mirror of
https://github.com/Sneed-Group/Poodletooth-iLand
synced 2024-10-31 16:57:54 +00:00
450 lines
16 KiB
Python
450 lines
16 KiB
Python
"""Base classes for server/gateway implementations"""
|
|
|
|
from types import StringType
|
|
from util import FileWrapper, guess_scheme, is_hop_by_hop
|
|
from headers import Headers
|
|
|
|
import sys, os, time
|
|
|
|
__all__ = ['BaseHandler', 'SimpleHandler', 'BaseCGIHandler', 'CGIHandler']
|
|
|
|
try:
|
|
dict
|
|
except NameError:
|
|
def dict(items):
|
|
d = {}
|
|
for k,v in items:
|
|
d[k] = v
|
|
return d
|
|
|
|
# Uncomment for 2.2 compatibility.
|
|
#try:
|
|
# True
|
|
# False
|
|
#except NameError:
|
|
# True = not None
|
|
# False = not True
|
|
|
|
|
|
# Weekday and month names for HTTP date/time formatting; always English!
|
|
_weekdayname = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]
|
|
_monthname = [None, # Dummy so we can use 1-based month numbers
|
|
"Jan", "Feb", "Mar", "Apr", "May", "Jun",
|
|
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
|
|
|
|
def format_date_time(timestamp):
|
|
year, month, day, hh, mm, ss, wd, y, z = time.gmtime(timestamp)
|
|
return "%s, %02d %3s %4d %02d:%02d:%02d GMT" % (
|
|
_weekdayname[wd], day, _monthname[month], year, hh, mm, ss
|
|
)
|
|
|
|
|
|
class BaseHandler:
|
|
"""Manage the invocation of a WSGI application"""
|
|
|
|
# Configuration parameters; can override per-subclass or per-instance
|
|
wsgi_version = (1,0)
|
|
wsgi_multithread = True
|
|
wsgi_multiprocess = True
|
|
wsgi_run_once = False
|
|
|
|
origin_server = True # We are transmitting direct to client
|
|
http_version = "1.0" # Version that should be used for response
|
|
server_software = None # String name of server software, if any
|
|
|
|
# os_environ is used to supply configuration from the OS environment:
|
|
# by default it's a copy of 'os.environ' as of import time, but you can
|
|
# override this in e.g. your __init__ method.
|
|
os_environ = dict(os.environ.items())
|
|
|
|
# Collaborator classes
|
|
wsgi_file_wrapper = FileWrapper # set to None to disable
|
|
headers_class = Headers # must be a Headers-like class
|
|
|
|
# Error handling (also per-subclass or per-instance)
|
|
traceback_limit = None # Print entire traceback to self.get_stderr()
|
|
error_status = "500 Internal Server Error"
|
|
error_headers = [('Content-Type','text/plain')]
|
|
error_body = "A server error occurred. Please contact the administrator."
|
|
|
|
# State variables (don't mess with these)
|
|
status = result = None
|
|
headers_sent = False
|
|
headers = None
|
|
bytes_sent = 0
|
|
|
|
def run(self, application):
|
|
"""Invoke the application"""
|
|
# Note to self: don't move the close()! Asynchronous servers shouldn't
|
|
# call close() from finish_response(), so if you close() anywhere but
|
|
# the double-error branch here, you'll break asynchronous servers by
|
|
# prematurely closing. Async servers must return from 'run()' without
|
|
# closing if there might still be output to iterate over.
|
|
try:
|
|
self.setup_environ()
|
|
self.result = application(self.environ, self.start_response)
|
|
self.finish_response()
|
|
except:
|
|
try:
|
|
self.handle_error()
|
|
except:
|
|
# If we get an error handling an error, just give up already!
|
|
self.close()
|
|
raise # ...and let the actual server figure it out.
