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Edit File: default_handler.py

# -*- Mode: Python -*-
#
# Author: Sam Rushing <rushing@nightmare.com>
# Copyright 1997 by Sam Rushing
# All Rights Reserved.
#

RCS_ID = '$Id: default_handler.py,v 1.8 2002/08/01 18:15:45 akuchling Exp $'

# standard python modules
import mimetypes
import re
import stat

# medusa modules
import supervisor.medusa.http_date as http_date
import supervisor.medusa.http_server as http_server
import supervisor.medusa.producers as producers

from supervisor.medusa.util import html_repr

unquote = http_server.unquote

# This is the 'default' handler. it implements the base set of
# features expected of a simple file-delivering HTTP server. file
# services are provided through a 'filesystem' object, the very same
# one used by the FTP server.
#
# You can replace or modify this handler if you want a non-standard
# HTTP server. You can also derive your own handler classes from
# it.
#
# support for handling POST requests is available in the derived
# class <default_with_post_handler>, defined below.
#

from supervisor.medusa.counter import counter

class default_handler:

valid_commands = ['GET', 'HEAD']

IDENT = 'Default HTTP Request Handler'

# Pathnames that are tried when a URI resolves to a directory name
    directory_defaults = [
            'index.html',
            'default.html'
            ]

default_file_producer = producers.file_producer

def __init__ (self, filesystem):
        self.filesystem = filesystem
        # count total hits
        self.hit_counter = counter()
        # count file deliveries
        self.file_counter = counter()
        # count cache hits
        self.cache_counter = counter()

hit_counter = 0

def __repr__ (self):
 return '<%s (%s hits) at %x>' % (
 self.IDENT,
 self.hit_counter,
 id (self)
 )

# always match, since this is a default
    def match (self, request):
        return 1

# handle a file request, with caching.

def handle_request (self, request):

if request.command not in self.valid_commands:
            request.error (400) # bad request
            return

self.hit_counter.increment()

path, params, query, fragment = request.split_uri()

if '%' in path:
            path = unquote (path)

# strip off all leading slashes
        while path and path[0] == '/':
            path = path[1:]

if self.filesystem.isdir (path):
            if path and path[-1] != '/':
                request['Location'] = 'http://%s/%s/' % (
                        request.channel.server.server_name,
                        path
                        )
                request.error (301)
                return

# we could also generate a directory listing here,
            # may want to move this into another method for that
            # purpose
            found = 0
            if path and path[-1] != '/':
                path += '/'
            for default in self.directory_defaults:
                p = path + default
                if self.filesystem.isfile (p):
                    path = p
                    found = 1
                    break
            if not found:
                request.error (404) # Not Found
                return

elif not self.filesystem.isfile (path):
            request.error (404) # Not Found
            return

file_length = self.filesystem.stat (path)[stat.ST_SIZE]

ims = get_header_match (IF_MODIFIED_SINCE, request.header)

length_match = 1
        if ims:
            length = ims.group (4)
            if length:
                try:
                    length = int(length)
                    if length != file_length:
                        length_match = 0
                except:
                    pass

ims_date = 0

if ims:
            ims_date = http_date.parse_http_date (ims.group (1))

try:
            mtime = self.filesystem.stat (path)[stat.ST_MTIME]
        except:
            request.error (404)
            return

if length_match and ims_date:
 if mtime <= ims_date:
 request.reply_code = 304
 request.done()
 self.cache_counter.increment()
 return
 try:
 file = self.filesystem.open (path, 'rb')
 except IOError:
 request.error (404)
 return

request['Last-Modified'] = http_date.build_http_date (mtime)
        request['Content-Length'] = file_length
        self.set_content_type (path, request)

if request.command == 'GET':
            request.push (self.default_file_producer (file))

self.file_counter.increment()
        request.done()

def set_content_type (self, path, request):
        typ, encoding = mimetypes.guess_type(path)
        if typ is not None:
            request['Content-Type'] = typ
        else:
            # TODO: test a chunk off the front of the file for 8-bit
            # characters, and use application/octet-stream instead.
            request['Content-Type'] = 'text/plain'

def status (self):
 return producers.simple_producer (
 '<li>%s' % html_repr (self)
 + '<ul>'
 + ' <li>Total Hits: %s' % self.hit_counter
 + ' <li>Files Delivered: %s' % self.file_counter
 + ' <li>Cache Hits: %s' % self.cache_counter
 + '</ul>'
 )

# HTTP/1.0 doesn't say anything about the "; length=nnnn" addition
# to this header.  I suppose its purpose is to avoid the overhead
# of parsing dates...
IF_MODIFIED_SINCE = re.compile (
        'If-Modified-Since: ([^;]+)((; length=([0-9]+)$)|$)',
        re.IGNORECASE
        )

USER_AGENT = re.compile ('User-Agent: (.*)', re.IGNORECASE)

CONTENT_TYPE = re.compile (
        r'Content-Type: ([^;]+)((; boundary=([A-Za-z0-9\'+_,./:=?-]+)$)|$)',
        re.IGNORECASE
        )

get_header = http_server.get_header
get_header_match = http_server.get_header_match

def get_extension (path):
    dirsep = path.rfind('/')
    dotsep = path.rfind('.')
    if dotsep > dirsep:
        return path[dotsep+1:]
    else:
        return ''

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