_options.copy().items():
+        #    NSLog("config[%s] = %s", str(k), str(v))
+    # /
+    # We do this from a thread so as to not delay app startup by importing more stuff we don't strictly need.
+    threading.Thread(target=thrdfunc, args=(config_options,), daemon=True).start()

ios/ElectronCash/electroncash_gui/ios_native/gui.py

@@ -367,6 +367,11 @@ def register_network_callbacks(self):
             # methods of this class only, and specifically not be
             # partials, lambdas or methods of subobjects.  Hence...
             self.daemon.network.register_callback(self.on_network, interests)
+            # Set the node and server retry interval to more reasonable valus for iOS
+            # This is because on mobile we really may have a spotty connection so
+            # it pays to retry often
+            self.daemon.network.NODES_RETRY_INTERVAL = 20  # seconds
+            self.daemon.network.SERVER_RETRY_INTERVAL = 3  # seconds
             utils.NSLog("REGISTERED NETWORK CALLBACKS")
 
     def unregister_network_callbacks(self):
@@ -644,20 +649,22 @@ def on_status_update(self):
                 walletStatus = wallets.StatusOnline
                 networkStatusText = _("Online")
                 c, u, x = self.wallet.get_balance()
-                walletBalanceTxt = self.format_amount(c)
+                walletBalanceTxt = self.format_amount(c+u+x)
                 walletUnitTxt = self.base_unit()
-                text =  _("Balance" ) + ": %s "%(self.format_amount_and_units(c))
+                text =  _("Balance" ) + ": %s "%(self.format_amount_and_units(c+u+x))
                 ux = 0
+                adjective = 'unconf.'
                 if u:
-                    s = " [%s unconfirmed]"%(self.format_amount(u, True).strip())
+                    s = " [%s unconfirmed]"%(self.format_amount(u, u < 0).strip())
                     text +=  s
                     ux += u
                 if x:
-                    s = " [%s unmatured]"%(self.format_amount(x, True).strip())
+                    s = " [%s unmatured]"%(self.format_amount(x, x < 0).strip())
                     text += s
                     ux += x
+                    adjective = 'unavail.'
                 if ux:
-                    walletUnconfTxt += "[%s unconf.]"%(self.format_amount(ux, True)).strip()
+                    walletUnconfTxt += "[%s %s]"%(self.format_amount(ux, ux < 0).strip(), adjective)  # [134 unconf.]
 
                 # append fiat balance and price
                 if self.daemon.fx.is_enabled():

ios/ElectronCash/electroncash_gui/ios_native/wallets.py

@@ -159,20 +159,25 @@ def setStatus_(self, mode : int) -> None:
 
     @objc_method
     def setAmount_andUnits_unconf_(self, amt, units, unconf) -> None:
-        #ats = NSMutableAttributedString.alloc().initWithString_(units).autorelease()
+        ats = None
         if unconf:
             unconf = " " + unconf.strip()
-            '''ats.appendAttributedString_(NSAttributedString.alloc().initWithString_attributes_(
-                unconf,
+            ats = NSAttributedString.alloc().initWithString_attributes_(
+                amt,
                 {
-                    NSFontAttributeName: UIFont.systemFontOfSize_(11.0)
+                    NSForegroundColorAttributeName: utils.uicolor_custom('nav')
                 }
-                ).autorelease())
-            '''
+            ).autorelease()
         else:
             unconf = ''
-        self.walletAmount.text = amt
-        #self.walletUnits.attributedText = ats
+        if ats:
+            # User has unconfired balance -- show blue text
+            self.walletAmount.text = None
+            self.walletAmount.attributedText = ats
+        else:
+            # User has regular balance -- show regular text
+            self.walletAmount.attributedText = None
+            self.walletAmount.text = amt
         self.walletUnits.text = units+unconf
         if self.modalDrawerVC:
             self.modalDrawerVC.amount.text = amt

ios/make_ios_project.sh

@@ -2,11 +2,11 @@
 
 . ./common.sh
 
-/usr/bin/env python3 --version | grep -q " 3.5"
+/usr/bin/env python3 --version | grep -q " 3.[6789]"
 if [ "$?" != "0" ]; then
 	if /usr/bin/env python3 --version; then
-		echo "WARNING:: Creating the Briefcase-based Xcode project for iOS requires Python 3.5."
-		echo "We will proceed anyway -- but if you get errors, try switching to Python 3.5."
+		echo "WARNING:: Creating the Briefcase-based Xcode project for iOS requires Python 3.6+."
+		echo "We will proceed anyway -- but if you get errors, try switching to Python 3.6+."
 	else
 		echo "ERROR: Python3+ is required"
 		exit 1

ios/recompile_python.sh

@@ -23,10 +23,10 @@ elif [ -n "$1" ]; then
 else
 	originaldir=`pwd`
 	cd "$dir1" 
-	python3.5 -O -m compileall . || exit 1
+	python3 -O -m compileall . || exit 1
 	cd "$originaldir" 
 	cd "$dir2"
-	python3.5 -O -m compileall . || exit 1
+	python3 -O -m compileall . || exit 1
 	cd "$originaldir"
 fi
 

lib/network.py

@@ -46,9 +46,7 @@
 
 
 DEFAULT_AUTO_CONNECT = True
-NODES_RETRY_INTERVAL = 60
-SERVER_RETRY_INTERVAL = 10
-
+DEFAULT_WHITELIST_SERVERS_ONLY = True
 
 def parse_servers(result):
     """ parse servers list into dict format"""
@@ -200,6 +198,11 @@ class Network(util.DaemonThread):
 
     INSTANCE = None # Only 1 Network instance is ever alive during app lifetime (it's a singleton)
 
+    # These defaults are decent for the desktop app. Other platforms may
+    # override these at any time (iOS sets these to lower values).
+    NODES_RETRY_INTERVAL = 60  # How often to retry a node we know about in secs, if we are connected to less than 10 nodes
+    SERVER_RETRY_INTERVAL = 10  # How often to reconnect when server down in secs
+
     def __init__(self, config=None):
         if config is None:
             config = {}  # Do not use mutables as default values!
@@ -957,7 +960,7 @@ def maintain_sockets(self):
             server_count = len(self.interfaces) + len(self.connecting)
             if server_count < self.num_server:
                 self.start_random_interface()
-                if now - self.nodes_retry_time > NODES_RETRY_INTERVAL:
+                if now - self.nodes_retry_time > self.NODES_RETRY_INTERVAL:
                     self.print_error('network: retrying connections')
                     self.disconnected_servers = set([])
                     self.nodes_retry_time = now
@@ -970,7 +973,7 @@ def maintain_sockets(self):
                         self.switch_to_random_interface()
                 else:
                     if self.default_server in self.disconnected_servers:
-                        if now - self.server_retry_time > SERVER_RETRY_INTERVAL:
+                        if now - self.server_retry_time > self.SERVER_RETRY_INTERVAL:
                             self.disconnected_servers.remove(self.default_server)
                             self.server_retry_time = now
                     else:
@@ -1858,7 +1861,7 @@ def _compute_whitelist(self):
         ret -= set(self.config.get('server_whitelist_removed', [])) # this key is all the servers that were hardcoded in the whitelist that the user explicitly removed
         return ret, servers_to_hostmap(ret)
 
-    def is_whitelist_only(self): return bool(self.config.get('whitelist_servers_only', True))
+    def is_whitelist_only(self): return bool(self.config.get('whitelist_servers_only', DEFAULT_WHITELIST_SERVERS_ONLY))
 
     def set_whitelist_only(self, b):
         if bool(b) == self.is_whitelist_only():