|
|
|
|
|
|
def setup_environ(self):
|
|
"""Set up the environment for one request"""
|
|
|
|
env = self.environ = self.os_environ.copy()
|
|
self.add_cgi_vars()
|
|
|
|
env['wsgi.input'] = self.get_stdin()
|
|
env['wsgi.errors'] = self.get_stderr()
|
|
env['wsgi.version'] = self.wsgi_version
|
|
env['wsgi.run_once'] = self.wsgi_run_once
|
|
env['wsgi.url_scheme'] = self.get_scheme()
|
|
env['wsgi.multithread'] = self.wsgi_multithread
|
|
env['wsgi.multiprocess'] = self.wsgi_multiprocess
|
|
|
|
if self.wsgi_file_wrapper is not None:
|
|
env['wsgi.file_wrapper'] = self.wsgi_file_wrapper
|
|
|
|
if self.origin_server and self.server_software:
|
|
env.setdefault('SERVER_SOFTWARE',self.server_software)
|
|
|
|
|
|
def finish_response(self):
|
|
"""Send any iterable data, then close self and the iterable
|
|
|
|
Subclasses intended for use in asynchronous servers will
|
|
want to redefine this method, such that it sets up callbacks
|
|
in the event loop to iterate over the data, and to call
|
|
'self.close()' once the response is finished.
|
|
"""
|
|
try:
|
|
if not self.result_is_file() or not self.sendfile():
|
|
for data in self.result:
|
|
self.write(data)
|
|
self.finish_content()
|
|
finally:
|
|
self.close()
|
|
|
|
|
|
def get_scheme(self):
|
|
"""Return the URL scheme being used"""
|
|
return guess_scheme(self.environ)
|
|
|
|
|
|
def set_content_length(self):
|
|
"""Compute Content-Length or switch to chunked encoding if possible"""
|
|
try:
|
|
blocks = len(self.result)
|
|
except (TypeError,AttributeError,NotImplementedError):
|
|
pass
|
|
else:
|
|
if blocks==1:
|
|
self.headers['Content-Length'] = str(self.bytes_sent)
|
|
return
|
|
# XXX Try for chunked encoding if origin server and client is 1.1
|
|
|
|
|
|
def cleanup_headers(self):
|
|
"""Make any necessary header changes or defaults
|
|
|
|
Subclasses can extend this to add other defaults.
|
|
"""
|
|
if 'Content-Length' not in self.headers:
|
|
self.set_content_length()
|
|
|
|
def start_response(self, status, headers,exc_info=None):
|
|
"""'start_response()' callable as specified by PEP 333"""
|
|
|
|
if exc_info:
|
|
try:
|
|
if self.headers_sent:
|
|
# Re-raise original exception if headers sent
|
|
raise exc_info[0], exc_info[1], exc_info[2]
|
|
finally:
|
|
exc_info = None # avoid dangling circular ref
|
|
elif self.headers is not None:
|
|
raise AssertionError("Headers already set!")
|
|
|
|
assert type(status) is StringType,"Status must be a string"
|
|
assert len(status)>=4,"Status must be at least 4 characters"
|
|
assert int(status[:3]),"Status message must begin w/3-digit code"
|
|
assert status[3]==" ", "Status message must have a space after code"
|
|
if __debug__:
|
|
for name,val in headers:
|
|
assert type(name) is StringType,"Header names must be strings"
|
|
assert type(val) is StringType,"Header values must be strings"
|
|
assert not is_hop_by_hop(name),"Hop-by-hop headers not allowed"
|
|
self.status = status
|
|
self.headers = self.headers_class(headers)
|
|
return self.write
|
|
|
|
|
|
def send_preamble(self):
|
|
"""Transmit version/status/date/server, via self._write()"""
|
|
if self.origin_server:
|
|
if self.client_is_modern():
|
|
self._write('HTTP/%s %s\r\n' % (self.http_version,self.status))
|
|
if 'Date' not in self.headers:
|
|
self._write(
|
|
'Date: %s\r\n' % format_date_time(time.time())
|
|
)
|
|
if self.server_software and 'Server' not in self.headers:
|
|
self._write('Server: %s\r\n' % self.server_software)
|
|
else:
|
|
self._write('Status: %s\r\n' % self.status)
|
|
|
|
def write(self, data):
|
|
"""'write()' callable as specified by PEP 333"""
|
|
|
|
assert type(data) is StringType,"write() argument must be string"
|
|
|
|
if not self.status:
|
|
raise AssertionError("write() before start_response()")
|
|
|
|
elif not self.headers_sent:
|
|
# Before the first output, send the stored headers
|
|
self.bytes_sent = len(data) # make sure we know content-length
|
|
self.send_headers()
|
|
else:
|
|
self.bytes_sent += len(data)
|
|
|
|
# XXX check Content-Length and truncate if too many bytes written?
|
|
self._write(data)
|
|
self._flush()
|
|
|
|
|
|
def sendfile(self):
|
|
"""Platform-specific file transmission
|
|
|
|
Override this method in subclasses to support platform-specific
|
|
file transmission. It is only called if the application's
|
|
return iterable ('self.result') is an instance of
|
|
'self.wsgi_file_wrapper'.
