Finger 的演变：使用 Perspective Broker 的 Twisted 客户端支持¶
简介¶
这是 Twisted 教程的第七部分 从头开始使用 Twisted，或 Finger 的演变 。
在本部分中，我们在 finger 应用程序中添加了一个 Perspective Broker 服务，以便 Twisted 客户端可以访问 finger 服务器。Perspective Broker 在其自己的 部分 中进行了深入介绍，该部分位于核心操作指南索引中。
使用 Perspective Broker¶
我们添加了对 Perspective Broker 的支持，它是 Twisted 的原生远程对象协议。现在，Twisted 客户端无需再通过 XML-RPC 类的曲折方式来获取有关用户的的信息。
# Do everything properly, and componentize
from zope.interface import Interface, implementer
from twisted.application import internet, service, strports
from twisted.internet import defer, endpoints, protocol, reactor
from twisted.protocols import basic
from twisted.python import components
from twisted.spread import pb
from twisted.web import resource, server, static, xmlrpc
from twisted.words.protocols import irc
class IFingerService(Interface):
def getUser(user):
"""
Return a deferred returning L{bytes}.
"""
def getUsers():
"""
Return a deferred returning a L{list} of L{bytes}.
"""
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 + "\r\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.
"""
@implementer(IFingerFactory)
class FingerFactoryFromService(protocol.ServerFactory):
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.
"""
@implementer(IFingerSetterFactory)
class FingerSetterFactoryFromService(protocol.ServerFactory):
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.encode("ascii"))
d.addErrback(catchError)
d.addCallback(lambda m: f"Status of {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.
"""
@implementer(IIRCClientFactory)
class IRCClientFactoryFromService(protocol.ClientFactory):
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):
def __init__(self, service):
resource.Resource.__init__(self)
self.service = service
# add a specific child for the path "RPC2"
self.putChild("RPC2", UserStatusXR(self.service))
# need to do this for resources at the root of the site
self.putChild("", self)
def _cb_render_GET(self, users, request):
userOutput = "".join(
[f'<li><a href="{user}">{user}</a></li>' for user in users]
)
request.write(
"""
<html><head><title>Users</title></head><body>
<h1>Users</h1>
<ul>
%s
</ul></body></html>"""
% userOutput
)
request.finish()
def render_GET(self, request):
d = self.service.getUsers()
d.addCallback(self._cb_render_GET, request)
# signal that the rendering is not complete
return server.NOT_DONE_YET
def getChild(self, path, request):
return UserStatus(user=path, service=self.service)
components.registerAdapter(UserStatusTree, IFingerService, resource.IResource)
class UserStatus(resource.Resource):
def __init__(self, user, service):
resource.Resource.__init__(self)
self.user = user
self.service = service
def _cb_render_GET(self, status, request):
request.write(
"""<html><head><title>%s</title></head>
<body><h1>%s</h1>
<p>%s</p>
</body></html>"""
% (self.user, self.user, status)
)
request.finish()
def render_GET(self, request):
d = self.service.getUser(self.user)
d.addCallback(self._cb_render_GET, request)
# signal that the rendering is not complete
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.
"""
@implementer(IPerspectiveFinger)
class PerspectiveFingerFromService(pb.Root):
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
)
@implementer(IFingerService)
class FingerService(service.Service):
def __init__(self, filename):
self.filename = filename
self.users = {}
def _read(self):
self.users.clear()
with open(self.filename, "rb") as f:
for line in f:
user, status = line.split(b":", 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, b"No such user"))
def getUsers(self):
return defer.succeed(list(self.users.keys()))
def startService(self):
self._read()
service.Service.startService(self)
def stopService(self):
service.Service.stopService(self)
self.call.cancel()
application = service.Application("finger", uid=1, gid=1)
f = FingerService("/etc/users")
serviceCollection = service.IServiceCollection(application)
f.setServiceParent(serviceCollection)
strports.service("tcp:79", IFingerFactory(f)).setServiceParent(serviceCollection)
strports.service("tcp:8000", server.Site(resource.IResource(f))).setServiceParent(
serviceCollection
)
i = IIRCClientFactory(f)
i.nickname = "fingerbot"
internet.ClientService(
endpoints.clientFromString(reactor, "tcp:irc.freenode.org:6667"), i
).setServiceParent(serviceCollection)
strports.service(
"tcp:8889", pb.PBServerFactory(IPerspectiveFinger(f))
).setServiceParent(serviceCollection)
一个简单的客户端，用于测试 Perspective Broker finger
# test the PB finger on port 8889
# this code is essentially the same as
# the first example in howto/pb-usage
from twisted.internet import endpoints, reactor
from twisted.spread import pb
def gotObject(object):
print("got object:", object)
object.callRemote("getUser", "moshez").addCallback(gotData)
# or
# object.callRemote("getUsers").addCallback(gotData)
def gotData(data):
print("server sent:", data)
reactor.stop()
def gotNoObject(reason):
print("no object:", reason)
reactor.stop()
factory = pb.PBClientFactory()
clientEndpoint = endpoints.clientFromString("tcp:127.0.0.1:8889")
clientEndpoint.connect(factory)
factory.getRootObject().addCallbacks(gotObject, gotNoObject)
reactor.run()