检查有效的 gravatar （PHP）

我建议你试试卢卡斯·阿劳霍（Lucas Araújo）的php gravatar类。

/**
*  Class Gravatar
*
* From Gravatar Help:
*        "A gravatar is a dynamic image resource that is requested from our server. The request
*        URL is presented here, broken into its segments."
* Source:
*    http://site.gravatar.com/site/implement
*
* Usage:
* <code>
*        $email = "[email protected]";
*        $default = "http://www.yourhost.com/default_image.jpg";    // Optional
*        $gravatar = new Gravatar($email, $default);
*        $gravatar->size = 80;
*        $gravatar->rating = "G";
*        $gravatar->border = "FF0000";
*
*        echo $gravatar; // Or echo $gravatar->toHTML();
* </code>
*
*    Class Page: http://www.phpclasses.org/browse/package/4227.html
*
* @author Lucas Araújo <[email protected]>
* @version 1.0
* @package Gravatar
*/
class Gravatar
{
    /**
     *    Gravatar's url
     */
    const GRAVATAR_URL = "http://www.gravatar.com/avatar.php";

    /**
     *    Ratings available
     */
    private $GRAVATAR_RATING = array("G", "PG", "R", "X");

    /**
     *    Query string. key/value
     */
    protected $properties = array(
        "gravatar_id"    => NULL,
        "default"        => NULL,
        "size"            => 80,        // The default value
        "rating"        => NULL,
        "border"        => NULL,
    );

    /**
     *    E-mail. This will be converted to md5($email)
     */
    protected $email = "";

    /**
     *    Extra attributes to the IMG tag like ALT, CLASS, STYLE...
     */
    protected $extra = "";

    /**
     *    
     */
    public function __construct($email=NULL, $default=NULL) {
        $this->setEmail($email);
        $this->setDefault($default);
    }

    /**
     *    
     */
    public function setEmail($email) {
        if ($this->isValidEmail($email)) {
            $this->email = $email;
            $this->properties['gravatar_id'] = md5(strtolower($this->email));
            return true;
        }
        return false;
    }

    /**
     *    
     */
    public function setDefault($default) {
        $this->properties['default'] = $default;
    }

    /**
     *    
     */
    public function setRating($rating) {
        if (in_array($rating, $this->GRAVATAR_RATING)) {
            $this->properties['rating'] = $rating;
            return true;
        }
        return false;
    }

    /**
     *    
     */
    public function setSize($size) {
        $size = (int) $size;
        if ($size <= 0)
            $size = NULL;        // Use the default size
        $this->properties['size'] = $size;
    }

    /**
     *    
     */
    public function setExtra($extra) {
        $this->extra = $extra;
    }

    /**
     *    
     */
    public function isValidEmail($email) {
        // Source: http://www.zend.com/zend/spotlight/ev12apr.php
        return eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $email);
    }

    /**
     *    Object property overloading
     */
    public function __get($var) { return @$this->properties[$var]; }

    /**
     *    Object property overloading
     */
    public function __set($var, $value) {
        switch($var) {
            case "email":    return $this->setEmail($value);
            case "rating":    return $this->setRating($value);
            case "default":    return $this->setDefault($value);
            case "size":    return $this->setSize($value);
            // Cannot set gravatar_id
            case "gravatar_id": return;
        }
        return @$this->properties[$var] = $value;
    }

    /**
     *    Object property overloading
     */
    public function __isset($var) { return isset($this->properties[$var]); }

    /**
     *    Object property overloading
     */
    public function __unset($var) { return @$this->properties[$var] == NULL; }

    /**
     *    Get source
     */
    public function getSrc() {
        $url = self::GRAVATAR_URL ."?";
        $first = true;
        foreach($this->properties as $key => $value) {
            if (isset($value)) {
                if (!$first)
                    $url .= "&";
                $url .= $key."=".urlencode($value);
                $first = false;
            }
        }
        return $url;    
    }

