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# Copyright (C) 2015 Custodia Project Contributors - see LICENSE file
try:
# pylint: disable=import-error
from BaseHTTPServer import BaseHTTPRequestHandler
from SocketServer import ForkingMixIn, UnixStreamServer
from urlparse import urlparse, parse_qs
except ImportError:
# pylint: disable=import-error
from http.server import BaseHTTPRequestHandler
from socketserver import ForkingMixIn, UnixStreamServer
from urllib.parse import urlparse, parse_qs
import io
import os
import shutil
import six
import socket
import struct
import sys
import traceback
SO_PEERCRED = 17
class HTTPError(Exception):
def __init__(self, code=None, message=None):
self.code = code if code is not None else 500
self.mesg = message
super(HTTPError, self).__init__('%d: %s' % (self.code, self.mesg))
def stacktrace():
with io.BytesIO() as f:
_, _, tb = sys.exc_info()
traceback.print_tb(tb, None, file=f)
del tb
return f.getvalue()
class ForkingLocalHTTPServer(ForkingMixIn, UnixStreamServer):
"""
A forking HTTP Server.
Each request runs into a forked server so that the whole environment
is clean and isolated, and parallel requests cannot unintentionally
influence one another.
When a request is received it is parsed by the handler_class provided
at server initialization. The hanlder is suppoed to call the pipeline()
function provided by the server to handle requests after parsing.
The pipeline() function handles authentication and invocation of the
correct consumer based on the server configuration, that is provided
at initialization time.
When authentication is performed the request dictionary will have
a 'valid_auth' boolean member set to True if authentication was
successful. Additional attributes may be set by authentication plugins.
Once authentication is successful the pipeline will parse the path
component and find the consumer plugin that handles the provided path
walking up the path component by component until a consumer is found.
Paths are walked up from the leaf to the root, so if two consumers hang
on the same tree, the one closer to the leaf will be used. If there is
a trailing path when the conumer is selected then it will be stored in
the request dicstionary named 'trail'. The 'trail' is an ordered list
of the path components below the consumer entry point.
"""
server_string = "Custodia/0.1"
allow_reuse_address = True
socket_file = None
def __init__(self, server_address, handler_class, config):
UnixStreamServer.__init__(self, server_address, handler_class)
if 'consumers' not in config:
raise ValueError('Configuration does not provide any consumer')
self.config = config
if 'server_string' in self.config:
self.server_string = self.config['server_string']
def server_bind(self):
UnixStreamServer.server_bind(self)
self.socket_file = self.socket.getsockname()
def pipeline(self, request):
# auth framework here
authers = self.config.get('authenticators')
if authers is None:
raise HTTPError(403)
for auth in authers:
authers[auth].handle(request)
if 'valid_auth' not in request or request['valid_auth'] is not True:
raise HTTPError(403)
# Select consumer
path = request.get('path', '')
if not os.path.isabs(path):
raise HTTPError(400)
trail = []
while path != '':
if path in self.config['consumers']:
con = self.config['consumers'][path]
if len(trail) != 0:
request['trail'] = trail
return con.handle(request)
if path == '/':
path = ''
else:
head, tail = os.path.split(path)
trail.insert(0, tail)
path = head
raise HTTPError(404)
class LocalHTTPRequestHandler(BaseHTTPRequestHandler):
"""
This request handler is a slight modification of BaseHTTPRequestHandler
where the per-request handler is replaced.
When a request comes in it is parsed and the 'request' dictionary is
populated accordingly. Additionally a 'creds' structure is added to the
request.
The 'creds' structure contains the data retrieved via a call to
getsockopt with the SO_PEERCRED option. This retrieves via kernel assist
the uid,gid and pid of the process on the other side of the unix socket
on which the request has been made. This can be used for authentication
and/or authorization purposes.
after the request is parsed the server's pipeline() function is invoked
in order to handle it. The pipeline() should return a response object,
where te return 'code', the 'output' and 'headers' may be found.
If no 'code' is present the request is assumed to be successful and a
'200 OK' status code will be sent back to the client.
The 'output' parameter can be a string or a file like object.
The 'headers' objct must be a dictionary where keys are headers names.
By default we assume HTTP1.1, so connections may remain open.
"""
protocol_version = "HTTP/1.1"
def __init__(self, *args, **kwargs):
BaseHTTPRequestHandler.__init__(self, *args, **kwargs)
self.requestline = ''
self.request_version = ''
self.command = ''
self.raw_requestline = None
self.close_connection = 0
def version_string(self):
return self.server.server_string
@property
def peer_creds(self):
creds = self.request.getsockopt(socket.SOL_SOCKET, SO_PEERCRED,
struct.calcsize('3i'))
pid, uid, gid = struct.unpack('3i', creds)
return {'pid': pid, 'uid': uid, 'gid': gid}
def parse_request(self, *args, **kwargs):
if not BaseHTTPRequestHandler.parse_request(self, *args, **kwargs):
return False
# after basic parsing also use urlparse to retrieve individual
# elements of a request.
url = urlparse(self.path)
# Yes, override path with the path part only
self.path = url.path
# Create dict out of query
self.query = parse_qs(url.query)
# keep the rest into the 'url' element in case someone needs it
self.url = url
return True
def handle_one_request(self):
# Set a fake client address to make log functions happy
self.client_address = ['127.0.0.1', 0]
try:
if not self.server.pipeline:
self.close_connection = 1
return
self.raw_requestline = self.rfile.readline(65537)
if not self.raw_requestline:
self.close_connection = 1
return
if len(self.raw_requestline) > 65536:
self.requestline = ''
self.request_version = ''
self.command = ''
self.send_error(414)
self.wfile.flush()
return
if not self.parse_request():
self.close_connection = 1
return
request = {'creds': self.peer_creds,
'command': self.command,
'path': self.path,
'query': self.query,
'url': self.url,
'version': self.request_version,
'headers': self.headers}
try:
response = self.server.pipeline(request)
if response is None:
raise HTTPError(500)
except HTTPError as e:
self.send_error(e.code, e.mesg)
self.wfile.flush()
return
except socket.timeout as e:
self.log_error("Request timed out: %r", e)
self.close_connection = 1
return
except Exception as e: # pylint: disable=broad-except
self.log_error("Handler failed: %r", e)
self.log_traceback()
self.send_error(500)
self.wfile.flush()
return
self.send_response(response.get('code', 200))
for header, value in six.iteritems(response.get('headers', {})):
self.send_header(header, value)
self.end_headers()
output = response.get('output', None)
if hasattr(output, 'read'):
shutil.copyfileobj(output, self.wfile)
output.close()
else:
self.wfile.write(output.encode('utf-8'))
self.wfile.flush()
return
except socket.timeout as e:
self.log_error("Request timed out: %r", e)
self.close_connection = 1
return
def log_traceback(self):
self.log_error('Traceback:\n%s' % stacktrace())
class LocalHTTPServer(object):
def __init__(self, address, config):
if address[0] != '/':
raise ValueError('Must use absolute unix socket name')
if os.path.exists(address):
os.remove(address)
self.httpd = ForkingLocalHTTPServer(address, LocalHTTPRequestHandler,
config)
def get_socket(self):
return (self.httpd.socket, self.httpd.socket_file)
def serve(self):
return self.httpd.serve_forever()
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