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A headless browser intended for use in testing web-based applications.
/*
* Copyright (c) 2002-2021 Gargoyle Software Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.gargoylesoftware.htmlunit.util;
import static java.nio.charset.StandardCharsets.US_ASCII;
import static java.nio.charset.StandardCharsets.UTF_16BE;
import static java.nio.charset.StandardCharsets.UTF_16LE;
import static java.nio.charset.StandardCharsets.UTF_8;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import org.apache.commons.io.ByteOrderMark;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.gargoylesoftware.htmlunit.HttpHeader;
/**
* Sniffs encoding settings from HTML, XML or other content. The HTML encoding sniffing algorithm is based on the
* HTML5
* encoding sniffing algorithm.
*
* @author Daniel Gredler
* @author Ahmed Ashour
* @author Ronald Brill
*/
public final class EncodingSniffer {
/** Logging support. */
private static final Log LOG = LogFactory.getLog(EncodingSniffer.class);
/** Sequence(s) of bytes indicating the beginning of a comment. */
private static final byte[][] COMMENT_START = {
new byte[] {'<'},
new byte[] {'!'},
new byte[] {'-'},
new byte[] {'-'}
};
/** Sequence(s) of bytes indicating the beginning of a meta HTML tag. */
private static final byte[][] META_START = {
new byte[] {'<'},
new byte[] {'m', 'M'},
new byte[] {'e', 'E'},
new byte[] {'t', 'T'},
new byte[] {'a', 'A'},
new byte[] {0x09, 0x0A, 0x0C, 0x0D, 0x20, 0x2F}
};
/** Sequence(s) of bytes indicating the beginning of miscellaneous HTML content. */
private static final byte[][] OTHER_START = {
new byte[] {'<'},
new byte[] {'!', '/', '?'}
};
/** Sequence(s) of bytes indicating the beginning of a charset specification. */
private static final byte[][] CHARSET_START = {
new byte[] {'c', 'C'},
new byte[] {'h', 'H'},
new byte[] {'a', 'A'},
new byte[] {'r', 'R'},
new byte[] {'s', 'S'},
new byte[] {'e', 'E'},
new byte[] {'t', 'T'}
};
private static final byte[] WHITESPACE = {0x09, 0x0A, 0x0C, 0x0D, 0x20, 0x3E};
private static final byte[] COMMENT_END = {'-', '-', '>'};
/** Reference */
private static final Map ENCODING_FROM_LABEL;
static {
ENCODING_FROM_LABEL = new HashMap<>();
// The Encoding
// ------------
ENCODING_FROM_LABEL.put("unicode-1-1-utf-8", "utf-8");
ENCODING_FROM_LABEL.put("utf-8", "utf-8");
ENCODING_FROM_LABEL.put("utf8", "utf-8");
// Legacy single-byte encodings
// ----------------------------
// ibm866
ENCODING_FROM_LABEL.put("866", "ibm866");
ENCODING_FROM_LABEL.put("cp866", "ibm866");
ENCODING_FROM_LABEL.put("csibm866", "ibm866");
ENCODING_FROM_LABEL.put("ibm866", "ibm866");
// iso-8859-2
ENCODING_FROM_LABEL.put("csisolatin2", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso-8859-2", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso-ir-101", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso8859-2", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso88592", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso_8859-2", "iso-8859-2");
ENCODING_FROM_LABEL.put("iso_8859-2:1987", "iso-8859-2");
ENCODING_FROM_LABEL.put("l2", "iso-8859-2");
ENCODING_FROM_LABEL.put("latin2", "iso-8859-2");
// iso-8859-3
ENCODING_FROM_LABEL.put("csisolatin2", "iso-8859-3");
ENCODING_FROM_LABEL.put("csisolatin3", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso-8859-3", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso-ir-109", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso8859-3", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso88593", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso_8859-3", "iso-8859-3");
ENCODING_FROM_LABEL.put("iso_8859-3:1988", "iso-8859-3");
ENCODING_FROM_LABEL.put("l3", "iso-8859-3");
ENCODING_FROM_LABEL.put("latin3", "iso-8859-3");
// iso-8859-4
ENCODING_FROM_LABEL.put("csisolatin4", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso-8859-4", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso-ir-110", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso8859-4", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso88594", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso_8859-4", "iso-8859-4");
ENCODING_FROM_LABEL.put("iso_8859-4:1988", "iso-8859-4");
ENCODING_FROM_LABEL.put("l4", "iso-8859-4");
