# This is a sample configuration file for an ISAPI filter and extension
# written in Python.
#
# Please see README.txt in this directory, and specifically the
# information about the "loader" DLL - installing this sample will create
# "_redirector_with_filter.dll" in the current directory. The readme explains
# this.
# Executing this script (or any server config script) will install the extension
# into your web server. As the server executes, the PyISAPI framework will load
# this module and create your Extension and Filter objects.
# This sample provides sample redirector:
# It is implemented by a filter and an extension, so that some requests can
# be ignored. Compare with 'redirector_simple' which avoids the filter, but
# is unable to selectively ignore certain requests.
# The process is sample uses is:
# * The filter is installed globally, as all filters are.
# * A Virtual Directory named "python" is setup. This dir has our ISAPI
# extension as the only application, mapped to file-extension '*'. Thus, our
# extension handles *all* requests in this directory.
# The basic process is that the filter does URL rewriting, redirecting every
# URL to our Virtual Directory. Our extension then handles this request,
# forwarding the data from the proxied site.
# For example:
# * URL of "index.html" comes in.
# * Filter rewrites this to "/python/index.html"
# * Our extension sees the full "/python/index.html", removes the leading
# portion, and opens and forwards the remote URL.
# This sample is very small - it avoid most error handling, etc. It is for
# demonstration purposes only.
from isapi import isapicon, threaded_extension
from isapi.simple import SimpleFilter
import sys
import traceback
import urllib
# sys.isapidllhandle will exist when we are loaded by the IIS framework.
# In this case we redirect our output to the win32traceutil collector.
if hasattr(sys, "isapidllhandle"):
import win32traceutil
# The site we are proxying.
proxy = "http://www.python.org"
# The name of the virtual directory we install in, and redirect from.
virtualdir = "/python"
# The key feature of this redirector over the simple redirector is that it
# can choose to ignore certain responses by having the filter not rewrite them
# to our virtual dir. For this sample, we just exclude the IIS help directory.
# The ISAPI extension - handles requests in our virtual dir, and sends the
# response to the client.
class Extension(threaded_extension.ThreadPoolExtension):
"Python sample Extension"
def Dispatch(self, ecb):
# Note that our ThreadPoolExtension base class will catch exceptions
# in our Dispatch method, and write the traceback to the client.
# That is perfect for this sample, so we don't catch our own.
#print 'IIS dispatching "%s"' % (ecb.GetServerVariable("URL"),)
url = ecb.GetServerVariable("URL")
if url.startswith(virtualdir):
new_url = proxy + url[len(virtualdir):]
print "Opening", new_url
fp = urllib.urlopen(new_url)
headers = fp.info()
ecb.SendResponseHeaders("200 OK", str(headers) + "\r\n", False)
ecb.WriteClient(fp.read())
ecb.DoneWithSession()
print "Returned data from '%s'!" % (new_url,)
else:
# this should never happen - we should only see requests that
# start with our virtual directory name.
print "Not proxying '%s'" % (url,)
# The ISAPI filter.
class Filter(SimpleFilter):
"Sample Python Redirector"
filter_flags = isapicon.SF_NOTIFY_PREPROC_HEADERS | \
isapicon.SF_NOTIFY_ORDER_DEFAULT
def HttpFilterProc(self, fc):
#print "Filter Dispatch"
nt = fc.NotificationType
if nt != isapicon.SF_NOTIFY_PREPROC_HEADERS:
return isapicon.SF_STATUS_REQ_NEXT_NOTIFICATION
pp = fc.GetData()
url = pp.GetHeader("url")
#print "URL is '%s'" % (url,)
prefix = virtualdir
if not url.startswith(prefix):
new_url = prefix + url
print "New proxied URL is '%s'" % (new_url,)
pp.SetHeader("url", new_url)
# For the sake of demonstration, show how the FilterContext
# attribute is used. It always starts out life as None, and
# any assignments made are automatically decref'd by the
# framework during a SF_NOTIFY_END_OF_NET_SESSION notification.
if fc.FilterContext is None:
fc.FilterContext = 0
fc.FilterContext += 1
print "This is request number %d on this connection" % fc.FilterContext
return isapicon.SF_STATUS_REQ_HANDLED_NOTIFICATION
else:
print "Filter ignoring URL '%s'" % (url,)
# Some older code that handled SF_NOTIFY_URL_MAP.
#~ print "Have URL_MAP notify"
#~ urlmap = fc.GetData()
#~ print "URI is", urlmap.URL
#~ print "Path is", urlmap.PhysicalPath
#~ if urlmap.URL.startswith("/UC/"):
#~ # Find the /UC/ in the physical path, and nuke it (except
#~ # as the path is physical, it is \)
#~ p = urlmap.PhysicalPath
#~ pos = p.index("\\UC\\")
#~ p = p[:pos] + p[pos+3:]
#~ p = r"E:\src\pyisapi\webroot\PyTest\formTest.htm"
#~ print "New path is", p
#~ urlmap.PhysicalPath = p
# The entry points for the ISAPI extension.
def __FilterFactory__():
return Filter()
def __ExtensionFactory__():
return Extension()
if __name__=='__main__':
# If run from the command-line, install ourselves.
from isapi.install import *
params = ISAPIParameters()
# Setup all filters - these are global to the site.
params.Filters = [
FilterParameters(Name="PythonRedirector",
Description=Filter.__doc__),
]
# Setup the virtual directories - this is a list of directories our
# extension uses - in this case only 1.
# Each extension has a "script map" - this is the mapping of ISAPI
# extensions.
sm = [
ScriptMapParams(Extension="*", Flags=0)
]
vd = VirtualDirParameters(Name=virtualdir[1:],
Description = Extension.__doc__,
ScriptMaps = sm,
ScriptMapUpdate = "replace"
)
params.VirtualDirs = [vd]
HandleCommandLine(params)
