This is the eleventh part of the Twisted tutorial Twisted from Scratch, or The Evolution of Finger .
In this part, we make it easier for non-programmers to configure a finger server and show how to package it in the .deb and RPM package formats. Plugins are discussed further in the Twisted Plugin System howto. Writing twistd plugins is covered in Writing a twistd Plugin , and .tac applications are covered in Using the Twisted Application Framework .
So far, the user had to be somewhat of a programmer to be able to configure
stuff. Maybe we can eliminate even that? Move old code
to finger/__init__.py and…
Full source code for finger module here:
# finger.py module
from zope.interface import Interface, implements
from twisted.application import internet, service
from twisted.internet import protocol, reactor, defer
from twisted.words.protocols import irc
from twisted.protocols import basic
from twisted.python import components, log
from twisted.web import resource, server, xmlrpc
from twisted.spread import pb
from OpenSSL import SSL
class IFingerService(Interface):
def getUser(user):
"""
Return a deferred returning a string.
"""
def getUsers():
"""
Return a deferred returning a list of strings.
"""
class IFingerSetterService(Interface):
def setUser(user, status):
"""
Set the user's status to something.
"""
def catchError(err):
return "Internal error in server"
class FingerProtocol(basic.LineReceiver):
def lineReceived(self, user):
d = self.factory.getUser(user)
d.addErrback(catchError)
def writeValue(value):
self.transport.write(value+'\n')
self.transport.loseConnection()
d.addCallback(writeValue)
class IFingerFactory(Interface):
def getUser(user):
"""
Return a deferred returning a string.
"""
def buildProtocol(addr):
"""
Return a protocol returning a string.
"""
class FingerFactoryFromService(protocol.ServerFactory):
implements(IFingerFactory)
protocol = FingerProtocol
def __init__(self, service):
self.service = service
def getUser(self, user):
return self.service.getUser(user)
components.registerAdapter(FingerFactoryFromService,
IFingerService,
IFingerFactory)
class FingerSetterProtocol(basic.LineReceiver):
def connectionMade(self):
self.lines = []
def lineReceived(self, line):
self.lines.append(line)
def connectionLost(self, reason):
if len(self.lines) == 2:
self.factory.setUser(*self.lines)
class IFingerSetterFactory(Interface):
def setUser(user, status):
"""
Return a deferred returning a string.
"""
def buildProtocol(addr):
"""
Return a protocol returning a string.
"""
class FingerSetterFactoryFromService(protocol.ServerFactory):
implements(IFingerSetterFactory)
protocol = FingerSetterProtocol
def __init__(self, service):
self.service = service
def setUser(self, user, status):
self.service.setUser(user, status)
components.registerAdapter(FingerSetterFactoryFromService,
IFingerSetterService,
IFingerSetterFactory)
class IRCReplyBot(irc.IRCClient):
def connectionMade(self):
self.nickname = self.factory.nickname
irc.IRCClient.connectionMade(self)
def privmsg(self, user, channel, msg):
user = user.split('!')[0]
if self.nickname.lower() == channel.lower():
d = self.factory.getUser(msg)
d.addErrback(catchError)
d.addCallback(lambda m: "Status of %s: %s" % (msg, m))
d.addCallback(lambda m: self.msg(user, m))
class IIRCClientFactory(Interface):
"""
@ivar nickname
"""
def getUser(user):
"""
Return a deferred returning a string.
"""
def buildProtocol(addr):
"""
Return a protocol.
"""
class IRCClientFactoryFromService(protocol.ClientFactory):
implements(IIRCClientFactory)
protocol = IRCReplyBot
nickname = None
def __init__(self, service):
self.service = service
def getUser(self, user):
return self.service.getUser(user)
components.registerAdapter(IRCClientFactoryFromService,
IFingerService,
IIRCClientFactory)
class UserStatusTree(resource.Resource):
template = """<html><head><title>Users</title></head><body>
<h1>Users</h1>
<ul>
%(users)s
</ul>
</body>
</html>"""
def __init__(self, service):
resource.Resource.__init__(self)
self.service = service
def getChild(self, path, request):
if path == '':
return self
elif path == 'RPC2':
return UserStatusXR(self.service)
else:
return UserStatus(path, self.service)
def render_GET(self, request):
users = self.service.getUsers()
def cbUsers(users):