ENCODING_FROM_LABEL.put("latin4", "iso-8859-4");
// iso-8859-5
ENCODING_FROM_LABEL.put("csisolatincyrillic", "iso-8859-5");
ENCODING_FROM_LABEL.put("csisolatincyrillic", "iso-8859-5");
ENCODING_FROM_LABEL.put("cyrillic", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso-8859-5", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso-ir-144", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso8859-5", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso88595", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso_8859-5", "iso-8859-5");
ENCODING_FROM_LABEL.put("iso_8859-5:1988", "iso-8859-5");
// iso-8859-6
ENCODING_FROM_LABEL.put("arabic", "iso-8859-6");
ENCODING_FROM_LABEL.put("asmo-708", "iso-8859-6");
ENCODING_FROM_LABEL.put("csiso88596e", "iso-8859-6");
ENCODING_FROM_LABEL.put("csiso88596i", "iso-8859-6");
ENCODING_FROM_LABEL.put("csisolatinarabic", "iso-8859-6");
ENCODING_FROM_LABEL.put("ecma-114", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso-8859-6", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso-8859-6-e", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso-8859-6-i", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso-ir-127", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso8859-6", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso88596", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso_8859-6", "iso-8859-6");
ENCODING_FROM_LABEL.put("iso_8859-6:1987", "iso-8859-6");
// iso-8859-7
ENCODING_FROM_LABEL.put("csisolatingreek", "iso-8859-7");
ENCODING_FROM_LABEL.put("ecma-118", "iso-8859-7");
ENCODING_FROM_LABEL.put("elot_928", "iso-8859-7");
ENCODING_FROM_LABEL.put("greek", "iso-8859-7");
ENCODING_FROM_LABEL.put("greek8", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso-8859-7", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso-ir-126", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso8859-7", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso88597", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso_8859-7", "iso-8859-7");
ENCODING_FROM_LABEL.put("iso_8859-7:1987", "iso-8859-7");
ENCODING_FROM_LABEL.put("sun_eu_greek", "iso-8859-7");
// iso-8859-8
ENCODING_FROM_LABEL.put("csisolatingreek", "iso-8859-8");
ENCODING_FROM_LABEL.put("csiso88598e", "iso-8859-8");
ENCODING_FROM_LABEL.put("csisolatinhebrew", "iso-8859-8");
ENCODING_FROM_LABEL.put("hebrew", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso-8859-8", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso-8859-8-e", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso-ir-138", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso8859-8", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso88598", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso_8859-8", "iso-8859-8");
ENCODING_FROM_LABEL.put("iso_8859-8:1988", "iso-8859-8");
ENCODING_FROM_LABEL.put("visual", "iso-8859-8");
// iso-8859-8-i
ENCODING_FROM_LABEL.put("csiso88598i", "iso-8859-8-i");
ENCODING_FROM_LABEL.put("iso-8859-8-i", "iso-8859-8-i");
ENCODING_FROM_LABEL.put("logical", "iso-8859-8-i");
// iso-8859-10
ENCODING_FROM_LABEL.put("csisolatin6", "iso-8859-10");
ENCODING_FROM_LABEL.put("iso-8859-10", "iso-8859-10");
ENCODING_FROM_LABEL.put("iso-ir-157", "iso-8859-10");
ENCODING_FROM_LABEL.put("iso8859-10", "iso-8859-10");
ENCODING_FROM_LABEL.put("iso885910", "iso-8859-10");
ENCODING_FROM_LABEL.put("l6", "iso-8859-10");
ENCODING_FROM_LABEL.put("latin6", "iso-8859-10");
// iso-8859-13
ENCODING_FROM_LABEL.put("iso-8859-13", "iso-8859-13");
ENCODING_FROM_LABEL.put("iso8859-13", "iso-8859-13");
ENCODING_FROM_LABEL.put("iso885913", "iso-8859-13");
// iso-8859-14
ENCODING_FROM_LABEL.put("iso-8859-14", "iso-8859-14");
ENCODING_FROM_LABEL.put("iso8859-14", "iso-8859-14");
ENCODING_FROM_LABEL.put("iso885914", "iso-8859-14");
// iso-8859-15
ENCODING_FROM_LABEL.put("csisolatin9", "iso-8859-15");
ENCODING_FROM_LABEL.put("iso-8859-15", "iso-8859-15");
ENCODING_FROM_LABEL.put("iso8859-15", "iso-8859-15");
ENCODING_FROM_LABEL.put("iso885915", "iso-8859-15");
ENCODING_FROM_LABEL.put("iso_8859-15", "iso-8859-15");
ENCODING_FROM_LABEL.put("l9", "iso-8859-15");
// iso-8859-16
ENCODING_FROM_LABEL.put("iso-8859-16", "iso-8859-16");
// koi8-r
ENCODING_FROM_LABEL.put("cskoi8r", "koi8-r");
ENCODING_FROM_LABEL.put("koi", "koi8-r");
