文章目录
- 前言
- 根本原因
- [XSS 攻击防护拦截配置处理](#XSS 攻击防护拦截配置处理)
-
- 数据准备
- [后端适配处理 XSS 攻击请求](#后端适配处理 XSS 攻击请求)
-
- 1、增加配置项
- 2、定义配置项注入bean
- [3、定义 XssFilter 处理过滤器](#3、定义 XssFilter 处理过滤器)
前言
最近碰见一个很奇怪的报错，在SpringBoot MVC层面出现一个报错信息。
JSON parse error: Unexpected character ('>' (code 62)): was expecting either '*' or '/' for a comment; nested exception is com.fasterxml.jackson.core.JsonParseException: Unexpected character ('>' (code 62)): was expecting either '*' or '/' for a comment\n at
...........根本原因
服务器中的网关为了防止XSS攻击，通常会追加一些防攻击的策略和替换方案。
如前端传入参数携带HTML标签的文本信息，网关会将敏感的前端代码进行转换，导致后端再将已被转换的数据，使用Jacson反序列化处理转成自定义实体类时，出现转换异常。
当然，有时候有些接口又不能转换，则需要做排除处理。
处理方式分两种：
要么是前端兄弟进行数据的转换。另一种是后端做适配处理。为了服务器的服务安全，当然更多的是采取后端处理。
一切前端的请求都是不安全的，需要后端增加统一拦截过滤。
XSS 攻击防护拦截配置处理
处理方案也很简单，核心思想就是将前端的敏感 Html标签进行转换操作。
比如将 < 转换为<等。
数据准备
假设前端兄弟请求后端POST接口，body中传参数据内容如下所示：
json
{
"file_id": "6218a7c8bb811a20c98acb27",
"file_name": null,
"file_url": "https://aik.pkpm.cn:8884/aik_manager/api/v1/air/file/download/null",
"file_content": "<p>耐撞击性能</p> \n <p>5.1.7.1 耐撞击性能应满足设计要求。人员流动密度大或青少年、幼儿活动的公共建筑的建筑幕墙，耐撞击性能指标不应低于表22中2级。</p> \n <p>5.1.7.2 撞击能量E和撞击物体的降落高度H分级指标和表示方法应符合表22的要求。</p> \n <p style=\"text-align: center;\"><strong><span style=\"font-size: 14px;\">表22 建筑幕墙耐撞击性能分级</span></strong></p> \n <p style=\"text-align: center;\"><strong><span style=\"font-size: 14px;\"><img src=\"https://dt.pkpm.cn/dms_symbol/api/bim/obs/docs/download?objectId=20220225-20220225175752007614.png\"><img src=\"https://dt.pkpm.cn/dms_symbol/api/bim/obs/docs/download?objectId=20220225-20220225175801007615.png\"></span></strong></p>\n",
"file_orgin": "network"
}后端适配处理 XSS 攻击请求
不管是CloudAlibaba项目架构还是Springboot 微服务架构，都能采取Filter的思想进行控制和转换。
本次以
GateWay中增加XSS Filter为例。
1、增加配置项
在配置文件*.yml或者nacos中增加如下配置。
yml
security:
xss:
enabled: true #是否启用 xss 拦截过滤处理
excludeUrls: # 排除接口项(白名单)
- /ai/xxx2、定义配置项注入bean
yml 中的配置内容的注入bean实体类的定义如下：
java
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;
import java.util.ArrayList;
import java.util.List;
/**
* XSS跨站脚本配置
*/
@Data
@Configuration
@ConfigurationProperties(prefix = "security.xss") // 支持动态刷新
public class XssProperties {
/**
* Xss开关
*/
private Boolean enabled;
/**
* 排除路径
*/
private List<String> excludeUrls = new ArrayList<>();
}3、定义 XssFilter 处理过滤器
定义XssFilter.java类，注册过滤器，进行指定url处理的前置处理。
java
import io.netty.buffer.ByteBufAllocator;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.*;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.nio.charset.StandardCharsets;
/**
* 跨站脚本过滤器
*/
@Component
public class XssFilter implements GlobalFilter, Ordered {
/**
* 跨站脚本的 xss 配置，nacos自行添加
*/
@Autowired
private XssProperties xss;
@Override
public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
ServerHttpRequest request = exchange.getRequest();
// xss开关未开启 或 通过nacos关闭，不过滤
if (!xss.getEnabled()) {
return chain.filter(exchange);
}
// GET DELETE 不过滤
HttpMethod method = request.getMethod();
if (method == null || method == HttpMethod.GET || method == HttpMethod.DELETE) {
return chain.filter(exchange);
}
// 非json类型，不过滤
if (!isJsonRequest(exchange)) {
return chain.filter(exchange);
}
// 排除项 不做敏感html标签替换操作
String url = request.getURI().getPath();
if (CollUtil.contains(xss.getExcludeUrls(), url)) {
return chain.filter(exchange);
}
// 排除项外的其余接口，将其做转换替换
ServerHttpRequestDecorator httpRequestDecorator = requestDecorator(exchange);
return chain.filter(exchange.mutate().request(httpRequestDecorator).build());
}
private ServerHttpRequestDecorator requestDecorator(ServerWebExchange exchange) {
return new ServerHttpRequestDecorator(exchange.getRequest()) {
@Override
public Flux<DataBuffer> getBody() {
