| author |
Steve Losh <steve@stevelosh.com> |
| date |
Tue, 02 Mar 2010 19:45:54 -0500 |
| parents |
(none) |
| children |
(none) |
"""WSGI interface (see PEP 333)."""
import sys as _sys
import cherrypy as _cherrypy
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
from cherrypy import _cperror
from cherrypy.lib import httputil
def downgrade_wsgi_ux_to_1x(environ):
"""Return a new environ dict for WSGI 1.x from the given WSGI u.x environ."""
env1x = {}
url_encoding = environ[u'wsgi.url_encoding']
for k, v in environ.items():
if k in [u'PATH_INFO', u'SCRIPT_NAME', u'QUERY_STRING']:
v = v.encode(url_encoding)
elif isinstance(v, unicode):
v = v.encode('ISO-8859-1')
env1x[k.encode('ISO-8859-1')] = v
return env1x
class VirtualHost(object):
"""Select a different WSGI application based on the Host header.
This can be useful when running multiple sites within one CP server.
It allows several domains to point to different applications. For example:
root = Root()
RootApp = cherrypy.Application(root)
Domain2App = cherrypy.Application(root)
SecureApp = cherrypy.Application(Secure())
vhost = cherrypy._cpwsgi.VirtualHost(RootApp,
domains={'www.domain2.example': Domain2App,
'www.domain2.example:443': SecureApp,
})
cherrypy.tree.graft(vhost)
default: required. The default WSGI application.
use_x_forwarded_host: if True (the default), any "X-Forwarded-Host"
request header will be used instead of the "Host" header. This
is commonly added by HTTP servers (such as Apache) when proxying.
domains: a dict of {host header value: application} pairs.
The incoming "Host" request header is looked up in this dict,
and, if a match is found, the corresponding WSGI application
will be called instead of the default. Note that you often need
separate entries for "example.com" and "www.example.com".
In addition, "Host" headers may contain the port number.
"""
def __init__(self, default, domains=None, use_x_forwarded_host=True):
self.default = default
self.domains = domains or {}
self.use_x_forwarded_host = use_x_forwarded_host
def __call__(self, environ, start_response):
domain = environ.get('HTTP_HOST', '')
if self.use_x_forwarded_host:
domain = environ.get("HTTP_X_FORWARDED_HOST", domain)
nextapp = self.domains.get(domain)
if nextapp is None:
nextapp = self.default
return nextapp(environ, start_response)
class InternalRedirector(object):
"""WSGI middleware that handles raised cherrypy.InternalRedirect."""
def __init__(self, nextapp, recursive=False):
self.nextapp = nextapp
self.recursive = recursive
def __call__(self, environ, start_response):
redirections = []
while True:
environ = environ.copy()
try:
return self.nextapp(environ, start_response)
except _cherrypy.InternalRedirect, ir:
sn = environ.get('SCRIPT_NAME', '')
path = environ.get('PATH_INFO', '')
qs = environ.get('QUERY_STRING', '')
# Add the *previous* path_info + qs to redirections.
old_uri = sn + path
if qs:
old_uri += "?" + qs
redirections.append(old_uri)
if not self.recursive:
# Check to see if the new URI has been redirected to already
new_uri = sn + ir.path
if ir.query_string:
new_uri += "?" + ir.query_string
if new_uri in redirections:
ir.request.close()
raise RuntimeError("InternalRedirector visited the "
"same URL twice: %r" % new_uri)
# Munge the environment and try again.
environ['REQUEST_METHOD'] = "GET"
environ['PATH_INFO'] = ir.path
environ['QUERY_STRING'] = ir.query_string
environ['wsgi.input'] = StringIO()
environ['CONTENT_LENGTH'] = "0"
environ['cherrypy.previous_request'] = ir.request
class ExceptionTrapper(object):
def __init__(self, nextapp, throws=(KeyboardInterrupt, SystemExit)):
self.nextapp = nextapp
self.throws = throws
def __call__(self, environ, start_response):
return _TrappedResponse(self.nextapp, environ, start_response, self.throws)
class _TrappedResponse(object):
response = iter([])
def __init__(self, nextapp, environ, start_response, throws):
self.nextapp = nextapp
self.environ = environ
self.start_response = start_response
self.throws = throws
self.started_response = False
self.response = self.trap(self.nextapp, self.environ, self.start_response)
self.iter_response = iter(self.response)
def __iter__(self):
self.started_response = True
return self
def next(self):
return self.trap(self.iter_response.next)
def close(self):
if hasattr(self.response, 'close'):
self.response.close()
def trap(self, func, *args, **kwargs):
try:
return func(*args, **kwargs)
except self.throws:
raise
except StopIteration:
raise
except:
tb = _cperror.format_exc()
#print('trapped (started %s):' % self.started_response, tb)
_cherrypy.log(tb, severity=40)
if not _cherrypy.request.show_tracebacks:
tb = ""
s, h, b = _cperror.bare_error(tb)
if self.started_response:
# Empty our iterable (so future calls raise StopIteration)
self.iter_response = iter([])
else:
self.iter_response = iter(b)
try:
self.start_response(s, h, _sys.exc_info())
except:
# "The application must not trap any exceptions raised by
# start_response, if it called start_response with exc_info.
# Instead, it should allow such exceptions to propagate
# back to the server or gateway."
# But we still log and call close() to clean up ourselves.
_cherrypy.log(traceback=True, severity=40)
raise
if self.started_response:
return "".join(b)
else:
return b
# WSGI-to-CP Adapter #
class AppResponse(object):
"""WSGI response iterable for CherryPy applications."""