ENCODING_FROM_LABEL.put("koi8", "koi8-r");
ENCODING_FROM_LABEL.put("koi8-r", "koi8-r");
ENCODING_FROM_LABEL.put("koi8_r", "koi8-r");
// koi8-u
ENCODING_FROM_LABEL.put("koi8-u", "koi8-u");
// macintosh
ENCODING_FROM_LABEL.put("csmacintosh", "macintosh");
ENCODING_FROM_LABEL.put("mac", "macintosh");
ENCODING_FROM_LABEL.put("macintosh", "macintosh");
ENCODING_FROM_LABEL.put("x-mac-roman", "macintosh");
// windows-874
ENCODING_FROM_LABEL.put("dos-874", "windows-874");
ENCODING_FROM_LABEL.put("iso-8859-11", "windows-874");
ENCODING_FROM_LABEL.put("iso8859-11", "windows-874");
ENCODING_FROM_LABEL.put("iso885911", "windows-874");
ENCODING_FROM_LABEL.put("tis-620", "windows-874");
ENCODING_FROM_LABEL.put("windows-874", "windows-874");
// windows-1250
ENCODING_FROM_LABEL.put("cp1250", "windows-1250");
ENCODING_FROM_LABEL.put("windows-1250", "windows-1250");
ENCODING_FROM_LABEL.put("x-cp1250", "windows-1250");
// windows-1251
ENCODING_FROM_LABEL.put("cp1251", "windows-1251");
ENCODING_FROM_LABEL.put("windows-1251", "windows-1251");
ENCODING_FROM_LABEL.put("x-cp1251", "windows-1251");
// windows-1252
ENCODING_FROM_LABEL.put("ansi_x3.4-1968", "windows-1252");
ENCODING_FROM_LABEL.put("ascii", "windows-1252");
ENCODING_FROM_LABEL.put("cp1252", "windows-1252");
ENCODING_FROM_LABEL.put("cp819", "windows-1252");
ENCODING_FROM_LABEL.put("csisolatin1", "windows-1252");
ENCODING_FROM_LABEL.put("ibm819", "windows-1252");
ENCODING_FROM_LABEL.put("iso-8859-1", "windows-1252");
ENCODING_FROM_LABEL.put("iso-ir-100", "windows-1252");
ENCODING_FROM_LABEL.put("iso8859-1", "windows-1252");
ENCODING_FROM_LABEL.put("iso88591", "windows-1252");
ENCODING_FROM_LABEL.put("iso_8859-1", "windows-1252");
ENCODING_FROM_LABEL.put("iso_8859-1:1987", "windows-1252");
ENCODING_FROM_LABEL.put("l1", "windows-1252");
ENCODING_FROM_LABEL.put("latin1", "windows-1252");
ENCODING_FROM_LABEL.put("us-ascii", "windows-1252");
ENCODING_FROM_LABEL.put("windows-1252", "windows-1252");
ENCODING_FROM_LABEL.put("x-cp1252", "windows-1252");
// windows-1253
ENCODING_FROM_LABEL.put("cp1253", "windows-1253");
ENCODING_FROM_LABEL.put("windows-1253", "windows-1253");
ENCODING_FROM_LABEL.put("x-cp1253", "windows-1253");
// windows-1254
ENCODING_FROM_LABEL.put("cp1254", "windows-1254");
ENCODING_FROM_LABEL.put("csisolatin5", "windows-1254");
ENCODING_FROM_LABEL.put("iso-8859-9", "windows-1254");
ENCODING_FROM_LABEL.put("iso-ir-148", "windows-1254");
ENCODING_FROM_LABEL.put("iso8859-9", "windows-1254");
ENCODING_FROM_LABEL.put("iso88599", "windows-1254");
ENCODING_FROM_LABEL.put("iso_8859-9", "windows-1254");
ENCODING_FROM_LABEL.put("iso_8859-9:1989", "windows-1254");
ENCODING_FROM_LABEL.put("l5", "windows-1254");
ENCODING_FROM_LABEL.put("latin5", "windows-1254");
ENCODING_FROM_LABEL.put("windows-1254", "windows-1254");
ENCODING_FROM_LABEL.put("x-cp1254", "windows-1254");
// windows-1255
ENCODING_FROM_LABEL.put("cp1255", "windows-1255");
ENCODING_FROM_LABEL.put("windows-1255", "windows-1255");
ENCODING_FROM_LABEL.put("x-cp1255", "windows-1255");
// windows-1256
ENCODING_FROM_LABEL.put("cp1256", "windows-1256");
ENCODING_FROM_LABEL.put("windows-1256", "windows-1256");
ENCODING_FROM_LABEL.put("x-cp1256", "windows-1256");
// windows-1257
ENCODING_FROM_LABEL.put("cp1257", "windows-1257");
ENCODING_FROM_LABEL.put("windows-1257", "windows-1257");
ENCODING_FROM_LABEL.put("x-cp1257", "windows-1257");
// windows-1258
ENCODING_FROM_LABEL.put("cp1258", "windows-1258");
ENCODING_FROM_LABEL.put("windows-1258", "windows-1258");
ENCODING_FROM_LABEL.put("x-cp1258", "windows-1258");
// x-mac-cyrillic
ENCODING_FROM_LABEL.put("x-mac-cyrillic", "x-mac-cyrillic");
ENCODING_FROM_LABEL.put("x-mac-ukrainian", "x-mac-cyrillic");
// Legacy multi-byte Chinese (simplified) encodings
// ------------------------------------------------
// gb18030
ENCODING_FROM_LABEL.put("chinese", "gb18030");
ENCODING_FROM_LABEL.put("csgb2312", "gb18030");
ENCODING_FROM_LABEL.put("csiso58gb231280", "gb18030");
ENCODING_FROM_LABEL.put("gb18030", "gb18030");
ENCODING_FROM_LABEL.put("gb2312", "gb18030");
ENCODING_FROM_LABEL.put("gb_2312", "gb18030");
ENCODING_FROM_LABEL.put("gb_2312-80", "gb18030");
ENCODING_FROM_LABEL.put("gbk", "gb18030");
ENCODING_FROM_LABEL.put("iso-ir-58", "gb18030");
