Python Entrouvert

import glob

from django.db import connection

from django.http import Http404

from django.contrib.contenttypes.models import ContentType

from tenant_schemas.utils import get_tenant_model, remove_www_and_dev, get_public_schema_name

class TenantNotFound(RuntimeError):

    pass

class TenantMiddleware(object):

    """

    This middleware should be placed at the very top of the middleware stack.

    Selects the proper database schema using the request host. Can fail in

    various ways which is better than corrupting or revealing data...

    """

    @classmethod

    def base(cls):

        return settings.TENANT_BASE

    @classmethod

    def hostname2schema(cls, hostname):

        '''Convert hostname to PostgreSQL schema name'''

        if hostname in getattr(settings, 'TENANT_MAPPING', {}):

            return settings.TENANT_MAPPING[hostname]

        return hostname.replace('.', '_').replace('-', '_')

    @classmethod

    def get_tenant_by_hostname(cls, hostname):

        '''Retrieve a tenant object for this hostname'''

        schema = cls.hostname2schema(hostname)

        p = os.path.join(cls.base(), schema)

        if not os.path.exists(p):

            raise TenantNotFound

        return get_tenant_model()(schema_name=schema, domain_url=hostname)

    @classmethod

    def get_tenants(cls):

        self = cls()

        for path in glob.glob(os.path.join(cls.base(), '*')):

            hostname = os.path.basename(path)

            yield get_tenant_model()(

                    schema_name=self.hostname2schema(hostname),

                    domain_url=hostname)

        # connection needs first to be at the public schema, as this is where the

        # tenant informations are saved

        connection.set_schema_to_public()

        hostname_without_port = remove_www_and_dev(request.get_host().split(':')[0])

        try:

            request.tenant = self.get_tenant_by_hostname(hostname_without_port)

        except TenantNotFound:

            raise Http404

        connection.set_tenant(request.tenant)

        # content type can no longer be cached as public and tenant schemas have different

        # models. if someone wants to change this, the cache needs to be separated between

        # public and shared schemas. if this cache isn't cleared, this can cause permission

        # problems. for example, on public, a particular model has id 14, but on the tenants

        # it has the id 15. if 14 is cached instead of 15, the permissions for the wrong

        # model will be fetched.

        ContentType.objects.clear_cache()

        # do we have a public-specific token?

        if hasattr(settings, 'PUBLIC_SCHEMA_URLCONF') and request.tenant.schema_name == get_public_schema_name():

            request.urlconf = settings.PUBLIC_SCHEMA_URLCONF