Provided by: libmojolicious-perl_9.31+dfsg-1_all bug

NAME

       Mojo::UserAgent - Non-blocking I/O HTTP and WebSocket user agent

SYNOPSIS

         use Mojo::UserAgent;

         # Fine grained response handling (dies on connection errors)
         my $ua  = Mojo::UserAgent->new;
         my $res = $ua->get('docs.mojolicious.org')->result;
         if    ($res->is_success)  { say $res->body }
         elsif ($res->is_error)    { say $res->message }
         elsif ($res->code == 301) { say $res->headers->location }
         else                      { say 'Whatever...' }

         # Say hello to the Unicode snowman and include an Accept header
         say $ua->get('www.☃.net?hello=there' => {Accept => '*/*'})->result->body;

         # Extract data from HTML and XML resources with CSS selectors
         say $ua->get('www.perl.org')->result->dom->at('title')->text;

         # Scrape the latest headlines from a news site
         say $ua->get('blogs.perl.org')->result->dom->find('h2 > a')->map('text')->join("\n");

         # IPv6 PUT request with Content-Type header and content
         my $tx = $ua->put('[::1]:3000' => {'Content-Type' => 'text/plain'} => 'Hi!');

         # Quick JSON API request with Basic authentication
         my $url = Mojo::URL->new('https://example.com/test.json')->userinfo('sri:☃');
         my $value = $ua->get($url)->result->json;

         # JSON POST (application/json) with TLS certificate authentication
         my $tx = $ua->cert('tls.crt')->key('tls.key')->post('https://example.com' => json => {top => 'secret'});

         # Form POST (application/x-www-form-urlencoded)
         my $tx = $ua->post('https://metacpan.org/search' => form => {q => 'mojo'});

         # Search DuckDuckGo anonymously through Tor
         $ua->proxy->http('socks://127.0.0.1:9050');
         say $ua->get('api.3g2upl4pq6kufc4m.onion/?q=mojolicious&format=json')->result->json('/Abstract');

         # GET request via UNIX domain socket "/tmp/myapp.sock" (percent encoded slash)
         say $ua->get('http+unix://%2Ftmp%2Fmyapp.sock/test')->result->body;

         # Follow redirects to download Mojolicious from GitHub
         $ua->max_redirects(5)
           ->get('https://www.github.com/mojolicious/mojo/tarball/main')
           ->result->save_to('/home/sri/mojo.tar.gz');

         # Non-blocking request
         $ua->get('mojolicious.org' => sub ($ua, $tx) { say $tx->result->dom->at('title')->text });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

         # Concurrent non-blocking requests (synchronized with promises)
         my $mojo_promise = $ua->get_p('mojolicious.org');
         my $cpan_promise = $ua->get_p('cpan.org');
         Mojo::Promise->all($mojo_promise, $cpan_promise)->then(sub ($mojo, $cpan) {
           say $mojo->[0]->result->dom->at('title')->text;
           say $cpan->[0]->result->dom->at('title')->text;
         })->wait;

         # WebSocket connection sending and receiving JSON via UNIX domain socket
         $ua->websocket('ws+unix://%2Ftmp%2Fmyapp.sock/echo.json' => sub ($ua, $tx) {
           say 'WebSocket handshake failed!' and return unless $tx->is_websocket;
           $tx->on(json => sub ($tx, $hash) {
             say "WebSocket message via JSON: $hash->{msg}";
             $tx->finish;
           });
           $tx->send({json => {msg => 'Hello World!'}});
         });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

DESCRIPTION

       Mojo::UserAgent is a full featured non-blocking I/O HTTP and WebSocket user agent, with
       IPv6, TLS, SNI, IDNA, HTTP/SOCKS5 proxy, UNIX domain socket, Comet (long polling),
       Promises/A+, keep-alive, connection pooling, timeout, cookie, multipart, gzip compression
       and multiple event loop support.

       All connections will be reset automatically if a new process has been forked, this allows
       multiple processes to share the same Mojo::UserAgent object safely.