ENCODING_FROM_LABEL.put("x-gbk", "gb18030");
// hz-gb-2312
ENCODING_FROM_LABEL.put("hz-gb-2312", "hz-gb-2312");
// Legacy multi-byte Chinese (traditional) encodings
// ------------------------------------------------
// big5
ENCODING_FROM_LABEL.put("big5", "big5");
ENCODING_FROM_LABEL.put("big5-hkscs", "big5");
ENCODING_FROM_LABEL.put("cn-big5", "big5");
ENCODING_FROM_LABEL.put("csbig5", "big5");
ENCODING_FROM_LABEL.put("x-x-big5", "big5");
// Legacy multi-byte Japanese encodings
// ------------------------------------
// euc-jp
ENCODING_FROM_LABEL.put("cseucpkdfmtjapanese", "euc-jp");
ENCODING_FROM_LABEL.put("euc-jp", "euc-jp");
ENCODING_FROM_LABEL.put("x-euc-jp", "euc-jp");
// iso-2022-jp
ENCODING_FROM_LABEL.put("csiso2022jp", "iso-2022-jp");
ENCODING_FROM_LABEL.put("iso-2022-jp", "iso-2022-jp");
// iso-2022-jp
ENCODING_FROM_LABEL.put("csshiftjis", "shift_jis");
ENCODING_FROM_LABEL.put("ms_kanji", "shift_jis");
ENCODING_FROM_LABEL.put("shift-jis", "shift_jis");
ENCODING_FROM_LABEL.put("shift_jis", "shift_jis");
ENCODING_FROM_LABEL.put("sjis", "shift_jis");
ENCODING_FROM_LABEL.put("windows-31j", "shift_jis");
ENCODING_FROM_LABEL.put("x-sjis", "shift_jis");
// Legacy multi-byte Korean encodings
// ------------------------------------
// euc-kr
ENCODING_FROM_LABEL.put("cseuckr", "euc-kr");
ENCODING_FROM_LABEL.put("csksc56011987", "euc-kr");
ENCODING_FROM_LABEL.put("euc-kr", "euc-kr");
ENCODING_FROM_LABEL.put("iso-ir-149", "euc-kr");
ENCODING_FROM_LABEL.put("korean", "euc-kr");
ENCODING_FROM_LABEL.put("ks_c_5601-1987", "euc-kr");
ENCODING_FROM_LABEL.put("ks_c_5601-1989", "euc-kr");
ENCODING_FROM_LABEL.put("ksc5601", "euc-kr");
ENCODING_FROM_LABEL.put("ksc_5601", "euc-kr");
ENCODING_FROM_LABEL.put("windows-949", "euc-kr");
// Legacy miscellaneous encodings
// ------------------------------------
// replacement
ENCODING_FROM_LABEL.put("csiso2022kr", "replacement");
ENCODING_FROM_LABEL.put("iso-2022-cn", "replacement");
ENCODING_FROM_LABEL.put("iso-2022-cn-ext", "replacement");
ENCODING_FROM_LABEL.put("iso-2022-kr", "replacement");
// utf-16be
ENCODING_FROM_LABEL.put("utf-16be", "utf-16be");
// utf-16le
ENCODING_FROM_LABEL.put("utf-16", "utf-16le");
ENCODING_FROM_LABEL.put("utf-16le", "utf-16le");
// x-user-defined
ENCODING_FROM_LABEL.put("x-user-defined", "x-user-defined");
}
private static final byte[] XML_DECLARATION_PREFIX = "meta tags;
* relatively large because we don't have a fallback.
*/
private static final int SIZE_OF_HTML_CONTENT_SNIFFED = 4096;
/**
* The number of XML bytes to sniff for encoding info embedded in the XML declaration;
* relatively small because it's always at the very beginning of the file.
*/
private static final int SIZE_OF_XML_CONTENT_SNIFFED = 512;
/**
* Disallow instantiation of this class.
*/
private EncodingSniffer() {
// Empty.
}
/**
* If the specified content is HTML content, this method sniffs encoding settings
* from the specified HTML content and/or the corresponding HTTP headers based on the
* HTML5
* encoding sniffing algorithm.
*
* If the specified content is XML content, this method sniffs encoding settings
* from the specified XML content and/or the corresponding HTTP headers using a custom algorithm.
*
* Otherwise, this method sniffs encoding settings from the specified content of unknown type by looking for
* Content-Type information in the HTTP headers and
* Byte Order Mark information in the content.
*
* Note that if an encoding is found but it is not supported on the current platform, this method returns
* {@code null}, as if no encoding had been found.
*
* @param headers the HTTP response headers sent back with the content to be sniffed
* @param content the content to be sniffed
* @return the encoding sniffed from the specified content and/or the corresponding HTTP headers,
* or {@code null} if the encoding could not be determined
* @throws IOException if an IO error occurs
*/
public static Charset sniffEncoding(final List headers, final InputStream content)
throws IOException {
if (isHtml(headers)) {
return sniffHtmlEncoding(headers, content);
}
else if (isXml(headers)) {
return sniffXmlEncoding(headers, content);
}
else {
return sniffUnknownContentTypeEncoding(headers, content);
}
}
/**
* Returns {@code true} if the specified HTTP response headers indicate an HTML response.
