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README  view on Meta::CPAN

    This is a very simple module that helps you carry around execution
    context in async programs.

    Idea is simple:

    *   you create a "new" context for an entry point

        It can be a new web request, a new message from a queue to process
        or command line script command

    *   use "cb_w_context" to create all callbacks in your application

    *   correct context restored when your callbacks are called

    *   use "context" to access data

METHODS and FUNCTIONS
  new
    Creates a new context and makes it the current one. Takes named pairs
    and stores them in the context.

        Async::ContextSwitcher->new( request => $psgi_env );

  context
    Returns the current context. Function is exported. Always returns
    context.

        my $ct = context->{request}{HTTP_CONTENT_TYPE};
        context->{user} = $user;

  cb_w_context
    Wrapper for callbacks. Function is exported. Wraps a callback with code
    that stores and restores context to make sure correct context travels
    with your code.

        async_call( callback => cb_w_context { context->{good} = shift } );

    Make sure that all callbacks in your code are created with this function
    or you can loose track of your context.

AUTHOR
    Ruslan Zakirov <Ruslan.Zakirov@gmail.com>

LICENSE
    Under the same terms as perl itself.

lib/Async/ContextSwitcher.pm  view on Meta::CPAN

Idea is simple:

=over 4

=item * you create a L</new> context for an entry point

It can be a new web request, a new message from a queue to process
or command line script command

=item * use L</cb_w_context> to create all callbacks in your application

=item * correct context restored when your callbacks are called

=item * use L</context> to access data

=back

=cut


our $CTX;

lib/Async/ContextSwitcher.pm  view on Meta::CPAN

=cut

sub context() {
    return $CTX if $CTX;
    return $CTX = __PACKAGE__->new;
}

=head2 cb_w_context

Wrapper for callbacks. Function is exported. Wraps a callback with code
that stores and restores context to make sure correct context travels
with your code.

    async_call( callback => cb_w_context { context->{good} = shift } );

Make sure that all callbacks in your code are created with this function
or you can loose track of your context.

=cut

sub cb_w_context(&) {
    my $cb = $_[0];
    my $ctx = $CTX;
    return sub {
        $CTX = $ctx;
        goto &$cb;