       For better scalability (epoll, kqueue) and to provide non-blocking name resolution, SOCKS5
       as well as TLS support, the optional modules EV (4.32+), Net::DNS::Native (0.15+),
       IO::Socket::Socks (0.64+) and IO::Socket::SSL (2.009+) will be used automatically if
       possible. Individual features can also be disabled with the "MOJO_NO_NNR", "MOJO_NO_SOCKS"
       and "MOJO_NO_TLS" environment variables.

       See "USER AGENT" in Mojolicious::Guides::Cookbook for more.

EVENTS

       Mojo::UserAgent inherits all events from Mojo::EventEmitter and can emit the following new
       ones.

   prepare
         $ua->on(prepare => sub ($ua, $tx) {...});

       Emitted whenever a new transaction is being prepared, before relative URLs are rewritten
       and cookies added. This includes automatically prepared proxy "CONNECT" requests and
       followed redirects.

         $ua->on(prepare => sub ($ua, $tx) {
           $tx->req->url(Mojo::URL->new('/mock-mojolicious')) if $tx->req->url->host eq 'mojolicious.org';
         });

   start
         $ua->on(start => sub ($ua, $tx) {...});

       Emitted whenever a new transaction is about to start. This includes automatically prepared
       proxy "CONNECT" requests and followed redirects.

         $ua->on(start => sub ($ua, $tx) {
           $tx->req->headers->header('X-Bender' => 'Bite my shiny metal ass!');
         });

ATTRIBUTES

       Mojo::UserAgent implements the following attributes.

   ca
         my $ca = $ua->ca;
         $ua    = $ua->ca('/etc/tls/ca.crt');

       Path to TLS certificate authority file used to verify the peer certificate, defaults to
       the value of the "MOJO_CA_FILE" environment variable.

         # Show certificate authorities for debugging
         IO::Socket::SSL::set_defaults(SSL_verify_callback => sub { say "Authority: $_[2]" and return $_[0] });

   cert
         my $cert = $ua->cert;
         $ua      = $ua->cert('/etc/tls/client.crt');

       Path to TLS certificate file, defaults to the value of the "MOJO_CERT_FILE" environment
       variable.

   connect_timeout
         my $timeout = $ua->connect_timeout;
         $ua         = $ua->connect_timeout(5);

       Maximum amount of time in seconds establishing a connection may take before getting
       canceled, defaults to the value of the "MOJO_CONNECT_TIMEOUT" environment variable or 10.

   cookie_jar
         my $cookie_jar = $ua->cookie_jar;
         $ua            = $ua->cookie_jar(Mojo::UserAgent::CookieJar->new);

       Cookie jar to use for requests performed by this user agent, defaults to a
       Mojo::UserAgent::CookieJar object.

         # Ignore all cookies
         $ua->cookie_jar->ignore(sub { 1 });

         # Ignore cookies for public suffixes
         my $ps = IO::Socket::SSL::PublicSuffix->default;
         $ua->cookie_jar->ignore(sub ($cookie) {
           return undef unless my $domain = $cookie->domain;
           return ($ps->public_suffix($domain))[0] eq '';
         });

         # Add custom cookie to the jar
         $ua->cookie_jar->add(
           Mojo::Cookie::Response->new(
             name   => 'foo',
             value  => 'bar',
             domain => 'docs.mojolicious.org',
             path   => '/Mojolicious'
           )
         );

   inactivity_timeout
         my $timeout = $ua->inactivity_timeout;
         $ua         = $ua->inactivity_timeout(15);

       Maximum amount of time in seconds a connection can be inactive before getting closed,
       defaults to the value of the "MOJO_INACTIVITY_TIMEOUT" environment variable or 40. Setting
       the value to 0 will allow connections to be inactive indefinitely.

   insecure
         my $bool = $ua->insecure;
         $ua      = $ua->insecure($bool);

       Do not require a valid TLS certificate to access HTTPS/WSS sites, defaults to the value of
       the "MOJO_INSECURE" environment variable.