*
* @param headers the HTTP response headers
* @return {@code true} if the specified HTTP response headers indicate an HTML response
*/
static boolean isHtml(final List headers) {
return contentTypeEndsWith(headers, MimeType.TEXT_HTML);
}
/**
* Returns {@code true} if the specified HTTP response headers indicate an XML response.
*
* @param headers the HTTP response headers
* @return {@code true} if the specified HTTP response headers indicate an XML response
*/
static boolean isXml(final List headers) {
return contentTypeEndsWith(headers, MimeType.TEXT_XML, "application/xml", "text/vnd.wap.wml", "+xml");
}
/**
* Returns {@code true} if the specified HTTP response headers contain a Content-Type that
* ends with one of the specified strings.
*
* @param headers the HTTP response headers
* @param contentTypeEndings the content type endings to search for
* @return {@code true} if the specified HTTP response headers contain a Content-Type that
* ends with one of the specified strings
*/
static boolean contentTypeEndsWith(final List headers, final String... contentTypeEndings) {
for (final NameValuePair pair : headers) {
final String name = pair.getName();
if (HttpHeader.CONTENT_TYPE_LC.equalsIgnoreCase(name)) {
String value = pair.getValue();
final int i = value.indexOf(';');
if (i != -1) {
value = value.substring(0, i);
}
value = value.trim().toLowerCase(Locale.ROOT);
for (final String ending : contentTypeEndings) {
if (value.endsWith(ending.toLowerCase(Locale.ROOT))) {
return true;
}
}
return false;
}
}
return false;
}
/**
* Sniffs encoding settings from the specified HTML content and/or the corresponding HTTP headers based on the
* HTML5
* encoding sniffing algorithm.
*
* Note that if an encoding is found but it is not supported on the current platform, this method returns
* {@code null}, as if no encoding had been found.
*
* @param headers the HTTP response headers sent back with the HTML content to be sniffed
* @param content the HTML content to be sniffed
* @return the encoding sniffed from the specified HTML content and/or the corresponding HTTP headers,
* or {@code null} if the encoding could not be determined
* @throws IOException if an IO error occurs
*/
public static Charset sniffHtmlEncoding(final List headers, final InputStream content)
throws IOException {
Charset encoding = sniffEncodingFromHttpHeaders(headers);
if (encoding != null || content == null) {
return encoding;
}
byte[] bytes = read(content, 3);
encoding = sniffEncodingFromUnicodeBom(bytes);
if (encoding != null) {
return encoding;
}
bytes = readAndPrepend(content, SIZE_OF_HTML_CONTENT_SNIFFED, bytes);
encoding = sniffEncodingFromMetaTag(bytes);
return encoding;
}
/**
* Sniffs encoding settings from the specified XML content and/or the corresponding HTTP headers using
* a custom algorithm.
*
* Note that if an encoding is found but it is not supported on the current platform, this method returns
* {@code null}, as if no encoding had been found.
*
* @param headers the HTTP response headers sent back with the XML content to be sniffed
* @param content the XML content to be sniffed
* @return the encoding sniffed from the specified XML content and/or the corresponding HTTP headers,
* or {@code null} if the encoding could not be determined
* @throws IOException if an IO error occurs
*/
public static Charset sniffXmlEncoding(final List headers, final InputStream content)
throws IOException {
Charset encoding = sniffEncodingFromHttpHeaders(headers);
if (encoding != null || content == null) {
return encoding;
}
byte[] bytes = read(content, 3);
encoding = sniffEncodingFromUnicodeBom(bytes);
if (encoding != null) {
return encoding;
}
bytes = readAndPrepend(content, SIZE_OF_XML_CONTENT_SNIFFED, bytes);
encoding = sniffEncodingFromXmlDeclaration(bytes);
return encoding;
}
/**
* Sniffs encoding settings from the specified content of unknown type by looking for Content-Type
* information in the HTTP headers and Byte Order Mark
* information in the content.
*
* Note that if an encoding is found but it is not supported on the current platform, this method returns
* {@code null}, as if no encoding had been found.
*
* @param headers the HTTP response headers sent back with the content to be sniffed
* @param content the content to be sniffed
* @return the encoding sniffed from the specified content and/or the corresponding HTTP headers,
* or {@code null} if the encoding could not be determined
* @throws IOException if an IO error occurs
*/
public static Charset sniffUnknownContentTypeEncoding(final List headers, final InputStream content)
throws IOException {
Charset encoding = sniffEncodingFromHttpHeaders(headers);
if (encoding != null || content == null) {
return encoding;
}
final byte[] bytes = read(content, 3);
encoding = sniffEncodingFromUnicodeBom(bytes);
return encoding;
}
/**
* Attempts to sniff an encoding from the specified HTTP headers.
*
* @param headers the HTTP headers to examine
* @return the encoding sniffed from the specified HTTP headers, or {@code null} if the encoding
* could not be determined
*/
public static Charset sniffEncodingFromHttpHeaders(final List headers) {
for (final NameValuePair pair : headers) {
final String name = pair.getName();
if (HttpHeader.CONTENT_TYPE_LC.equalsIgnoreCase(name)) {
final Charset encoding = extractEncodingFromContentType(pair.getValue());
if (encoding != null) {
if (LOG.isDebugEnabled()) {
LOG.debug("Encoding found in HTTP headers: '" + encoding + "'.");
}
return encoding;
}
}
}
return null;
}
/**
* Attempts to sniff an encoding from a Byte Order Mark
* in the specified byte array.
