Writing the Post Model

import errno
import os
import re
import socket
import sys
from datetime import datetime

from django.conf import settings
from django.core.management.base import BaseCommand, CommandError
from django.core.servers.basehttp import WSGIServer, get_internal_wsgi_application, run
from django.utils import autoreload
from django.utils.regex_helper import _lazy_re_compile

naiveip_re = _lazy_re_compile(
    r"""^(?:
(?P<addr>
    (?P<ipv4>\d{1,3}(?:\.\d{1,3}){3}) |         # IPv4 address
    (?P<ipv6>\[[a-fA-F0-9:]+\]) |               # IPv6 address
    (?P<fqdn>[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*) # FQDN
):)?(?P<port>\d+)$""",
    re.X,
)


class Command(BaseCommand):
    help = "Starts a lightweight web server for development."

    # Validation is called explicitly each time the server is reloaded.
    requires_system_checks = []
    stealth_options = ("shutdown_message",)
    suppressed_base_arguments = {"--verbosity", "--traceback"}

    default_addr = "0.0.0.0"
    default_addr_ipv6 = "::1"
    default_port = "8000"
    protocol = "http"
    server_cls = WSGIServer

    def add_arguments(self, parser):
        parser.add_argument(
            "addrport", nargs="?", help="Optional port number, or ipaddr:port"
        )
        parser.add_argument(
            "--ipv6",
            "-6",
            action="store_true",
            dest="use_ipv6",
            help="Tells Django to use an IPv6 address.",
        )
        parser.add_argument(
            "--nothreading",
            action="store_false",
            dest="use_threading",
            help="Tells Django to NOT use threading.",
        )
        parser.add_argument(
            "--noreload",
            action="store_false",
            dest="use_reloader",
            help="Tells Django to NOT use the auto-reloader.",
        )
        parser.add_argument(
            "--skip-checks",
            action="store_true",
            help="Skip system checks.",
        )

    def execute(self, *args, **options):
        if options["no_color"]:
            # We rely on the environment because it's currently the only
            # way to reach WSGIRequestHandler. This seems an acceptable
            # compromise considering `runserver` runs indefinitely.
            os.environ["DJANGO_COLORS"] = "nocolor"
        super().execute(*args, **options)

    def get_handler(self, *args, **options):
        """Return the default WSGI handler for the runner."""
        return get_internal_wsgi_application()

    def handle(self, *args, **options):
        if not settings.DEBUG and not settings.ALLOWED_HOSTS:
            raise CommandError("You must set settings.ALLOWED_HOSTS if DEBUG is False.")

        self.use_ipv6 = options["use_ipv6"]
        if self.use_ipv6 and not socket.has_ipv6:
            raise CommandError("Your Python does not support IPv6.")
        self._raw_ipv6 = False
        if not options["addrport"]:
            self.addr = ""
            self.port = self.default_port
        else:
            m = re.match(naiveip_re, options["addrport"])
            if m is None:
                raise CommandError(
                    '"%s" is not a valid port number '
                    "or address:port pair." % options["addrport"]
                )
            self.addr, _ipv4, _ipv6, _fqdn, self.port = m.groups()
            if not self.port.isdigit():
                raise CommandError("%r is not a valid port number." % self.port)
            if self.addr:
                if _ipv6:
                    self.addr = self.addr[1:-1]
                    self.use_ipv6 = True
                    self._raw_ipv6 = True
                elif self.use_ipv6 and not _fqdn:
                    raise CommandError('"%s" is not a valid IPv6 address.' % self.addr)
        if not self.addr:
            self.addr = self.default_addr_ipv6 if self.use_ipv6 else self.default_addr
            self._raw_ipv6 = self.use_ipv6
        self.run(**options)

    def run(self, **options):
        """Run the server, using the autoreloader if needed."""
        use_reloader = options["use_reloader"]

        if use_reloader:
            autoreload.run_with_reloader(self.inner_run, **options)
        else:
            self.inner_run(None, **options)

    def inner_run(self, *args, **options):
        # If an exception was silenced in ManagementUtility.execute in order
        # to be raised in the child process, raise it now.
        autoreload.raise_last_exception()

        threading = options["use_threading"]
        # 'shutdown_message' is a stealth option.
        shutdown_message = options.get("shutdown_message", "")

        if not options["skip_checks"]:
            self.stdout.write("Performing system checks...\n\n")
            self.check(display_num_errors=True)
        # Need to check migrations here, so can't use the
        # requires_migrations_check attribute.
        self.check_migrations()

        try:
            handler = self.get_handler(*args, **options)
            run(
                self.addr,
                int(self.port),
                handler,
                ipv6=self.use_ipv6,
                threading=threading,
                on_bind=self.on_bind,
                server_cls=self.server_cls,
            )
        except OSError as e:
            # Use helpful error messages instead of ugly tracebacks.
            ERRORS = {
                errno.EACCES: "You don't have permission to access that port.",
                errno.EADDRINUSE: "That port is already in use.",
                errno.EADDRNOTAVAIL: "That IP address can't be assigned to.",
            }
            try:
                error_text = ERRORS[e.errno]
            except KeyError:
                error_text = e
            self.stderr.write("Error: %s" % error_text)
            # Need to use an OS exit because sys.exit doesn't work in a thread
            os._exit(1)
        except KeyboardInterrupt:
            if shutdown_message:
                self.stdout.write(shutdown_message)
            sys.exit(0)

    def on_bind(self, server_port):
        quit_command = "CTRL-BREAK" if sys.platform == "win32" else "CONTROL-C"

        if self._raw_ipv6:
            addr = f"[{self.addr}]"
        elif self.addr == "0":
            addr = "0.0.0.0"
        else:
            addr = self.addr

        now = datetime.now().strftime("%B %d, %Y - %X")
        version = self.get_version()
        print(
            f"{now}\n"
            f"Django version {version}, using settings {settings.SETTINGS_MODULE!r}\n"
            f"Starting development server at {self.protocol}://{addr}:{server_port}/\n"
            f"Quit the server with {quit_command}.",
            file=self.stdout,
        )