DOKK / manpages / debian 11 / libmojolicious-perl / Mojolicious::Plugin::DefaultHelpers.3pm.en
Mojolicious::Plugin::DefaultHelpers(3pm) User Contributed Perl Documentation Mojolicious::Plugin::DefaultHelpers(3pm)

Mojolicious::Plugin::DefaultHelpers - Default helpers plugin

  # Mojolicious
  $app->plugin('DefaultHelpers');
  # Mojolicious::Lite
  plugin 'DefaultHelpers';

Mojolicious::Plugin::DefaultHelpers is a collection of helpers for Mojolicious.

This is a core plugin, that means it is always enabled and its code a good example for learning to build new plugins, you're welcome to fork it.

See "PLUGINS" in Mojolicious::Plugins for a list of plugins that are available by default.

Mojolicious::Plugin::DefaultHelpers implements the following helpers.

  my $formats = $c->accepts;
  my $format  = $c->accepts('html', 'json', 'txt');

Select best possible representation for resource from "format" "GET"/"POST" parameter, "format" stash value or "Accept" request header with "accepts" in Mojolicious::Renderer, defaults to returning the first extension if no preference could be detected.

  # Check if JSON is acceptable
  $c->render(json => {hello => 'world'}) if $c->accepts('json');
  # Check if JSON was specifically requested
  $c->render(json => {hello => 'world'}) if $c->accepts('', 'json');
  # Unsupported representation
  $c->render(data => '', status => 204)
    unless my $format = $c->accepts('html', 'json');
  # Detected representations to select from
  my @formats = @{$c->accepts};


  %= app->secrets->[0]

Alias for "app" in Mojolicious::Controller.

  %= b('Joel is a slug')->slugify

Turn string into a Mojo::ByteStream object.

  %= c('a', 'b', 'c')->shuffle->join

Turn list into a Mojo::Collection object.

  %= config 'something'

Alias for "config" in Mojolicious.

  %= content foo => begin
    test
  % end
  %= content bar => 'Hello World!'
  %= content 'foo'
  %= content 'bar'
  %= content

Store partial rendered content in a named buffer and retrieve it later, defaults to retrieving the named buffer "content", which is used by the renderer for the "layout" and "extends" features. New content will be ignored if the named buffer is already in use.

  % content_for foo => begin
    test
  % end
  %= content_for 'foo'

Same as "content", but appends content to named buffers if they are already in use.

  % content_for message => begin
    Hello
  % end
  % content_for message => begin
    world!
  % end
  %= content 'message'


  % content_with foo => begin
    test
  % end
  %= content_with 'foo'

Same as "content", but replaces content of named buffers if they are already in use.

  % content message => begin
    world!
  % end
  % content_with message => begin
    Hello <%= content 'message' %>
  % end
  %= content 'message'


  %= csrf_token

Get CSRF token from "session", and generate one if none exists.

  % if (current_route 'login') {
    Welcome to Mojolicious!
  % }
  %= current_route

Check or get name of current route.

  %= dumper {some => 'data'}

Dump a Perl data structure with "dumper" in Mojo::Util, very useful for debugging.

  % extends 'blue';
  % extends 'blue', title => 'Blue!';

Set "extends" stash value, all additional key/value pairs get merged into the "stash".

  my $foo = $c->flash('foo');
  $c      = $c->flash({foo => 'bar'});
  $c      = $c->flash(foo => 'bar');
  %= flash 'foo'

Data storage persistent only for the next request, stored in the "session".

  # Show message after redirect
  $c->flash(message => 'User created successfully!');
  $c->redirect_to('show_user', id => 23);


  $c = $c->inactivity_timeout(3600);

Use "stream" in Mojo::IOLoop to find the current connection and increase timeout if possible.

  # Longer version
  Mojo::IOLoop->stream($c->tx->connection)->timeout(3600);


  %= include 'menubar'
  %= include 'menubar', format => 'txt'

Alias for "render_to_string" in Mojolicious::Controller.

  my $bool = $c->is_fresh;
  my $bool = $c->is_fresh(etag => 'abc');
  my $bool = $c->is_fresh(etag => 'W/"def"');
  my $bool = $c->is_fresh(last_modified => $epoch);

Check freshness of request by comparing the "If-None-Match" and "If-Modified-Since" request headers to the "ETag" and "Last-Modified" response headers with "is_fresh" in Mojolicious::Static.