*
* @param bytes the bytes to check for a Byte Order Mark
* @return the encoding sniffed from the specified bytes, or {@code null} if the encoding
* could not be determined
*/
static Charset sniffEncodingFromUnicodeBom(final byte[] bytes) {
if (bytes == null) {
return null;
}
Charset encoding = null;
if (startsWith(bytes, ByteOrderMark.UTF_8)) {
encoding = UTF_8;
}
else if (startsWith(bytes, ByteOrderMark.UTF_16BE)) {
encoding = UTF_16BE;
}
else if (startsWith(bytes, ByteOrderMark.UTF_16LE)) {
encoding = UTF_16LE;
}
if (encoding != null && LOG.isDebugEnabled()) {
LOG.debug("Encoding found in Unicode Byte Order Mark: '" + encoding + "'.");
}
return encoding;
}
/**
* Returns whether the specified byte array starts with the given {@link ByteOrderMark}, or not.
* @param bytes the byte array to check
* @param bom the {@link ByteOrderMark}
* @return whether the specified byte array starts with the given {@link ByteOrderMark}, or not
*/
private static boolean startsWith(final byte[] bytes, final ByteOrderMark bom) {
final byte[] bomBytes = bom.getBytes();
final byte[] firstBytes = Arrays.copyOfRange(bytes, 0, Math.min(bytes.length, bomBytes.length));
return Arrays.equals(firstBytes, bomBytes);
}
/**
* Attempts to sniff an encoding from an HTML meta tag in the specified byte array.
*
* @param bytes the bytes to check for an HTML meta tag
* @return the encoding sniffed from the specified bytes, or {@code null} if the encoding
* could not be determined
*/
static Charset sniffEncodingFromMetaTag(final byte[] bytes) {
for (int i = 0; i < bytes.length; i++) {
if (matches(bytes, i, COMMENT_START)) {
i = indexOfSubArray(bytes, COMMENT_END, i);
if (i == -1) {
break;
}
i += 2;
}
else if (matches(bytes, i, META_START)) {
i += META_START.length;
for (Attribute att = getAttribute(bytes, i); att != null; att = getAttribute(bytes, i)) {
i = att.getUpdatedIndex();
final String name = att.getName();
final String value = att.getValue();
if ("charset".equals(name) || "content".equals(name)) {
Charset charset = null;
if ("charset".equals(name)) {
charset = toCharset(value);
}
else if ("content".equals(name)) {
charset = extractEncodingFromContentType(value);
if (charset == null) {
continue;
}
}
if (UTF_16BE == charset || UTF_16LE == charset) {
charset = UTF_8;
}
if (charset != null) {
if (LOG.isDebugEnabled()) {
LOG.debug("Encoding found in meta tag: '" + charset + "'.");
}
return charset;
}
}
}
}
else if (i + 1 < bytes.length && bytes[i] == '<' && Character.isLetter(bytes[i + 1])) {
i = skipToAnyOf(bytes, i, WHITESPACE);
if (i == -1) {
break;
}
Attribute att = getAttribute(bytes, i);
while (att != null) {
i = att.getUpdatedIndex();
att = getAttribute(bytes, i);
}
}
else if (i + 2 < bytes.length && bytes[i] == '<' && bytes[i + 1] == '/' && Character.isLetter(bytes[i + 2])) {
i = skipToAnyOf(bytes, i, new byte[] {0x09, 0x0A, 0x0C, 0x0D, 0x20, 0x3E});
if (i == -1) {
break;
}
Attribute attribute = getAttribute(bytes, i);
while (attribute != null) {
i = attribute.getUpdatedIndex();
attribute = getAttribute(bytes, i);
}
}
else if (matches(bytes, i, OTHER_START)) {
i = skipToAnyOf(bytes, i, new byte[] {0x3E});
if (i == -1) {
break;
}
}
}
return null;
}
/**
* Extracts an attribute from the specified byte array, starting at the specified index, using the
* HTML5
* attribute algorithm.
