414 lines
10 KiB
JavaScript
414 lines
10 KiB
JavaScript
/**
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* 默认配置
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*
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* @author 老雷<leizongmin@gmail.com>
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*/
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var FilterCSS = require('cssfilter').FilterCSS;
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var getDefaultCSSWhiteList = require('cssfilter').getDefaultWhiteList;
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var _ = require('./util');
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// 默认白名单
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function getDefaultWhiteList () {
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return {
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a: ['target', 'href', 'title'],
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abbr: ['title'],
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address: [],
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area: ['shape', 'coords', 'href', 'alt'],
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article: [],
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aside: [],
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audio: ['autoplay', 'controls', 'loop', 'preload', 'src'],
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b: [],
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bdi: ['dir'],
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bdo: ['dir'],
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big: [],
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blockquote: ['cite'],
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br: [],
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caption: [],
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center: [],
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cite: [],
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code: [],
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col: ['align', 'valign', 'span', 'width'],
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colgroup: ['align', 'valign', 'span', 'width'],
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dd: [],
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del: ['datetime'],
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details: ['open'],
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div: [],
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dl: [],
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dt: [],
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em: [],
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font: ['color', 'size', 'face'],
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footer: [],
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h1: [],
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h2: [],
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h3: [],
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h4: [],
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h5: [],
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h6: [],
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header: [],
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hr: [],
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i: [],
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img: ['src', 'alt', 'title', 'width', 'height'],
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ins: ['datetime'],
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li: [],
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mark: [],
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nav: [],
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ol: [],
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p: [],
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pre: [],
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s: [],
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section:[],
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small: [],
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span: [],
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sub: [],
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sup: [],
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strong: [],
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table: ['width', 'border', 'align', 'valign'],
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tbody: ['align', 'valign'],
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td: ['width', 'rowspan', 'colspan', 'align', 'valign'],
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tfoot: ['align', 'valign'],
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th: ['width', 'rowspan', 'colspan', 'align', 'valign'],
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thead: ['align', 'valign'],
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tr: ['rowspan', 'align', 'valign'],
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tt: [],
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u: [],
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ul: [],
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video: ['autoplay', 'controls', 'loop', 'preload', 'src', 'height', 'width']
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};
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}
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// 默认CSS Filter
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var defaultCSSFilter = new FilterCSS();
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/**
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* 匹配到标签时的处理方法
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*
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* @param {String} tag
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* @param {String} html
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* @param {Object} options
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* @return {String}
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*/
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function onTag (tag, html, options) {
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// do nothing
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}
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/**
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* 匹配到不在白名单上的标签时的处理方法
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*
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* @param {String} tag
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* @param {String} html
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* @param {Object} options
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* @return {String}
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*/
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function onIgnoreTag (tag, html, options) {
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// do nothing
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}
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/**
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* 匹配到标签属性时的处理方法
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*
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* @param {String} tag
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* @param {String} name
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* @param {String} value
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* @return {String}
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*/
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function onTagAttr (tag, name, value) {
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// do nothing
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}
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/**
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* 匹配到不在白名单上的标签属性时的处理方法
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*
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* @param {String} tag
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* @param {String} name
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* @param {String} value
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* @return {String}
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*/
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function onIgnoreTagAttr (tag, name, value) {
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// do nothing
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}
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/**
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* HTML转义
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*
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* @param {String} html
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*/
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function escapeHtml (html) {
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return html.replace(REGEXP_LT, '<').replace(REGEXP_GT, '>');
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}
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/**
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* 安全的标签属性值
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*
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* @param {String} tag
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* @param {String} name
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* @param {String} value
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* @param {Object} cssFilter
