我的页面的 HTML 结构如下所示。我已经添加了所有元 og 标签，但 facebook 仍然无法从我的网站上抓取任何信息。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2008/fbml">
<head>
<meta http-equiv="Content-Type" content="text/html;" charset=utf-8"></meta>
<title>My Site</title>
<meta content="This is my title" property="og:title">
<meta content="This is my description" property="og:description">
<meta content="http://ia.media-imdb.com/images/rock.jpg" property="og:image">
<meta content="<MYPAGEID>" property="fb:page_id">
.......
</head>
<body>
.....
当我在 facebook 调试器（https://developers.facebook.com/tools/debug）中输入 URL 时，我收到以下消息：
Scrape Information
Response Code 404
Critical Errors That Must Be Fixed
Bad Response Code URL returned a bad HTTP response code.
Errors that must be fixed
Missing Required Property The 'og:url' property is required, but not present.
Missing Required Property The 'og:type' property is required, but not present.
Missing Required Property The 'og:title' property is required, but not present.
Open Graph Warnings That Should Be Fixed
Inferred Property The 'og:url' property should be explicitly provided, even if a value can be inferred from other tags.
Inferred Property The 'og:title' property should be explicitly provided, even if a value can be inferred from other tags.
为什么 facebook 不读取元标签信息？该页面是可访问的，而不是隐藏在登录等后面。
更新
好的，我做了一些调试，这就是我发现的。我在我的目录中设置了 htaccess 规则-我正在使用 PHP Codeigniter 框架并有 htaccess 规则从 url 中删除 index.php。
因此，当我将 url 提供给没有 index.php 的 facebook 调试器（https://developers.facebook.com/tools/debug）时，facebook 显示 404，但是当我使用 index.php 提供 url 时，它能够解析我的页面。
现在，当 url 没有 index.php 时，如何让 facebook 抓取内容？
这是我的 htaccess 规则：
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#Removes access to the system folder by users.
#Additionally this will allow you to create a System.php controller,
#previously this would not have been possible.
#'system' can be replaced if you have renamed your system folder.
RewriteCond %{REQUEST_URI} ^system.*
RewriteRule ^(.*)$ /index.php?/$1 [L]
#When your application folder isn't in the system folder
#This snippet prevents user access to the application folder
#Submitted by: Fabdrol
#Rename 'application' to your applications folder name.
RewriteCond %{REQUEST_URI} ^application.*
RewriteRule ^(.*)$ /index.php?/$1 [L]
#Checks to see if the user is attempting to access a valid file,
#such as an image or css document, if this isn't true it sends the
#request to index.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?/$1 [L]
</IfModule>
<IfModule !mod_rewrite.c>
# If we don't have mod_rewrite installed, all 404's
# can be sent to index.php, and everything works as normal.
# Submitted by: ElliotHaughin
ErrorDocument 404 /index.php
</IfModule>