    /**
     *    toHTML
     */
    public function toHTML() {
        return     '<img src="'. $this->getSrc() .'"'
                .(!isset($this->size) ? "" : ' width="'.$this->size.'" height="'.$this->size.'"')
                .$this->extra
                .' />';    
    }

    /**
     *    toString
     */
    public function __toString() { return $this->toHTML(); }
} 

这就是你使用它的方式：

include 'gravatar.php';
$eMail = '[email protected]';
$defImg = 'http://www.example.com/images/myphoto.jpg';
$avatar = new Gravatar($eMail, $defImg);
$avatar->setSize(90);
$avatar->setRating('G');
$avatar->setExtra('alt="my gravatar"');

<p>
<?php echo $avatar->toHTML(); ?>
</p>

文件名（内容处置：内联;文件名=“5ed352b75af7175464e354f6651c6e9e.jpg”）是否与“未找到/无效”Gravatar图像一致？如果是这样，您可以使用它来识别无效图像吗？

一个真正不高性能的解决方案可能是发布到 http://en.gravatar.com/accounts/signup 并检查......emailSorry, that email address is already used!

编辑

好的，他们使用一些cookie来指示是否发生了错误... ;-）

function isUsed($email)
{
    $url   = 'http://en.gravatar.com/accounts/signup';
    $email = strtolower($email);

    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, 'commit=Signup&email=' . urlencode($email));
    curl_setopt($ch, CURLOPT_HEADER, true);
    $response = curl_exec($ch);
    curl_close($ch);

    return (false !== strpos($response, 'Set-Cookie: gravatar-notices'));
}

var_dump(isUsed('[email protected]'));

一旦你得到这些信息，不确定你想如何使用它......但是你能：

将图像加载到网页上，并附加 onload 或 onerror 处理程序...如果 OnLoad 触发，则您有一个匹配项，如果 OnError 触发，则它不存在（或加载它时出现问题）

例如

<img
  src="http://www.gravatar.com/avatar/282eed17fcb9682bb2816697482b64ec?s=128&d=identicon&r=PG"
  onload="itWorked();"
  onerror="itFailed();"/>

注意：在撰写本文时，这是唯一的选择。然而，后来增加了一些时间，使安德鲁的答案更加清晰。?d=404

---

虽然你说你知道 d 参数，但你知道它在适用时实际上会返回一个重定向标头吗？因此，由于头像不存在，因此产生了 302 Found：

http://www.gravatar.com/avatar/3b3be63a4c2a439b013787725dfce802?d=http%3A%2F%2Fwww.google.com%2Fimages%2Flogo.gif

HTTP/1.1 302 Found  
...  
Last-Modified: Wed, 11 Jan 1984 08:00:00 GMT  
Location: http://www.google.com/images/logo.gif  
Content-Length: 0  
...  
Expires: Sun, 26 Jul 2009 23:18:33 GMT  
Cache-Control: max-age=300

在我看来，您需要做的就是添加该参数并检查HTTP结果代码。d

在检查 Gravatar 时将“default”参数添加到图像 URL，如果找不到图像，这将提供 302 重定向。

$grav_url = 'http://www.gravatar.com/avatar/'.md5(mb_strtolower($email)).'?default=http://www.mysite.com/null.jpg&size=310';

然后，如果希望 null 图像:)，则 null 图像可以返回 404

Gravatar在“d”参数中添加了一个选项，这意味着如果你传入d=404，如果没有图片，你会得到一个404页面（而不是重定向到默认图片），而不必使用启发式方法。302

扩展 Andrew Aylett 关于 d=404 的答案，实际上可以用 （或 ） 编写 Gravatar 查询，然后查看 key 是否包含值 404 或 200 的标头。d=404default=404[0]

$email = md5(strtolower("[email protected]"));
$gravatar = "http://www.gravatar.com/avatar/$email?d=404";
$headers = get_headers($gravatar,1);
if (strpos($headers[0],'200')) echo "<img src='$gravatar'>"; // OK
else if (strpos($headers[0],'404')) echo "No Gravatar"; // Not Found

最初的问题可以追溯到三年前。也许在那个时候，Gravatar的头球略有不同。