com.gargoylesoftware.htmlunit.protocol.data.DataUrlDecoder Maven / Gradle / Ivy
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A headless browser intended for use in testing web-based applications.
/*
* Copyright (c) 2002-2018 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.protocol.data;
import static java.nio.charset.StandardCharsets.US_ASCII;
import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.nio.charset.Charset;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;
import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.net.URLCodec;
import org.apache.commons.lang3.StringUtils;
/**
* Helper to work with data URLs.
* @see RFC2397
* @author Marc Guillemot
* @author Ronald Brill
* @author Carsten Steul
*/
public class DataUrlDecoder {
private static final Charset DEFAULT_CHARSET = US_ASCII;
private static final String DEFAULT_MEDIA_TYPE = "text/plain";
private final String mediaType_;
private final Charset charset_;
private byte[] content_;
/**
* C'tor.
* @param data the data
* @param mediaType the media type
* @param charset the charset
*/
protected DataUrlDecoder(final byte[] data, final String mediaType, final Charset charset) {
content_ = data;
mediaType_ = mediaType;
charset_ = charset;
}
/**
* Decodes a data URL providing simple access to the information contained by the URL.
* @param url the URL to decode
* @return the {@link DataUrlDecoder} holding decoded information
* @throws UnsupportedEncodingException if the encoding specified by the data URL is invalid or not
* available on the JVM
* @throws DecoderException if decoding didn't success
*/
public static DataUrlDecoder decode(final URL url) throws UnsupportedEncodingException, DecoderException {
return decodeDataURL(url.toExternalForm());
}
/**
* Decodes a data URL providing simple access to the information contained by the URL.
* @param url the string representation of the URL to decode
* @return the {@link DataUrlDecoder} holding decoded information
* @throws UnsupportedEncodingException if the encoding specified by the data URL is invalid or not
* available on the JVM
* @throws DecoderException if decoding didn't success
*/
public static DataUrlDecoder decodeDataURL(final String url) throws UnsupportedEncodingException,
DecoderException {
if (!url.startsWith("data")) {
throw new IllegalArgumentException("Not a data url: " + url);
}
final int comma = url.indexOf(',');
String beforeData = url.substring("data:".length(), comma);
final boolean base64 = beforeData.endsWith(";base64");
if (base64) {
beforeData = beforeData.substring(0, beforeData.length() - 7);
}
final String mediaType = extractMediaType(beforeData);
final Charset charset = extractCharset(beforeData);
byte[] data = url.substring(comma + 1).getBytes(charset);
if (base64) {
data = Base64.decodeBase64(decodeUrl(data));
}
else {
data = URLCodec.decodeUrl(data);
}
return new DataUrlDecoder(data, mediaType, charset);
}
private static Charset extractCharset(final String beforeData) {
if (beforeData.contains(";")) {
String charsetName = StringUtils.substringAfter(beforeData, ";");
charsetName = charsetName.trim();
if (charsetName.startsWith("charset=")) {
charsetName = charsetName.substring(8);
}
try {
return Charset.forName(charsetName);
}
catch (final UnsupportedCharsetException | IllegalCharsetNameException e) {
return DEFAULT_CHARSET;
}
}
return DEFAULT_CHARSET;
}
private static String extractMediaType(final String beforeData) {
if (beforeData.contains("/")) {
if (beforeData.contains(";")) {
return StringUtils.substringBefore(beforeData, ";");
}
return beforeData;
}
return DEFAULT_MEDIA_TYPE;
}
/**
* Gets the media type information contained in the data URL.
* @return "text/plain" if the URL didn't contain any media type information
*/
public String getMediaType() {
return mediaType_;
}
/**
* Gets the charset information specified in the data URL.
* @return "US-ASCII" if the URL didn't contain any charset information
*/
public String getCharset() {
return charset_.name();
}
/**
* Gets the bytes contained in the data URL.
* @return the content
*/
public byte[] getBytes() {
return content_;
}
/**
* Gets the text content of the data URL. This makes sense only for data URL that
* represents some text.
* @return the text content
* @throws UnsupportedEncodingException if decoding failed using the specified charset
*/
public String getDataAsString() throws UnsupportedEncodingException {
return new String(content_, charset_);
}
// adapted from apache commons codec
private static byte[] decodeUrl(final byte[] bytes) throws DecoderException {
if (bytes == null) {
return null;
}
final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
for (int i = 0; i < bytes.length; i++) {
final int b = bytes[i];
if (b == '%') {
try {
final int u = digit16(bytes[++i]);
final int l = digit16(bytes[++i]);
buffer.write((char) ((u << 4) + l));
}
catch (final ArrayIndexOutOfBoundsException e) {
throw new DecoderException("Invalid URL encoding: ", e);
}
}
else {
buffer.write(b);
}
}
return buffer.toByteArray();
}
private static int digit16(final byte b) throws DecoderException {
final int i = Character.digit((char) b, 16);
if (i == -1) {
throw new DecoderException("Invalid URL encoding: not a valid digit (radix 16): " + b);
}
return i;
}
}