PyDatagram issue

Scripting Issues
1

I am writing a networked game and I need to send lists between two clients. But I cannot find a way to attack a list to a PyDatagram.

2

you can use pythons pickle module which can convert almost anything into a string. (except things like vec3 which is custom-panda)
you can send those strings with the string datagramthingy.

      datagram = PyDatagram()
      datagram.addString( pickle.dumps( yourList , 2) )
      self.cWriter.send( datagram,  self.Connection )

you can reconstruct the list on the other end with

    
if self.cReader.dataAvailable():
      datagram = NetDatagram()
      if self.cReader.getData(datagram):
           pkg = PyDatagramIterator(datagram)
           yourList = pickle.loads( pkg.getString() )

if you’r trying to send lists which contain non-standart-python data-types python will complain. in most cases you can use standart stuff. like a list (x,y,z) instead of the vec3 position.

you can also compress those strings to reduce traffic.
use

aCompressedString = zlib.compress( anUncompressedString)

and

anUncompressedString = zlib.decompress( aCompressedString )

for this :slight_smile:

3

Thomas, why not using cPickle ? It’s a lot faster than pickle, right ?

I have a simple benchmark of them :

aList=[]
for n in range(5000000):
    aList.append('ABCDE')

myFile=open('abcde','w')
#pickle.dump(aList,myFile) # 32 seconds
cPickle.dump(aList,myFile) #  7 seconds
myFile.close()
4

well i use it only 5 times per second to send a few dozen characters… so i wouldnt notice^^
thx for the hint :slight_smile: in case i run into problems with 100000 players on my server wandering around at the same time i’ll remember it :smiley:

5

Thanks that worked very well.