Personal Computer World 2009 February/PCWFEB09.iso/Software/Linux/Kubuntu 8.10/kubuntu-8.10-desktop-i386.iso/casper/filesystem.squashfs/usr/lib/python2.5/wsgiref/handlers.pyc

Python Compiled Bytecode | 2008-10-29 | 15.9 KB | 473 lines

# Source Generated with Decompyle++
# File: in.pyc (Python 2.5)

'''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
import os
import time
__all__ = [
    'BaseHandler',
    'SimpleHandler',
    'BaseCGIHandler',
    'CGIHandler']

try:
    dict
except NameError:

    def dict(items):
        d = { }
        for k, v in items:
            d[k] = v

        return d



try:
    True
    False
except NameError:
    True = not None
    False = not True

_weekdayname = [
    'Mon',
    'Tue',
    'Wed',
    'Thu',
    'Fri',
    'Sat',
    'Sun']
_monthname = [
    None,
    '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'''
    wsgi_version = (1, 0)
    wsgi_multithread = True
    wsgi_multiprocess = True
    wsgi_run_once = False
    origin_server = True
    http_version = '1.0'
    server_software = None
    os_environ = dict(os.environ.items())
    wsgi_file_wrapper = FileWrapper
    headers_class = Headers
    traceback_limit = None
    error_status = '500 Dude, this is whack!'
    error_headers = [
        ('Content-Type', 'text/plain')]
    error_body = 'A server error occurred.  Please contact the administrator.'
    status = None
    result = None
    headers_sent = False
    headers = None
    bytes_sent = 0

    def run(self, application):
        '''Invoke the application'''

        try:
            self.setup_environ()
            self.result = application(self.environ, self.start_response)
            self.finish_response()
        except:

            try:
                self.handle_error()
            self.close()
            raise




    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.
        """
        if not self.result_is_file() or not self.sendfile():
            for data in self.result:
                self.write(data)

            self.finish_content()

        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

        if blocks == 1:
            self.headers['Content-Length'] = str(self.bytes_sent)
            return None



    def cleanup_headers(self):
        '''Make any necessary header changes or defaults

        Subclasses can extend this to add other defaults.
        '''
        if not self.headers.has_key('Content-Length'):
            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:
                    raise exc_info[0], exc_info[1], exc_info[2]
            finally:
                exc_info = None

        elif self.headers is not None:
            raise AssertionError('Headers already set!')

        if not type(status) is StringType:
            raise AssertionError, 'Status must be a string'
        if not len(status) >= 4:
            raise AssertionError, 'Status must be at least 4 characters'
        if not int(status[:3]):
            raise AssertionError, 'Status message must begin w/3-digit code'
        if not status[3] == ' ':
            raise AssertionError, 'Status message must have a space after code'
        for name, val in headers:
            if not type(name) is StringType:
                raise AssertionError, 'Header names must be strings'
            if not type(val) is StringType:
                raise AssertionError, 'Header values must be strings'
            if not not is_hop_by_hop(name):
                raise AssertionError, '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 not self.headers.has_key('Date'):
                    self._write('Date: %s\r\n' % format_date_time(time.time()))

                if self.server_software and not self.headers.has_key('Server'):
                    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"""
        if not type(data) is StringType:
            raise AssertionError, 'write() argument must be string'
        if not self.status:
            raise AssertionError('write() before start_response()')
        elif not self.headers_sent:
            self.bytes_sent = len(data)
            self.send_headers()
        else:
            self.bytes_sent += len(data)
        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


    def finish_content(self):
        '''Ensure headers and content have both been sent'''
        if not self.headers_sent:
            self.headers['Content-Length'] = '0'
            self.send_headers()



    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 = None
            self.headers = None
            self.status = None
            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
        if wrapper is not None:
            pass
        return 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:
            print_exception = print_exception
            import traceback
            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()



    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]


    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

    def __init__(self):
        BaseCGIHandler.__init__(self, sys.stdin, sys.stdout, sys.stderr, dict(os.environ.items()), multithread = False, multiprocess = True)