  # Add ETag/Last-Modified headers and check freshness before rendering
  $c->is_fresh(etag => 'abc', last_modified => 1424985708)
    ? $c->rendered(304)
    : $c->render(text => 'I ♥ Mojolicious!');


  % layout 'green';
  % layout 'green', title => 'Green!';

Set "layout" stash value, all additional key/value pairs get merged into the "stash".

  my $log = $c->log;

Alternative to "log" in Mojolicious that includes "request_id" in Mojo::Message::Request with every log message.

  # Log message with context
  $c->log->debug('This is a log message with request id');
  # Pass logger with context to model
  my $log = $c->log;
  $c->some_model->create({foo => $foo}, $log);


  %= param 'foo'

Alias for "param" in Mojolicious::Controller.

  my $promise = $c->proxy->get_p('http://example.com' => {Accept => '*/*'});

Perform non-blocking "GET" request and forward response as efficiently as possible, takes the same arguments as "get" in Mojo::UserAgent and returns a Mojo::Promise object.

  # Forward with exception handling
  $c->proxy->get_p('http://mojolicious.org')->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });


  my $promise = $c->proxy->post_p('http://example.com' => {Accept => '*/*'});

Perform non-blocking "POST" request and forward response as efficiently as possible, takes the same arguments as "post" in Mojo::UserAgent and returns a Mojo::Promise object.

  # Forward with exception handling
  $c->proxy->post_p('example.com' => form => {test => 'pass'})->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });


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

Perform non-blocking request for a custom Mojo::Transaction::HTTP object and forward response as efficiently as possible, returns a Mojo::Promise object.

  # Forward with exception handling
  my $tx = $c->ua->build_tx(GET => 'http://mojolicious.org');
  $c->proxy->start_p($tx)->catch(sub ($err) {
    $c->log->debug("Proxy error: $err");
    $c->render(text => 'Something went wrong!', status => 400);
  });
  # Forward with custom request and response headers
  my $headers = $c->req->headers->clone->dehop;
  $headers->header('X-Proxy' => 'Mojo');
  my $tx = $c->ua->build_tx(GET => 'http://example.com' => $headers->to_hash);
  $c->proxy->start_p($tx);
  $tx->res->content->once(body => sub ($content) { $c->res->headers->header('X-Proxy' => 'Mojo') });


  $c = $c->redirect_to('named', foo => 'bar');
  $c = $c->redirect_to('named', {foo => 'bar'});
  $c = $c->redirect_to('/index.html');
  $c = $c->redirect_to('http://example.com/index.html');

Prepare a 302 (if the status code is not already "3xx") redirect response with "Location" header, takes the same arguments as "url_for".

  # Moved Permanently
  $c->res->code(301);
  $c->redirect_to('some_route');
  # Temporary Redirect
  $c->res->code(307);
  $c->redirect_to('some_route');


  $c->reply->asset(Mojo::Asset::File->new);

Reply with a Mojo::Asset::File or Mojo::Asset::Memory object using "serve_asset" in Mojolicious::Static, and perform content negotiation with "Range", "If-Modified-Since" and "If-None-Match" headers.

  # Serve asset with custom modification time
  my $asset = Mojo::Asset::Memory->new;
  $asset->add_chunk('Hello World!')->mtime(784111777);
  $c->res->headers->content_type('text/plain');
  $c->reply->asset($asset);
  # Serve static file if it exists
  if (my $asset = $c->app->static->file('images/logo.png')) {
    $c->res->headers->content_type('image/png');
    $c->reply->asset($asset);
  }


  $c = $c->reply->exception('Oops!');
  $c = $c->reply->exception(Mojo::Exception->new);

Render the exception template "exception.$mode.$format.*" or "exception.$format.*" and set the response status code to 500. Also sets the stash values "exception" to a Mojo::Exception object and "snapshot" to a copy of the "stash" for use in the templates.

  $c->reply->file('/etc/passwd');

Reply with a static file from an absolute path anywhere on the file system using "static" in Mojolicious.

  # Longer version
  $c->reply->asset(Mojo::Asset::File->new(path => '/etc/passwd'));
  # Serve file from an absolute path with a custom content type
  $c->res->headers->content_type('application/myapp');
  $c->reply->file('/home/sri/foo.txt');
  # Serve file from a secret application directory
  $c->reply->file($c->app->home->child('secret', 'file.txt'));


  $c = $c->reply->not_found;

Render the not found template "not_found.$mode.$format.*" or "not_found.$format.*" and set the response status code to 404. Also sets the stash value "snapshot" to a copy of the "stash" for use in the templates.

  my $bool = $c->reply->static('images/logo.png');
  my $bool = $c->reply->static('../lib/MyApp.pm');

Reply with a static file using "static" in Mojolicious, usually from the "public" directories or "DATA" sections of your application. Note that this helper uses a relative path, but does not protect from traversing to parent directories.

