问题
CherryPy keeps returning blank pages or with the values I return in the controllers. I rewrote a django and jinja2 version that did work, apparently this one doesn't which is almost identical to the previous mentioned.
I did some pprint's in the tool bit which does fill the request.body with parsed html but doesn't output it when pass is set in the controller. If I return a {'user':True} in the controller that is shown in the form of a simple "User".
with a few examples online and the code of SickBeard I came to the following:
controller:
class RootController(object):
@cherrypy.expose
@cherrypy.tools.render(template="page/home.html")
def index(self):
pass
tool:
class CheetahTool(cherrypy.Tool):
def __init__(self):
cherrypy.Tool.__init__(self, 'on_start_resource',
self._render,
priority=30)
def _render(self, template=None, debug=False):
if cherrypy.response.status > 399:
return
# retrieve the data returned by the handler
data = cherrypy.response.body or {}
template = cherrypy.engine.publish("lookup-template", template).pop()
if template and isinstance(data, dict):
for k,v in data:
template.__setattr__(k, v)
# dump the template using the dictionary
if debug:
try:
cherrypy.response.body = unicode(template).encode('utf-8', 'xmlcharrefreplace')
except Exception as e:
from pprint import pprint
pprint(e.message)
else:
cherrypy.response.body = template.respond()
plugin:
class PageTemplate(Template):
"""
Thank you SickBeard
"""
def __init__(self, base_dir, template, *args, **KWs):
KWs['file'] = os.path.join(base_dir, template)
super(PageTemplate, self).__init__(*args, **KWs)
application = cherrypy.tree.apps['']
config = application.config
self.sbRoot = base_dir
self.sbHttpPort = config['global']['server.socket_port']
self.sbHttpsPort = self.sbHttpPort
self.sbHttpsEnabled = False
if cherrypy.request.headers['Host'][0] == '[':
self.sbHost = re.match("^\[.*\]", cherrypy.request.headers['Host'], re.X|re.M|re.S).group(0)
else:
self.sbHost = re.match("^[^:]+", cherrypy.request.headers['Host'], re.X|re.M|re.S).group(0)
if "X-Forwarded-Host" in cherrypy.request.headers:
self.sbHost = cherrypy.request.headers['X-Forwarded-Host']
if "X-Forwarded-Port" in cherrypy.request.headers:
self.sbHttpPort = cherrypy.request.headers['X-Forwarded-Port']
self.sbHttpsPort = self.sbHttpPort
if "X-Forwarded-Proto" in cherrypy.request.headers:
self.sbHttpsEnabled = True if cherrypy.request.headers['X-Forwarded-Proto'] == 'https' else False
self.sbPID = str(aquapi.PID)
self.menu = [
{ 'title': 'Home', 'key': 'home' },
{ 'title': 'Users', 'key': 'users' },
{ 'title': 'Config', 'key': 'config' },
]
def render(self):
return unicode(self).encode('utf-8', 'xmlcharrefreplace')
class CheetahTemplatePlugin(plugins.SimplePlugin):
def __init__(self, bus, base_dir=None, base_cache_dir=None,
collection_size=50, encoding='utf-8'):
plugins.SimplePlugin.__init__(self, bus)
self.base_dir = base_dir
self.base_cache_dir = base_cache_dir or tempfile.gettempdir()
self.encoding = encoding
self.collection_size = collection_size
def start(self):
self.bus.log('Setting up Cheetah resources')
self.bus.subscribe("lookup-template", self.get_template)
def stop(self):
self.bus.log('Freeing up Cheetah resources')
self.bus.unsubscribe("lookup-template", self.get_template)
self.lookup = None
def get_template(self, name):
"""
Returns Cheetah's template by name.
