NAME

Web::Magic - HTTP dwimmery

SYNOPSIS

use Web::Magic;
say Web::Magic->new('http://json-schema.org/card')->{description};

use Web::Magic -sub => 'W'; 
say W('http://json-schema.org/card')->{description};

DESCRIPTION

On the surface of it, Web::Magic appears to just perform HTTP requests, but it's more than that. A URL blessed into the Web::Magic package can be interacted with in all sorts of useful ways.

Constructor

new ([$method,] $uri [, %args])

$method is the HTTP method to use with the URI, such as 'GET', 'POST', 'PUT' or 'DELETE'. The HTTP method must be capitalised to avoid it being interpreted by the constructor as a URI. It defaults to 'GET'.

The URI should be an HTTP or HTTPS URL. Other URI schemes may work to varying degress of success.

The %args hash is a convenience for constructing HTTP query strings. Hash values should be scalars, or at least overload stringification. The following are all equivalent...

Web::Magic->new(GET => 'http://www.google.com/search', q => 'kittens');
Web::Magic->new('http://www.google.com/search', q => 'kittens');
Web::Magic->new(GET => 'http://www.google.com/search?q=kittens');
Web::Magic->new('http://www.google.com/search?q=kittens');

Export

You can import a sub to act as a shortcut for the constructor.

use Web::Magic -sub => 'W';
W(GET => 'http://www.google.com/search', q => 'kittens');
W('http://www.google.com/search', q => 'kittens');
W(GET => 'http://www.google.com/search?q=kittens');
W('http://www.google.com/search?q=kittens');

There is experimental support for a quote-like operator similar to q() or qq():

use Web::Magic -quotelike => 'qW';
qW(http://www.google.com/search?q=kittens);

But it doesn't always behave as expected. (See https://rt.cpan.org/Ticket/Display.html?id=72822.)

Pre-Request Methods

Constructing a Web::Magic object doesn't actually perform a request for the URI. Web::Magic defers requesting the URI until the last possible moment. (Which in some cases will be when it slips out of scope, or even not at all.)

Pre-request methods are those that can be called before the request is made. Unless otherwise noted they will not themselves trigger the request to be made. Unless otherwise noted, they return a reference to the Web::Magic object itself, so can be chained:

my $magic = Web::Magic
  ->new(GET => 'http://www.google.com/')
  ->User_Agent('MyBot/0.1')
  ->Accept('text/html');

The following methods are pre-request.

set_request_method($method, [$body])

Sets the HTTP request method (e.g. 'GET' or 'POST'). You can optionally set the HTTP request body at the same time.

As a shortcut, you can use the method name as an object method. That is, the following are equivalent:

$magic->set_request_method(POST => $body);
$magic->POST($body);

Using the latter technique, methods need to conform to this regular expression: /^[A-Z][A-Z0-9]{0,19}$/.

This will throw an error if called on a Web::Magic object that has already been requested.

set_request_header($header, $value)

Sets an HTTP request header (e.g. 'User-Agent').

As a shortcut, you can use the header name as an object method, substituting hyphens for underscores. That is, the following are equivalent:

$magic->set_request_header('User-Agent', 'MyBot/0.1');
$magic->User_Agent('MyBot/0.1');

Using the latter technique, methods need to begin with a capital letter and contain at least one lower-case letter.

This will throw an error if called on a Web::Magic object that has already been requested.

set_request_body($body)

Sets the body for a POST, PUT or other request that needs a body.

$body may be a string, but can be a hash or array reference, an XML::LibXML::Document or an RDF::Trine::Model, in which case they'll be serialised appropriately based on the Content-Type header of the request.

my $magic = W('http://www.example.com/document-submission')
  ->POST
  ->set_request_body($document_dom)
  ->Content_Type('text/html');

Yes, that's right. Even though the content-type is set *after* the body, it is still serialised appropriately. This is because serialisation is deferred until just before the request is made.

This will throw an error if called on a Web::Magic object that has already been requested.

cancel

This method may be called to show you do not intend for this object to be requested. Attempting to request an object that has been cancelled will throw an exception.

my $magic = W('http://www.google.com/');
$magic->cancel;
$magic->do_request; # throws

Why is this needed? Because even if you don't explicitly call do_request, the request will be made implicitly in some cases. cancel allows you to avoid the implicit request.

This will throw an error if called on a Web::Magic object that has already been requested.

do_request

Actually performs the HTTP request. You rarely need to call this method implicitly, as calling any Post-Request method will automatically call do_request.

do_request will be called automatically (via DESTROY) on any Web::Magic object that gets destroyed (e.g. goes out of scope) unless the request has been cancelled, or the request is unlikely to have had side-effects (i.e. its method is 'GET', 'HEAD', 'OPTIONS', 'TRACE' or 'SEARCH').

This will throw an error if called on a Web::Magic object that has been cancelled.

Post-Request Methods

The following methods can be called after a request has been made, and will implicitly call do_request if called on an object which has not yet been requested.

These do not typically return a reference to the invocant Web::Magic object, so cannot always easily be chained.

response

The response, as an HTTP::Response object.

content

The response body, as a string.

Web::Magic overloads stringification calling this method. Thus:

print W('http://www.example.com/');

will print the body of 'http://www.example.com/'.

to_hashref

Parses the response body as JSON or YAML (depending on Content-Type header) and returns the result as a hashref (or arrayref).

Actually, technically it returns an JSON::JOM object which can be accessed as if it were a hashref or arrayref.

