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node_modules/xss/lib/xss.js

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+/**
+ * filter xss
+ *
+ * @author Zongmin Lei<leizongmin@gmail.com>
+ */
+
+var FilterCSS = require("cssfilter").FilterCSS;
+var DEFAULT = require("./default");
+var parser = require("./parser");
+var parseTag = parser.parseTag;
+var parseAttr = parser.parseAttr;
+var _ = require("./util");
+
+/**
+ * returns `true` if the input value is `undefined` or `null`
+ *
+ * @param {Object} obj
+ * @return {Boolean}
+ */
+function isNull(obj) {
+  return obj === undefined || obj === null;
+}
+
+/**
+ * get attributes for a tag
+ *
+ * @param {String} html
+ * @return {Object}
+ *   - {String} html
+ *   - {Boolean} closing
+ */
+function getAttrs(html) {
+  var i = _.spaceIndex(html);
+  if (i === -1) {
+    return {
+      html: "",
+      closing: html[html.length - 2] === "/",
+    };
+  }
+  html = _.trim(html.slice(i + 1, -1));
+  var isClosing = html[html.length - 1] === "/";
+  if (isClosing) html = _.trim(html.slice(0, -1));
+  return {
+    html: html,
+    closing: isClosing,
+  };
+}
+
+/**
+ * shallow copy
+ *
+ * @param {Object} obj
+ * @return {Object}
+ */
+function shallowCopyObject(obj) {
+  var ret = {};
+  for (var i in obj) {
+    ret[i] = obj[i];
+  }
+  return ret;
+}
+
+function keysToLowerCase(obj) {
+  var ret = {};
+  for (var i in obj) {
+    if (Array.isArray(obj[i])) {
+      ret[i.toLowerCase()] = obj[i].map(function (item) {
+        return item.toLowerCase();
+      });
+    } else {
+      ret[i.toLowerCase()] = obj[i];
+    }
+  }
+  return ret;
+}
+
+/**
+ * FilterXSS class
+ *
+ * @param {Object} options
+ *        whiteList (or allowList), onTag, onTagAttr, onIgnoreTag,
+ *        onIgnoreTagAttr, safeAttrValue, escapeHtml
+ *        stripIgnoreTagBody, allowCommentTag, stripBlankChar
+ *        css{whiteList, onAttr, onIgnoreAttr} `css=false` means don't use `cssfilter`
+ */
+function FilterXSS(options) {
+  options = shallowCopyObject(options || {});
+
+  if (options.stripIgnoreTag) {
+    if (options.onIgnoreTag) {
+      console.error(
+        'Notes: cannot use these two options "stripIgnoreTag" and "onIgnoreTag" at the same time'
+      );
+    }
+    options.onIgnoreTag = DEFAULT.onIgnoreTagStripAll;
+  }
+  if (options.whiteList || options.allowList) {
+    options.whiteList = keysToLowerCase(options.whiteList || options.allowList);
+  } else {
+    options.whiteList = DEFAULT.whiteList;
+  }
+
+  this.attributeWrapSign = options.singleQuotedAttributeValue === true ? "'" : DEFAULT.attributeWrapSign;
+
+  options.onTag = options.onTag || DEFAULT.onTag;
+  options.onTagAttr = options.onTagAttr || DEFAULT.onTagAttr;
+  options.onIgnoreTag = options.onIgnoreTag || DEFAULT.onIgnoreTag;
+  options.onIgnoreTagAttr = options.onIgnoreTagAttr || DEFAULT.onIgnoreTagAttr;
+  options.safeAttrValue = options.safeAttrValue || DEFAULT.safeAttrValue;
+  options.escapeHtml = options.escapeHtml || DEFAULT.escapeHtml;
+  this.options = options;
+
+  if (options.css === false) {
+    this.cssFilter = false;
+  } else {
+    options.css = options.css || {};
+    this.cssFilter = new FilterCSS(options.css);
+  }
+}
+
+/**
+ * start process and returns result
+ *
+ * @param {String} html
+ * @return {String}
+ */
+FilterXSS.prototype.process = function (html) {
+  // compatible with the input
+  html = html || "";
+  html = html.toString();
+  if (!html) return "";
+
+  var me = this;
+  var options = me.options;
+  var whiteList = options.whiteList;
+  var onTag = options.onTag;
+  var onIgnoreTag = options.onIgnoreTag;
+  var onTagAttr = options.onTagAttr;
+  var onIgnoreTagAttr = options.onIgnoreTagAttr;
+  var safeAttrValue = options.safeAttrValue;
+  var escapeHtml = options.escapeHtml;
+  var attributeWrapSign = me.attributeWrapSign;
+  var cssFilter = me.cssFilter;
+
+  // remove invisible characters
+  if (options.stripBlankChar) {
+    html = DEFAULT.stripBlankChar(html);
+  }
+
+  // remove html comments
+  if (!options.allowCommentTag) {
+    html = DEFAULT.stripCommentTag(html);
+  }
+
+  // if enable stripIgnoreTagBody
+  var stripIgnoreTagBody = false;
+  if (options.stripIgnoreTagBody) {
+    stripIgnoreTagBody = DEFAULT.StripTagBody(
+      options.stripIgnoreTagBody,
+      onIgnoreTag
+    );
+    onIgnoreTag = stripIgnoreTagBody.onIgnoreTag;
+  }
+
+  var retHtml = parseTag(
+    html,
+    function (sourcePosition, position, tag, html, isClosing) {
+      var info = {
+        sourcePosition: sourcePosition,
+        position: position,
+        isClosing: isClosing,
+        isWhite: Object.prototype.hasOwnProperty.call(whiteList, tag),
+      };
+
+      // call `onTag()`
+      var ret = onTag(tag, html, info);
+      if (!isNull(ret)) return ret;
+
+      if (info.isWhite) {
+        if (info.isClosing) {
+          return "</" + tag + ">";
+        }
+
+        var attrs = getAttrs(html);
+        var whiteAttrList = whiteList[tag];
+        var attrsHtml = parseAttr(attrs.html, function (name, value) {
+          // call `onTagAttr()`
+          var isWhiteAttr = _.indexOf(whiteAttrList, name) !== -1;
+          var ret = onTagAttr(tag, name, value, isWhiteAttr);
+          if (!isNull(ret)) return ret;
+
+          if (isWhiteAttr) {
+            // call `safeAttrValue()`
+            value = safeAttrValue(tag, name, value, cssFilter);
+            if (value) {
+              return name + '=' + attributeWrapSign + value + attributeWrapSign;
+            } else {
+              return name;
+            }
+          } else {
+            // call `onIgnoreTagAttr()`
+            ret = onIgnoreTagAttr(tag, name, value, isWhiteAttr);
+            if (!isNull(ret)) return ret;
+            return;
+          }
+        });
+
+        // build new tag html
+        html = "<" + tag;
+        if (attrsHtml) html += " " + attrsHtml;
+        if (attrs.closing) html += " /";
+        html += ">";
+        return html;
+      } else {
+        // call `onIgnoreTag()`
+        ret = onIgnoreTag(tag, html, info);
+        if (!isNull(ret)) return ret;
+        return escapeHtml(html);
+      }
+    },
+    escapeHtml
+  );
+
+  // if enable stripIgnoreTagBody
+  if (stripIgnoreTagBody) {
+    retHtml = stripIgnoreTagBody.remove(retHtml);
+  }
+
+  return retHtml;
+};
+
+module.exports = FilterXSS;