Item::get_links( string $rel = 'alternate' ): array|null

844    public function get_links($rel = 'alternate')845    {846        if (!isset($this->data['links'])) {847            $this->data['links'] = [];848            foreach ((array) $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_ATOM_10, 'link') as $link) {849                if (isset($link['attribs']['']['href'])) {850                    $link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';851                    $this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($link));852                }853            }854            foreach ((array) $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_ATOM_03, 'link') as $link) {855                if (isset($link['attribs']['']['href'])) {856                    $link_rel = (isset($link['attribs']['']['rel'])) ? $link['attribs']['']['rel'] : 'alternate';857                    $this->data['links'][$link_rel][] = $this->sanitize($link['attribs']['']['href'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($link));858                }859            }860            if ($links = $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_RSS_10, 'link')) {861                $this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($links[0]));862            }863            if ($links = $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_RSS_090, 'link')) {864                $this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($links[0]));865            }866            if ($links = $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_RSS_20, 'link')) {867                $this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($links[0]));868            }869            if ($links = $this->get_item_tags(\SimplePie\SimplePie::NAMESPACE_RSS_20, 'guid')) {870                if (!isset($links[0]['attribs']['']['isPermaLink']) || strtolower(trim($links[0]['attribs']['']['isPermaLink'])) === 'true') {871                    $this->data['links']['alternate'][] = $this->sanitize($links[0]['data'], \SimplePie\SimplePie::CONSTRUCT_IRI, $this->get_base($links[0]));872                }873            }874 875            $keys = array_keys($this->data['links']);876            foreach ($keys as $key) {877                if ($this->registry->call(Misc::class, 'is_isegment_nz_nc', [$key])) {878                    if (isset($this->data['links'][\SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY . $key])) {879                        $this->data['links'][\SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY . $key] = array_merge($this->data['links'][$key], $this->data['links'][\SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY . $key]);880                        $this->data['links'][$key] = &$this->data['links'][\SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY . $key];881                    } else {882                        $this->data['links'][\SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY . $key] = &$this->data['links'][$key];883                    }884                } elseif (substr($key, 0, 41) === \SimplePie\SimplePie::IANA_LINK_RELATIONS_REGISTRY) {885                    $this->data['links'][substr($key, 41)] = &$this->data['links'][$key];886                }887                $this->data['links'][$key] = array_unique($this->data['links'][$key]);888            }889        }890        if (isset($this->data['links'][$rel])) {891            return $this->data['links'][$rel];892        }893 894        return null;895    }