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* @return {String}
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*/
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function safeAttrValue (tag, name, value, cssFilter) {
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// 转换为友好的属性值，再做判断
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value = friendlyAttrValue(value);
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if (name === 'href' || name === 'src') {
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// 过滤 href 和 src 属性
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// 仅允许 http:// | https:// | mailto: | / | # 开头的地址
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value = _.trim(value);
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if (value === '#') return '#';
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if (!(value.substr(0, 7) === 'http://' ||
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value.substr(0, 8) === 'https://' ||
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value.substr(0, 7) === 'mailto:' ||
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value[0] === '#' ||
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value[0] === '/')) {
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return '';
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}
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} else if (name === 'background') {
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// 过滤 background 属性 （这个xss漏洞较老了，可能已经不适用）
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// javascript:
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REGEXP_DEFAULT_ON_TAG_ATTR_4.lastIndex = 0;
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if (REGEXP_DEFAULT_ON_TAG_ATTR_4.test(value)) {
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return '';
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}
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} else if (name === 'style') {
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// /*注释*/
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/*REGEXP_DEFAULT_ON_TAG_ATTR_3.lastIndex = 0;
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if (REGEXP_DEFAULT_ON_TAG_ATTR_3.test(value)) {
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return '';
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}*/
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// expression()
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REGEXP_DEFAULT_ON_TAG_ATTR_7.lastIndex = 0;
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if (REGEXP_DEFAULT_ON_TAG_ATTR_7.test(value)) {
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return '';
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}
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// url()
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REGEXP_DEFAULT_ON_TAG_ATTR_8.lastIndex = 0;
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if (REGEXP_DEFAULT_ON_TAG_ATTR_8.test(value)) {
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REGEXP_DEFAULT_ON_TAG_ATTR_4.lastIndex = 0;
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if (REGEXP_DEFAULT_ON_TAG_ATTR_4.test(value)) {
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return '';
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}
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}
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if (cssFilter !== false) {
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cssFilter = cssFilter || defaultCSSFilter;
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value = cssFilter.process(value);
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}
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}
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// 输出时需要转义<>"
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value = escapeAttrValue(value);
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return value;
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}
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// 正则表达式
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var REGEXP_LT = /</g;
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var REGEXP_GT = />/g;
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var REGEXP_QUOTE = /"/g;
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var REGEXP_QUOTE_2 = /"/g;
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var REGEXP_ATTR_VALUE_1 = /&#([a-zA-Z0-9]*);?/img;
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var REGEXP_ATTR_VALUE_COLON = /:?/img;
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var REGEXP_ATTR_VALUE_NEWLINE = /&newline;?/img;
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var REGEXP_DEFAULT_ON_TAG_ATTR_3 = /\/\*|\*\//mg;
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var REGEXP_DEFAULT_ON_TAG_ATTR_4 = /((j\s*a\s*v\s*a|v\s*b|l\s*i\s*v\s*e)\s*s\s*c\s*r\s*i\s*p\s*t\s*|m\s*o\s*c\s*h\s*a)\:/ig;
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var REGEXP_DEFAULT_ON_TAG_ATTR_5 = /^[\s"'`]*(d\s*a\s*t\s*a\s*)\:/ig;
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var REGEXP_DEFAULT_ON_TAG_ATTR_6 = /^[\s"'`]*(d\s*a\s*t\s*a\s*)\:\s*image\//ig;
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var REGEXP_DEFAULT_ON_TAG_ATTR_7 = /e\s*x\s*p\s*r\s*e\s*s\s*s\s*i\s*o\s*n\s*\(.*/ig;
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var REGEXP_DEFAULT_ON_TAG_ATTR_8 = /u\s*r\s*l\s*\(.*/ig;
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/**
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* 对双引号进行转义
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*
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* @param {String} str
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* @return {String} str
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*/
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function escapeQuote (str) {
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return str.replace(REGEXP_QUOTE, '"');
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}
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/**
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* 对双引号进行转义
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*
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* @param {String} str
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* @return {String} str
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*/
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function unescapeQuote (str) {
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return str.replace(REGEXP_QUOTE_2, '"');
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}
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/**
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* 对html实体编码进行转义
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*
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* @param {String} str
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* @return {String}
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*/
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function escapeHtmlEntities (str) {
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return str.replace(REGEXP_ATTR_VALUE_1, function replaceUnicode (str, code) {
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return (code[0] === 'x' || code[0] === 'X')
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? String.fromCharCode(parseInt(code.substr(1), 16))
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: String.fromCharCode(parseInt(code, 10));
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});
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}
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/**
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* 对html5新增的危险实体编码进行转义
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*
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* @param {String} str
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* @return {String}
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*/
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function escapeDangerHtml5Entities (str) {
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return str.replace(REGEXP_ATTR_VALUE_COLON, ':')
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.replace(REGEXP_ATTR_VALUE_NEWLINE, ' ');
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}
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/**
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* 清除不可见字符
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*
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* @param {String} str
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* @return {String}
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*/
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function clearNonPrintableCharacter (str) {
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var str2 = '';
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for (var i = 0, len = str.length; i < len; i++) {
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str2 += str.charCodeAt(i) < 32 ? ' ' : str.charAt(i);
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}
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return _.trim(str2);
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}
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/**
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* 将标签的属性值转换成一般字符，便于分析
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*
