使用HTML Purifier 过滤HTML 防范 XSS攻击

最近使用Parsedown转换Markdown语法为HTML， 但是该包不会转义和过滤XSS， 因为Markdown语法里面只支持直接写HTML的。所以只能找其他的方法实现。

HTML Purifier 很多富文本编辑器都是使用它来过滤XSS。除了过滤恶意代码外，还支持下面的一些特性。

• 闭合HTML TAG，比如你只输入了一个<a href="#hash"> 会自动给你补全为<a href="#hash"></a>
• 清除不需要的标签和属性。
• 过滤iframe加载URL
• 删除无用的空TAG

使用

<?php
require_once '/path/to/HTMLPurifier.auto.php';

$config = HTMLPurifier_Config::createDefault();
$purifier = new HTMLPurifier($config);
$clean_html = $purifier->purify($dirty_html);

项目地址： https://github.com/ezyang/htmlpurifier

Laravel 封装

Laravel封装的版本。更易用一些。 项目地址：https://github.com/mewebstudio/Purifier

只用像下面这样配置即可

//config/purifier.php
return [
    'encoding'      => 'UTF-8',
    'finalize'      => true,
    'cachePath'     => storage_path('app/purifier'),
    'cacheFileMode' => 0755,
    'settings'      => [
        'default' => [
            'HTML.Doctype'             => 'HTML 4.01 Transitional',
            'HTML.Allowed'             => 'div,b,strong,i,em,u,a[href|title],ul,ol,li,p[style],br,span[style],img[width|height|alt|src]',
            'CSS.AllowedProperties'    => 'font,font-size,font-weight,font-style,font-family,text-decoration,padding-left,color,background-color,text-align',
            'AutoFormat.AutoParagraph' => true,
            'AutoFormat.RemoveEmpty'   => true,
        ],
        'test'    => [
            'Attr.EnableID' => 'true',
        ],
        "youtube" => [
            "HTML.SafeIframe"      => 'true',
            "URI.SafeIframeRegexp" => "%^(http://|https://|//)(www.youtube.com/embed/|player.vimeo.com/video/)%",
        ],
        'custom_definition' => [
            'id'  => 'html5-definitions',
            'rev' => 1,
            'debug' => false,
            'elements' => [
                // http://developers.whatwg.org/sections.html
                ['section', 'Block', 'Flow', 'Common'],
                ['nav',     'Block', 'Flow', 'Common'],
                ['article', 'Block', 'Flow', 'Common'],
                ['aside',   'Block', 'Flow', 'Common'],
                ['header',  'Block', 'Flow', 'Common'],
                ['footer',  'Block', 'Flow', 'Common'],

                // Content model actually excludes several tags, not modelled here
                ['address', 'Block', 'Flow', 'Common'],
                ['hgroup', 'Block', 'Required: h1 | h2 | h3 | h4 | h5 | h6', 'Common'],

                // http://developers.whatwg.org/grouping-content.html
                ['figure', 'Block', 'Optional: (figcaption, Flow) | (Flow, figcaption) | Flow', 'Common'],
                ['figcaption', 'Inline', 'Flow', 'Common'],

                // http://developers.whatwg.org/the-video-element.html#the-video-element
                ['video', 'Block', 'Optional: (source, Flow) | (Flow, source) | Flow', 'Common', [
                    'src' => 'URI',
                    'type' => 'Text',
                    'width' => 'Length',
                    'height' => 'Length',
                    'poster' => 'URI',
                    'preload' => 'Enum#auto,metadata,none',
                    'controls' => 'Bool',
                ]],
                ['source', 'Block', 'Flow', 'Common', [
                    'src' => 'URI',
                    'type' => 'Text',
                ]],

                // http://developers.whatwg.org/text-level-semantics.html
                ['s',    'Inline', 'Inline', 'Common'],
                ['var',  'Inline', 'Inline', 'Common'],
                ['sub',  'Inline', 'Inline', 'Common'],
                ['sup',  'Inline', 'Inline', 'Common'],
                ['mark', 'Inline', 'Inline', 'Common'],
                ['wbr',  'Inline', 'Empty', 'Core'],

                // http://developers.whatwg.org/edits.html
                ['ins', 'Block', 'Flow', 'Common', ['cite' => 'URI', 'datetime' => 'CDATA']],
                ['del', 'Block', 'Flow', 'Common', ['cite' => 'URI', 'datetime' => 'CDATA']],
            ],
            'attributes' => [
                ['iframe', 'allowfullscreen', 'Bool'],
                ['table', 'height', 'Text'],
                ['td', 'border', 'Text'],
                ['th', 'border', 'Text'],
                ['tr', 'width', 'Text'],
                ['tr', 'height', 'Text'],
                ['tr', 'border', 'Text'],
            ],
        ],
        'custom_attributes' => [
            ['a', 'target', 'Enum#_blank,_self,_target,_top'],
        ],
        'custom_elements' => [
            ['u', 'Inline', 'Inline', 'Common'],
        ],
    ],

];