# Django 1.8.18.dev20170123152445 documentation

# Source code for django.contrib.auth.views

    import warnings

    from django.conf import settings
    # Avoid shadowing the login() and logout() views below.
    from django.contrib.auth import (
        REDIRECT_FIELD_NAME, get_user_model, login as auth_login,
        logout as auth_logout, update_session_auth_hash,
    )
    from django.contrib.auth.decorators import login_required
    from django.contrib.auth.forms import (
        AuthenticationForm, PasswordChangeForm, PasswordResetForm, SetPasswordForm,
    )
    from django.contrib.auth.tokens import default_token_generator
    from django.contrib.sites.shortcuts import get_current_site
    from django.core.urlresolvers import reverse
    from django.http import HttpResponseRedirect, QueryDict
    from django.shortcuts import resolve_url
    from django.template.response import TemplateResponse
    from django.utils.deprecation import RemovedInDjango110Warning
    from django.utils.encoding import force_text
    from django.utils.http import is_safe_url, urlsafe_base64_decode
    from django.utils.six.moves.urllib.parse import urlparse, urlunparse
    from django.utils.translation import ugettext as _
    from django.views.decorators.cache import never_cache
    from django.views.decorators.csrf import csrf_protect
    from django.views.decorators.debug import sensitive_post_parameters

    @sensitive_post_parameters()
    @csrf_protect
    @never_cache
    def login(request, template_name='registration/login.html',
              redirect_field_name=REDIRECT_FIELD_NAME,
              authentication_form=AuthenticationForm,
              current_app=None, extra_context=None):
        """
        Displays the login form and handles the login action.
        """
        redirect_to = request.POST.get(redirect_field_name,
                                       request.GET.get(redirect_field_name, ''))

        if request.method == "POST":
            form = authentication_form(request, data=request.POST)
            if form.is_valid():

                # Ensure the user-originating redirection url is safe.
                if not is_safe_url(url=redirect_to, host=request.get_host()):
                    redirect_to = resolve_url(settings.LOGIN_REDIRECT_URL)

                # Okay, security check complete. Log the user in.
                auth_login(request, form.get_user())

                return HttpResponseRedirect(redirect_to)
        else:
            form = authentication_form(request)

        current_site = get_current_site(request)

        context = {
            'form': form,
            redirect_field_name: redirect_to,
            'site': current_site,
            'site_name': current_site.name,
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    def logout(request, next_page=None,
               template_name='registration/logged_out.html',
               redirect_field_name=REDIRECT_FIELD_NAME,
               current_app=None, extra_context=None):
        """
        Logs out the user and displays 'You are logged out' message.
        """
        auth_logout(request)

        if next_page is not None:
            next_page = resolve_url(next_page)

        if (redirect_field_name in request.POST or
                redirect_field_name in request.GET):
            next_page = request.POST.get(redirect_field_name,
                                         request.GET.get(redirect_field_name))
            # Security check -- don't allow redirection to a different host.
            if not is_safe_url(url=next_page, host=request.get_host()):
                next_page = request.path

        if next_page:
            # Redirect to this page until the session has been cleared.
            return HttpResponseRedirect(next_page)

        current_site = get_current_site(request)
        context = {
            'site': current_site,
            'site_name': current_site.name,
            'title': _('Logged out')
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    def logout_then_login(request, login_url=None, current_app=None, extra_context=None):
        """
        Logs out the user if they are logged in. Then redirects to the log-in page.
        """
        if not login_url:
            login_url = settings.LOGIN_URL
        login_url = resolve_url(login_url)
        return logout(request, login_url, current_app=current_app, extra_context=extra_context)

    def redirect_to_login(next, login_url=None,
                          redirect_field_name=REDIRECT_FIELD_NAME):
        """
        Redirects the user to the login page, passing the given 'next' page
        """
        resolved_url = resolve_url(login_url or settings.LOGIN_URL)

        login_url_parts = list(urlparse(resolved_url))
        if redirect_field_name:
            querystring = QueryDict(login_url_parts[4], mutable=True)
            querystring[redirect_field_name] = next
            login_url_parts[4] = querystring.urlencode(safe='/')

        return HttpResponseRedirect(urlunparse(login_url_parts))

    # 4 views for password reset:
    # - password_reset sends the mail
    # - password_reset_done shows a success message for the above
    # - password_reset_confirm checks the link the user clicked and
    #   prompts for a new password
    # - password_reset_complete shows a success message for the above

