add autodiscovery of server to client

client.py

@@ -5,9 +5,12 @@ Inspired by the PixelFlut beamer on eth0:winter 2016 and
 code from https://github.com/defnull/pixelflut/
 """
 
-__version__ = 0.1
+__version__ = 0.2
 __author__ = "Jan Klopper <jan@underdark.nl>"
 
+MAX_PROTOCOL_VERSION = 1;
+PROTOCOL_PREAMBLE = 'pixelvloed'
+
 import socket
 import struct
 import random
@@ -65,15 +68,48 @@ def SendPacket(ipaddress, port, message):
                        socket.SOCK_DGRAM) # UDP
   sock.sendto(message, (ipaddress, port))
 
-def main():
-  """Sends some random pixels untill we break with ctrl+c"""
-  ipaddress = "127.0.0.1"
-  port = 5005
+def DiscoverServers(discoveryport, timeout=5):
+  """Discover servers that send out the pixelfvloed preample"""
+  DiscoverySock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+  DiscoverySock.bind(('', discoveryport))
+  starttime = time.time()
+  servers = []
+  foundhash = {}
+  while (time.time() - timeout) < starttime:
+    data, addr = DiscoverySock.recvfrom(1024)
+    try:
+      if data.startswith(PROTOCOL_PREAMBLE):
+        dataset = data.split(' ')
+        if float(dataset[0].split(':')[1]) <= MAX_PROTOCOL_VERSION:
+          ip = dataset[1].split(':')[0]
+          port = int(dataset[1].split(':')[1])
+          width = int(dataset[2].split('*')[0])
+          height = int(dataset[2].split('*')[1])
+          if data not in foundhash:
+            newserver = {'ip': ip,
+                         'port': port,
+                         'width': width,
+                         'height': height}
+            foundhash[data] = True
+            print 'New pixelvloed screen found: %r' % newserver
+            servers.append(newserver)
+    except:
+      pass
+  if servers:
+    return servers
+  return False
 
+def main():
+  """Discover the servers and start sending to the first one"""
+  discoveryport = 5006
+  servers = False
+  while servers == False:
+    servers = DiscoverServers(discoveryport)
+  print 'displaying on %(ip)s:%(port)d, %(width)d*%(height)dpx' % servers[0]
   while True:
-    for packet in RandomFill():
+    for packet in RandomFill(servers[0]['width'], servers[0]['height']):
       time.sleep(0.01)
-      SendPacket(ipaddress, port, packet)
+      SendPacket(servers[0]['ip'], servers[0]['port'], packet)
 
 if __name__ == '__main__':
   main()

vloed.py

@@ -19,6 +19,8 @@ from gevent.queue import Queue
 monkey.patch_all()
 UDP_IP = "127.0.0.1"
 UDP_PORT= 5005
+PROTOCOL_VERSION = 1
+PROTOCOL_PREAMBLE = "pixelvloed"
 
 def main():
   """Runs a pixelvloed server"""
@@ -27,7 +29,7 @@ def main():
 class Canvas(object):
   """PixelVloed server class"""
 
-  def __init__(self, queue, debug=False):
+  def __init__(self, queue, width=1366, height=768, debug=True):
     """Init the pixelVloed server"""
     self.debug = debug
     self.pixeloffset = 2
@@ -35,10 +37,15 @@ class Canvas(object):
     self.screen = None
     self.udp_ip = UDP_IP
     self.udp_port = UDP_PORT
+    self.width = width
+    self.height = height
     self.canvas()    
     self.set_title()
     self.queue = queue
     self.limit = 140
+    self.broadcastSocket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+    self.broadcastSocket.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
+    self.broadcastSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
 
   @staticmethod
   def set_title(text=None):
@@ -48,12 +55,12 @@ class Canvas(object):
       title += ' ' + text
     pygame.display.set_caption(title)
 
-  def canvas(self, width=1366, height=768):
+  def canvas(self):
     """Init the pygame canvas"""
     pygame.init()
     pygame.mixer.quit()
     flags = DOUBLEBUF
-    self.screen = pygame.display.set_mode((width, height), flags)
+    self.screen = pygame.display.set_mode((self.width, self.height), flags)
 
   def clear(self, r=0, g=0, b=0): # pylint: disable=C0103
     """ Fill the entire screen with a solid colour (default: black)"""
@@ -69,9 +76,14 @@ class Canvas(object):
   def CanvasUpdate(self):
     """Updates the screen according to self.fps"""
     lasttime = time.time()
+    lastbroadcast = time.time()
     changed = False
     while True:
       changed = self.Draw() or changed
+      if time.time() - lastbroadcast > 2:
+        lastbroadcast = time.time()
+        self.SendDiscoveryPacket()
+
       if time.time() - lasttime >= 1.0 / self.fps and changed:
         self.pixels = None # release the lock on these pixels so we can flip
         pygame.display.flip()
@@ -99,10 +111,10 @@ class Canvas(object):
                      if preamble else 
                      7 #xx,yy,r,g,b
                      )
-      pixelcount = (len(data)-1) / pixellength
+      pixelcount = min(((len(data)-1) / pixellength),
+                       self.limit)
       if self.debug:
-        print '%d pixels received, protocol V %d ' % (
-            min(pixelcount, self.limit), protocol)
+        print '%d pixels received, protocol V %d ' % (pixelcount, protocol)
       for i in xrange(0, pixelcount):
         pixel = struct.unpack_from(
             packetformat,
@@ -114,6 +126,20 @@ class Canvas(object):
     # indicate that we have been drawing stuff
     return True
 
+  def SendDiscoveryPacket(self):
+    """Lets send out our ip/port/resolution to any listening clients"""
+    self.broadcastSocket.sendto(
+        '%s:%f %s:%d %d*%d' % (PROTOCOL_PREAMBLE, PROTOCOL_VERSION,
+                               UDP_IP, UDP_PORT,
+                               self.width, self.height),
+        ('<broadcast>', UDP_PORT+1))
+    if self.debug:
+      print 'sending discovery packet'
+
+  def __del__(self):
+    """Clean up any sockets we created"""
+    self.broadcastSocket.close()
+
 class PixelVloed(DatagramServer):
   """PixelVloed server class"""
   queue = Queue()