package Mojo::UserAgent;
use Mojo::Base 'Mojo::EventEmitter';

# "Fry: Since when is the Internet about robbing people of their privacy?
#  Bender: August 6, 1991."
use Mojo::IOLoop;
use Mojo::Util qw(monkey_patch term_escape);
use Mojo::UserAgent::CookieJar;
use Mojo::UserAgent::Proxy;
use Mojo::UserAgent::Server;
use Mojo::UserAgent::Transactor;
use Scalar::Util 'weaken';

use constant DEBUG => $ENV{MOJO_USERAGENT_DEBUG} || 0;

has ca              => sub { $ENV{MOJO_CA_FILE} };
has cert            => sub { $ENV{MOJO_CERT_FILE} };
has connect_timeout => sub { $ENV{MOJO_CONNECT_TIMEOUT} || 10 };
has cookie_jar      => sub { Mojo::UserAgent::CookieJar->new };
has 'local_address';
has inactivity_timeout => sub { $ENV{MOJO_INACTIVITY_TIMEOUT} // 20 };
has ioloop             => sub { Mojo::IOLoop->new };
has key                => sub { $ENV{MOJO_KEY_FILE} };
has max_connections    => 5;
has max_redirects => sub { $ENV{MOJO_MAX_REDIRECTS} || 0 };
has proxy => sub { Mojo::UserAgent::Proxy->new };
has request_timeout => sub { $ENV{MOJO_REQUEST_TIMEOUT} // 0 };
has server => sub { Mojo::UserAgent::Server->new(ioloop => shift->ioloop) };
has transactor => sub { Mojo::UserAgent::Transactor->new };

# Common HTTP methods
for my $name (qw(DELETE GET HEAD OPTIONS PATCH POST PUT)) {
  monkey_patch __PACKAGE__, lc $name, sub {
    my $self = shift;
    my $cb = ref $_[-1] eq 'CODE' ? pop : undef;
    return $self->start($self->build_tx($name, @_), $cb);
  };
}

sub DESTROY { Mojo::Util::_global_destruction() or shift->_cleanup }

sub build_tx           { shift->transactor->tx(@_) }
sub build_websocket_tx { shift->transactor->websocket(@_) }

sub start {
  my ($self, $tx, $cb) = @_;

  # Fork-safety
  $self->_cleanup->server->restart unless ($self->{pid} //= $$) eq $$;

  # Non-blocking
  if ($cb) {
    warn "-- Non-blocking request (@{[_url($tx)]})\n" if DEBUG;
    return $self->_start(Mojo::IOLoop->singleton, $tx, $cb);
  }

  # Blocking
  warn "-- Blocking request (@{[_url($tx)]})\n" if DEBUG;
  $self->_start($self->ioloop, $tx => sub { shift->ioloop->stop; $tx = shift });
  $self->ioloop->start;

  return $tx;
}

sub websocket {
  my ($self, $cb) = (shift, pop);
  $self->start($self->build_websocket_tx(@_), $cb);
}

sub _cleanup {
  my $self = shift;
  delete $self->{pid};
  $self->_finish($_, 1) for keys %{$self->{connections} || {}};
  return $self;
}

sub _connect {
  my ($self, $loop, $peer, $tx, $handle, $cb) = @_;

  my $t = $self->transactor;
  my ($proto, $host, $port) = $peer ? $t->peer($tx) : $t->endpoint($tx);
  my %options
    = (address => $host, port => $port, timeout => $self->connect_timeout);
  if (my $local = $self->local_address) { $options{local_address} = $local }
  $options{handle} = $handle if $handle;

  # SOCKS
  if ($proto eq 'socks') {
    @options{qw(socks_address socks_port)} = @options{qw(address port)};
    ($proto, @options{qw(address port)}) = $t->endpoint($tx);
    my $userinfo = $tx->req->via_proxy(0)->proxy->userinfo;
    @options{qw(socks_user socks_pass)} = split ':', $userinfo if $userinfo;
  }

  # TLS
  map { $options{"tls_$_"} = $self->$_ } qw(ca cert key)
    if ($options{tls} = $proto eq 'https');

  weaken $self;
  my $id;
  return $id = $loop->client(
    %options => sub {
      my ($loop, $err, $stream) = @_;

      # Connection error
      return unless $self;
      return $self->_error($id, $err) if $err;

      # Connection established
      $stream->on(timeout => sub { $self->_error($id, 'Inactivity timeout') });
      $stream->on(close => sub { $self && $self->_finish($id, 1) });
      $stream->on(error => sub { $self && $self->_error($id, pop) });
      $stream->on(read => sub { $self->_read($id, pop) });
      $self->$cb($id);
    }
  );
}

sub _connect_proxy {
  my ($self, $loop, $old, $cb) = @_;

