extract html cleaning code to its own service

This commit is contained in:
Athou
2024-01-07 13:45:15 +01:00
parent deb51f2ccc
commit ed45746f52
2 changed files with 179 additions and 162 deletions

View File

@@ -0,0 +1,174 @@
package com.commafeed.backend.service;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.apache.commons.lang3.StringUtils;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Document.OutputSettings;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Entities.EscapeMode;
import org.jsoup.safety.Cleaner;
import org.jsoup.safety.Safelist;
import org.w3c.css.sac.CSSException;
import org.w3c.css.sac.CSSParseException;
import org.w3c.css.sac.ErrorHandler;
import org.w3c.css.sac.InputSource;
import org.w3c.dom.css.CSSStyleDeclaration;
import com.steadystate.css.parser.CSSOMParser;
import jakarta.inject.Inject;
import jakarta.inject.Singleton;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
@RequiredArgsConstructor(onConstructor = @__({ @Inject }))
@Slf4j
@Singleton
public class FeedEntryContentCleaningService {
private static final Safelist HTML_WHITELIST = buildWhiteList();
private static final List<String> ALLOWED_IFRAME_CSS_RULES = Arrays.asList("height", "width", "border");
private static final List<String> ALLOWED_IMG_CSS_RULES = Arrays.asList("display", "width", "height");
private static final char[] FORBIDDEN_CSS_RULE_CHARACTERS = new char[] { '(', ')' };
public String clean(String content, String baseUri, boolean keepTextOnly) {
if (StringUtils.isNotBlank(content)) {
baseUri = StringUtils.trimToEmpty(baseUri);
Document dirty = Jsoup.parseBodyFragment(content, baseUri);
Cleaner cleaner = new Cleaner(HTML_WHITELIST);
Document clean = cleaner.clean(dirty);
for (Element e : clean.select("iframe[style]")) {
String style = e.attr("style");
String escaped = escapeIFrameCss(style);
e.attr("style", escaped);
}
for (Element e : clean.select("img[style]")) {
String style = e.attr("style");
String escaped = escapeImgCss(style);
e.attr("style", escaped);
}
clean.outputSettings(new OutputSettings().escapeMode(EscapeMode.base).prettyPrint(false));
Element body = clean.body();
if (keepTextOnly) {
content = body.text();
} else {
content = body.html();
}
}
return content;
}
private static Safelist buildWhiteList() {
Safelist whitelist = new Safelist();
whitelist.addTags("a", "b", "blockquote", "br", "caption", "cite", "code", "col", "colgroup", "dd", "div", "dl", "dt", "em", "h1",
"h2", "h3", "h4", "h5", "h6", "i", "iframe", "img", "li", "ol", "p", "pre", "q", "small", "strike", "strong", "sub", "sup",
"table", "tbody", "td", "tfoot", "th", "thead", "tr", "u", "ul");
whitelist.addAttributes("div", "dir");
whitelist.addAttributes("pre", "dir");
whitelist.addAttributes("code", "dir");
whitelist.addAttributes("table", "dir");
whitelist.addAttributes("p", "dir");
whitelist.addAttributes("a", "href", "title");
whitelist.addAttributes("blockquote", "cite");
whitelist.addAttributes("col", "span", "width");
whitelist.addAttributes("colgroup", "span", "width");
whitelist.addAttributes("iframe", "src", "height", "width", "allowfullscreen", "frameborder", "style");
whitelist.addAttributes("img", "align", "alt", "height", "src", "title", "width", "style");
whitelist.addAttributes("ol", "start", "type");
whitelist.addAttributes("q", "cite");
whitelist.addAttributes("table", "border", "bordercolor", "summary", "width");
whitelist.addAttributes("td", "border", "bordercolor", "abbr", "axis", "colspan", "rowspan", "width");
whitelist.addAttributes("th", "border", "bordercolor", "abbr", "axis", "colspan", "rowspan", "scope", "width");
