Handle the case when an image is unavailable

Author: yatch

otbox.py

@@ -18,8 +18,9 @@
 import base64
 import argparse
 import logging
+import sys
 
-try: 
+try:
     from PIL import Image
     from PIL import ImageFont
     from PIL import ImageDraw
@@ -126,10 +127,19 @@ def _mqtt_handler_picturetoscreen(self, deviceType, deviceId, payload):
         {{TESTBED}}/deviceType/box/deviceId/box1/cmd/picturetoscreen
         '''
         assert deviceType==DEVICETYPE_BOX
-        image = Image.open(requests.get(json.loads(payload)['url'], stream=True).raw)
-        image.thumbnail((480,320),Image.ANTIALIAS)
-        self._otbox.change_image_queue.put(image)
-        self._otbox.change_image_queue.join()
+        try:
+            image_url = json.loads(payload)['url']
+            response = requests.get(image_url, stream=True)
+            image = Image.open(response.raw)
+        except IOError:
+            # the image is not available now; skip this one
+            print('image at {0} is not available, '.format(image_url)
+                  + 'HTTP response code {0}'.format(response.status_code))
+            sys.stdout.flush()
+        else:
+            image.thumbnail((480,320),Image.ANTIALIAS)
+            self._otbox.change_image_queue.put(image)
+            self._otbox.change_image_queue.join()
         return {}
 
     def _mqtt_handler_colortoscreen(self, deviceType, deviceId, payload):
@@ -283,7 +293,7 @@ def _on_mqtt_connect(self, client, userdata, flags, rc):
         self.mqttconnected   = True
 
         # subscribe to box commands (device-specific and 'all')
-        # note that unknown commands will be ignored by _execute_command_safely 
+        # note that unknown commands will be ignored by _execute_command_safely
         client.subscribe('{0}/#'.format(self.mqtttopic_box_cmd_prefix))
         client.subscribe('{0}/deviceType/box/deviceId/all/cmd/#'.format(self.testbed))
 
@@ -541,13 +551,13 @@ def _mqtt_handler_program(self, deviceType, deviceId, payload):
 
         payload    = json.loads(payload) # shorthand
         mote       = self._eui64_to_moteinfoelem(deviceId)
-        
+
         # reset the mote first
         self._mqtt_handler_reset(deviceType, deviceId, payload=None)
 
         # disconnect from the serialports
         self.SerialportHandlers[mote['serialport']].disconnectSerialPort()
-        
+
         if isinstance(self.tb, OpenTestbed):
             # For OpenTestbed, we will use a separate firmware_temp
             # for each deviceId. Although other testbeds may need to
@@ -667,18 +677,18 @@ def _bootload_motes(self, serialports, firmware_file):
         # start bootloading each mote
         ongoing_bootloads    = {}
         for serialport in serialports:
-        
+
             # simply the name
             port = serialport.split('/')[-1]
-        
+
             # stop serial reader
             ongoing_bootloads[port] = self.tb.bootload_mote(serialport, firmware_file)
 
         returnVal = []
         for ongoing_bootload in ongoing_bootloads:
             # wait for this bootload process to finish
             (stdout, stderr) = ongoing_bootloads[ongoing_bootload].communicate()
-            
+
             # record the last output of bootload process
             with open("log_{0}.txt".format(ongoing_bootload),'w') as f:
                 f.write("stdout: {0} stderr {1}".format(stdout,stderr))