  # Start CONNECT request
  return undef unless my $new = $self->transactor->proxy_connect($old);
  return $self->_start(
    ($loop, $new) => sub {
      my ($self, $tx) = @_;

      # CONNECT failed (connection needs to be kept alive)
      $old->res->error({message => 'Proxy connection failed'})
        and return $self->$cb($old)
        if $tx->error || !$tx->res->is_status_class(200) || !$tx->keep_alive;

      # Start real transaction
      $old->req->via_proxy(0);
      my $id = $tx->connection;
      return $self->_start($loop, $old->connection($id), $cb)
        unless $tx->req->url->protocol eq 'https';

      # TLS upgrade
      my $handle = $loop->stream($id)->steal_handle;
      $self->_remove($id);
      $id = $self->_connect($loop, 0, $old, $handle,
        sub { shift->_start($loop, $old->connection($id), $cb) });
      $self->{connections}{$id} = {cb => $cb, ioloop => $loop, tx => $old};
    }
  );
}

sub _connected {
  my ($self, $id) = @_;

  my $c      = $self->{connections}{$id};
  my $stream = $c->{ioloop}->stream($id)->timeout($self->inactivity_timeout);
  my $tx     = $c->{tx}->connection($id);
  my $handle = $stream->handle;
  $tx->local_address($handle->sockhost)->local_port($handle->sockport);
  $tx->remote_address($handle->peerhost)->remote_port($handle->peerport);

  weaken $self;
  $tx->on(resume => sub { $self->_write($id) });
  $self->_write($id);
}

sub _connection {
  my ($self, $loop, $tx, $cb) = @_;

  # Reuse connection
  my ($proto, $host, $port) = $self->transactor->endpoint($tx);
  my $id = $tx->connection || $self->_dequeue($loop, "$proto:$host:$port", 1);
  if ($id) {
    warn "-- Reusing connection $id ($proto://$host:$port)\n" if DEBUG;
    @{$self->{connections}{$id}}{qw(cb tx)} = ($cb, $tx);
    $tx->kept_alive(1) unless $tx->connection;
    $self->_connected($id);
    return $id;
  }

  # CONNECT request to proxy required
  if (my $id = $self->_connect_proxy($loop, $tx, $cb)) { return $id }

  # New connection
  $id = $self->_connect($loop, 1, $tx, undef, \&_connected);
  warn "-- Connect $id ($proto://$host:$port)\n" if DEBUG;
  $self->{connections}{$id} = {cb => $cb, ioloop => $loop, tx => $tx};

  return $id;
}

sub _dequeue {
  my ($self, $loop, $name, $test) = @_;

  my $old = $self->{queue}{$loop} ||= [];
  my ($found, @new);
  for my $queued (@$old) {
    push @new, $queued and next if $found || !grep { $_ eq $name } @$queued;

    # Search for id/name and sort out corrupted connections if necessary
    next unless my $stream = $loop->stream($queued->[1]);
    $test && $stream->is_readable ? $stream->close : ($found = $queued->[1]);
  }
  @$old = @new;

  return $found;
}

sub _error {
  my ($self, $id, $err) = @_;
  my $tx = $self->{connections}{$id}{tx};
  $tx->res->error({message => $err}) if $tx;
  $self->_finish($id, 1);
}

sub _finish {
  my ($self, $id, $close) = @_;

  # Remove request timeout and finish transaction
  return unless my $c = $self->{connections}{$id};
  $c->{ioloop}->remove($c->{timeout}) if $c->{timeout};
  return $self->_reuse($id, $close) unless my $old = $c->{tx};

  # Premature connection close or 4xx/5xx
  my $res = $old->closed->res->finish;
  if ($close && !$res->code && !$res->error) {
    $res->error({message => 'Premature connection close'});
  }
  elsif ($res->is_status_class(400) || $res->is_status_class(500)) {
    $res->error({message => $res->message, code => $res->code});
  }

  # Always remove connection for WebSockets
  return $self->_remove($id) if $old->is_websocket;

  $self->cookie_jar->collect($old);

  # Upgrade connection to WebSocket
  if (my $new = $self->transactor->upgrade($old)) {
    weaken $self;
    $new->on(resume => sub { $self->_write($id) });
    $c->{cb}($self, $c->{tx} = $new);
    return $new->client_read($old->res->content->leftovers);
  }

