NAME
Mojo::WebSocketProxy - WebSocket proxy for JSON-RPC 2.0 server
SYNOPSIS
# lib/your-application.pm
use parent 'Mojolicious';
sub startup {
my $self = shift;
$self->plugin(
'web_socket_proxy' => {
actions => [
['json_key', {some_param => 'some_value'}]
],
base_path => '/api',
url => 'http://rpc-host.com:8080/',
}
);
}
Or to manually call RPC server:
# lib/your-application.pm
use parent 'Mojolicious';
sub startup {
my $self = shift;
$self->plugin(
'web_socket_proxy' => {
actions => [
[
'json_key',
{
instead_of_forward => sub {
shift->call_rpc({
args => [ qw(args here) ],
method => 'json_key', # it'll call 'http://rpc-host.com:8080/json_key'
rpc_response_cb => sub {...}
});
}
}
]
],
base_path => '/api',
url => 'http://rpc-host.com:8080/',
}
);
}
DESCRIPTION
Using this module you can forward WebSocket-JSON requests to RPC
server.
For every message it creates separate hash ref storage, which is
available from hooks as $req_storage. Request storage have RPC call
parameters in $req_storage->{call_params}. It copies message args to
$req_storage->{call_params}->{args}. You can use Mojolicious stash to
store data between messages in one connection.
Proxy responses
The plugin sends websocket messages to client with RPC response data.
If RPC reponse looks like this:
{status => 1}
It returns simple response like this:
{$msg_type => 1, msg_type => $msg_type}
If RPC returns something like this:
{
response_data => [..],
status => 1,
}
Plugin returns common response like this:
{
$msg_type => $rpc_response,
msg_type => $msg_type,
}
You can customize ws proxy response using 'response' hook.
Plugin parameters
The plugin understands the following parameters.
actions
A reference to array of action details, which contain stash_params,
request-response callbacks, other call parameters.
$self->plugin(
'web_socket_proxy' => {
actions => [
['action1_json_key', {details_key1 => details_value1}],
['action2_json_key']
]
});
backends
An optional reference to a hash of alternate backends to pick for
certain RPC calls. Hash keys are names of backends, and values are
themselves hash references containing backend parameters. Currently
only the url key is supported.
backends => {
server2 => {url => "http://server2.rpc-host:8080/"},
}
Alternate backends are selected by using the backend action option.
rpc_failure_cb
A subroutine reference to call when the RPC call fails at the HTTP
level. Called with Mojolicious::Controller the rpc_response and
$req_storage
A default rpc_failure_cb could be provided in the startup sub routine
sub startup {
my $self = shift;
$self->plugin(
'web_socket_proxy' => {
actions => [
['json_key', {some_param => 'some_value'}]
],
base_path => '/api',
url => 'http://rpc-host.com:8080/',
rpc_failure_cb => sub {
my ($c, $res, $req_storage, $error) = @_;
warn "RPC call failed";
return undef;
}
}
);
}
Call specific sub routine could be specified in call_rpc arguments
$c->call_rpc({
args => $args,
origin_args => $req_storage->{origin_args},
method => 'ticks_history',
rpc_failure_cb => sub {
if ($worker) {
warn "Something went wrong with this rpc call : " . $method;
$worker->unregister;
}
},
}
before_forward
before_forward => [sub { my ($c, $req_storage) = @_; ... }, sub {...}]
Global hooks which will run after request is dispatched and before to
start preparing RPC call. It'll run every hook or until any hook
returns some non-empty result. If returns any hash ref then that value
will be JSON encoded and send to client, without forward action to RPC.
To call RPC every hook should return empty or undefined value. It's
good place to some validation or subscribe actions.
after_forward
after_forward => [sub { my ($c, $result, $req_storage) = @_; ... }, sub {...}]
Global hooks which will run after every forwarded RPC call done. Or
even forward action isn't running. It can view or modify result value
from 'before_forward' hook. It'll run every hook or until any hook
returns some non-empty result. If returns any hash ref then that value
will be JSON encoded and send to client.
after_dispatch
after_dispatch => [sub { my $c = shift; ... }, sub {...}]
Global hooks which will run at the end of request handling.
before_get_rpc_response (global)
before_get_rpc_response => [sub { my ($c, $req_storage) = @_; ... }, sub {...}]
Global hooks which will run when asynchronous RPC call is answered.
after_got_rpc_response (global)
after_got_rpc_response => [sub { my ($c, $req_storage) = @_; ... }, sub {...}]
Global hooks which will run after checked that response exists.
before_send_api_response (global)
before_send_api_response => [sub { my ($c, $req_storage, $api_response) = @_; ... }, sub {...}]
Global hooks which will run immediately before send API response.
after_sent_api_response (global)
before_send_api_response => [sub { my ($c, $req_storage) = @_; ... }, sub {...}]
Global hooks which will run immediately after sent API response.
base_path
API url for make route.
stream_timeout
See "timeout" in Mojo::IOLoop::Stream
max_connections
See "max_connections" in Mojo::IOLoop
max_response_size
Returns error if RPC response size is over value.
opened_connection
Callback for doing something once after connection is opened
finish_connection
Callback for doing something every time when connection is closed.
url
RPC host url - store url string or function to set url dynamically for
manually RPC calls. When using forwarded call then url storing in
request storage. You can store url in every action options, or make it
at before_forward hook.
Actions options
stash_params
stash_params => [qw/ stash_key1 stash_key2 /]
Will send specified parameters from Mojolicious $c->stash. You can
store RPC response data to Mojolicious stash returning data like this:
rpc_response => {
stast => {..} # data to store in Mojolicious stash
response_key1 => response_value1, # response to API client
response_key2 => response_value2
}
success
success => sub { my ($c, $rpc_response) = @_; ... }
Hook which will run if RPC returns success value.
error
error => sub { my ($c, $rpc_response) = @_; ... }
Hook which will run if RPC returns value with error key, e.g.
{ result => { error => { code => 'some_error' } } }
response
response => sub { my ($c, $rpc_response) = @_; ... }
Hook which will run every time when success or error callbacks is
running. It good place to modify API response format.
backend
Selects an alternative backend to forward requests onto, rather than
the default.
backend => "server2"
SEE ALSO
Mojolicious::Plugin::WebSocketProxy, Mojo::WebSocketProxy
Mojo::WebSocketProxy::Backend, Mojo::WebSocketProxy::Dispatcher,
Mojo::WebSocketProxy::Config Mojo::WebSocketProxy::Parser
COPYRIGHT AND LICENSE
Copyright (C) 2016 binary.com