         # Disable TLS certificate verification for testing
         say $ua->insecure(1)->get('https://127.0.0.1:3000')->result->code;

   ioloop
         my $loop = $ua->ioloop;
         $ua      = $ua->ioloop(Mojo::IOLoop->new);

       Event loop object to use for blocking I/O operations, defaults to a Mojo::IOLoop object.

   key
         my $key = $ua->key;
         $ua     = $ua->key('/etc/tls/client.crt');

       Path to TLS key file, defaults to the value of the "MOJO_KEY_FILE" environment variable.

   max_connections
         my $max = $ua->max_connections;
         $ua     = $ua->max_connections(5);

       Maximum number of keep-alive connections that the user agent will retain before it starts
       closing the oldest ones, defaults to 5. Setting the value to 0 will prevent any
       connections from being kept alive.

   max_redirects
         my $max = $ua->max_redirects;
         $ua     = $ua->max_redirects(3);

       Maximum number of redirects the user agent will follow before it fails, defaults to the
       value of the "MOJO_MAX_REDIRECTS" environment variable or 0.

   max_response_size
         my $max = $ua->max_response_size;
         $ua     = $ua->max_response_size(16777216);

       Maximum response size in bytes, defaults to the value of "max_message_size" in
       Mojo::Message::Response. Setting the value to 0 will allow responses of indefinite size.
       Note that increasing this value can also drastically increase memory usage, should you for
       example attempt to parse an excessively large response body with the methods "dom" in
       Mojo::Message or "json" in Mojo::Message.

   proxy
         my $proxy = $ua->proxy;
         $ua       = $ua->proxy(Mojo::UserAgent::Proxy->new);

       Proxy manager, defaults to a Mojo::UserAgent::Proxy object.

         # Detect proxy servers from environment
         $ua->proxy->detect;

         # Manually configure HTTP proxy (using CONNECT for HTTPS/WebSockets)
         $ua->proxy->http('http://127.0.0.1:8080')->https('http://127.0.0.1:8080');

         # Manually configure Tor (SOCKS5)
         $ua->proxy->http('socks://127.0.0.1:9050')->https('socks://127.0.0.1:9050');

         # Manually configure UNIX domain socket (using CONNECT for HTTPS/WebSockets)
         $ua->proxy->http('http+unix://%2Ftmp%2Fproxy.sock') ->https('http+unix://%2Ftmp%2Fproxy.sock');

   request_timeout
         my $timeout = $ua->request_timeout;
         $ua         = $ua->request_timeout(5);

       Maximum amount of time in seconds establishing a connection, sending the request and
       receiving a whole response may take before getting canceled, defaults to the value of the
       "MOJO_REQUEST_TIMEOUT" environment variable or 0.  Setting the value to 0 will allow the
       user agent to wait indefinitely. The timeout will reset for every followed redirect.

         # Total limit of 5 seconds, of which 3 seconds may be spent connecting
         $ua->max_redirects(0)->connect_timeout(3)->request_timeout(5);

   server
         my $server = $ua->server;
         $ua        = $ua->server(Mojo::UserAgent::Server->new);

       Application server relative URLs will be processed with, defaults to a
       Mojo::UserAgent::Server object.

         # Mock web service
         $ua->server->app(Mojolicious->new);
         $ua->server->app->routes->get('/time' => sub ($c) {
           $c->render(json => {now => time});
         });
         my $time = $ua->get('/time')->result->json->{now};

         # Change log level
         $ua->server->app->log->level('fatal');

         # Port currently used for processing relative URLs blocking
         say $ua->server->url->port;

         # Port currently used for processing relative URLs non-blocking
         say $ua->server->nb_url->port;

   socket_options
         my $options = $ua->socket_options;
         $ua         = $ua->socket_options({LocalAddr => '127.0.0.1'});

       Additional options for IO::Socket::IP when opening new connections.

   tls_options
         my $options = $ua->tls_options;
         $ua         = $ua->tls_options({SSL_cipher_list => 'DEFAULT:!DH@SECLEVEL=1'});

       Additional options for IO::Socket::SSL when opening new connections.

   transactor
         my $t = $ua->transactor;
         $ua   = $ua->transactor(Mojo::UserAgent::Transactor->new);

       Transaction builder, defaults to a Mojo::UserAgent::Transactor object.

         # Change name of user agent
         $ua->transactor->name('MyUA 1.0');

         # Disable compression
         $ua->transactor->compressed(0);

METHODS

       Mojo::UserAgent inherits all methods from Mojo::EventEmitter and implements the following
       new ones.

   build_tx
         my $tx = $ua->build_tx(GET => 'example.com');
         my $tx = $ua->build_tx(PUT => 'http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->build_tx(PUT => 'http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->build_tx(PUT => 'http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Generate Mojo::Transaction::HTTP object with "tx" in Mojo::UserAgent::Transactor.