|
|
|
|
This method should return a true value if it was able to actually
|
|
transmit the wrapped file-like object using a platform-specific
|
|
approach. It should return a false value if normal iteration
|
|
should be used instead. An exception can be raised to indicate
|
|
that transmission was attempted, but failed.
|
|
|
|
NOTE: this method should call 'self.send_headers()' if
|
|
'self.headers_sent' is false and it is going to attempt direct
|
|
transmission of the file.
|
|
"""
|
|
return False # No platform-specific transmission by default
|
|
|
|
|
|
def finish_content(self):
|
|
"""Ensure headers and content have both been sent"""
|
|
if not self.headers_sent:
|
|
# Only zero Content-Length if not set by the application (so
|
|
# that HEAD requests can be satisfied properly, see #3839)
|
|
self.headers.setdefault('Content-Length', "0")
|
|
self.send_headers()
|
|
else:
|
|
pass # XXX check if content-length was too short?
|
|
|
|
def close(self):
|
|
"""Close the iterable (if needed) and reset all instance vars
|
|
|
|
Subclasses may want to also drop the client connection.
|
|
"""
|
|
try:
|
|
if hasattr(self.result,'close'):
|
|
self.result.close()
|
|
finally:
|
|
self.result = self.headers = self.status = self.environ = None
|
|
self.bytes_sent = 0; self.headers_sent = False
|
|
|
|
|
|
def send_headers(self):
|
|
"""Transmit headers to the client, via self._write()"""
|
|
self.cleanup_headers()
|
|
self.headers_sent = True
|
|
if not self.origin_server or self.client_is_modern():
|
|
self.send_preamble()
|
|
self._write(str(self.headers))
|
|
|
|
|
|
def result_is_file(self):
|
|
"""True if 'self.result' is an instance of 'self.wsgi_file_wrapper'"""
|
|
wrapper = self.wsgi_file_wrapper
|
|
return wrapper is not None and isinstance(self.result,wrapper)
|
|
|
|
|
|
def client_is_modern(self):
|
|
"""True if client can accept status and headers"""
|
|
return self.environ['SERVER_PROTOCOL'].upper() != 'HTTP/0.9'
|
|
|
|
|
|
def log_exception(self,exc_info):
|
|
"""Log the 'exc_info' tuple in the server log
|
|
|
|
Subclasses may override to retarget the output or change its format.
|
|
"""
|
|
try:
|
|
from traceback import print_exception
|
|
stderr = self.get_stderr()
|
|
print_exception(
|
|
exc_info[0], exc_info[1], exc_info[2],
|
|
self.traceback_limit, stderr
|
|
)
|
|
stderr.flush()
|
|
finally:
|
|
exc_info = None
|
|
|
|
def handle_error(self):
|
|
"""Log current error, and send error output to client if possible"""
|
|
self.log_exception(sys.exc_info())
|
|
if not self.headers_sent:
|
|
self.result = self.error_output(self.environ, self.start_response)
|
|
self.finish_response()
|
|
# XXX else: attempt advanced recovery techniques for HTML or text?
|
|
|
|
def error_output(self, environ, start_response):
|
|
"""WSGI mini-app to create error output
|
|
|
|
By default, this just uses the 'error_status', 'error_headers',
|
|
and 'error_body' attributes to generate an output page. It can
|
|
be overridden in a subclass to dynamically generate diagnostics,
|
|
choose an appropriate message for the user's preferred language, etc.
|
|
|
|
Note, however, that it's not recommended from a security perspective to
|
|
spit out diagnostics to any old user; ideally, you should have to do
|
|
something special to enable diagnostic output, which is why we don't
|
|
include any here!
|
|
"""
|
|
start_response(self.error_status,self.error_headers[:],sys.exc_info())
|
|
return [self.error_body]
|
|
|
|
|
|
# Pure abstract methods; *must* be overridden in subclasses
|
|
|
|
def _write(self,data):
|
|
"""Override in subclass to buffer data for send to client
|
|
|
|
It's okay if this method actually transmits the data; BaseHandler
|
|
just separates write and flush operations for greater efficiency
|
|
when the underlying system actually has such a distinction.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def _flush(self):
|
|
"""Override in subclass to force sending of recent '_write()' calls
|
|
|
|
It's okay if this method is a no-op (i.e., if '_write()' actually
|
|
sends the data.