"""
return PageTemplate(self.base_dir, name)
init:
# Template engine tool
from aquapi.web.tools.template import CheetahTool
cherrypy.tools.render = CheetahTool()
# Tool to load the logged in user or redirect
# the client to the login page
from aquapi.web.tools.user import UserTool
cherrypy.tools.user = UserTool()
from aquapi.web.controllers import RootController
webapp = RootController()
# Let's mount the application so that CherryPy can serve it
app = cherrypy.tree.mount(webapp, '/', os.path.join(self.base_dir, "app.cfg"))
# Template engine plugin
from aquapi.web.plugin.template import CheetahTemplatePlugin
engine.cheetah = CheetahTemplatePlugin(engine,
os.path.join(self.base_dir, 'aquapi/web/templates'),
os.path.join(self.base_dir, 'cache'))
engine.cheetah.subscribe()
回答1:
In general, to me it's some sort of over-engineering happened in your snippets. CherryPy plugins are usually used for a system task (e.g. put PID-file on engine start, remove it on stop) or for an asynchronous task (e.g. sending email in separate thread). Template rendering happens clearly synchronously to the request handling, so I don't see the point of extracting this logic out of CherryPy tool. There's a class in CherryPy, cherrypy._cptools.HandlerWrapperTool, which demonstrate the suggested approach to wrapping handler return values.
I haven't ever used Cheetah, so my example is Jinja2-based. You will just have to change the templating engine instance (to Cheetah) and correct its calls. The rest is the same.
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import os
import types
import cherrypy
import jinja2
path = os.path.abspath(os.path.dirname(__file__))
config = {
'global' : {
'server.socket_host' : '127.0.0.1',
'server.socket_port' : 8080,
'server.thread_pool' : 4
}
}
class TemplateTool(cherrypy.Tool):
_engine = None
'''Jinja environment instance'''
def __init__(self):
viewLoader = jinja2.FileSystemLoader(os.path.join(path, 'view'))
self._engine = jinja2.Environment(loader = viewLoader)
cherrypy.Tool.__init__(self, 'before_handler', self.render)
def __call__(self, *args, **kwargs):
if args and isinstance(args[0], (types.FunctionType, types.MethodType)):
# @template
args[0].exposed = True
return cherrypy.Tool.__call__(self, **kwargs)(args[0])
else:
# @template()
def wrap(f):
f.exposed = True
return cherrypy.Tool.__call__(self, *args, **kwargs)(f)
return wrap
def render(self, name = None):
cherrypy.request.config['template'] = name
handler = cherrypy.serving.request.handler
def wrap(*args, **kwargs):
return self._render(handler, *args, **kwargs)
cherrypy.serving.request.handler = wrap
def _render(self, handler, *args, **kwargs):
template = cherrypy.request.config['template']
if not template:
parts = []
if hasattr(handler.callable, '__self__'):
parts.append(handler.callable.__self__.__class__.__name__.lower())
if hasattr(handler.callable, '__name__'):
parts.append(handler.callable.__name__.lower())
template = u'/'.join(parts)
data = handler(*args, **kwargs) or {}
renderer = self._engine.get_template(u'{0}.html'.format(template))
return renderer.render(**data)
cherrypy.tools.template = TemplateTool()
class App:
@cherrypy.expose
def index(self):
'''No renderer applied, CherryPy outputs dict keys'''
return {'user': 123}
@cherrypy.tools.template
def auto(self):
return {'user': 123}
@cherrypy.tools.template(name = 'app/auto')
def manual(self):
return {'user': 234}
if __name__ == '__main__':
cherrypy.quickstart(App(), '/', config)
Along the python file, create directory view/app and put the following in file named auto.html there.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv='content-type' content='text/html; charset=utf-8' />
<title>Test</title>
</head>
<body>
<p>User: <em>{{ user }}</em></p>
</body>
</html>
Some notes on the TemplateTool. First, you can use it as a decorator in two ways: not making a call, and making a call with template name argument. You can use the tool as any other CherryPy tool in the configuration (e.g. make all controller methods to render templates). Second, following convention-over-configuration principle, the tool when not provided with template name will use classname/methodname.html. Third, the decorator exposes the method, so you don't need to add @cherrypy.expose on top.
来源：https://stackoverflow.com/questions/24578794/cherrypy-with-cheetah-as-plugin-tool-blank-pages