When a Web::Magic object is accessed as a hashref, this implicitly calls to_hashref. So the following are equivalent:

W('http://example.com/data')->to_hashref->{people}[0]{name};
W('http://example.com/data')->{people}[0]{name};

When to_hashref is called on an unrequested Web::Magic object, it implicitly sets the HTTP Accept header to include JSON and YAML unless the Accept header has already been set.

to_dom

Parses the response body as XML or HTML (depending on Content-Type header) and returns the result as an XML::LibXML::Document.

When to_dom is called on an unrequested Web::Magic object, it implicitly sets the HTTP Accept header to include XML and HTML unless the Accept header has already been set.

Additionally, the following methods can be called which implicitly call to_dom: getElementsByTagName getElementsByTagNameNS getElementsByLocalName getElementsById documentElement cloneNode firstChild lastChild findnodes find findvalue exists childNodes attributes getNamespaces. So, for example, the following are equivalent:

W('http://example.com/')->to_dom->getElementsByTagName('title');
W('http://example.com/')->getElementsByTagName('title');

to_model

Parses the response body as RDF/XML, Turtle, RDF/JSON or RDFa (depending on Content-Type header) and returns the result as an RDF::Trine::Model.

When to_model is called on an unrequested Web::Magic object, it implicitly sets the HTTP Accept header to include RDF/XML and Turtle unless the Accept header has already been set.

Additionally, the following methods can be called which implicitly call to_model: subjects predicates objects objects_for_predicate_list get_pattern get_statements count_statements get_sparql as_stream. So, for example, the following are equivalent:

W('http://example.com/')->to_model->get_pattern($pattern);
W('http://example.com/')->get_pattern($pattern);

to_feed

Parses the response body as Atom or RSS (depending on Content-Type header) and returns the result as an XML::Feed.

When to_feed is called on an unrequested Web::Magic object, it implicitly sets the HTTP Accept header to include Atom and RSS unless the Accept header has already been set.

Additionally, the following methods can be called which implicitly call to_feed: entries. So, for example, the following are equivalent:

W('http://example.com/')->to_feed->entries;
W('http://example.com/')->entries;

Any Time Methods

These can be called either before or after the request, and do not trigger the request to be made. They do not usually return the invocant Web::Magic object, so are not usually suitable for chaning.

uri

Returns the original URI, as a URI object.

Additionally, the following methods can be called which implicitly call uri: scheme authority path query host port. So, for example, the following are equivalent:

W('http://example.com/')->uri->host;
W('http://example.com/')->host;

If you need a copy of the URI as a string, two methods are:

my $magic = W('http://example.com/');
my $str_1 = $magic->uri->as_string;
my $str_2 = $$magic;

The former perhaps makes for easier to read code; the latter is maybe slightly faster code.

is_requested

Returns true if the invocant has already been requested.

is_cancelled

Returns true if the invocant has been cancelled.

assert_response($name, $coderef)

Checks an assertion about the HTTP response. Web::Magic will blithely allow you to call to_hashref on a non-JSON/YAML response, or getElementsByTagName on an HTTP error page. This may not be what you want. assert_response allows you to check things are as expected before continuing, croaking otherwise.

$coderef should be a subroutine that accepts an HTTP::Response, and returns true if everything is OK, and false if something bad has happened. $name is just a label for the assertion, to provide a more helpful error message if the assertion fails.

print W('http://example.com/data.json')
  ->assert_response(correct_type => sub { (shift)->content_type =~ /json/i })
  ->{people}[0]{name};

An assertion can be made at any time. If made before the request, then it is queued up for checking later. If the assertion is made after the request, it is checked immediately.

This method returns the invocant, so may be chained.

assert_success

A shortcut for:

assert_response(success => sub { (shift)->is_success })

This checks the HTTP response has a 2XX HTTP status code.

has_response_assertions

Returns true if the Web::Magic object has had any response assertions made. (In fact, returns the number of such assertions.)

user_agent

Returns the LWP::UserAgent that will be used (or has been used) to issue the request.

acme_24

Returns the string 'Acme::24'.

Additionally, the following methods can be called which implicitly call acme_24: random_jackbauer_fact. So, for example, the following are equivalent:

W('http://example.com/')->acme_24->random_jackbauer_fact;
W('http://example.com/')->random_jackbauer_fact;

This method exists to emphasize the whimsical and experimental status of the current release of Web::Magic. If Web::Magic ever becomes ready for serious production use, expect the following to evaluate to false:

W('http://example.com/')->can('random_jackbauer_fact')

BUGS

Inumerable, almost certainly.

Have a go at enumerating them here: http://rt.cpan.org/Dist/Display.html?Queue=Web-Magic.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

To install Web::Magic, copy and paste the appropriate command in to your terminal.

cpanm

cpanm Web::Magic

CPAN shell

perl -MCPAN -e shell
install Web::Magic

For more information on module installation, please visit the detailed CPAN module installation guide.

	Global
`s`	Focus search bar
`?`	Bring up this help dialog

	GitHub
`g` `p`	Go to pull requests
`g` `i`	go to github issues (only if github is preferred repository)

	POD
`g` `a`	Go to author
`g` `c`	Go to changes
`g` `i`	Go to issues
`g` `d`	Go to dist
`g` `r`	Go to repository/SCM
`g` `s`	Go to source
`g` `b`	Go to file browse

	Search terms
module: (e.g. module:Plugin)
distribution: (e.g. distribution:Dancer auth)
author: (e.g. author:SONGMU Redis)
version: (e.g. version:1.00)

NAME

SYNOPSIS

DESCRIPTION

Constructor

Export

Pre-Request Methods

Post-Request Methods

Any Time Methods

BUGS

SEE ALSO

AUTHOR

COPYRIGHT AND LICENCE

DISCLAIMER OF WARRANTIES

Module Install Instructions