whitelist.addAttributes("ul", "type");
whitelist.addProtocols("a", "href", "ftp", "http", "https", "magnet", "mailto");
whitelist.addProtocols("blockquote", "cite", "http", "https");
whitelist.addProtocols("img", "src", "http", "https");
whitelist.addProtocols("q", "cite", "http", "https");
whitelist.addEnforcedAttribute("a", "target", "_blank");
whitelist.addEnforcedAttribute("a", "rel", "noreferrer");
return whitelist;
}
private String escapeIFrameCss(String orig) {
String rule = "";
try {
List<String> rules = new ArrayList<>();
CSSStyleDeclaration decl = buildCssParser().parseStyleDeclaration(new InputSource(new StringReader(orig)));
for (int i = 0; i < decl.getLength(); i++) {
String property = decl.item(i);
String value = decl.getPropertyValue(property);
if (StringUtils.isBlank(property) || StringUtils.isBlank(value)) {
continue;
}
if (ALLOWED_IFRAME_CSS_RULES.contains(property) && StringUtils.containsNone(value, FORBIDDEN_CSS_RULE_CHARACTERS)) {
rules.add(property + ":" + decl.getPropertyValue(property) + ";");
}
}
rule = StringUtils.join(rules, "");
} catch (Exception e) {
log.error(e.getMessage(), e);
}
return rule;
}
private String escapeImgCss(String orig) {
String rule = "";
try {
List<String> rules = new ArrayList<>();
CSSStyleDeclaration decl = buildCssParser().parseStyleDeclaration(new InputSource(new StringReader(orig)));
for (int i = 0; i < decl.getLength(); i++) {
String property = decl.item(i);
String value = decl.getPropertyValue(property);
if (StringUtils.isBlank(property) || StringUtils.isBlank(value)) {
continue;
}
if (ALLOWED_IMG_CSS_RULES.contains(property) && StringUtils.containsNone(value, FORBIDDEN_CSS_RULE_CHARACTERS)) {
rules.add(property + ":" + decl.getPropertyValue(property) + ";");
}
}
rule = StringUtils.join(rules, "");
} catch (Exception e) {
log.error(e.getMessage(), e);
}
return rule;
}
private CSSOMParser buildCssParser() {
CSSOMParser parser = new CSSOMParser();
parser.setErrorHandler(new ErrorHandler() {
@Override
public void warning(CSSParseException exception) throws CSSException {
log.debug("warning while parsing css: {}", exception.getMessage(), exception);
}
@Override
public void error(CSSParseException exception) throws CSSException {
log.debug("error while parsing css: {}", exception.getMessage(), exception);
}
@Override
public void fatalError(CSSParseException exception) throws CSSException {
log.debug("fatal error while parsing css: {}", exception.getMessage(), exception);
}
});
return parser;
}
}

View File

@@ -1,26 +1,11 @@
package com.commafeed.backend.service;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.builder.EqualsBuilder;
import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;
import org.jsoup.nodes.Document.OutputSettings;
import org.jsoup.nodes.Element;
import org.jsoup.nodes.Entities.EscapeMode;
import org.jsoup.safety.Cleaner;
import org.jsoup.safety.Safelist;
import org.w3c.css.sac.CSSException;
import org.w3c.css.sac.CSSParseException;
import org.w3c.css.sac.ErrorHandler;
import org.w3c.css.sac.InputSource;
import org.w3c.dom.css.CSSStyleDeclaration;
import com.commafeed.backend.dao.FeedEntryContentDAO;
import com.commafeed.backend.feed.FeedUtils;
@@ -28,33 +13,26 @@ import com.commafeed.backend.feed.parser.FeedParserResult.Content;
import com.commafeed.backend.feed.parser.FeedParserResult.Enclosure;
import com.commafeed.backend.feed.parser.FeedParserResult.Media;
import com.commafeed.backend.model.FeedEntryContent;
import com.steadystate.css.parser.CSSOMParser;
import jakarta.inject.Inject;
