PHP 7.0 isset 中的非法偏移类型或空

Question

在我的 Apache ErrorLog 文件中，我多次看到此警告消息：

[2017 年 8 月 23 日星期三 17:27:25.146025] [:error] [pid 14989] [client 66.249.76.54:44935] PHP 警告：isset 中的偏移量类型非法或 /var/www/html/blog/ 中为空wp-content/plugins/ilab-media-tools/classes/tools/s3/ilab-media-s3-tool.php 在第 1012 行

它与一个 Wordpress 插件有关，我尝试使用 Github 向作者（和其他许多人一样）寻求帮助，但没有。

警告指向这个函数：

public function imageDownsize($fail,$id,$size) {
    if (apply_filters('ilab_imgix_enabled', false)) {
            return $fail;
    }

    $meta=wp_get_attachment_metadata($id);
    // This is the line of the warning:
    if (!isset($meta['sizes']) || !isset($meta['sizes'][$size])) {
            return $fail;
    }

    $sizeMeta = $meta['sizes'][$size];
    if (!isset($sizeMeta['s3'])) {
            return $fail;
    }

    $url = $sizeMeta['s3']['url'];

    $result=[
            $url,
            $sizeMeta['width'],
            $sizeMeta['height'],
        true
    ];

    return $result;
}

Apache 每分钟打印一次此警告。 有没有办法解决这个烦人的消息警告？

这是var_dump($meta);的输出：

array(7) {
  ["width"]=>
  int(140)
  ["height"]=>
  int(140)
  ["file"]=>
  string(31) "2016/01/logo_retina.png"
  ["sizes"]=>
  array(0) {
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    int(0)
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    int(0)
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    int(0)
    ["iso"]=>
    int(0)
    ["shutter_speed"]=>
    int(0)
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    int(0)
    ["keywords"]=>
    array(0) {
    }
  }
  ["ewww_image_optimizer"]=>
  string(30) "Reduced by 16.3% (1.3 kB)"
  ["s3"]=>
  array(3) {
    ["url"]=>
    string(79) "https://s3-eu-west-1.amazonaws.com/blog-example/2016/01/logo_retina.png"
    ["bucket"]=>
    string(12) "blog-example"
    ["key"]=>
    string(31) "2016/01/logo_retina.png"
  }
}
array(7) {
  ["width"]=>
  int(140)
  ["height"]=>
  int(140)
  ["file"]=>
  string(31) "2016/01/logo_retina.png"
  ["sizes"]=>
  array(0) {
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    int(0)
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    int(0)
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    int(0)
    ["iso"]=>
    int(0)
    ["shutter_speed"]=>
    int(0)
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    int(0)
    ["keywords"]=>
    array(0) {
    }
  }
  ["ewww_image_optimizer"]=>
  string(30) "Reduced by 16.3% (1.3 kB)"
  ["s3"]=>
  array(3) {
    ["url"]=>
    string(79) "https://s3-eu-west-1.amazonaws.com/blog-example/2016/01/logo_retina.png"
    ["bucket"]=>
    string(12) "blog-example"
    ["key"]=>
    string(31) "2016/01/logo_retina.png"
  }
}
array(7) {
  ["width"]=>
  int(140)
  ["height"]=>
  int(140)
  ["file"]=>
  string(31) "2016/01/logo_retina.png"
  ["sizes"]=>
  array(0) {
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    int(0)
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    int(0)
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    int(0)
    ["iso"]=>
    int(0)
    ["shutter_speed"]=>
    int(0)
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    int(0)
    ["keywords"]=>
    array(0) {
    }
  }
  ["ewww_image_optimizer"]=>
  string(30) "Reduced by 16.3% (1.3 kB)"
  ["s3"]=>
  array(3) {
    ["url"]=>
    string(79) "https://s3-eu-west-1.amazonaws.com/blog-example/2016/01/logo_retina.png"
    ["bucket"]=>
    string(12) "blog-example"
    ["key"]=>
    string(31) "2016/01/logo_retina.png"
  }
}
array(7) {
  ["width"]=>
  int(140)
  ["height"]=>
  int(140)
  ["file"]=>
  string(31) "2016/01/logo_retina.png"
  ["sizes"]=>
  array(0) {
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    int(0)
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    int(0)
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    int(0)
    ["iso"]=>
    int(0)
    ["shutter_speed"]=>
    int(0)
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    int(0)
    ["keywords"]=>
    array(0) {
    }
  }
  ["ewww_image_optimizer"]=>
  string(30) "Reduced by 16.3% (1.3 kB)"
  ["s3"]=>
  array(3) {
    ["url"]=>
    string(79) "https://s3-eu-west-1.amazonaws.com/blog-example/2016/01/logo_retina.png"
    ["bucket"]=>
    string(12) "blog-example"
    ["key"]=>
    string(31) "2016/01/logo_retina.png"
  }
}
array(7) {
  ["width"]=>
  int(140)
  ["height"]=>
  int(140)
  ["file"]=>
  string(31) "2016/01/logo_retina.png"
  ["sizes"]=>
  array(0) {
  }
  ["image_meta"]=>
  array(12) {
    ["aperture"]=>
    int(0)
    ["credit"]=>
    string(0) ""
    ["camera"]=>
    string(0) ""
    ["caption"]=>
    string(0) ""
    ["created_timestamp"]=>
    int(0)
    ["copyright"]=>
    string(0) ""
    ["focal_length"]=>
    int(0)
    ["iso"]=>
    int(0)
    ["shutter_speed"]=>
    int(0)
    ["title"]=>
    string(0) ""
    ["orientation"]=>
    int(0)
    ["keywords"]=>
    array(0) {
    }
  }
  ["ewww_image_optimizer"]=>
  string(30) "Reduced by 16.3% (1.3 kB)"
  ["s3"]=>
  array(3) {
    ["url"]=>
    string(79) "https://s3-eu-west-1.amazonaws.com/blog-example/2016/01/logo_retina.png"
    ["bucket"]=>
    string(12) "blog-example"
    ["key"]=>
    string(31) "2016/01/logo_retina.png"
  }
}

还有var_dump($size);的输出：

string(4) "full"
array(2) {
  [0]=>
  int(32)
  [1]=>
  int(32)
}
array(2) {
  [0]=>
  int(192)
  [1]=>
  int(192)
}
array(2) {
  [0]=>
  int(180)
  [1]=>
  int(180)
}
array(2) {
  [0]=>
  int(270)
  [1]=>
  int(270)
}

Answer 1

所以，根据 GitHub 问题，这条线似乎以某种方式失败了

$meta=wp_get_attachment_metadata($id);

根据WP reference返回

附件元字段。失败时为假。

代码错误地假设它总是会返回一个数组。因此，您可以通过更改以下内容来解决此问题，以确保 $meta 不为假

if (!$meta || !isset($meta['sizes']) || !isset($meta['sizes'][$size])) {
        return $fail;
}