Flux<DataBuffer> body = super.getBody();
return body.buffer().map(dataBuffers -> {
DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();
DataBuffer join = dataBufferFactory.join(dataBuffers);
byte[] content = new byte[join.readableByteCount()];
join.read(content);
DataBufferUtils.release(join);
String bodyStr = new String(content, StandardCharsets.UTF_8);
// 防xss攻击过滤
bodyStr = EscapeUtil.clean(bodyStr);
// 转成字节
byte[] bytes = bodyStr.getBytes();
NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(
ByteBufAllocator.DEFAULT);
DataBuffer buffer = nettyDataBufferFactory.allocateBuffer(bytes.length);
buffer.write(bytes);
return buffer;
});
}
@Override
public HttpHeaders getHeaders() {
HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.putAll(super.getHeaders());
// 由于修改了请求体的body，导致content-length长度不确定，因此需要删除原先的content-length
httpHeaders.remove(HttpHeaders.CONTENT_LENGTH);
httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked");
return httpHeaders;
}
};
}
/**
* 是否是Json请求
*
* @param exchange HTTP请求
*/
public boolean isJsonRequest(ServerWebExchange exchange) {
String header = exchange.getRequest().getHeaders().getFirst(HttpHeaders.CONTENT_TYPE);
return StrUtil.startWithIgnoreCase(header, MediaType.APPLICATION_JSON_VALUE);
}
@Override
public int getOrder() {
return -100;
}
}定义转义与反转义工具类EscapeUtil.java。
java
/**
* 转义和反转义工具类
*/
public class EscapeUtil {
public static final String RE_HTML_MARK = "(<[^<]*?>)|(<[\\s]*?/[^<]*?>)|(<[^<]*?/[\\s]*?>)";
public static final int CHAR_LENGTH = 64;
private static final char[][] TEXT = new char[CHAR_LENGTH][];
static {
for (int i = 0; i < CHAR_LENGTH; i++) {
TEXT[i] = new char[]{(char) i};
}
// special HTML characters
// 单引号
TEXT['\''] = "'".toCharArray();
// 双引号
TEXT['"'] = """.toCharArray();
// &符
TEXT['&'] = "&".toCharArray();
// 小于号
TEXT['<'] = "<".toCharArray();
// 大于号
TEXT['>'] = ">".toCharArray();
}
/**
* 转义文本中的HTML字符为安全的字符
*
* @param text 被转义的文本
* @return 转义后的文本
*/
public static String escape(String text) {
return encode(text);
}
/**
* 还原被转义的HTML特殊字符
*
* @param content 包含转义符的HTML内容
* @return 转换后的字符串
*/
public static String unescape(String content) {
return decode(content);
}
/**
* 清除所有HTML标签，但是不删除标签内的内容
*
* @param content 文本
* @return 清除标签后的文本
*/
public static String clean(String content) {
return new HtmlFilter().filter(content);
}
/**
* Escape编码
*
* @param text 被编码的文本
* @return 编码后的字符
*/
private static String encode(String text) {
if (StrUtil.isEmpty(text)) {
return StrUtil.EMPTY;
}
final StringBuilder tmp = new StringBuilder(text.length() * 6);
char c;
for (int i = 0; i < text.length(); i++) {
c = text.charAt(i);
if (c < 256) {
tmp.append("%");
if (c < 16) {
tmp.append("0");
}
tmp.append(Integer.toString(c, 16));
} else {
tmp.append("%u");
if (c <= 0xfff) {
// issue#I49JU8@Gitee
tmp.append("0");
}
tmp.append(Integer.toString(c, 16));
}
}
return tmp.toString();
}
/**
* Escape解码
*
* @param content 被转义的内容
* @return 解码后的字符串
*/
public static String decode(String content) {
if (StrUtil.isEmpty(content)) {
return content;
}
StringBuilder tmp = new StringBuilder(content.length());
int lastPos = 0, pos = 0;
char ch;
while (lastPos < content.length()) {
pos = content.indexOf("%", lastPos);
if (pos == lastPos) {
if (content.charAt(pos + 1) == 'u') {
ch = (char) Integer.parseInt(content.substring(pos + 2, pos + 6), 16);
tmp.append(ch);
lastPos = pos + 6;
} else {
ch = (char) Integer.parseInt(content.substring(pos + 1, pos + 3), 16);
tmp.append(ch);
lastPos = pos + 3;
}
} else {
if (pos == -1) {
tmp.append(content.substring(lastPos));
lastPos = content.length();
} else {
