Merge pull request #1181 from aaugustin/better-api-to-disable-atomic-requests

        self._request_middleware = request_middleware

    def make_view_atomic(self, view):

        if getattr(view, 'transactions_per_request', True):

        non_atomic_requests = getattr(view, '_non_atomic_requests', set())

        for db in connections.all():

                if db.settings_dict['ATOMIC_REQUESTS']:

            if (db.settings_dict['ATOMIC_REQUESTS']

                    and db.alias not in non_atomic_requests):

                view = transaction.atomic(using=db.alias)(view)

        return view

        return Atomic(using, savepoint)

def _non_atomic_requests(view, using):

    try:

        view._non_atomic_requests.add(using)

    except AttributeError:

        view._non_atomic_requests = set([using])

    return view

def non_atomic_requests(using=None):

    if callable(using):

        return _non_atomic_requests(using, DEFAULT_DB_ALIAS)

    else:

        if using is None:

            using = DEFAULT_DB_ALIAS

        return lambda view: _non_atomic_requests(view, using)

############################################

# Deprecated decorators / context managers #

############################################

the :func:`atomic` context manager. However, at the end of the view, either

all the changes will be committed, or none of them.

To disable this behavior for a specific view, you must set the

``transactions_per_request`` attribute of the view function itself to

``False``, like this::

    def my_view(request):

        do_stuff()

    my_view.transactions_per_request = False

.. warning::

    While the simplicity of this transaction model is appealing, it also makes it

Middleware runs outside of the transaction, and so does the rendering of

template responses.

When :setting:`ATOMIC_REQUESTS <DATABASE-ATOMIC_REQUESTS>` is enabled, it's

still possible to prevent views from running in a transaction.

.. function:: non_atomic_requests(using=None)

    This decorator will negate the effect of :setting:`ATOMIC_REQUESTS

    <DATABASE-ATOMIC_REQUESTS>` for a given view::

        from django.db import transaction

        @transaction.non_atomic_requests

        def my_view(request):

            do_stuff()

        @transaction.non_atomic_requests(using='other')

        def my_other_view(request):

            do_stuff_on_the_other_database()

    It only works if it's applied to the view itself.

.. versionchanged:: 1.6

    Django used to provide this feature via ``TransactionMiddleware``, which is

------------------

The three functions described above relied on a concept called "transaction

states". This mechanisme was deprecated in Django 1.6, but it's still

available until Django 1.8.

states". This mechanism was deprecated in Django 1.6, but it's still available

until Django 1.8.

At any time, each database connection is in one of these two states:

In Django 1.6, ``TransactionMiddleware`` is deprecated and replaced

:setting:`ATOMIC_REQUESTS <DATABASE-ATOMIC_REQUESTS>`. While the general

behavior is the same, there are a few differences.

With the transaction middleware, it was still possible to switch to autocommit

or to commit explicitly in a view. Since :func:`atomic` guarantees atomicity,

this isn't allowed any longer.

behavior is the same, there are two differences.

To avoid wrapping a particular view in a transaction, instead of::

    @transaction.autocommit

    def my_view(request):

        do_stuff()

you must now use this pattern::

    def my_view(request):

        do_stuff()

    my_view.transactions_per_request = False

With the previous API, it was possible to switch to autocommit or to commit

explicitly anywhere inside a view. Since :setting:`ATOMIC_REQUESTS

<DATABASE-ATOMIC_REQUESTS>` relies on :func:`atomic` which enforces atomicity,

this isn't allowed any longer. However, at the toplevel, it's still possible

to avoid wrapping an entire view in a transaction. To achieve this, decorate

the view with :func:`non_atomic_requests` instead of :func:`autocommit`.

The transaction middleware applied not only to view functions, but also to

middleware modules that came after it. For instance, if you used the session

    finally:

        transaction.set_autocommit(False)

Unless you're implementing a transaction management framework, you shouldn't

ever need to do this.

Disabling transaction management

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you're executing several :ref:`custom SQL queries <executing-custom-sql>`

in a row, each one now runs in its own transaction, instead of sharing the

same "automatic transaction". If you need to enforce atomicity, you must wrap

the sequence of queries in :func:`commit_on_success`.

the sequence of queries in :func:`atomic`.

To check for this problem, look for calls to ``cursor.execute()``. They're

usually followed by a call to ``transaction.commit_unless_managed()``, which

from __future__ import unicode_literals

from django.db import connection

from django.db import connection, transaction

from django.http import HttpResponse, StreamingHttpResponse

def regular(request):

def in_transaction(request):

    return HttpResponse(str(connection.in_atomic_block))

@transaction.non_atomic_requests

def not_in_transaction(request):

    return HttpResponse(str(connection.in_atomic_block))

not_in_transaction.transactions_per_request = False