def __init__(self, environ, start_response, cpapp):
if environ.get(u'wsgi.version') == (u'u', 0):
environ = downgrade_wsgi_ux_to_1x(environ)
self.environ = environ
self.cpapp = cpapp
try:
self.run()
except:
self.close()
raise
r = _cherrypy.serving.response
self.iter_response = iter(r.body)
self.write = start_response(r.output_status, r.header_list)
def __iter__(self):
return self
def next(self):
return self.iter_response.next()
def close(self):
"""Close and de-reference the current request and response. (Core)"""
self.cpapp.release_serving()
def run(self):
"""Create a Request object using environ."""
env = self.environ.get
local = httputil.Host('', int(env('SERVER_PORT', 80)),
env('SERVER_NAME', ''))
remote = httputil.Host(env('REMOTE_ADDR', ''),
int(env('REMOTE_PORT', -1)),
env('REMOTE_HOST', ''))
scheme = env('wsgi.url_scheme')
sproto = env('ACTUAL_SERVER_PROTOCOL', "HTTP/1.1")
request, resp = self.cpapp.get_serving(local, remote, scheme, sproto)
# LOGON_USER is served by IIS, and is the name of the
# user after having been mapped to a local account.
# Both IIS and Apache set REMOTE_USER, when possible.
request.login = env('LOGON_USER') or env('REMOTE_USER') or None
request.multithread = self.environ['wsgi.multithread']
request.multiprocess = self.environ['wsgi.multiprocess']
request.wsgi_environ = self.environ
request.prev = env('cherrypy.previous_request', None)
meth = self.environ['REQUEST_METHOD']
path = httputil.urljoin(self.environ.get('SCRIPT_NAME', ''),
self.environ.get('PATH_INFO', ''))
qs = self.environ.get('QUERY_STRING', '')
rproto = self.environ.get('SERVER_PROTOCOL')
headers = self.translate_headers(self.environ)
rfile = self.environ['wsgi.input']
request.run(meth, path, qs, rproto, headers, rfile)
headerNames = {'HTTP_CGI_AUTHORIZATION': 'Authorization',
'CONTENT_LENGTH': 'Content-Length',
'CONTENT_TYPE': 'Content-Type',
'REMOTE_HOST': 'Remote-Host',
'REMOTE_ADDR': 'Remote-Addr',
}
def translate_headers(self, environ):
"""Translate CGI-environ header names to HTTP header names."""
for cgiName in environ:
# We assume all incoming header keys are uppercase already.
if cgiName in self.headerNames:
yield self.headerNames[cgiName], environ[cgiName]
elif cgiName[:5] == "HTTP_":
# Hackish attempt at recovering original header names.
translatedHeader = cgiName[5:].replace("_", "-")
yield translatedHeader, environ[cgiName]
class CPWSGIApp(object):
"""A WSGI application object for a CherryPy Application.
pipeline: a list of (name, wsgiapp) pairs. Each 'wsgiapp' MUST be a
constructor that takes an initial, positional 'nextapp' argument,
plus optional keyword arguments, and returns a WSGI application
(that takes environ and start_response arguments). The 'name' can
be any you choose, and will correspond to keys in self.config.
head: rather than nest all apps in the pipeline on each call, it's only
done the first time, and the result is memoized into self.head. Set
this to None again if you change self.pipeline after calling self.
config: a dict whose keys match names listed in the pipeline. Each
value is a further dict which will be passed to the corresponding
named WSGI callable (from the pipeline) as keyword arguments.
"""
pipeline = [('ExceptionTrapper', ExceptionTrapper),
('InternalRedirector', InternalRedirector),
]
head = None
config = {}
response_class = AppResponse
def __init__(self, cpapp, pipeline=None):
self.cpapp = cpapp
self.pipeline = self.pipeline[:]
if pipeline:
self.pipeline.extend(pipeline)
self.config = self.config.copy()
def tail(self, environ, start_response):
"""WSGI application callable for the actual CherryPy application.
You probably shouldn't call this; call self.__call__ instead,
so that any WSGI middleware in self.pipeline can run first.
"""
return self.response_class(environ, start_response, self.cpapp)
def __call__(self, environ, start_response):
head = self.head
if head is None:
# Create and nest the WSGI apps in our pipeline (in reverse order).
# Then memoize the result in self.head.
head = self.tail
for name, callable in self.pipeline[::-1]:
conf = self.config.get(name, {})
head = callable(head, **conf)
self.head = head
return head(environ, start_response)
def namespace_handler(self, k, v):
"""Config handler for the 'wsgi' namespace."""
if k == "pipeline":
# Note this allows multiple 'wsgi.pipeline' config entries
# (but each entry will be processed in a 'random' order).
# It should also allow developers to set default middleware
# in code (passed to self.__init__) that deployers can add to
# (but not remove) via config.
self.pipeline.extend(v)
elif k == "response_class":
self.response_class = v
else:
name, arg = k.split(".", 1)
bucket = self.config.setdefault(name, {})
bucket[arg] = v