Introduction
This is the sixth part of the Twisted tutorial Twisted from Scratch, or The Evolution of Finger.
In this part, we demonstrate adding a web frontend using the Woven templating system.
Use Woven
Here we convert to using Woven, instead of manually constructing HTML snippets. Woven is a sophisticated web templating system. Its main features are to disallow any code inside the HTML, and transparent integration with deferred results.
# Do everything properly, and componentize from twisted.application import internet, service from twisted.internet import protocol, reactor, defer from twisted.protocols import basic, irc from twisted.python import components from twisted.web import resource, server, static, xmlrpc, microdom from twisted.web.woven import page, model, interfaces import cgi class IFingerService(components.Interface): def getUser(self, user): """Return a deferred returning a string""" def getUsers(self): """Return a deferred returning a list of strings""" class IFingerSetterService(components.Interface): def setUser(self, 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(components.Interface): def getUser(self, user): """Return a deferred returning a string""" def buildProtocol(self, 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(components.Interface): def setUser(self, user, status): """Return a deferred returning a string""" def buildProtocol(self, 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(components.Interface): """ @ivar nickname """ def getUser(self, user): """Return a deferred returning a string""" def buildProtocol(self, 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 UsersModel(model.MethodModel): def initialize(self, *args, **kwargs): self.service=args[0] def wmfactory_users(self, request): return self.service.getUsers() components.registerAdapter(UsersModel, IFingerService, interfaces.IModel) class UserStatusTree(page.Page): template = """<html><head><title>Users</title></head><body> <h1>Users</h1> <ul model="users" view="List"> <li pattern="listItem"><a view="Anchor" /></li> </ul></body></html>""" def initialize(self, *args, **kwargs): self.service=args[0] def getDynamicChild(self, path, request): return UserStatus(user=path, service=self.service) def wchild_RPC2 (self, request): return UserStatusXR(self.service) components.registerAdapter(UserStatusTree, IFingerService, resource.IResource) class UserStatus(page.Page): template='''<html><head><title view="Text" model="user"/></head> <body><h1 view="Text" model="user"/> <p model="status" view="Text" /> </body></html>''' def initialize(self, **kwargs): self.user = kwargs['user'] self.service = kwargs['service'] def wmfactory_user(self, request): return self.user def wmfactory_status(self, request): return self.service.getUser(self.user) 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 FingerService(service.Service): __implements__ = IFingerService, def __init__(self, filename): self.filename = filename self._read() 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()) application = service.Application('finger', uid=1, gid=1) f = FingerService('/etc/users') serviceCollection = service.IServiceCollection(application) internet.TCPServer(79, IFingerFactory(f) ).setServiceParent(serviceCollection) internet.TCPServer(8000, server.Site(resource.IResource(f)) ).setServiceParent(serviceCollection) i = IIRCClientFactory(f) i.nickname = 'fingerbot' internet.TCPClient('irc.freenode.org', 6667, i ).setServiceParent(serviceCollection)
Source listing - listings/finger/finger20.py