         # Request with custom cookie
         my $tx = $ua->build_tx(GET => 'https://example.com/account');
         $tx->req->cookies({name => 'user', value => 'sri'});
         $tx = $ua->start($tx);

         # Deactivate gzip compression
         my $tx = $ua->build_tx(GET => 'example.com');
         $tx->req->headers->remove('Accept-Encoding');
         $tx = $ua->start($tx);

         # Interrupt response by raising an error
         my $tx = $ua->build_tx(GET => 'http://example.com');
         $tx->res->on(progress => sub ($res) {
           return unless my $server = $res->headers->server;
           $res->error({message => 'Oh noes, it is IIS!'}) if $server =~ /IIS/;
         });
         $tx = $ua->start($tx);

   build_websocket_tx
         my $tx = $ua->build_websocket_tx('ws://example.com');
         my $tx = $ua->build_websocket_tx( 'ws://example.com' => {DNT => 1} => ['v1.proto']);

       Generate Mojo::Transaction::HTTP object with "websocket" in Mojo::UserAgent::Transactor.

         # Custom WebSocket handshake with cookie
         my $tx = $ua->build_websocket_tx('wss://example.com/echo');
         $tx->req->cookies({name => 'user', value => 'sri'});
         $ua->start($tx => sub ($ua, $tx) {
           say 'WebSocket handshake failed!' and return unless $tx->is_websocket;
           $tx->on(message => sub ($tx, $msg) {
             say "WebSocket message: $msg";
             $tx->finish;
           });
           $tx->send('Hi!');
         });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   delete
         my $tx = $ua->delete('example.com');
         my $tx = $ua->delete('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->delete('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->delete('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "DELETE" request and return resulting Mojo::Transaction::HTTP object,
       takes the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "DELETE"
       method, which is implied). You can also append a callback to perform requests non-
       blocking.

         $ua->delete('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   delete_p
         my $promise = $ua->delete_p('http://example.com');

       Same as "delete", but performs all requests non-blocking and returns a Mojo::Promise
       object instead of accepting a callback.

         $ua->delete_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   get
         my $tx = $ua->get('example.com');
         my $tx = $ua->get('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->get('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->get('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "GET" request and return resulting Mojo::Transaction::HTTP object, takes
       the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "GET" method,
       which is implied). You can also append a callback to perform requests non-blocking.

         $ua->get('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   get_p
         my $promise = $ua->get_p('http://example.com');

       Same as "get", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         $ua->get_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   head
         my $tx = $ua->head('example.com');
         my $tx = $ua->head('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->head('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->head('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "HEAD" request and return resulting Mojo::Transaction::HTTP object, takes
       the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "HEAD" method,
       which is implied). You can also append a callback to perform requests non-blocking.

         $ua->head('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   head_p
         my $promise = $ua->head_p('http://example.com');

       Same as "head", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         $ua->head_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   options
         my $tx = $ua->options('example.com');
         my $tx = $ua->options('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->options('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->options('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "OPTIONS" request and return resulting Mojo::Transaction::HTTP object,
       takes the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "OPTIONS"
       method, which is implied). You can also append a callback to perform requests non-
       blocking.

         $ua->options('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   options_p
         my $promise = $ua->options_p('http://example.com');

       Same as "options", but performs all requests non-blocking and returns a Mojo::Promise
       object instead of accepting a callback.

         $ua->options_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   patch
         my $tx = $ua->patch('example.com');
         my $tx = $ua->patch('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->patch('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->patch('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "PATCH" request and return resulting Mojo::Transaction::HTTP object,
       takes the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "PATCH"
       method, which is implied). You can also append a callback to perform requests non-
       blocking.

         $ua->patch('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   patch_p
         my $promise = $ua->patch_p('http://example.com');

       Same as "patch", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         $ua->patch_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   post
         my $tx = $ua->post('example.com');
         my $tx = $ua->post('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->post('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->post('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "POST" request and return resulting Mojo::Transaction::HTTP object, takes
       the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "POST" method,
       which is implied). You can also append a callback to perform requests non-blocking.