|
|
"""
|
|
raise NotImplementedError
|
|
|
|
def get_stdin(self):
|
|
"""Override in subclass to return suitable 'wsgi.input'"""
|
|
raise NotImplementedError
|
|
|
|
def get_stderr(self):
|
|
"""Override in subclass to return suitable 'wsgi.errors'"""
|
|
raise NotImplementedError
|
|
|
|
def add_cgi_vars(self):
|
|
"""Override in subclass to insert CGI variables in 'self.environ'"""
|
|
raise NotImplementedError
|
|
|
|
|
|
class SimpleHandler(BaseHandler):
|
|
"""Handler that's just initialized with streams, environment, etc.
|
|
|
|
This handler subclass is intended for synchronous HTTP/1.0 origin servers,
|
|
and handles sending the entire response output, given the correct inputs.
|
|
|
|
Usage::
|
|
|
|
handler = SimpleHandler(
|
|
inp,out,err,env, multithread=False, multiprocess=True
|
|
)
|
|
handler.run(app)"""
|
|
|
|
def __init__(self,stdin,stdout,stderr,environ,
|
|
multithread=True, multiprocess=False
|
|
):
|
|
self.stdin = stdin
|
|
self.stdout = stdout
|
|
self.stderr = stderr
|
|
self.base_env = environ
|
|
self.wsgi_multithread = multithread
|
|
self.wsgi_multiprocess = multiprocess
|
|
|
|
def get_stdin(self):
|
|
return self.stdin
|
|
|
|
def get_stderr(self):
|
|
return self.stderr
|
|
|
|
def add_cgi_vars(self):
|
|
self.environ.update(self.base_env)
|
|
|
|
def _write(self,data):
|
|
self.stdout.write(data)
|
|
self._write = self.stdout.write
|
|
|
|
def _flush(self):
|
|
self.stdout.flush()
|
|
self._flush = self.stdout.flush
|
|
|
|
|
|
class BaseCGIHandler(SimpleHandler):
|
|
|
|
"""CGI-like systems using input/output/error streams and environ mapping
|
|
|
|
Usage::
|
|
|
|
handler = BaseCGIHandler(inp,out,err,env)
|
|
handler.run(app)
|
|
|
|
This handler class is useful for gateway protocols like ReadyExec and
|
|
FastCGI, that have usable input/output/error streams and an environment
|
|
mapping. It's also the base class for CGIHandler, which just uses
|
|
sys.stdin, os.environ, and so on.
|
|
|
|
The constructor also takes keyword arguments 'multithread' and
|
|
'multiprocess' (defaulting to 'True' and 'False' respectively) to control
|
|
the configuration sent to the application. It sets 'origin_server' to
|
|
False (to enable CGI-like output), and assumes that 'wsgi.run_once' is
|
|
False.
|
|
"""
|
|
|
|
origin_server = False
|
|
|
|
|
|
class CGIHandler(BaseCGIHandler):
|
|
|
|
"""CGI-based invocation via sys.stdin/stdout/stderr and os.environ
|
|
|
|
Usage::
|
|
|
|
CGIHandler().run(app)
|
|
|
|
The difference between this class and BaseCGIHandler is that it always
|
|
uses 'wsgi.run_once' of 'True', 'wsgi.multithread' of 'False', and
|
|
'wsgi.multiprocess' of 'True'. It does not take any initialization
|
|
parameters, but always uses 'sys.stdin', 'os.environ', and friends.
|
|
|
|
If you need to override any of these parameters, use BaseCGIHandler
|
|
instead.
|
|
"""
|
|
|
|
wsgi_run_once = True
|
|
# Do not allow os.environ to leak between requests in Google App Engine
|
|
# and other multi-run CGI use cases. This is not easily testable.
|
|
# See http://bugs.python.org/issue7250
|
|
os_environ = {}
|
|
|
|
def __init__(self):
|
|
BaseCGIHandler.__init__(
|
|
self, sys.stdin, sys.stdout, sys.stderr, dict(os.environ.items()),
|
|
multithread=False, multiprocess=True
|
|
)
|