"""

FastCGI (or SCGI, or AJP1.3 ...) server that implements the WSGI protocol.

Uses the flup python package: http://www.saddi.com/software/flup/

This is a adaptation of the flup package to add FastCGI server support

to run Django apps from Web servers that support the FastCGI protocol.

This module can be run standalone or from the django-admin / manage.py

scripts using the "runfcgi" directive.

Run with the extra option "help" for a list of additional options you can

pass to this server.

"""

import sys, os

__version__ = "0.1"

__all__ = ["runfastcgi"]

FASTCGI_HELP = r"""

  Run this project as a fastcgi (or some other protocol supported

  by flup) application. To do this, the flup package from

  http://www.saddi.com/software/flup/ is required.

   runfcgi [options] [fcgi settings]

Optional Fcgi settings: (setting=value)

  protocol=PROTOCOL    fcgi, scgi, ajp, ... (default fcgi)

  host=HOSTNAME        hostname to listen on..

  port=PORTNUM         port to listen on.

  socket=FILE          UNIX socket to listen on.

  method=IMPL          prefork or threaded (default prefork)

  maxrequests=NUMBER   number of requests a child handles before it is 

                       killed and a new child is forked (0 = no limit).

  maxspare=NUMBER      max number of spare processes / threads

  minspare=NUMBER      min number of spare processes / threads.

  maxchildren=NUMBER   hard limit number of processes / threads

  daemonize=BOOL       whether to detach from terminal.

  pidfile=FILE         write the spawned process-id to this file.

  workdir=DIRECTORY    change to this directory when daemonizing.

  outlog=FILE          write stdout to this file.

  errlog=FILE          write stderr to this file.

  umask=UMASK          umask to use when daemonizing (default 022).

Examples:

  Run a "standard" fastcgi process on a file-descriptor

  (for webservers which spawn your processes for you)

    $ manage.py runfcgi method=threaded

  Run a scgi server on a TCP host/port

    $ manage.py runfcgi protocol=scgi method=prefork host=127.0.0.1 port=8025

  Run a fastcgi server on a UNIX domain socket (posix platforms only)

    $ manage.py runfcgi method=prefork socket=/tmp/fcgi.sock

  Run a fastCGI as a daemon and write the spawned PID in a file

    $ manage.py runfcgi socket=/tmp/fcgi.sock method=prefork \

        daemonize=true pidfile=/var/run/django-fcgi.pid

"""

FASTCGI_OPTIONS = {

    'protocol': 'fcgi',

    'host': None,

    'port': None,

    'socket': None,

    'method': 'fork',

    'daemonize': None,

    'workdir': '/',

    'pidfile': None,

    'maxspare': 5,

    'minspare': 2,

    'maxchildren': 50,

    'maxrequests': 0,

    'outlog': None,

    'errlog': None,

    'umask': None,

}

def fastcgi_help(message=None):

    print FASTCGI_HELP

    if message:

        print message

    return False

def runfastcgi(argset=[], **kwargs):

    options = FASTCGI_OPTIONS.copy()

    options.update(kwargs)

    for x in argset:

        if "=" in x:

            k, v = x.split('=', 1)

        else:

            k, v = x, True

        options[k.lower()] = v

    if "help" in options:

        return fastcgi_help()

    try:

        import flup

    except ImportError, e:

        print >> sys.stderr, "ERROR: %s" % e

        print >> sys.stderr, "  Unable to load the flup package.  In order to run django"

        print >> sys.stderr, "  as a FastCGI application, you will need to get flup from"

        print >> sys.stderr, "  http://www.saddi.com/software/flup/   If you've already"

        print >> sys.stderr, "  installed flup, then make sure you have it in your PYTHONPATH."

        return False

    flup_module = 'server.' + options['protocol']

    if options['method'] in ('prefork', 'fork'):

        wsgi_opts = {

            'maxSpare': int(options["maxspare"]),

            'minSpare': int(options["minspare"]),

            'maxChildren': int(options["maxchildren"]),

            'maxRequests': int(options["maxrequests"]), 

        }

        flup_module += '_fork'

    elif options['method'] in ('thread', 'threaded'):

        wsgi_opts = {

            'maxSpare': int(options["maxspare"]),

            'minSpare': int(options["minspare"]),

            'maxThreads': int(options["maxchildren"]),

        }

    else:

        return fastcgi_help("ERROR: Implementation must be one of prefork or thread.")

    wsgi_opts['debug'] = False # Turn off flup tracebacks

    try:

        WSGIServer = getattr(__import__('flup.' + flup_module, '', '', flup_module), 'WSGIServer')

    except:

        print "Can't import flup." + flup_module

        return False

    # Prep up and go

    from django.core.handlers.wsgi import WSGIHandler

    if options["host"] and options["port"] and not options["socket"]:

        wsgi_opts['bindAddress'] = (options["host"], int(options["port"]))

    elif options["socket"] and not options["host"] and not options["port"]:

        wsgi_opts['bindAddress'] = options["socket"]

    elif not options["socket"] and not options["host"] and not options["port"]:

        wsgi_opts['bindAddress'] = None

    else:

        return fastcgi_help("Invalid combination of host, port, socket.")

    if options["daemonize"] is None:

        # Default to daemonizing if we're running on a socket/named pipe.

        daemonize = (wsgi_opts['bindAddress'] is not None)

    else:

        if options["daemonize"].lower() in ('true', 'yes', 't'):

            daemonize = True

        elif options["daemonize"].lower() in ('false', 'no', 'f'):

            daemonize = False

        else:

            return fastcgi_help("ERROR: Invalid option for daemonize parameter.")

    daemon_kwargs = {}

    if options['outlog']:

        daemon_kwargs['out_log'] = options['outlog']

    if options['errlog']:

        daemon_kwargs['err_log'] = options['errlog']

    if options['umask']:

        daemon_kwargs['umask'] = int(options['umask'])

    if daemonize:

        from django.utils.daemonize import become_daemon

        become_daemon(our_home_dir=options["workdir"], **daemon_kwargs)

    if options["pidfile"]:

        fp = open(options["pidfile"], "w")

        fp.write("%d\n" % os.getpid())

        fp.close()

    WSGIServer(WSGIHandler(), **wsgi_opts).run()

if __name__ == '__main__':

    runfastcgi(sys.argv[1:])