从 PHP 对象数组中获取单个值

Question

我是 PHP 的新手，我想从 OpenGraph 对象中获取单个值并打印它。不确定我做错了什么？我不断得到 "Array" 作为打印输出。

class OpenGraph implements Iterator{

public static $TYPES = array(
    'activity' => array('activity', 'sport'),
    'business' => array('bar', 'company', 'cafe', 'hotel', 'restaurant'),
    'group' => array('cause', 'sports_league', 'sports_team'),
    'organization' => array('band', 'government', 'non_profit', 'school', 'university'),
    'person' => array('actor', 'athlete', 'author', 'director', 'musician', 'politician', 'public_figure'),
    'place' => array('city', 'country', 'landmark', 'state_province'),
    'product' => array('album', 'book', 'drink', 'food', 'game', 'movie', 'product', 'song', 'tv_show'),
    'website' => array('blog', 'website'),
);

private $_values = array();

static public function fetch($URI) {
    $curl = curl_init($URI);
    curl_setopt($curl, CURLOPT_FAILONERROR, true);
    curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($curl, CURLOPT_TIMEOUT, 15);
    curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($curl, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT']);
    $response = curl_exec($curl);
    curl_close($curl);
    if (!empty($response)) {
        return self::_parse($response);
    } else {
        return false;
    }
}

static private function _parse($HTML) {
    $old_libxml_error = libxml_use_internal_errors(true);
    $doc = new DOMDocument();
    $doc->loadHTML($HTML);

    libxml_use_internal_errors($old_libxml_error);
    $tags = $doc->getElementsByTagName('meta');
    if (!$tags || $tags->length === 0) {
        return false;
    }
    $page = new self();
    $nonOgDescription = null;

    foreach ($tags AS $tag) {
        if ($tag->hasAttribute('property') &&
            strpos($tag->getAttribute('property'), 'og:') === 0) {
            $key = strtr(substr($tag->getAttribute('property'), 3), '-', '_');
            $page->_values[$key] = $tag->getAttribute('content');
        }

        //Added this if loop to retrieve description values from sites like the New York Times who have malformed it. 
        if ($tag ->hasAttribute('value') && $tag->hasAttribute('property') &&
            strpos($tag->getAttribute('property'), 'og:') === 0) {
            $key = strtr(substr($tag->getAttribute('property'), 3), '-', '_');
            $page->_values[$key] = $tag->getAttribute('value');
        }
        //Based on modifications at https://github.com/bashofmann/opengraph/blob/master/src/OpenGraph/OpenGraph.php
        if ($tag->hasAttribute('name') && $tag->getAttribute('name') === 'description') {
            $nonOgDescription = $tag->getAttribute('content');
        }

    }
    //Based on modifications at https://github.com/bashofmann/opengraph/blob/master/src/OpenGraph/OpenGraph.php
    if (!isset($page->_values['title'])) {
        $titles = $doc->getElementsByTagName('title');
        if ($titles->length > 0) {
            $page->_values['title'] = $titles->item(0)->textContent;
        }
    }
    if (!isset($page->_values['description']) && $nonOgDescription) {
        $page->_values['description'] = $nonOgDescription;
    }
    //Fallback to use image_src if ogp::image isn't set.
    if (!isset($page->values['image'])) {
        $domxpath = new DOMXPath($doc);
        $elements = $domxpath->query("//link[@rel='image_src']");
        if ($elements->length > 0) {
            $domattr = $elements->item(0)->attributes->getNamedItem('href');
            if ($domattr) {
                $page->_values['image'] = $domattr->value;
                $page->_values['image_src'] = $domattr->value;
            }
        }
    }
    if (empty($page->_values)) { return false; }

    return $page;
}

public function __get($key) {
    if (array_key_exists($key, $this->_values)) {
        return $this->_values[$key];
    }

    if ($key === 'schema') {
        foreach (self::$TYPES AS $schema => $types) {
            if (array_search($this->_values['type'], $types)) {
                return $schema;
            }
        }
    }
}

public function keys() {
    return array_keys($this->_values);
}

public function __isset($key) {
    return array_key_exists($key, $this->_values);
}

public function hasLocation() {
    if (array_key_exists('latitude', $this->_values) && array_key_exists('longitude', $this->_values)) {
        return true;
    }

    $address_keys = array('street_address', 'locality', 'region', 'postal_code', 'country_name');
    $valid_address = true;
    foreach ($address_keys AS $key) {
        $valid_address = ($valid_address && array_key_exists($key, $this->_values));
    }
    return $valid_address;
}

private $_position = 0;
public function rewind() { reset($this->_values); $this->_position = 0; }
public function current() { return current($this->_values); }
public function key() { return key($this->_values); }
public function next() { next($this->_values); ++$this->_position; }
public function valid() { return $this->_position < sizeof($this->_values); }}

实施：

require_once('OpenGraph.php');
$graph = OpenGraph::fetch('http://www.google.com');
echo $graph->keys('description');

我实际上是从 github 那里得到这段代码的：https://github.com/scottmac/opengraph

Answer 1

keys() 方法 returns 一个数组，它不带任何参数。当你使用

时你在做什么

echo $graph->keys('description')

以 'description' 作为参数调用该方法，它将忽略它，然后回显整个数组。当您在数组上使用 echo 时，它只会像您看到的那样打印 Array 。因为 __get() magic method，我想你应该可以只使用

echo $graph->description

从 PHP 对象数组中获取单个值

Get single value from PHP object array

php

arrays

object

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