    @csrf_protect
    def password_reset(request, is_admin_site=False,
                       template_name='registration/password_reset_form.html',
                       email_template_name='registration/password_reset_email.html',
                       subject_template_name='registration/password_reset_subject.txt',
                       password_reset_form=PasswordResetForm,
                       token_generator=default_token_generator,
                       post_reset_redirect=None,
                       from_email=None,
                       current_app=None,
                       extra_context=None,
                       html_email_template_name=None):
        if post_reset_redirect is None:
            post_reset_redirect = reverse('password_reset_done')
        else:
            post_reset_redirect = resolve_url(post_reset_redirect)
        if request.method == "POST":
            form = password_reset_form(request.POST)
            if form.is_valid():
                opts = {
                    'use_https': request.is_secure(),
                    'token_generator': token_generator,
                    'from_email': from_email,
                    'email_template_name': email_template_name,
                    'subject_template_name': subject_template_name,
                    'request': request,
                    'html_email_template_name': html_email_template_name,
                }
                if is_admin_site:
                    warnings.warn(
                        "The is_admin_site argument to "
                        "django.contrib.auth.views.password_reset() is deprecated "
                        "and will be removed in Django 1.10.",
                        RemovedInDjango110Warning, 3
                    )
                    opts = dict(opts, domain_override=request.get_host())
                form.save(**opts)
                return HttpResponseRedirect(post_reset_redirect)
        else:
            form = password_reset_form()
        context = {
            'form': form,
            'title': _('Password reset'),
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    def password_reset_done(request,
                            template_name='registration/password_reset_done.html',
                            current_app=None, extra_context=None):
        context = {
            'title': _('Password reset sent'),
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    # Doesn't need csrf_protect since no-one can guess the URL
    @sensitive_post_parameters()
    @never_cache
    def password_reset_confirm(request, uidb64=None, token=None,
                               template_name='registration/password_reset_confirm.html',
                               token_generator=default_token_generator,
                               set_password_form=SetPasswordForm,
                               post_reset_redirect=None,
                               current_app=None, extra_context=None):
        """
        View that checks the hash in a password reset link and presents a
        form for entering a new password.
        """
        UserModel = get_user_model()
        assert uidb64 is not None and token is not None  # checked by URLconf
        if post_reset_redirect is None:
            post_reset_redirect = reverse('password_reset_complete')
        else:
            post_reset_redirect = resolve_url(post_reset_redirect)
        try:
            # urlsafe_base64_decode() decodes to bytestring on Python 3
            uid = force_text(urlsafe_base64_decode(uidb64))
            user = UserModel._default_manager.get(pk=uid)
        except (TypeError, ValueError, OverflowError, UserModel.DoesNotExist):
            user = None

        if user is not None and token_generator.check_token(user, token):
            validlink = True
            title = _('Enter new password')
            if request.method == 'POST':
                form = set_password_form(user, request.POST)
                if form.is_valid():
                    form.save()
                    return HttpResponseRedirect(post_reset_redirect)
            else:
                form = set_password_form(user)
        else:
            validlink = False
            form = None
            title = _('Password reset unsuccessful')
        context = {
            'form': form,
            'title': title,
            'validlink': validlink,
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    def password_reset_complete(request,
                                template_name='registration/password_reset_complete.html',
                                current_app=None, extra_context=None):
        context = {
            'login_url': resolve_url(settings.LOGIN_URL),
            'title': _('Password reset complete'),
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    @sensitive_post_parameters()
    @csrf_protect
    @login_required
    def password_change(request,
                        template_name='registration/password_change_form.html',
                        post_change_redirect=None,
                        password_change_form=PasswordChangeForm,
                        current_app=None, extra_context=None):
        if post_change_redirect is None:
            post_change_redirect = reverse('password_change_done')
        else:
            post_change_redirect = resolve_url(post_change_redirect)
        if request.method == "POST":
            form = password_change_form(user=request.user, data=request.POST)
            if form.is_valid():
                form.save()
                # Updating the password logs out all other sessions for the user
                # except the current one if
                # django.contrib.auth.middleware.SessionAuthenticationMiddleware
                # is enabled.
                update_session_auth_hash(request, form.user)
                return HttpResponseRedirect(post_change_redirect)
        else:
            form = password_change_form(user=request.user)
        context = {
            'form': form,
            'title': _('Password change'),
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)

    @login_required
    def password_change_done(request,
                             template_name='registration/password_change_done.html',
                             current_app=None, extra_context=None):
        context = {
            'title': _('Password change successful'),
        }
        if extra_context is not None:
            context.update(extra_context)

        if current_app is not None:
            request.current_app = current_app

        return TemplateResponse(request, template_name, context)