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* @param {String} str
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* @return {String}
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*/
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function friendlyAttrValue (str) {
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str = unescapeQuote(str); // 双引号
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str = escapeHtmlEntities(str); // 转换HTML实体编码
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str = escapeDangerHtml5Entities(str); // 转换危险的HTML5新增实体编码
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str = clearNonPrintableCharacter(str); // 清除不可见字符
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return str;
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}
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/**
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* 转义用于输出的标签属性值
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*
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* @param {String} str
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* @return {String}
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*/
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function escapeAttrValue (str) {
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str = escapeQuote(str);
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str = escapeHtml(str);
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return str;
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}
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/**
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* 去掉不在白名单中的标签onIgnoreTag处理方法
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*/
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function onIgnoreTagStripAll () {
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return '';
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}
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/**
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* 删除标签体
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*
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* @param {array} tags 要删除的标签列表
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* @param {function} next 对不在列表中的标签的处理函数，可选
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*/
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function StripTagBody (tags, next) {
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if (typeof(next) !== 'function') {
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next = function () {};
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}
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var isRemoveAllTag = !Array.isArray(tags);
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function isRemoveTag (tag) {
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if (isRemoveAllTag) return true;
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return (_.indexOf(tags, tag) !== -1);
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}
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var removeList = []; // 要删除的位置范围列表
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var posStart = false; // 当前标签开始位置
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return {
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onIgnoreTag: function (tag, html, options) {
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if (isRemoveTag(tag)) {
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if (options.isClosing) {
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var ret = '[/removed]';
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var end = options.position + ret.length;
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removeList.push([posStart !== false ? posStart : options.position, end]);
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posStart = false;
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return ret;
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} else {
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if (!posStart) {
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posStart = options.position;
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}
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return '[removed]';
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}
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} else {
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return next(tag, html, options);
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}
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},
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remove: function (html) {
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var rethtml = '';
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var lastPos = 0;
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_.forEach(removeList, function (pos) {
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rethtml += html.slice(lastPos, pos[0]);
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lastPos = pos[1];
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});
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rethtml += html.slice(lastPos);
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return rethtml;
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}
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};
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}
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/**
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* 去除备注标签
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*
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* @param {String} html
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* @return {String}
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*/
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function stripCommentTag (html) {
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return html.replace(STRIP_COMMENT_TAG_REGEXP, '');
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}
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var STRIP_COMMENT_TAG_REGEXP = /<!--[\s\S]*?-->/g;
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/**
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* 去除不可见字符
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*
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* @param {String} html
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* @return {String}
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*/
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function stripBlankChar (html) {
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var chars = html.split('');
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chars = chars.filter(function (char) {
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var c = char.charCodeAt(0);
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if (c === 127) return false;
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if (c <= 31) {
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if (c === 10 || c === 13) return true;
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return false;
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}
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return true;
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});
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return chars.join('');
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}
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exports.whiteList = getDefaultWhiteList();
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exports.getDefaultWhiteList = getDefaultWhiteList;
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exports.onTag = onTag;
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exports.onIgnoreTag = onIgnoreTag;
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exports.onTagAttr = onTagAttr;
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exports.onIgnoreTagAttr = onIgnoreTagAttr;
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exports.safeAttrValue = safeAttrValue;
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exports.escapeHtml = escapeHtml;
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exports.escapeQuote = escapeQuote;
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exports.unescapeQuote = unescapeQuote;
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exports.escapeHtmlEntities = escapeHtmlEntities;
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exports.escapeDangerHtml5Entities = escapeDangerHtml5Entities;
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exports.clearNonPrintableCharacter = clearNonPrintableCharacter;
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exports.friendlyAttrValue = friendlyAttrValue;
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exports.escapeAttrValue = escapeAttrValue;
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exports.onIgnoreTagStripAll = onIgnoreTagStripAll;
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exports.StripTagBody = StripTagBody;
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exports.stripCommentTag = stripCommentTag;
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exports.stripBlankChar = stripBlankChar;
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exports.cssFilter = defaultCSSFilter;
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exports.getDefaultCSSWhiteList = getDefaultCSSWhiteList;
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