         $ua->post('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   post_p
         my $promise = $ua->post_p('http://example.com');

       Same as "post", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         $ua->post_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   put
         my $tx = $ua->put('example.com');
         my $tx = $ua->put('http://example.com' => {Accept => '*/*'} => 'Content!');
         my $tx = $ua->put('http://example.com' => {Accept => '*/*'} => form => {a => 'b'});
         my $tx = $ua->put('http://example.com' => {Accept => '*/*'} => json => {a => 'b'});

       Perform blocking "PUT" request and return resulting Mojo::Transaction::HTTP object, takes
       the same arguments as "tx" in Mojo::UserAgent::Transactor (except for the "PUT" method,
       which is implied). You can also append a callback to perform requests non-blocking.

         $ua->put('http://example.com' => json => {a => 'b'} => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   put_p
         my $promise = $ua->put_p('http://example.com');

       Same as "put", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         $ua->put_p('http://example.com' => json => {a => 'b'})->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   start
         my $tx = $ua->start(Mojo::Transaction::HTTP->new);

       Perform blocking request for a custom Mojo::Transaction::HTTP object, which can be
       prepared manually or with "build_tx". You can also append a callback to perform requests
       non-blocking.

         my $tx = $ua->build_tx(GET => 'http://example.com');
         $ua->start($tx => sub ($ua, $tx) { say $tx->result->body });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

   start_p
         my $promise = $ua->start_p(Mojo::Transaction::HTTP->new);

       Same as "start", but performs all requests non-blocking and returns a Mojo::Promise object
       instead of accepting a callback.

         my $tx = $ua->build_tx(GET => 'http://example.com');
         $ua->start_p($tx)->then(sub ($tx) {
           say $tx->result->body;
         })->catch(sub ($err) {
           warn "Connection error: $err";
         })->wait;

   websocket
         $ua->websocket('ws://example.com' => sub {...});
         $ua->websocket('ws://example.com' => {DNT => 1} => ['v1.proto'] => sub {...});

       Open a non-blocking WebSocket connection with transparent handshake, takes the same
       arguments as "websocket" in Mojo::UserAgent::Transactor. The callback will receive either
       a Mojo::Transaction::WebSocket or Mojo::Transaction::HTTP object, depending on if the
       handshake was successful.

         $ua->websocket('wss://example.com/echo' => ['v1.proto'] => sub ($ua, $tx) {
           say 'WebSocket handshake failed!' and return unless $tx->is_websocket;
           say 'Subprotocol negotiation failed!' and return unless $tx->protocol;
           $tx->on(finish => sub ($tx, $code, $reason) { say "WebSocket closed with status $code." });
           $tx->on(message => sub ($tx, $msg) {
             say "WebSocket message: $msg";
             $tx->finish;
           });
           $tx->send('Hi!');
         });
         Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

       You can activate "permessage-deflate" compression by setting the
       "Sec-WebSocket-Extensions" header, this can result in much better performance, but also
       increases memory usage by up to 300KiB per connection.

         $ua->websocket('ws://example.com/foo' => {
           'Sec-WebSocket-Extensions' => 'permessage-deflate'
         } => sub {...});

   websocket_p
         my $promise = $ua->websocket_p('ws://example.com');

       Same as "websocket", but returns a Mojo::Promise object instead of accepting a callback.

         $ua->websocket_p('wss://example.com/echo')->then(sub ($tx) {
           my $promise = Mojo::Promise->new;
           $tx->on(finish => sub { $promise->resolve });
           $tx->on(message => sub ($tx, $msg) {
             say "WebSocket message: $msg";
             $tx->finish;
           });
           $tx->send('Hi!');
           return $promise;
         })->catch(sub ($err) {
           warn "WebSocket error: $err";
         })->wait;

DEBUGGING

       You can set the "MOJO_CLIENT_DEBUG" environment variable to get some advanced diagnostics
       information printed to "STDERR".

         MOJO_CLIENT_DEBUG=1

SEE ALSO

       Mojolicious, Mojolicious::Guides, <https://mojolicious.org>.