  # Finish connection and handle redirects
  $self->_reuse($id, $close);
  $c->{cb}($self, $old) unless $self->_redirect($c, $old);
}

sub _read {
  my ($self, $id, $chunk) = @_;

  # Corrupted connection
  return $self->_remove($id) unless my $tx = $self->{connections}{$id}{tx};

  warn term_escape "-- Client <<< Server (@{[_url($tx)]})\n$chunk\n" if DEBUG;
  $tx->client_read($chunk);
  $self->_finish($id) if $tx->is_finished;
}

sub _redirect {
  my ($self, $c, $old) = @_;
  return undef unless my $new = $self->transactor->redirect($old);
  return undef unless @{$old->redirects} < $self->max_redirects;
  return $self->_start($c->{ioloop}, $new, delete $c->{cb});
}

sub _remove {
  my ($self, $id) = @_;
  my $c = delete $self->{connections}{$id};
  $self->_dequeue($c->{ioloop}, $id);
  $c->{ioloop}->remove($id);
}

sub _reuse {
  my ($self, $id, $close) = @_;

  # Connection close
  my $c   = $self->{connections}{$id};
  my $tx  = delete $c->{tx};
  my $max = $self->max_connections;
  return $self->_remove($id)
    if $close || !$tx || !$max || !$tx->keep_alive || $tx->error;

  # Keep connection alive
  my $queue = $self->{queue}{$c->{ioloop}} ||= [];
  $self->_remove(shift(@$queue)->[1]) while @$queue && @$queue >= $max;
  push @$queue, [join(':', $self->transactor->endpoint($tx)), $id];
}

sub _start {
  my ($self, $loop, $tx, $cb) = @_;

  # Application server
  my $url = $tx->req->url;
  unless ($url->is_abs) {
    my $base
      = $loop == $self->ioloop ? $self->server->url : $self->server->nb_url;
    $url->scheme($base->scheme)->authority($base->authority);
  }

  $_->prepare($tx) for $self->proxy, $self->cookie_jar;

  # Connect and add request timeout if necessary
  my $id = $self->emit(start => $tx)->_connection($loop, $tx, $cb);
  if (my $timeout = $self->request_timeout) {
    weaken $self;
    $self->{connections}{$id}{timeout}
      = $loop->timer($timeout => sub { $self->_error($id, 'Request timeout') });
  }

  return $id;
}

sub _url { shift->req->url->to_abs }

sub _write {
  my ($self, $id) = @_;

  # Protect from resume event recursion
  my $c = $self->{connections}{$id};
  return if !(my $tx = $c->{tx}) || $c->{writing};
  local $c->{writing} = 1;
  my $chunk = $tx->client_write;
  warn term_escape "-- Client >>> Server (@{[_url($tx)]})\n$chunk\n" if DEBUG;
  return unless length $chunk;
  weaken $self;
  $c->{ioloop}->stream($id)->write($chunk => sub { $self->_write($id) });
}

1;

=encoding utf8

=head1 NAME

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

=head1 SYNOPSIS

  use Mojo::UserAgent;

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

  # Form POST (application/x-www-form-urlencoded) with exception handling
  my $tx = $ua->post('https://metacpan.org/search' => form => {q => 'mojo'});
  if (my $res = $tx->success) { say $res->body }
  else {
    my $err = $tx->error;
    die "$err->{code} response: $err->{message}" if $err->{code};
    die "Connection error: $err->{message}";
  }

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

  # Scrape the latest headlines from a news site
  say $ua->get('blogs.perl.org')
    ->res->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 $value = $ua->get('https://sri:s3cret@example.com/test.json')->res->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'});

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

  # Follow redirects to download Mojolicious from GitHub
  $ua->max_redirects(5)
    ->get('https://www.github.com/kraih/mojo/tarball/master')
    ->res->content->asset->move_to('/home/sri/mojo.tar.gz');

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

  # Concurrent non-blocking requests (synchronized with a delay)
  Mojo::IOLoop->delay(
    sub {
      my $delay = shift;
      $ua->get('mojolicious.org' => $delay->begin);
      $ua->get('cpan.org'        => $delay->begin);
    },
    sub {
      my ($delay, $mojo, $cpan) = @_;
      say $mojo->res->dom->at('title')->text;
      say $cpan->res->dom->at('title')->text;
    }
  )->wait;

  # WebSocket connection sending and receiving JSON messages
  $ua->websocket('ws://example.com/echo.json' => sub {
    my ($ua, $tx) = @_;
    say 'WebSocket handshake failed!' and return unless $tx->is_websocket;
    $tx->on(json => sub {
      my ($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;

=head1 DESCRIPTION

L<Mojo::UserAgent> is a full featured non-blocking I/O HTTP and WebSocket user
agent, with IPv6, TLS, SNI, IDNA, HTTP/SOCKS5 proxy, Comet (long polling),
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 L<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 L<EV> (4.0+),
L<Net::DNS::Native> (0.15+), L<IO::Socket::Socks> (0.64+) and
L<IO::Socket::SSL> (1.94+) will be used automatically if possible. Individual
features can also be disabled with the C<MOJO_NO_NDN>, C<MOJO_NO_SOCKS> and
C<MOJO_NO_TLS> environment variables.