tmp.append(content.substring(lastPos, pos));
lastPos = pos;
}
}
}
return tmp.toString();
}
}定义HtmlFilter.java前端标签转换处理类。
java
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* HTML过滤器，用于去除XSS漏洞隐患。
*/
public final class HtmlFilter {
/**
* regex flag union representing /si modifiers in php
**/
private static final int REGEX_FLAGS_SI = Pattern.CASE_INSENSITIVE | Pattern.DOTALL;
private static final Pattern P_COMMENTS = Pattern.compile("<!--(.*?)-->", Pattern.DOTALL);
private static final Pattern P_COMMENT = Pattern.compile("^!--(.*)--$", REGEX_FLAGS_SI);
private static final Pattern P_TAGS = Pattern.compile("<(.*?)>", Pattern.DOTALL);
private static final Pattern P_END_TAG = Pattern.compile("^/([a-z0-9]+)", REGEX_FLAGS_SI);
private static final Pattern P_START_TAG = Pattern.compile("^([a-z0-9]+)(.*?)(/?)$", REGEX_FLAGS_SI);
private static final Pattern P_QUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)=([\"'])(.*?)\\2", REGEX_FLAGS_SI);
private static final Pattern P_UNQUOTED_ATTRIBUTES = Pattern.compile("([a-z0-9]+)(=)([^\"\\s']+)", REGEX_FLAGS_SI);
private static final Pattern P_PROTOCOL = Pattern.compile("^([^:]+):", REGEX_FLAGS_SI);
private static final Pattern P_ENTITY = Pattern.compile("&#(\\d+);?");
private static final Pattern P_ENTITY_UNICODE = Pattern.compile("&#x([0-9a-f]+);?");
private static final Pattern P_ENCODE = Pattern.compile("%([0-9a-f]{2});?");
private static final Pattern P_VALID_ENTITIES = Pattern.compile("&([^&;]*)(?=(;|&|$))");
private static final Pattern P_VALID_QUOTES = Pattern.compile("(>|^)([^<]+?)(<|$)", Pattern.DOTALL);
private static final Pattern P_END_ARROW = Pattern.compile("^>");
private static final Pattern P_BODY_TO_END = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_XML_CONTENT = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_STRAY_LEFT_ARROW = Pattern.compile("<([^>]*?)(?=<|$)");
private static final Pattern P_STRAY_RIGHT_ARROW = Pattern.compile("(^|>)([^<]*?)(?=>)");
private static final Pattern P_AMP = Pattern.compile("&");
private static final Pattern P_QUOTE = Pattern.compile("\"");
private static final Pattern P_LEFT_ARROW = Pattern.compile("<");
private static final Pattern P_RIGHT_ARROW = Pattern.compile(">");
private static final Pattern P_BOTH_ARROWS = Pattern.compile("<>");
/** @xxx could grow large... maybe use sesat's ReferenceMap */
private static final ConcurrentMap<String, Pattern> P_REMOVE_PAIR_BLANKS = new ConcurrentHashMap<>();
private static final ConcurrentMap<String, Pattern> P_REMOVE_SELF_BLANKS = new ConcurrentHashMap<>();
/**
* set of allowed html elements, along with allowed attributes for each element
**/
private final Map<String, List<String>> vAllowed;
/**
* counts of open tags for each (allowable) html element
**/
private final Map<String, Integer> vTagCounts = new HashMap<>();
/**
* html elements which must always be self-closing (e.g. "<img />")
**/
private final String[] vSelfClosingTags;
/**
* html elements which must always have separate opening and closing tags (e.g. "<b></b>")
**/
private final String[] vNeedClosingTags;
/**
* set of disallowed html elements
**/
private final String[] vDisallowed;
/**
* attributes which should be checked for valid protocols
**/
private final String[] vProtocolAtts;
/**
* allowed protocols
**/
private final String[] vAllowedProtocols;
/**
* tags which should be removed if they contain no content (e.g. "<b></b>" or "<b />")
**/
private final String[] vRemoveBlanks;
/**
* entities allowed within html markup
**/
private final String[] vAllowedEntities;
/**
* flag determining whether comments are allowed in input String.
