# $Id: HTTPHandler.py 2028 2006-01-16 23:39:04Z zzzeek $
# generic HTTP handler library for Myghty
# Copyright (C) 2004, 2005 Michael Bayer mike_mp@zzzcomputing.com
#
# This module is part of Myghty and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
#
#
import myghty.buffer
import types, string, re, sys
import myghty.resolver
import myghty.interp
from myghty.util import *
import myghty.session as session
import myghty.exception as exception
__all__ = ['HTTPHandler', 'HeaderTable', 'HTTPRequest', 'HTTPWriter', 'HTTPResolver', 'handle_http']
handlers = {}
def handle_http(handlerclass, interpreter_name = None, interp = None, request_impl = None, component = None, **params):
"""handles an HTTP request using the named HTTPHandler instance. if an instance of the name does not
exist, it is created using the given configuration parameters.
implementing modules should define their own handle() method that calls this one
with the appropriate arguments."""
return get_handler(handlerclass, interpreter_name, **params).handle(interp = interp, request_impl = request_impl, component = component, **params)
def get_handler(handlerclass, interpreter_name = None, **params):
"""returns an HTTPHandler instance keyed off the given name. if the named instance does not exist,
it is created using the given configuration parameters."""
interpreter_name = handlerclass.__name__ + "_" + (interpreter_name or 'main')
try:
handler = handlers[interpreter_name]
except KeyError:
handler = handlerclass(**params)
handlers[interpreter_name] = handler
return handler
class HTTPHandler:
"""entry point for HTTP requests, configures and maintains a reference to
an instance of a Myghty intepreter, and
serves as a factory for many of the
other implementing objects in this module. override the do_*** methods of
this class, and call the handle() method inside the
the request-handling point of the implementing environment."""
def __init__(self, httpreq, logbuffer, **params):
self.params = self._init_params(httpreq, logbuffer, **params)
self.interp = myghty.interp.Interpreter(**self.params)
def _init_params(self, httpreq, logbuffer, **params):
params = self.do_get_init_params(httpreq, **params)
if not params.has_key('allow_globals'):
params['allow_globals'] = []
params['allow_globals'].append('r')
if params.setdefault('use_session', False):
params['allow_globals'].append('s')
debug_elements = params.setdefault('debug_elements', [])
# deprecated
if params.setdefault('log_component_loading', False):
debug_elements.append('classloading')
# deprecated
if params.setdefault('log_cache_operations', False):
debug_elements.append('cache')
if len(debug_elements) > 0 and not params.has_key('debug_file'):
params['debug_file'] = logbuffer
if not params.has_key('resolver'):
d = dict(params)
if d.has_key('debug_file'): del d['debug_file']
params['resolver'] = self.do_get_resolver(debug_file = None, **d)
if not params.has_key('data_dir'):
raise exception.ConfigurationError("data_dir config is required")
if not params.has_key('component_root') and not params.has_key('module_components') and not params.has_key('resolver_strategy') and not params.has_key('module_root'):
raise exception.ConfigurationError("No file resolution rules detected - component_root, module_components, and/or resolver_strategy")
return params
def do_get_init_params(self, httpreq, **params):raise NotImplementedError()
def do_get_resolver(self, **params):raise NotImplementedError()
def do_make_request_impl(self, httpreq, **params):raise NotImplementedError()
def do_get_component(self, httpreq, **params):raise NotImplementedError()
def do_handle_result(self, httpreq, status_code, reason):
"""called at the end of the request. in a normal response, headers and probably
content have already been sent. in the case of errors or redirects, this method
should insure that headers have been properly sent as required by the environment.
in all cases, appropriate return data should be returned from this method which will
be returned to the calling environment."""
raise NotImplementedError()
def handle(self, httpreq, interp = None, request_impl = None, component = None, **params):
"""handles an HTTP request. implementing classes may want to override this
to provide environment-specific request arguments that are then translated into the implementing
module's own HTTPRequest implementation.
httpreq - HTTPRequest request object or compatible interface
interp - optional Interpreter object to override the default
request_impl - optional RequestImpl object the default
component - optional Component object or request path to serve
**params - configuration parameters which override the default parameters
"""
if interp is None:
interp = self.interp
implparams = self.params.copy()
implparams.update(params)
if not request_impl:
request_impl = self.do_make_request_impl(httpreq, **implparams)
if not component:
if implparams.has_key('component'):
component = implparams['component']
else:
component = self.do_get_component(httpreq, **implparams)
reason = None
request = interp.make_request(component = component, request_impl = request_impl, **params)
try:
request.execute()
ret = HTTP_OK
except IOError:
ret = HTTP_OK
except exception.Abort, e:
ret = e.aborted_value
reason = e.reason
except exception.TopLevelNotFound:
ret = HTTP_NOT_FOUND
except exception.ServerError:
ret = HTTP_INTERNAL_SERVER_ERROR
httpreq.status = ret
return self.do_handle_result(httpreq, ret, reason)
class HTTPRequestImpl(myghty.request.AbstractRequestImpl):
"""subclasses the myghty AbstractRequestImpl class, to provide the connector between
the "real" http request (HTTPRequest) and the Myghty request (Request).