*
* @param bytes the byte array to extract an attribute from
* @param i the index to start searching from
* @return the next attribute in the specified byte array, or {@code null} if one is not available
*/
static Attribute getAttribute(final byte[] bytes, int i) {
if (i >= bytes.length) {
return null;
}
while (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20 || bytes[i] == 0x2F) {
i++;
if (i >= bytes.length) {
return null;
}
}
if (bytes[i] == '>') {
return null;
}
final StringBuilder name = new StringBuilder();
final StringBuilder value = new StringBuilder();
for ( ;; i++) {
if (i >= bytes.length) {
return new Attribute(name.toString(), value.toString(), i);
}
if (bytes[i] == '=' && name.length() != 0) {
i++;
break;
}
if (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20) {
while (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20) {
i++;
if (i >= bytes.length) {
return new Attribute(name.toString(), value.toString(), i);
}
}
if (bytes[i] != '=') {
return new Attribute(name.toString(), value.toString(), i);
}
i++;
break;
}
if (bytes[i] == '/' || bytes[i] == '>') {
return new Attribute(name.toString(), value.toString(), i);
}
name.append((char) bytes[i]);
}
if (i >= bytes.length) {
return new Attribute(name.toString(), value.toString(), i);
}
while (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20) {
i++;
if (i >= bytes.length) {
return new Attribute(name.toString(), value.toString(), i);
}
}
if (bytes[i] == '"' || bytes[i] == '\'') {
final byte b = bytes[i];
for (i++; i < bytes.length; i++) {
if (bytes[i] == b) {
i++;
return new Attribute(name.toString(), value.toString(), i);
}
else if (bytes[i] >= 'A' && bytes[i] <= 'Z') {
final byte b2 = (byte) (bytes[i] + 0x20);
value.append((char) b2);
}
else {
value.append((char) bytes[i]);
}
}
return new Attribute(name.toString(), value.toString(), i);
}
else if (bytes[i] == '>') {
return new Attribute(name.toString(), value.toString(), i);
}
else if (bytes[i] >= 'A' && bytes[i] <= 'Z') {
final byte b = (byte) (bytes[i] + 0x20);
value.append((char) b);
i++;
}
else {
value.append((char) bytes[i]);
i++;
}
for ( ; i < bytes.length; i++) {
if (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20 || bytes[i] == 0x3E) {
return new Attribute(name.toString(), value.toString(), i);
}
else if (bytes[i] >= 'A' && bytes[i] <= 'Z') {
final byte b = (byte) (bytes[i] + 0x20);
value.append((char) b);
}
else {
value.append((char) bytes[i]);
}
}
return new Attribute(name.toString(), value.toString(), i);
}
/**
* Extracts an encoding from the specified Content-Type value using
* the IETF algorithm; if
* no encoding is found, this method returns {@code null}.
*
* @param s the Content-Type value to search for an encoding
* @return the encoding found in the specified Content-Type value, or {@code null} if no
* encoding was found
*/
static Charset extractEncodingFromContentType(final String s) {
if (s == null) {
return null;
}
final byte[] bytes = s.getBytes(US_ASCII);
int i;
for (i = 0; i < bytes.length; i++) {
if (matches(bytes, i, CHARSET_START)) {
i += CHARSET_START.length;
break;
}
}
if (i == bytes.length) {
return null;
}
while (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20) {
i++;
if (i == bytes.length) {
return null;
}
}
if (bytes[i] != '=') {
return null;
}
i++;
if (i == bytes.length) {
return null;
}
while (bytes[i] == 0x09 || bytes[i] == 0x0A || bytes[i] == 0x0C || bytes[i] == 0x0D || bytes[i] == 0x20) {
i++;
if (i == bytes.length) {
return null;
}
}
if (bytes[i] == '"') {
if (bytes.length <= i + 1) {
return null;
}
final int index = ArrayUtils.indexOf(bytes, (byte) '"', i + 1);
if (index == -1) {
return null;
}
final String charsetName = new String(ArrayUtils.subarray(bytes, i + 1, index), US_ASCII);
return toCharset(charsetName);
}
if (bytes[i] == '\'') {
if (bytes.length <= i + 1) {
return null;
}
final int index = ArrayUtils.indexOf(bytes, (byte) '\'', i + 1);
if (index == -1) {
return null;
}
final String charsetName = new String(ArrayUtils.subarray(bytes, i + 1, index), US_ASCII);
return toCharset(charsetName);
}
int end = skipToAnyOf(bytes, i, new byte[] {0x09, 0x0A, 0x0C, 0x0D, 0x20, 0x3B});
if (end == -1) {
end = bytes.length;
}
final String charsetName = new String(ArrayUtils.subarray(bytes, i, end), US_ASCII);
return toCharset(charsetName);
}
/**
* Searches the specified XML content for an XML declaration and returns the encoding if found,
* otherwise returns {@code null}.
*
* @param bytes the XML content to sniff
* @return the encoding of the specified XML content, or {@code null} if it could not be determined
*/
static Charset sniffEncodingFromXmlDeclaration(final byte[] bytes) {
Charset encoding = null;
if (bytes.length > 5
&& XML_DECLARATION_PREFIX[0] == bytes[0]
&& XML_DECLARATION_PREFIX[1] == bytes[1]
&& XML_DECLARATION_PREFIX[2] == bytes[2]
&& XML_DECLARATION_PREFIX[3] == bytes[3]
&& XML_DECLARATION_PREFIX[4] == bytes[4]
&& XML_DECLARATION_PREFIX[5] == bytes[5]) {
final int index = ArrayUtils.indexOf(bytes, (byte) '?', 2);
if (index + 1 < bytes.length && bytes[index + 1] == '>') {
final String declaration = new String(bytes, 0, index + 2, US_ASCII);
int start = declaration.indexOf("encoding");
if (start != -1) {
start += 8;
char delimiter;
outer:
while (true) {
switch (declaration.charAt(start)) {
case '"':
case '\'':
delimiter = declaration.charAt(start);
start = start + 1;
break outer;
default:
start++;
}
}
final int end = declaration.indexOf(delimiter, start);
encoding = toCharset(declaration.substring(start, end));
}
}
}
if (encoding != null && LOG.isDebugEnabled()) {
LOG.debug("Encoding found in XML declaration: '" + encoding + "'.");
}
return encoding;
}
/**
* Returns {@code Charset} if the specified charset name is supported on this platform.
