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lib/AnyEvent/JSONRPC/HTTP/Client.pm  view on Meta::CPAN

blockingly condvar condvars coroutine unix

=end stopwords

=head1 NAME

AnyEvent::JSONRPC::HTTP::Client - Simple HTTP-based JSONRPC client

=head1 SYNOPSIS

    use AnyEvent::JSONRPC::HTTP::Client;
    
    my $client = AnyEvent::JSONRPC::HTTP::Client->new(
        url      => 'http://rpc.example.net/issues',
        username => "pmakholm",
        password => "secret",
    );
    
    # blocking interface
    my $res = $client->call( echo => 'foo bar' )->recv; # => 'foo bar';
    
    # non-blocking interface
    $client->call( echo => 'foo bar' )->cb(sub {
        my $res = $_[0]->recv;  # => 'foo bar';
    });

=head1 DESCRIPTION

This module is the HTTP client part of L<AnyEvent::JSONRPC>.

=head2 AnyEvent condvars

The main thing you have to remember is that all the data retrieval methods
return an AnyEvent condvar, C<$cv>.  If you want the actual data from the
request, there are a few things you can do.

You may have noticed that many of the examples in the SYNOPSIS call C<recv>
on the condvar.  You're allowed to do this under 2 circumstances:

=over 4

=item Either you're in a main program,

Main programs are "allowed to call C<recv> blockingly", according to the
author of L<AnyEvent>.

=item or you're in a Coro + AnyEvent environment.

When you call C<recv> inside a coroutine, only that coroutine is blocked
while other coroutines remain active.  Thus, the program as a whole is
still responsive.

=back

If you're not using Coro, and you don't want your whole program to block,
what you should do is call C<cb> on the condvar, and give it a coderef to
execute when the results come back.  The coderef will be given a condvar
as a parameter, and it can call C<recv> on it to get the data.  The final
example in the SYNOPSIS gives a brief example of this.

Also note that C<recv> will throw an exception if the request fails, so be
prepared to catch exceptions where appropriate.

Please read the L<AnyEvent> documentation for more information on the proper
use of condvars.

=head1 METHODS

=head2 new (%options)

Create new client object and return it.

    my $client = AnyEvent::JSONRPC::HTTP::Client->new(
        host => '127.0.0.1',
        port => 4423,
        %options,
    );

Available options are:

=over 4

=item url => 'Str'

URL to json-RPC endpoint to connect. (Required)

=item username => 'Str'

Username to use for authorization (Optional).

If this is set an Authorization header containing basic auth credential is
always sent with request.

=item password => 'Str'

Password used for authorization (optional)

=back

=head2 call ($method, @params)

Call remote method named C<$method> with parameters C<@params>. And return condvar object for response.

    my $cv = $client->call( echo => 'Hello!' );
    my $res = $cv->recv;

If server returns an error, C<< $cv->recv >> causes croak by using C<< $cv->croak >>. So you can handle this like following:

    my $res;
    eval { $res = $cv->recv };
    
    if (my $error = $@) {
        # ...
    }

=head2 notify ($method, @params)

Same as call method, but not handle response. This method just notify to server.

    $client->notify( echo => 'Hello' );