/Users/maurits/Documents/studie/afstuderen/biosphere/python/biosphere/io.py

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import xlate
from types import *

"""The io module handles the actual connection to the Bio-SPHERE
daemon and the necessary wrapping of data structures.
"""

class BiosphereConnector:
    """This class can set up a connection with a Bio-SPHERE daemon.
    It can query the daemon for its services and can forward requests
    to it. It also performs type and error checking.
    """
    
    def __init__(self, address = 'localhost', port = 2915):
        """Initialize the BiosphereConnector class.
        
        Args:
        address -- The hostname or IP address of the daemon.
        port -- The TCP/IP port on which it is listening.
        """
        self.addressaddress = address
        self.portport = port
        self.errorerror = None
        self.parserparser = xlate.XMLParser()
    
    def SetAddress(self, address):
        """Set the address of the connector.
        
        Args:
        address -- a string with the address (if there's no port
        given, 2915 will be assumed.
        """
        a = address.split(':')
        self.addressaddress = a[0]
        if len(a) == 2: self.portport = int(a[1])
        else: self.portport = 2915
    
    def GetServices(self):
        """Connect to the daemon and request its service
        definitions which are returned as a bs_definitions class.
        """
        import urllib
        url = 'http://%s:%d/definitions' % (self.addressaddress, self.portport)
        try:
            data = urllib.urlopen(url)
        except IOError:
            return None

        definitions = self.parserparser.Parse(data.read())
        if definitions == None or self.parserparser.error != None:
            self.errorerror = self.parserparser.error
            return None
        else:
            return definitions
    
    def RequestService(self, bsrequest):
        """Make a service request to a Bio-SPHERE daemon.
        The resulting response is returned or None if there was an
        error.
        
        Args:
        bsrequest -- A bs_service_request class with the request.
        """
        import httplib
        
        xmlrequest = bsrequest.toXML()
        conn = httplib.HTTPConnection(self.addressaddress, self.portport)
        conn.set_debuglevel = 1
        conn.putrequest('POST', '/request', skip_host = True,
                        skip_accept_encoding = True)
        conn.putheader('User-Agent', 'BioSPHERE-python/0.0.2')
        conn.putheader('Content-Type', 'text/xml')
        conn.putheader('Content-Length', str(len(xmlrequest)))
        conn.endheaders()
        conn.send(xmlrequest)
        
        response = conn.getresponse()
        if response.status != 200:
            self.errorerror = (response.status, response.reason)
            conn.close()
            return None
        else:
            xmlresp = response.read()
            conn.close()
            resp = self.parserparser.Parse(xmlresp)
            if resp == None or self.parserparser.error != None:
                self.errorerror = self.parserparser.error
                return None
            else:
                self.errorerror = None
                return resp

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