*/
private final boolean stripComment;
private final boolean encodeQuotes;
/**
* flag determining whether to try to make tags when presented with "unbalanced" angle brackets (e.g. "<b text </b>"
* becomes "<b> text </b>"). If set to false, unbalanced angle brackets will be html escaped.
*/
private final boolean alwaysMakeTags;
/**
* Default constructor.
*/
public HtmlFilter() {
vAllowed = new HashMap<>();
final ArrayList<String> aAtts = new ArrayList<>();
aAtts.add("href");
aAtts.add("target");
vAllowed.put("a", aAtts);
final ArrayList<String> imgAtts = new ArrayList<>();
imgAtts.add("src");
imgAtts.add("width");
imgAtts.add("height");
imgAtts.add("alt");
vAllowed.put("img", imgAtts);
final ArrayList<String> noAtts = new ArrayList<>();
vAllowed.put("b", noAtts);
vAllowed.put("strong", noAtts);
vAllowed.put("i", noAtts);
vAllowed.put("em", noAtts);
vSelfClosingTags = new String[]{"img"};
vNeedClosingTags = new String[]{"a", "b", "strong", "i", "em"};
vDisallowed = new String[]{};
// no ftp.
vAllowedProtocols = new String[]{"http", "mailto", "https"};
vProtocolAtts = new String[]{"src", "href"};
vRemoveBlanks = new String[]{"a", "b", "strong", "i", "em"};
vAllowedEntities = new String[]{"amp", "gt", "lt", "quot"};
stripComment = true;
encodeQuotes = true;
alwaysMakeTags = false;
}
/**
* Map-parameter configurable constructor.
*
* @param conf map containing configuration. keys match field names.
*/
@SuppressWarnings("unchecked")
public HtmlFilter(final Map<String, Object> conf) {
assert conf.containsKey("vAllowed") : "configuration requires vAllowed";
assert conf.containsKey("vSelfClosingTags") : "configuration requires vSelfClosingTags";
assert conf.containsKey("vNeedClosingTags") : "configuration requires vNeedClosingTags";
assert conf.containsKey("vDisallowed") : "configuration requires vDisallowed";
assert conf.containsKey("vAllowedProtocols") : "configuration requires vAllowedProtocols";
assert conf.containsKey("vProtocolAtts") : "configuration requires vProtocolAtts";
assert conf.containsKey("vRemoveBlanks") : "configuration requires vRemoveBlanks";
assert conf.containsKey("vAllowedEntities") : "configuration requires vAllowedEntities";
vAllowed = Collections.unmodifiableMap((HashMap<String, List<String>>) conf.get("vAllowed"));
vSelfClosingTags = (String[]) conf.get("vSelfClosingTags");
vNeedClosingTags = (String[]) conf.get("vNeedClosingTags");
vDisallowed = (String[]) conf.get("vDisallowed");
vAllowedProtocols = (String[]) conf.get("vAllowedProtocols");
vProtocolAtts = (String[]) conf.get("vProtocolAtts");
vRemoveBlanks = (String[]) conf.get("vRemoveBlanks");
vAllowedEntities = (String[]) conf.get("vAllowedEntities");
stripComment = conf.containsKey("stripComment") ? (Boolean) conf.get("stripComment") : true;
encodeQuotes = conf.containsKey("encodeQuotes") ? (Boolean) conf.get("encodeQuotes") : true;
alwaysMakeTags = conf.containsKey("alwaysMakeTags") ? (Boolean) conf.get("alwaysMakeTags") : true;
}
private void reset() {
vTagCounts.clear();
}
// ---------------------------------------------------------------
/** my versions of some PHP library functions */
public static String chr(final int decimal) {
return String.valueOf((char) decimal);
}
public static String htmlSpecialChars(final String s) {
String result = s;
result = regexReplace(P_AMP, "&", result);
result = regexReplace(P_QUOTE, """, result);
result = regexReplace(P_LEFT_ARROW, "<", result);
result = regexReplace(P_RIGHT_ARROW, ">", result);
return result;
}
// ---------------------------------------------------------------
/**
* given a user submitted input String, filter out any invalid or restricted html.