request.write(self.template % {'users': ''.join([
# Name should be quoted properly these uses.
'<li><a href="%s">%s</a></li>' % (name, name)
for name in users])})
request.finish()
users.addCallback(cbUsers)
def ebUsers(err):
log.err(err, "UserStatusTree failed")
request.finish()
users.addErrback(ebUsers)
return server.NOT_DONE_YET
components.registerAdapter(UserStatusTree, IFingerService, resource.IResource)
class UserStatus(resource.Resource):
template='''<html><head><title>%(title)s</title></head>
<body><h1>%(name)s</h1><p>%(status)s</p></body></html>'''
def __init__(self, user, service):
resource.Resource.__init__(self)
self.user = user
self.service = service
def render_GET(self, request):
status = self.service.getUser(self.user)
def cbStatus(status):
request.write(self.template % {
'title': self.user,
'name': self.user,
'status': status})
request.finish()
status.addCallback(cbStatus)
def ebStatus(err):
log.err(err, "UserStatus failed")
request.finish()
status.addErrback(ebStatus)
return server.NOT_DONE_YET
class UserStatusXR(xmlrpc.XMLRPC):
def __init__(self, service):
xmlrpc.XMLRPC.__init__(self)
self.service = service
def xmlrpc_getUser(self, user):
return self.service.getUser(user)
def xmlrpc_getUsers(self):
return self.service.getUsers()
class IPerspectiveFinger(Interface):
def remote_getUser(username):
"""
Return a user's status.
"""
def remote_getUsers():
"""
Return a user's status.
"""
class PerspectiveFingerFromService(pb.Root):
implements(IPerspectiveFinger)
def __init__(self, service):
self.service = service
def remote_getUser(self, username):
return self.service.getUser(username)
def remote_getUsers(self):
return self.service.getUsers()
components.registerAdapter(PerspectiveFingerFromService,
IFingerService,
IPerspectiveFinger)
class FingerService(service.Service):
implements(IFingerService)
def __init__(self, filename):
self.filename = filename
def _read(self):
self.users = {}
for line in file(self.filename):
user, status = line.split(':', 1)
user = user.strip()
status = status.strip()
self.users[user] = status
self.call = reactor.callLater(30, self._read)
def getUser(self, user):
return defer.succeed(self.users.get(user, "No such user"))
def getUsers(self):
return defer.succeed(self.users.keys())
def startService(self):
self._read()
service.Service.startService(self)
def stopService(self):
service.Service.stopService(self)
self.call.cancel()
class ServerContextFactory:
def getContext(self):
"""
Create an SSL context.
This is a sample implementation that loads a certificate from a file
called 'server.pem'.
"""
ctx = SSL.Context(SSL.SSLv23_METHOD)
ctx.use_certificate_file('server.pem')
ctx.use_privatekey_file('server.pem')
return ctx
# Easy configuration
def makeService(config):
# finger on port 79
s = service.MultiService()
f = FingerService(config['file'])
h = internet.TCPServer(1079, IFingerFactory(f))
h.setServiceParent(s)
# website on port 8000
r = resource.IResource(f)
r.templateDirectory = config['templates']
site = server.Site(r)
j = internet.TCPServer(8000, site)
j.setServiceParent(s)
# ssl on port 443
# if config.get('ssl'):
# k = internet.SSLServer(443, site, ServerContextFactory())
# k.setServiceParent(s)
# irc fingerbot
if 'ircnick' in config:
i = IIRCClientFactory(f)
i.nickname = config['ircnick']
ircserver = config['ircserver']
b = internet.TCPClient(ircserver, 6667, i)
b.setServiceParent(s)
# Pespective Broker on port 8889
if 'pbport' in config:
m = internet.TCPServer(
int(config['pbport']),
pb.PBServerFactory(IPerspectiveFinger(f)))
m.setServiceParent(s)
return s
# finger/tap.py
from twisted.application import internet, service
from twisted.internet import interfaces
from twisted.python import usage
import finger
class Options(usage.Options):
optParameters = [
['file', 'f', '/etc/users'],
['templates', 't', '/usr/share/finger/templates'],
['ircnick', 'n', 'fingerbot'],
['ircserver', None, 'irc.freenode.net'],
['pbport', 'p', 8889],
]
optFlags = [['ssl', 's']]
def makeService(config):
return finger.makeService(config)
And register it all:
from twisted.application.service import ServiceMaker
finger = ServiceMaker(
'finger', 'finger.tap', 'Run a finger service', 'finger')
Note that the second argument to ServiceMaker ,``finger.tap`` , is a reference to a module
(finger/tap.py ), not to a filename.
And now, the following works
% sudo twistd -n finger --file=/etc/users --ircnick=fingerbot
For more details about this, see the twistd plugin documentation .
If we already have the “finger” package installed in
PYTHONPATH (e.g. we added it to site-packages ), we
can achieve easy integration:
% tap2deb --unsigned -m "Foo <foo@example.com>" --type=python finger.tac
% sudo dpkg -i .build/*.deb
% tap2rpm --type=python finger.tac
% sudo rpm -i *.rpm
These packages will properly install and register init.d
scripts, etc. for the given file.
If it doesn’t work on your favorite OS: patches accepted!