[![Build Status](https://travis-ci.org/jmacdotorg/webmention-perl.svg?branch=master)](https://travis-ci.org/jmacdotorg/webmention-perl) # NAME Web::Mention - Implementation of the IndieWeb Webmention protocol # SYNOPSIS use Web::Mention; use Try::Tiny; use v5.10; # Building a webmention from an incoming web request: my $wm; try { # $request can be any object that provides a 'param' method, such as # Catalyst::Request or Mojo::Message::Request. $wm = Web::Mention->new_from_request ( $request ) } catch { say "Oops, this wasn't a webmention at all: $_"; }; if ( $wm && $wm->is_verified ) { my $source = $wm->original_source; my $target = $wm->target; my $author = $wm->author; my $name; if ( $author ) { $name = $author->name; } else { $name = $wm->source->host; } if ( $wm->is_like ) { say "Hooray, $name likes $target!"; } elsif ( $wm->is_repost ) { say "Gadzooks, over at $source, $name reposted $target!"; } elsif ( $wm->is_reply ) { say "Hmm, over at $source, $name said this about $target:"; say $wm->content; } else { say "I'll be darned, $name mentioned $target at $source!"; } } else { say "This webmention doesn't actually mention its target URL, " . "so it is not verified."; } # Manually buidling and sending a webmention: $wm = Web::Mention->new( source => $url_of_the_thing_that_got_mentioned, target => $url_of_the_thing_that_did_the_mentioning, ); my $success = $wm->send; if ( $success ) { say "Webmention sent successfully!"; } else { say "The webmention wasn't sent successfully."; say "Here's the response we got back..." say $wm->response->as_string; } # Batch-sending a bunch of webmentions based on some published HTML my @wms = Web::Mention->new_from_html( source => $url_of_a_web_page_i_just_published, html => $relevant_html_content_of_that_web_page, ) for my $wm ( @wms ) { my $success = $wm->send; } # DESCRIPTION This class implements the Webmention protocol, as defined by the W3C and the IndieWeb community. (See: [https://indieweb.org/Webmention](https://indieweb.org/Webmention)) An object of this class represents a single webmention, with target and source URLs. It can verify itself, determining whether or not the document found at the source URL does indeed mention the target URL. It can also use IndieWeb algorithms to attempt identification of the source document's author, and to provide a short summary of that document's content, using Microformats2 metadata when available. # METHODS ## Class Methods ### new $wm = Web::Mention->new( source => $source_url, target => $target_url, ); Basic constructor. The **source** and **target** URLs are both required arguments. Either one can either be a [URI](https://metacpan.org/pod/URI) object, or a valid URL string. Per the Webmention protocol, the **source** URL represents the location of the document that made the mention described here, and **target** describes the location of the document that got mentioned. The two arguments cannot refer to the same URL (disregarding the `#fragment` part of either, if present). ### new\_from\_html @wms = Web::Mention->new_from_html( source => $source_url, html => $html, ); Convenience batch-construtor that returns a (possibly empty) _list_ of Web::Mention objects based on the single source URL (or _URI_ object) that you pass in, as well as a string containing HTML from which we can extract zero or more target URLs. These extracted URLs include the `href` attribute value of every <a> tag in the provided HTML. Note that (as with all this class's constructors) this method won't proceed to actually send the generated webmentions; that step remains yours to take. (See ["send"](#send).) ### new\_from\_request $wm = Web::Mention->new_from_request( $request_object ); Convenience constructor that looks into the given web-request object for **source** and **target** parameters, and attempts to build a new Web::Mention object out of them. The object must provide a `param( $param_name )` method that returns the value of the named HTTP parameter. So it could be a [Catalyst::Request](https://metacpan.org/pod/Catalyst::Request) object or a [Mojo::Message::Request](https://metacpan.org/pod/Mojo::Message::Request) object, for example. Throws an exception if the given argument doesn't meet this requirement, or if it does but does not define both required HTTP parameters. ### FROM\_JSON use JSON; $wm = Web::Mention->FROM_JSON( JSON::decode_json( $serialized_webmention ) ); Converts an unblessed hash reference resulting from an earlier serialization (via [JSON](https://metacpan.org/pod/JSON)) into a fully fledged Web::Mention object. See ["SERIALIZATION"](#serialization). The all-caps spelling comes from a perhaps-misguided attempt to pair well with the TO\_JSON method that [JSON](https://metacpan.org/pod/JSON) requires. As such, this method may end up deprecated in favor of a less convoluted approach in future releases of this module. ### content\_truncation\_marker Web::Mention->content_truncation_marker( $new_truncation_marker ) The text that the content method will append to text that it has truncated, if it did truncate it. (See ["content"](#content).) Defaults to `...`. ### max\_content\_length Web::Mention->max_content_length( $new_max_length ) Gets or sets the maximum length, in characters, of the content displayed by that object method prior to truncation. (See ["content"](#content).) Defaults to 200. ## Object Methods ### author $author = $wm->author; A Web::Mention::Author object representing the author of this webmention's source document, if we're able to determine it. If not, this returns undef. ### content $content = $wm->content; Returns a string representing this object's best determination of the _display-ready_ representation of this webmention's content, based on a number of factors. If the source document uses Microformats2 metadata and contains an `h-entry` MF2 item, then returned content may come from a variety of its constituent properties, according to [the IndieWeb comment-display algorithm](https://indieweb.org/comments#How_to_display). If not, then it returns the content of the source document's <title> element, with any further HTML stripped away. In any case, the string will get truncated if it's too long. See ["max\_content\_length"](#max_content_length) and ["content\_truncation\_marker"](#content_truncation_marker). ### endpoint my $uri = $wm->endpoint; Attempts to determine the webmention endpoint URL of this webmention's target. On success, returns a [URI](https://metacpan.org/pod/URI) object. On failure, returns undef. (If the endpoint is set to localhost or a loopback IP, will return undef and also emit a warning, because that's terribly rude behavior on the target's part.) ### is\_tested $bool = $wm->is_tested; Returns 1 if this object's `verify()` method has been called at least once, regardless of the results of that call. Returns 0 otherwise. ### is\_verified $bool = $wm->is_verified; Returns 1 if the webmention's source document actually does seem to mention the target URL. Otherwise returns 0. The first time this is called on a given webmention object, it will try to fetch the source document at its designated URL. If it cannot fetch the document on this first attempt, this method returns 0. ### original\_source $original_url = $wm->original_source; If the document fetched from the source URL seems to point at yet another URL as its original source, then this returns that URL. If not, this has the same return value as `source()`. (It makes this determination based on the possible presence a `u-url` property in an `h-entry` found within the source document.) ### response my $response = $wm->response; Returns the [HTTP::Response](https://metacpan.org/pod/HTTP::Response) object representing the response received by this webmention instance during its most recent attempt to send itself. Returns undef if this webmention instance hasn't tried to send itself. ### send my $bool = $wm->send; Attempts to send an HTTP-request representation of this webmention to its target's designated webmention endpoint. This involves querying the target URL to discover said endpoint's URL (via the `endpoint` object method), and then sending the actual webmention request via HTTP to that endpoint. If that whole process goes through successfully and the endpoint returns a success response (meaning that it has acknowledged the webmention, and most likely queued it for later processing), then this method returns true. Otherwise, it returns false. ### source $source_url = $wm->source; Returns the webmention's source URL, as a [URI](https://metacpan.org/pod/URI) object. ### source\_html $html = $wm->source_html; The HTML of the document fetched from the source URL. If nothing got fetched successfully, returns undef. ### source\_mf2\_document $mf2_doc = $wm->source_mf2_document; The [Web::Microformats2::Document](https://metacpan.org/pod/Web::Microformats2::Document) object that resulted from parsing the source document for Microformats2 metadata. If no such result, returns undef. ### target $target_url = $wm->target; Returns the webmention's target URL, as a [URI](https://metacpan.org/pod/URI) object. ### time\_received $dt = $wm->time_received; A [DateTime](https://metacpan.org/pod/DateTime) object corresponding to this object's creation time. ### time\_verified $dt = $wm->time_verified; If this webmention has been verified, then this will return a [DateTime](https://metacpan.org/pod/DateTime) object corresponding to the time of verification. (Otherwise, returns undef.) ### type $type = $wm->type; The type of webmention this is. One of: - mention _(default)_ - reply - like - repost - quotation # SERIALIZATION To serialize a Web::Mention object into JSON, enable [the JSON module's "convert\_blessed" feature](https://metacpan.org/pod/JSON#convert_blessed), and then use one of that module's JSON-encoding functions on this object. This will result in a JSON string containing all the pertinent information about the webmention, including its verification status, any content and metadata fetched from the target, and so on. To unserialize a Web::Mention object serialized in this way, first decode it into an unblessed hash reference via [JSON](https://metacpan.org/pod/JSON), and then pass that as the single argument to [the FROM\_JSON class method](#from_json). # NOTES AND BUGS This software is **alpha**; its author is still determining how it wants to work, and its interface might change dramatically. This library does not, at this time, support [the proposed "Vouch" anti-spam extension for Webmention](https://indieweb.org/Vouch). # SUPPORT To file issues or submit pull requests, please see [this module's repository on GitHub](https://github.com/jmacdotorg/webmention-perl). The author also welcomes any direct questions about this module via email. # AUTHOR Jason McIntosh (jmac@jmac.org) # CONTRIBUTORS - Mohammad S Anwar (mohammad.anwar@yahoo.com) # COPYRIGHT AND LICENSE This software is Copyright (c) 2018 by Jason McIntosh. This is free software, licensed under: The MIT (X11) License # A PERSONAL REQUEST My ability to share and maintain free, open-source software like this depends upon my living in a society that allows me the free time and personal liberty to create work benefiting people other than just myself or my immediate family. I recognize that I got a head start on this due to an accident of birth, and I strive to convert some of my unclaimed time and attention into work that, I hope, gives back to society in some small way. Worryingly, I find myself today living in a country experiencing a profound and unwelcome political upheaval, with its already flawed democracy under grave threat from powerful authoritarian elements. These powers wish to undermine this society, remolding it according to their deeply cynical and strictly zero-sum philosophies, where nobody can gain without someone else losing. Free and open-source software has no place in such a world. As such, these autocrats' further ascension would have a deleterious effect on my ability to continue working for the public good. Therefore, if you would like to financially support my work, I would ask you to consider a donation to one of the following causes. It would mean a lot to me if you did. (You can tell me about it if you'd like to, but you don't have to.) - [The American Civil Liberties Union](https://aclu.org) - [The Democratic National Committee](https://democrats.org) - [Earthjustice](https://earthjustice.org)