From d7f9b7ae7111d51d8a79cb36f99b07993ca3b78a Mon Sep 17 00:00:00 2001
From: root <root@envy.sin.cvut.cz>
Date: Sun, 12 May 2019 23:26:50 +0200
Subject: [PATCH] Add retries to the key functions

---
 sms_functions.py | 51 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 39 insertions(+), 12 deletions(-)

diff --git a/sms_functions.py b/sms_functions.py
index a23b211..9be00d1 100644
--- a/sms_functions.py
+++ b/sms_functions.py
@@ -1,6 +1,7 @@
 
 import logging
 import os
+import time
 from pydbus import SystemBus
 from gi.repository import GLib
 
@@ -31,12 +32,21 @@ def assemble_sms():
     return ''.join(str_list)
 
 def get_modem():
-    # Contact ModemManager, unlock SIM and send SMS to emergency numbers
-    with SystemBus() as bus:
-        mm = bus.get('.ModemManager1')
-        modems = mm.GetManagedObjects()
+        # Retry for 5 seconds and give the modems time
+        retries = 0
+        while retries < 5:
+            retries += 1
+            # Contact ModemManager, unlock SIM and send SMS to emergency numbers
+            with SystemBus() as bus:
+                mm = bus.get('.ModemManager1')
+                modems = mm.GetManagedObjects()
+                if not modems or len(modems) == 0:
+                    time.sleep(5)
+                else:
+                    break
+        
         if not modems or len(modems) == 0:
-           raise ModemManagerError('No modems found') 
+            raise ModemManagerError('No modems found') 
         modem_path = list(modems.keys())[0]
     
         logger.info("Going with %s", modem_path)
@@ -67,18 +77,35 @@ def send_sms(recipients, smsstring):
     # Assemble SMS
     logger.info("Sending SMS: %s", smsstring)
     
-    # Get modem, unlock SIM
-    modem = get_modem()
-    unlock_sim(modem)
-    
-    # enable the modem
-    modem.Enable(True)
+    retries = 0
+    # Retry the whole block, because once pydbus fetches the properties
+    # it does not really refresh them, including modems
+    while True:
+        try:
+            # enable the modem
+            # Get modem, unlock SIM
+            modem = get_modem()
+            unlock_sim(modem)
+            modem.Enable(True)
+            break
+        except SIMError:
+            # cannot continue with this one (could be a wrong PIN
+            # and then we waste our attempts)
+            raise
+        except:
+            retries += 1
+            time.sleep(1)
+            if retries > 5:
+                raise
     
     # test sending SMS
     modem_msg = modem['org.freedesktop.ModemManager1.Modem.Messaging']
     smses = modem_msg.List()
 
-    print(modem.GetStatus()['signal-quality'])
+    while not modem.GetStatus()['signal-quality'][1]:
+        modem = get_modem()
+        print(modem.GetStatus()['signal-quality'])
+        time.sleep(2)
 
     for line in recipients:
         line = line.strip()