See L<Mojolicious::Guides::Cookbook/"USER AGENT"> for more.

=head1 EVENTS

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

=head2 start

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

Emitted whenever a new transaction is about to start, this includes
automatically prepared proxy C<CONNECT> requests and followed redirects.

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

=head1 ATTRIBUTES

L<Mojo::UserAgent> implements the following attributes.

=head2 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 C<MOJO_CA_FILE> environment variable. Also
activates hostname verification.

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

=head2 cert

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

Path to TLS certificate file, defaults to the value of the C<MOJO_CERT_FILE>
environment variable.

=head2 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 C<MOJO_CONNECT_TIMEOUT>
environment variable or C<10>.

=head2 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
L<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 {
    my $cookie = shift;
    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 => 'mojolicious.org',
      path   => '/perldoc'
    )
  );

=head2 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 C<MOJO_INACTIVITY_TIMEOUT> environment
variable or C<20>. Setting the value to C<0> will allow connections to be
inactive indefinitely.

=head2 ioloop

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

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

=head2 key

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

Path to TLS key file, defaults to the value of the C<MOJO_KEY_FILE> environment
variable.

=head2 local_address

  my $address = $ua->local_address;
  $ua         = $ua->local_address('127.0.0.1');

Local address to bind to.

=head2 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 C<5>. Setting the value to C<0>
will prevent any connections from being kept alive.

=head2 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 C<MOJO_MAX_REDIRECTS> environment variable or
C<0>.

=head2 proxy

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

Proxy manager, defaults to a L<Mojo::UserAgent::Proxy> object.

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

  # Manually configure HTTP proxy (using CONNECT for HTTPS)
  $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');

=head2 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 C<MOJO_REQUEST_TIMEOUT> environment variable or
C<0>. Setting the value to C<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);

=head2 server

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

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

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

=head2 transactor

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

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

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

=head1 METHODS

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

=head2 build_tx

  my $tx = $ua->build_tx(GET => 'example.com');
  my $tx = $ua->build_tx(
    PUT => 'http://example.com' => {Accept => '*/*'} => 'Hi!');
  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 L<Mojo::Transaction::HTTP> object with
L<Mojo::UserAgent::Transactor/"tx">.

  # 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 {
    my $res = shift;
    return unless my $server = $res->headers->server;
    $res->error({message => 'Oh noes, it is IIS!'}) if $server =~ /IIS/;
  });
  $tx = $ua->start($tx);

=head2 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 L<Mojo::Transaction::HTTP> object with
L<Mojo::UserAgent::Transactor/"websocket">.

  # 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 {
    my ($ua, $tx) = @_;
    say 'WebSocket handshake failed!' and return unless $tx->is_websocket;
    $tx->on(message => sub {
      my ($tx, $msg) = @_;
      say "WebSocket message: $msg";
      $tx->finish;
    });
    $tx->send('Hi!');
  });
  Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

=head2 delete

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

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

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

=head2 get

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

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

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

=head2 head

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

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

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

=head2 options

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

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

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

=head2 patch

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

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

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

=head2 post

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

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

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

=head2 put

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

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

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

=head2 start

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

Perform blocking request for a custom L<Mojo::Transaction::HTTP> object, which
can be prepared manually or with L</"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 {
    my ($ua, $tx) = @_;
    say $tx->res->body;
  });
  Mojo::IOLoop->start unless Mojo::IOLoop->is_running;

=head2 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 L<Mojo::UserAgent::Transactor/"websocket">. The callback will
receive either a L<Mojo::Transaction::WebSocket> or L<Mojo::Transaction::HTTP>
object, depending on if the handshake was successful.

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

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

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

=head1 DEBUGGING

You can set the C<MOJO_USERAGENT_DEBUG> environment variable to get some
advanced diagnostics information printed to C<STDERR>.

  MOJO_USERAGENT_DEBUG=1

=head1 SEE ALSO

L<Mojolicious>, L<Mojolicious::Guides>, L<http://mojolicious.org>.

=cut