  # Serve file from a relative path with a custom content type
  $c->res->headers->content_type('application/myapp');
  $c->reply->static('foo.txt');


  $c = $c->respond_to(
    json => {json => {message => 'Welcome!'}},
    html => {template => 'welcome'},
    any  => sub {...}
  );

Automatically select best possible representation for resource from "format" "GET"/"POST" parameter, "format" stash value or "Accept" request header, defaults to "default_format" in Mojolicious::Renderer or rendering an empty 204 response. Each representation can be handled with a callback or a hash reference containing arguments to be passed to "render" in Mojolicious::Controller.

  # Everything else than "json" and "xml" gets a 204 response
  $c->respond_to(
    json => sub { $c->render(json => {just => 'works'}) },
    xml  => {text => '<just>works</just>'},
    any  => {data => '', status => 204}
  );

For more advanced negotiation logic you can also use "accepts".

  %= session 'foo'

Alias for "session" in Mojolicious::Controller.

  %= stash 'foo'
  % stash foo => 'bar';

Alias for "stash" in Mojolicious::Controller.

  %= stash('name') // 'Somebody'


  $c->timing->begin('foo');

Create named timestamp for "timing->elapsed".

  my $elapsed = $c->timing->elapsed('foo');

Return fractional amount of time in seconds since named timstamp has been created with "timing->begin" or "undef" if no such timestamp exists.

  # Log timing information
  $c->timing->begin('database_stuff');
  ...
  my $elapsed = $c->timing->elapsed('database_stuff');
  $c->app->log->debug("Database stuff took $elapsed seconds");


  my $rps = $c->timing->rps('0.001');

Return fractional number of requests that could be performed in one second if every singe one took the given amount of time in seconds or "undef" if the number is too low.

  # Log more timing information
  $c->timing->begin('web_stuff');
  ...
  my $elapsed = $c->timing->elapsed('web_stuff');
  my $rps     = $c->timing->rps($elapsed);
  $c->app->log->debug("Web stuff took $elapsed seconds ($rps per second)");


  $c->timing->server_timing('metric');
  $c->timing->server_timing('metric', 'Some Description');
  $c->timing->server_timing('metric', 'Some Description', '0.001');

Create "Server-Timing" header with optional description and duration.

  # "Server-Timing: miss"
  $c->timing->server_timing('miss');
  # "Server-Timing: dc;desc=atl"
  $c->timing->server_timing('dc', 'atl');
  # "Server-Timing: db;desc=Database;dur=0.0001"
  $c->timing->begin('database_stuff');
  ...
  my $elapsed = $c->timing->elapsed('database_stuff');
  $c->timing->server_timing('db', 'Database', $elapsed);
  # "Server-Timing: miss, dc;desc=atl"
  $c->timing->server_timing('miss');
  $c->timing->server_timing('dc', 'atl');


  %= title
  % title 'Welcome!';
  % title 'Welcome!', foo => 'bar';

Get or set "title" stash value, all additional key/value pairs get merged into the "stash".

  %= ua->get('mojolicious.org')->result->dom->at('title')->text

Alias for "ua" in Mojolicious.

  %= url_for 'named', controller => 'bar', action => 'baz'

Alias for "url_for" in Mojolicious::Controller.

  %= url_for('/index.html')->query(foo => 'bar')


  %= url_with 'named', controller => 'bar', action => 'baz'

Does the same as "url_for", but inherits query parameters from the current request.

  %= url_with->query({page => 2})


  my $v = $c->validation;

Get Mojolicious::Validator::Validation object for current request to validate file uploads as well as "GET" and "POST" parameters extracted from the query string and "application/x-www-form-urlencoded" or "multipart/form-data" message body. Parts of the request body need to be loaded into memory to parse "POST" parameters, so you have to make sure it is not excessively large. There's a 16MiB limit for requests by default.

  # Validate GET/POST parameter
  my $v = $c->validation;
  $v->required('title', 'trim')->size(3, 50);
  my $title = $v->param('title');
  # Validate file upload
  my $v = $c->validation;
  $v->required('tarball')->upload->size(1, 1048576);
  my $tarball = $v->param('tarball');

Mojolicious::Plugin::DefaultHelpers inherits all methods from Mojolicious::Plugin and implements the following new ones.

  $plugin->register(Mojolicious->new);

Register helpers in Mojolicious application.

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

2021-01-24 perl v5.32.0