*
* @param input text (i.e. submitted by a user) than may contain html
* @return "clean" version of input, with only valid, whitelisted html elements allowed
*/
public String filter(final String input) {
reset();
String s = input;
s = escapeComments(s);
s = balanceHtml(s);
s = checkTags(s);
s = processRemoveBlanks(s);
// s = validateEntities(s);
return s;
}
public boolean isAlwaysMakeTags() {
return alwaysMakeTags;
}
public boolean isStripComments() {
return stripComment;
}
private String escapeComments(final String s) {
final Matcher m = P_COMMENTS.matcher(s);
final StringBuffer buf = new StringBuffer();
if (m.find()) {
// (.*?)
final String match = m.group(1);
m.appendReplacement(buf, Matcher.quoteReplacement("<!--" + htmlSpecialChars(match) + "-->"));
}
m.appendTail(buf);
return buf.toString();
}
private String balanceHtml(String s) {
if (alwaysMakeTags) {
//
// try and form html
//
s = regexReplace(P_END_ARROW, "", s);
// 不追加结束标签
s = regexReplace(P_BODY_TO_END, "<$1>", s);
s = regexReplace(P_XML_CONTENT, "$1<$2", s);
} else {
//
// escape stray brackets
//
s = regexReplace(P_STRAY_LEFT_ARROW, "<$1", s);
s = regexReplace(P_STRAY_RIGHT_ARROW, "$1$2><", s);
//
// the last regexp causes '<>' entities to appear
// (we need to do a lookahead assertion so that the last bracket can
// be used in the next pass of the regexp)
//
s = regexReplace(P_BOTH_ARROWS, "", s);
}
return s;
}
private String checkTags(String s) {
Matcher m = P_TAGS.matcher(s);
final StringBuffer buf = new StringBuffer();
while (m.find()) {
String replaceStr = m.group(1);
replaceStr = processTag(replaceStr);
m.appendReplacement(buf, Matcher.quoteReplacement(replaceStr));
}
m.appendTail(buf);
// these get tallied in processTag
// (remember to reset before subsequent calls to filter method)
final StringBuilder sBuilder = new StringBuilder(buf.toString());
for (String key : vTagCounts.keySet()) {
for (int ii = 0; ii < vTagCounts.get(key); ii++) {
sBuilder.append("</").append(key).append(">");
}
}
s = sBuilder.toString();
return s;
}
private String processRemoveBlanks(final String s) {
String result = s;
for (String tag : vRemoveBlanks) {
if (!P_REMOVE_PAIR_BLANKS.containsKey(tag)) {
P_REMOVE_PAIR_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?></" + tag + ">"));
}
result = regexReplace(P_REMOVE_PAIR_BLANKS.get(tag), "", result);
if (!P_REMOVE_SELF_BLANKS.containsKey(tag)) {
P_REMOVE_SELF_BLANKS.putIfAbsent(tag, Pattern.compile("<" + tag + "(\\s[^>]*)?/>"));
}
result = regexReplace(P_REMOVE_SELF_BLANKS.get(tag), "", result);
}
return result;
}
private static String regexReplace(final Pattern regexPattern, final String replacement, final String s) {
Matcher m = regexPattern.matcher(s);
return m.replaceAll(replacement);
}
private String processTag(final String s) {
// ending tags
Matcher m = P_END_TAG.matcher(s);
if (m.find()) {
final String name = m.group(1).toLowerCase();
if (allowed(name)) {
if (!inArray(name, vSelfClosingTags)) {
if (vTagCounts.containsKey(name)) {
vTagCounts.put(name, vTagCounts.get(name) - 1);
return "</" + name + ">";
}
}
}
}
// starting tags
m = P_START_TAG.matcher(s);
if (m.find()) {
final String name = m.group(1).toLowerCase();
final String body = m.group(2);
String ending = m.group(3);
// debug( "in a starting tag, name='" + name + "'; body='" + body + "'; ending='" + ending + "'" );
if (allowed(name)) {
final StringBuilder params = new StringBuilder();
final Matcher m2 = P_QUOTED_ATTRIBUTES.matcher(body);
final Matcher m3 = P_UNQUOTED_ATTRIBUTES.matcher(body);
final List<String> paramNames = new ArrayList<>();
final List<String> paramValues = new ArrayList<>();
while (m2.find()) {
// ([a-z0-9]+)
paramNames.add(m2.group(1));
// (.*?)