this class is responsible for setting up the resources needed by Request, including
the output buffer, session, request arguments (usually via a FieldStorage type API),
sending redirects and handling errors and other exceptions.
"""
def __init__(self, httpreq, logger, errorlogger,
request_args = None,
use_session = False,
global_args = None,
log_errors = False, output_errors = True, error_handler=None, **params):
self.httpreq = httpreq
if request_args is None:
request_args = self.do_make_request_args(httpreq, **params)
self.request_args = request_args
if not global_args is None:
# copy the global_args in case they are synonymous with those
# given to the interpreter
self.global_args = global_args.copy()
else:
self.global_args = {}
self.global_args['r'] = self.httpreq
self.session_args = session.MyghtySessionArgs(**params)
self.error_handler = error_handler
self.use_session = use_session
if self.use_session:
self.global_args['s'] = self.get_session()
self.log_errors = log_errors
self.output_errors = output_errors
self.logger = logger
self.errorlogger = errorlogger
self.out_buffer = self.do_get_out_buffer(httpreq, **params)
buffer = property(lambda self:self.out_buffer)
def do_make_request_args(self, httpreq, **params):raise NotImplementedError()
def do_get_out_buffer(self, httpreq, out_buffer = None, **params):raise NotImplementedError()
def log(self, message):
self.logger.write(message)
def request_args_from_fieldstorage(self, fields):
"""based on FieldStorage request information, returns a dict of key values, where the values are
one of: a string, a list of strings, a Field object with an upload value, a list of
Field objects with upload values."""
def formatfield(field):
if type(field) == types.ListType:
return map(formatfield, field)
elif not field.file:
return field.value
else:
return field
request_args = {}
if fields.file:
request_args['_file'] = fields.file
elif fields.list:
for key in fields.keys():
request_args[key] = formatfield(fields[key])
return request_args
def get_session(self, **params):
if not hasattr(self, 'session'):
self.session = self.session_args.get_session(self.httpreq, **params)
return self.session
def handle_error(self, error, m, **params):
if self._run_error_handler(self.error_handler, self.errorlogger, error, m, r = self.httpreq, **params): return
if isinstance(error, exception.TopLevelNotFound):
if not error.silent:
self.errorlogger.write(error.singlelineformat())
raise error
else:
if self.log_errors:
self.errorlogger.writelines(string.split(error.format(), "\n"))
else:
self.errorlogger.write(error.singlelineformat())
if self.output_errors:
self.httpreq.content_type = "text/html"
self.out_buffer.write(error.htmlformat())
#self.out_buffer.write(error.textformat())
else:
raise exception.ServerError(wrapped = error)
def send_redirect(self, path):
self.httpreq.err_headers_out["Location"] = path
self.httpreq.content_type = "text/html"
self.httpreq.status = 302
self.out_buffer.write('The document has moved'
' here
\n'
% path)
raise exception.Redirected(path, 302)
def send_abort(self, ret, reason):
raise exception.Abort(ret, reason)
def clone(self, **params):
# quick shallow copy cloner. constructor clone doesnt
# really work in a superclass.
# override this if a more complex clone is needed
cloner = ConstructorClone(self, **params)
impl = cloner.copyclone()
return impl
class HeaderTable(OrderedDict):
"""a dictionary for storing HTTP headers, works similarly to the table object
in mod_python."""
def add(self, key, value):
if self.has_key(key):
list = self[key]
if type(list) != types.ListType:
list = [list]
self[key] = list
list.append(value)
else:
self[key] = value
def __getitem__(self, key):
return OrderedDict.__getitem__(self, string.lower(key))
def __setitem__(self, key, value):
OrderedDict.__setitem__(self, string.lower(key), value)
def has_headers(self):
return len(self) > 0
def get_output(self, buffer):
for key, value in self.iteritems():
key = re.sub('_', '-', key)
if type(value) == types.StringType:
buffer.write("%s: %s\n" % (key, value))
else:
for v in value:
buffer.write("%s: %s\n" % (key, v))
class HTTPResolver(myghty.resolver.FileResolver):
"""a subclass of the FileResolver, which can have HTTP-environment-specific
functionality attached to it if desired."""
