#!/usr/local/bin/python

import sys

from BaseHTTPServer import BaseHTTPRequestHandler

from ZSI import Fault, ParseException, FaultFromNotUnderstood, \
    FaultFromZSIException, FaultFromException, ParsedSoap, SoapWriter

from M2Crypto import SSL
from M2Crypto.SSL.SSLServer import SSLServer

from optparse import OptionParser

from fedd_util import fedd_ssl_context, fedid
from fedd_proj import new_feddservice

# The SSL server here is based on the implementation described at
# http://www.xml.com/pub/a/ws/2004/01/20/salz.html

# Turn off the matching of hostname to certificate ID
SSL.Connection.clientPostConnectionCheck = None

class fedd_server(SSLServer):
    def __init__(self, ME, handler, ssl_ctx, impl):
	SSLServer.__init__(self, ME, handler, ssl_ctx)
	self.impl = impl

class fedd_handler(BaseHTTPRequestHandler):
    server_version = "ZSI/2.0 fedd/0.1 " + BaseHTTPRequestHandler.server_version

    namespace = 'http://www.isi.edu/faber/fedd.wsdl'
    methods = {
	    'RequestAccess': 'soap_RequestAccess',
	    }


    def send_xml(self, text, code=200):
	"""Send an XML document as reply"""
	self.send_response(code)
	self.send_header('Content-type', 'text/xml; charset="utf-8"')
	self.send_header('Content-Length', str(len(text)))
	self.end_headers()
	self.wfile.write(text)
	self.wfile.flush()

    def send_fault(self, f, code=500):
	"""Send a SOAP encoded fault as reply"""
	self.send_xml(f.AsSOAP(), code)

    def check_headers(self, ps):
	"""Send a fault for any required envelope headers"""
	for (uri, localname) in ps.WhatMustIUnderstand():
	    self.send_fault(FaultFromNotUnderstood(uri, lname, 'fedd'))
	    return False
	return  True

    def check_method(self, ps):
	"""Confirm that this class implements the namespace and SOAP method"""
	root = ps.body_root
	if root.namespaceURI != fedd_handler.namespace:
	    self.send_fault(Fault(Fault.Client, 
		'Unknown namespace "%s"' % root.namespaceURI))
	    return False
	if not fedd_handler.methods.has_key(root.localName):
	    self.send_fault(Fault(Fault.Client, 'Unknown operation "%s"' % \
		    root.localName))
	    return False
	return True

    def do_POST(self):
	"""Treat an HTTP POST request as a SOAP service call"""
	try:
	    cl = int(self.headers['content-length'])
	    data = self.rfile.read(cl)
	    ps = ParsedSoap(data)
	except ParseException, e:
	    self.send_fault(FaultFromZSIException(e))
	    return
	except Exception, e:
	    self.send_fault(FaultFromException(e, 0, sys.exc_info()[2]))
	    return
	if not self.check_headers(ps): return
	if not self.check_method(ps): return
	try:
	    # We know this will work because check_method passed above
	    method = getattr(self.server.impl,
		    fedd_handler.methods[ps.body_root.localName])
	    resp = method(ps, fedid(cert=self.request.get_peer_cert()))
	except Fault, f:
	    self.send_fault(f)
	    resp = None
	
	if resp != None:
	    sw = SoapWriter()
	    sw.serialize(resp)
	    self.send_xml(str(sw))

class fedd_opts(OptionParser):
    """Encapsulate option processing in this class, rather than in main"""
    def __init__(self):
	OptionParser.__init__(self, usage="%prog [opts] (--help for details)",
		version="0.1")

	self.set_defaults(host="localhost", port=23235, debug=0)

	self.add_option("-d", "--debug", action="count", dest="debug", 
		help="Set debug.  Repeat for more information")
	self.add_option("-f", "--configfile", action="store",
		dest="configfile", help="Configuration file (required)")
	self.add_option("-H", "--host", action="store", type="string",
		dest="host", help="Hostname to listen on (default %default)")
	self.add_option("-p", "--port", action="store", type="int",
		dest="port", help="Port to listen on (default %default)")
	self.add_option("--trace", action="store_const", dest="tracefile", 
		const=sys.stderr, help="Print SOAP exchange to stderr")

opts, args = fedd_opts().parse_args()

if opts.configfile != None: 
    try:
	impl = new_feddservice(opts.configfile)
    except RuntimeError, e:
	sys.exit("Error configuring fedd: %s" % e.message)
else: 
    sys.exit("--configfile is required")

SOAP_port = (opts.host, opts.port)

if impl.cert_file == None:
    sys.exit("Must supply certificate file (probably in config)")

ctx = None
while ctx == None:
    try:
	ctx = fedd_ssl_context(impl.cert_file, impl.trusted_certs, 
		password=impl.cert_pwd)
    except SSL.SSLError, e:
	if str(e) != "bad decrypt" or impl.cert_pwd != None:
	    raise

s = fedd_server(SOAP_port, fedd_handler, ctx, impl)
s.serve_forever()