*
* @param charsetName the charset name to check
* @return {@code Charset} if the specified charset name is supported on this platform
*/
public static Charset toCharset(final String charsetName) {
if (StringUtils.isEmpty(charsetName)) {
return null;
}
try {
return Charset.forName(charsetName);
}
catch (final IllegalCharsetNameException | UnsupportedCharsetException e) {
return null;
}
}
/**
* Returns {@code true} if the byte in the specified byte array at the specified index matches one of the
* specified byte array patterns.
*
* @param bytes the byte array to search in
* @param i the index at which to search
* @param sought the byte array patterns to search for
* @return {@code true} if the byte in the specified byte array at the specified index matches one of the
* specified byte array patterns
*/
static boolean matches(final byte[] bytes, final int i, final byte[][] sought) {
if (i + sought.length > bytes.length) {
return false;
}
for (int x = 0; x < sought.length; x++) {
final byte[] possibilities = sought[x];
boolean match = false;
for (final byte possibility : possibilities) {
if (bytes[i + x] == possibility) {
match = true;
break;
}
}
if (!match) {
return false;
}
}
return true;
}
/**
* Skips ahead to the first occurrence of any of the specified targets within the specified array,
* starting at the specified index. This method returns -1 if none of the targets are found.
*
* @param bytes the array to search through
* @param i the index to start looking at
* @param targets the targets to search for
* @return the index of the first occurrence of any of the specified targets within the specified array
*/
static int skipToAnyOf(final byte[] bytes, int i, final byte[] targets) {
for ( ; i < bytes.length; i++) {
if (ArrayUtils.contains(targets, bytes[i])) {
break;
}
}
if (i == bytes.length) {
i = -1;
}
return i;
}
/**
* Finds the first index of the specified sub-array inside the specified array, starting at the
* specified index. This method returns -1 if the specified sub-array cannot be found.
*
* @param array the array to traverse for looking for the sub-array
* @param subarray the sub-array to find
* @param startIndex the start index to traverse forwards from
* @return the index of the sub-array within the array
*/
static int indexOfSubArray(final byte[] array, final byte[] subarray, final int startIndex) {
for (int i = startIndex; i < array.length; i++) {
boolean found = true;
if (i + subarray.length > array.length) {
break;
}
for (int j = 0; j < subarray.length; j++) {
final byte a = array[i + j];
final byte b = subarray[j];
if (a != b) {
found = false;
break;
}
}
if (found) {
return i;
}
}
return -1;
}
/**
* Attempts to read size bytes from the specified input stream. Note that this method is not guaranteed
* to be able to read size bytes; however, the returned byte array will always be the exact length of the
* number of bytes read.
*
* @param content the input stream to read from
* @param size the number of bytes to try to read
* @return the bytes read from the specified input stream
* @throws IOException if an IO error occurs
*/
static byte[] read(final InputStream content, final int size) throws IOException {
byte[] bytes = new byte[size];
final int count = content.read(bytes);
if (count == -1) {
bytes = new byte[0];
}
else if (count < size) {
final byte[] smaller = new byte[count];
System.arraycopy(bytes, 0, smaller, 0, count);
bytes = smaller;
}
return bytes;
}
/**
* Attempts to read size bytes from the specified input stream and then prepends the specified prefix to
* the bytes read, returning the resultant byte array. Note that this method is not guaranteed to be able to read
* size bytes; however, the returned byte array will always be the exact length of the number of bytes
* read plus the length of the prefix array.
*
* @param content the input stream to read from
* @param size the number of bytes to try to read
* @param prefix the byte array to prepend to the bytes read from the specified input stream
* @return the bytes read from the specified input stream, prefixed by the specified prefix
* @throws IOException if an IO error occurs
*/
static byte[] readAndPrepend(final InputStream content, final int size, final byte[] prefix) throws IOException {
final byte[] bytes = read(content, size);
final byte[] joined = new byte[prefix.length + bytes.length];
System.arraycopy(prefix, 0, joined, 0, prefix.length);
System.arraycopy(bytes, 0, joined, prefix.length, bytes.length);
return joined;
}
static class Attribute {
private final String name_;
private final String value_;
private final int updatedIndex_;
Attribute(final String name, final String value, final int updatedIndex) {
name_ = name;
value_ = value;
updatedIndex_ = updatedIndex;
}
String getName() {
return name_;
}
String getValue() {
return value_;
}
int getUpdatedIndex() {
return updatedIndex_;
}
}
/**
* Translates the given encoding label into a normalized form
* according to Reference.
* @param encodingLabel the label to translate
* @return the normalized encoding name or null if not found
*/
public static String translateEncodingLabel(final Charset encodingLabel) {
if (null == encodingLabel) {
return null;
}
final String encLC = encodingLabel.name().toLowerCase(Locale.ROOT);
final String enc = ENCODING_FROM_LABEL.get(encLC);
if (encLC.equals(enc)) {
return encodingLabel.name();
}
return enc;
}
}