import jakarta.inject.Singleton;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
@RequiredArgsConstructor(onConstructor = @__({ @Inject }))
@Slf4j
@Singleton
public class FeedEntryContentService {
private static final Safelist HTML_WHITELIST = buildWhiteList();
private static final List<String> ALLOWED_IFRAME_CSS_RULES = Arrays.asList("height", "width", "border");
private static final List<String> ALLOWED_IMG_CSS_RULES = Arrays.asList("display", "width", "height");
private static final char[] FORBIDDEN_CSS_RULE_CHARACTERS = new char[] { '(', ')' };
private final FeedEntryContentDAO feedEntryContentDAO;
private final FeedEntryContentCleaningService cleaningService;
/**
* this is NOT thread-safe
*/
public FeedEntryContent findOrCreate(Content content, String baseUrl) {
String title = FeedUtils.truncate(handleContent(content.title(), baseUrl, true), 2048);
String title = FeedUtils.truncate(cleaningService.clean(content.title(), baseUrl, true), 2048);
String titleHash = DigestUtils.sha1Hex(StringUtils.trimToEmpty(title));
String contentString = handleContent(content.content(), baseUrl, false);
String contentString = cleaningService.clean(content.content(), baseUrl, false);
String contentHash = DigestUtils.sha1Hex(StringUtils.trimToEmpty(contentString));
List<FeedEntryContent> existing = feedEntryContentDAO.findExisting(contentHash, titleHash);
@@ -70,7 +48,7 @@ public class FeedEntryContentService {
entryContent.setTitleHash(titleHash);
entryContent.setContent(contentString);
entryContent.setContentHash(contentHash);
entryContent.setAuthor(FeedUtils.truncate(handleContent(content.author(), baseUrl, true), 128));
entryContent.setAuthor(FeedUtils.truncate(cleaningService.clean(content.author(), baseUrl, true), 128));
entryContent.setCategories(FeedUtils.truncate(content.categories(), 4096));
Enclosure enclosure = content.enclosure();
@@ -81,7 +59,7 @@ public class FeedEntryContentService {
Media media = content.media();
if (media != null) {
entryContent.setMediaDescription(handleContent(media.description(), baseUrl, false));
entryContent.setMediaDescription(cleaningService.clean(media.description(), baseUrl, false));
entryContent.setMediaThumbnailUrl(media.thumbnailUrl());
entryContent.setMediaThumbnailWidth(media.thumbnailWidth());
entryContent.setMediaThumbnailHeight(media.thumbnailHeight());
@@ -111,139 +89,4 @@ public class FeedEntryContentService {
return builder.build();
}
private static Safelist buildWhiteList() {
Safelist whitelist = new Safelist();
whitelist.addTags("a", "b", "blockquote", "br", "caption", "cite", "code", "col", "colgroup", "dd", "div", "dl", "dt", "em", "h1",
"h2", "h3", "h4", "h5", "h6", "i", "iframe", "img", "li", "ol", "p", "pre", "q", "small", "strike", "strong", "sub", "sup",
"table", "tbody", "td", "tfoot", "th", "thead", "tr", "u", "ul");
whitelist.addAttributes("div", "dir");
whitelist.addAttributes("pre", "dir");
whitelist.addAttributes("code", "dir");
whitelist.addAttributes("table", "dir");
whitelist.addAttributes("p", "dir");
whitelist.addAttributes("a", "href", "title");
whitelist.addAttributes("blockquote", "cite");
whitelist.addAttributes("col", "span", "width");
whitelist.addAttributes("colgroup", "span", "width");
whitelist.addAttributes("iframe", "src", "height", "width", "allowfullscreen", "frameborder", "style");
whitelist.addAttributes("img", "align", "alt", "height", "src", "title", "width", "style");
whitelist.addAttributes("ol", "start", "type");
whitelist.addAttributes("q", "cite");
whitelist.addAttributes("table", "border", "bordercolor", "summary", "width");
