import os, time, socket

from marshal import dumps

from MiscUtils.Configurable import Configurable

class Adapter(Configurable):

def __init__(self, webKitDir):

Configurable.__init__(self)

self._webKitDir = webKitDir

self._respData = []

def name(self):

return self.__class__.__name__

def defaultConfig(self):

return dict(

NumRetries = 20, # 20 retries when we cannot connect

SecondsBetweenRetries = 3, # 3 seconds pause between retries

ResponseBufferSize = 8*1024, # 8 kBytes

Host = 'localhost', # host running the app server

AdapterPort = 8086) # the default app server port

def configFilename(self):

return os.path.join(self._webKitDir, 'Configs', '%s.config' % self.name())

def getChunksFromAppServer(self, env, myInput='',

host=None, port=None):

"""Get response from the application server.

Used by subclasses that are communicating with a separate app server

via socket. Yields the unmarshaled response in chunks.

"""

if host is None:

host = self.setting('Host')

if port is None:

port = self.setting('AdapterPort')

requestDict = dict(format='CGI', time=time.time(), environ=env)

retries = 0

while 1:

try:

# Send our request to the AppServer

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

s.connect((host, port))

except socket.error:

# Retry

if retries <= self.setting('NumRetries'):

retries += 1

time.sleep(self.setting('SecondsBetweenRetries'))

else:

raise socket.error('timed out waiting for connection to app server')

else:

break

data = dumps(requestDict)

s.send(dumps(int(len(data))))

s.send(data)

sent = 0

inputLength = len(myInput)

while sent < inputLength:

chunk = s.send(myInput[sent:])

sent += chunk

s.shutdown(1)

bufsize = self.setting('ResponseBufferSize')

while 1:

data = s.recv(bufsize)

if not data:

break

yield data

def transactWithAppServer(self, env, myInput='', host=None, port=None):

"""Get the full response from the application server."""

for data in self.getChunksFromAppServer(env, myInput, host, port):

self.processResponse(data)

return ''.join(self._respData)

def processResponse(self, data):

"""Process response data as it arrives."""

self._respData.append(data)