pass
class HTTPRequest(object):
"""represents the actual HTTP request. implementations have to provide this
object's implementation. in the case of mod_python, the actual mod_python
request object is used instead of this one. the interface should have a
compatible subset of the mod_python apache request object's attributes as follows:
# set up by the base class __init__ method
headers_in
err_headers_out
headers_out
status
headers_sent = False
# should be added by the implementing __init__ method
method
content_type
# not as required, but preferred:
path_info
args
filename
# required method is:
do_send_headers()
the headers attributes should use the HeaderTable class to implement.
"""
def __init__(self):
self.headers_in = HeaderTable()
self.headers_out = HeaderTable()
self.err_headers_out = HeaderTable()
self.status = HTTP_OK
self.headers_sent = False
def send_http_header(self):
if not self.headers_sent:
self.headers_sent = True
self.do_send_headers()
def do_send_headers(self):raise NotImplementedError()
def get_response_headers(self):
if len(self.err_headers_out):
self.err_headers_out['content-type'] = self.content_type
return self.err_headers_out
else:
self.headers_out['content-type'] = self.content_type
return self.headers_out
class HTTPWriter(myghty.buffer.BufferDecorator):
"""subclasses BufferDecorator to provide the output stream for the response.
also calls send_http_header() off of the request at the moment content is first
sent.
"""
def __init__(self, httpreq, out_buffer, *args, **params):
myghty.buffer.BufferDecorator.__init__(self, out_buffer)
self.httpreq = httpreq
self.headers_sent = False
def send_headers(self):
if not self.headers_sent:
self.headers_sent = True
self.httpreq.send_http_header()
def write(self, text):
if not self.headers_sent:
self.send_headers()
self.buffer.write(text)
def writelines(self, lines):
if not self.headers_sent:
self.send_headers()
self.buffer.writelines(lines)
# what HTTP thingamabob is complete without the HTTP status codes
# defined somewhere
HTTP_CONTINUE = 100
HTTP_SWITCHING_PROTOCOLS = 101
HTTP_PROCESSING = 102
HTTP_OK = 200
HTTP_CREATED = 201
HTTP_ACCEPTED = 202
HTTP_NON_AUTHORITATIVE = 203
HTTP_NO_CONTENT = 204
HTTP_RESET_CONTENT = 205
HTTP_PARTIAL_CONTENT = 206
HTTP_MULTI_STATUS = 207
HTTP_MULTIPLE_CHOICES = 300
HTTP_MOVED_PERMANENTLY = 301
HTTP_MOVED_TEMPORARILY = 302
HTTP_SEE_OTHER = 303
HTTP_NOT_MODIFIED = 304
HTTP_USE_PROXY = 305
HTTP_TEMPORARY_REDIRECT = 307
HTTP_BAD_REQUEST = 400
HTTP_UNAUTHORIZED = 401
HTTP_PAYMENT_REQUIRED = 402
HTTP_FORBIDDEN = 403
HTTP_NOT_FOUND = 404
HTTP_METHOD_NOT_ALLOWED = 405
HTTP_NOT_ACCEPTABLE = 406
HTTP_PROXY_AUTHENTICATION_REQUIRED= 407
HTTP_REQUEST_TIME_OUT = 408
HTTP_CONFLICT = 409
HTTP_GONE = 410
HTTP_LENGTH_REQUIRED = 411
HTTP_PRECONDITION_FAILED = 412
HTTP_REQUEST_ENTITY_TOO_LARGE = 413
HTTP_REQUEST_URI_TOO_LARGE = 414
HTTP_UNSUPPORTED_MEDIA_TYPE = 415
HTTP_RANGE_NOT_SATISFIABLE = 416
HTTP_EXPECTATION_FAILED = 417
HTTP_UNPROCESSABLE_ENTITY = 422
HTTP_LOCKED = 423
HTTP_FAILED_DEPENDENCY = 424
HTTP_INTERNAL_SERVER_ERROR = 500
HTTP_NOT_IMPLEMENTED = 501
HTTP_BAD_GATEWAY = 502
HTTP_SERVICE_UNAVAILABLE = 503
HTTP_GATEWAY_TIME_OUT = 504
HTTP_VERSION_NOT_SUPPORTED = 505
HTTP_VARIANT_ALSO_VARIES = 506
HTTP_INSUFFICIENT_STORAGE = 507
HTTP_NOT_EXTENDED = 510