whitelist.addAttributes("td", "border", "bordercolor", "abbr", "axis", "colspan", "rowspan", "width");
whitelist.addAttributes("th", "border", "bordercolor", "abbr", "axis", "colspan", "rowspan", "scope", "width");
whitelist.addAttributes("ul", "type");
whitelist.addProtocols("a", "href", "ftp", "http", "https", "magnet", "mailto");
whitelist.addProtocols("blockquote", "cite", "http", "https");
whitelist.addProtocols("img", "src", "http", "https");
whitelist.addProtocols("q", "cite", "http", "https");
whitelist.addEnforcedAttribute("a", "target", "_blank");
whitelist.addEnforcedAttribute("a", "rel", "noreferrer");
return whitelist;
}
private String handleContent(String content, String baseUri, boolean keepTextOnly) {
if (StringUtils.isNotBlank(content)) {
baseUri = StringUtils.trimToEmpty(baseUri);
Document dirty = Jsoup.parseBodyFragment(content, baseUri);
Cleaner cleaner = new Cleaner(HTML_WHITELIST);
Document clean = cleaner.clean(dirty);
for (Element e : clean.select("iframe[style]")) {
String style = e.attr("style");
String escaped = escapeIFrameCss(style);
e.attr("style", escaped);
}
for (Element e : clean.select("img[style]")) {
String style = e.attr("style");
String escaped = escapeImgCss(style);
e.attr("style", escaped);
}
clean.outputSettings(new OutputSettings().escapeMode(EscapeMode.base).prettyPrint(false));
Element body = clean.body();
if (keepTextOnly) {
content = body.text();
} else {
content = body.html();
}
}
return content;
}
private String escapeIFrameCss(String orig) {
String rule = "";
try {
List<String> rules = new ArrayList<>();
CSSStyleDeclaration decl = buildCssParser().parseStyleDeclaration(new InputSource(new StringReader(orig)));
for (int i = 0; i < decl.getLength(); i++) {
String property = decl.item(i);
String value = decl.getPropertyValue(property);
if (StringUtils.isBlank(property) || StringUtils.isBlank(value)) {
continue;
}
if (ALLOWED_IFRAME_CSS_RULES.contains(property) && StringUtils.containsNone(value, FORBIDDEN_CSS_RULE_CHARACTERS)) {
rules.add(property + ":" + decl.getPropertyValue(property) + ";");
}
}
rule = StringUtils.join(rules, "");
} catch (Exception e) {
log.error(e.getMessage(), e);
}
return rule;
}
private String escapeImgCss(String orig) {
String rule = "";
try {
List<String> rules = new ArrayList<>();
CSSStyleDeclaration decl = buildCssParser().parseStyleDeclaration(new InputSource(new StringReader(orig)));
for (int i = 0; i < decl.getLength(); i++) {
String property = decl.item(i);
String value = decl.getPropertyValue(property);
if (StringUtils.isBlank(property) || StringUtils.isBlank(value)) {
continue;
}
if (ALLOWED_IMG_CSS_RULES.contains(property) && StringUtils.containsNone(value, FORBIDDEN_CSS_RULE_CHARACTERS)) {
rules.add(property + ":" + decl.getPropertyValue(property) + ";");
}
}
rule = StringUtils.join(rules, "");
} catch (Exception e) {
log.error(e.getMessage(), e);
}
return rule;
}
private CSSOMParser buildCssParser() {
CSSOMParser parser = new CSSOMParser();
parser.setErrorHandler(new ErrorHandler() {
@Override
public void warning(CSSParseException exception) throws CSSException {
log.debug("warning while parsing css: {}", exception.getMessage(), exception);
}
@Override
public void error(CSSParseException exception) throws CSSException {
log.debug("error while parsing css: {}", exception.getMessage(), exception);
}
@Override
public void fatalError(CSSParseException exception) throws CSSException {
log.debug("fatal error while parsing css: {}", exception.getMessage(), exception);
}
});
return parser;
}
}