paramValues.add(m2.group(3));
}
while (m3.find()) {
// ([a-z0-9]+)
paramNames.add(m3.group(1));
// ([^\"\\s']+)
paramValues.add(m3.group(3));
}
String paramName, paramValue;
for (int ii = 0; ii < paramNames.size(); ii++) {
paramName = paramNames.get(ii).toLowerCase();
paramValue = paramValues.get(ii);
if (allowedAttribute(name, paramName)) {
if (inArray(paramName, vProtocolAtts)) {
paramValue = processParamProtocol(paramValue);
}
params.append(' ').append(paramName).append("=\\\"").append(paramValue).append("\\\"");
}
}
if (inArray(name, vSelfClosingTags)) {
ending = " /";
}
if (inArray(name, vNeedClosingTags)) {
ending = "";
}
if (ending == null || ending.length() < 1) {
if (vTagCounts.containsKey(name)) {
vTagCounts.put(name, vTagCounts.get(name) + 1);
} else {
vTagCounts.put(name, 1);
}
} else {
ending = " /";
}
return "<" + name + params + ending + ">";
} else {
return "";
}
}
// comments
m = P_COMMENT.matcher(s);
if (!stripComment && m.find()) {
return "<" + m.group() + ">";
}
return "";
}
private String processParamProtocol(String s) {
s = decodeEntities(s);
final Matcher m = P_PROTOCOL.matcher(s);
if (m.find()) {
final String protocol = m.group(1);
if (!inArray(protocol, vAllowedProtocols)) {
// bad protocol, turn into local anchor link instead
s = "#" + s.substring(protocol.length() + 1);
String poundSign = "#//";
if (s.startsWith(poundSign)) {
s = "#" + s.substring(3);
}
}
}
return s;
}
private String decodeEntities(String s) {
StringBuffer buf = new StringBuffer();
Matcher m = P_ENTITY.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.decode(match).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
buf = new StringBuffer();
m = P_ENTITY_UNICODE.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.valueOf(match, 16).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
buf = new StringBuffer();
m = P_ENCODE.matcher(s);
while (m.find()) {
final String match = m.group(1);
final int decimal = Integer.valueOf(match, 16).intValue();
m.appendReplacement(buf, Matcher.quoteReplacement(chr(decimal)));
}
m.appendTail(buf);
s = buf.toString();
s = validateEntities(s);
return s;
}
private String validateEntities(final String s) {
StringBuffer buf = new StringBuffer();
// validate entities throughout the string
Matcher m = P_VALID_ENTITIES.matcher(s);
while (m.find()) {
// ([^&;]*)
final String one = m.group(1);
// (?=(;|&|$))
final String two = m.group(2);
m.appendReplacement(buf, Matcher.quoteReplacement(checkEntity(one, two)));
}
m.appendTail(buf);
return encodeQuotes(buf.toString());
}
private String encodeQuotes(final String s) {
if (encodeQuotes) {
StringBuffer buf = new StringBuffer();
Matcher m = P_VALID_QUOTES.matcher(s);
while (m.find()) {
// (>|^)
final String one = m.group(1);
// ([^<]+?)
final String two = m.group(2);
// (<|$)
final String three = m.group(3);
// 不替换双引号为"，防止json格式无效 regexReplace(P_QUOTE, """, two)
m.appendReplacement(buf, Matcher.quoteReplacement(one + two + three));
}
m.appendTail(buf);
return buf.toString();
} else {
return s;
}
}
private String checkEntity(final String preamble, final String term) {
return ";".equals(term) && isValidEntity(preamble) ? '&' + preamble : "&" + preamble;
}
private boolean isValidEntity(final String entity) {
return inArray(entity, vAllowedEntities);
}
private static boolean inArray(final String s, final String[] array) {
for (String item : array) {
if (item != null && item.equals(s)) {
return true;
}
}
return false;
}
private boolean allowed(final String name) {
return (vAllowed.isEmpty() || vAllowed.containsKey(name)) && !inArray(name, vDisallowed);
}
private boolean allowedAttribute(final String name, final String paramName) {
return allowed(name) && (vAllowed.isEmpty() || vAllowed.get(name).contains(paramName));
}
}