/*
 * Copyright 2015 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.codec.http;

import io.netty.handler.codec.DefaultHeaders;
import io.netty.handler.codec.Headers;
import io.netty.handler.codec.ValueConverter;
import io.netty.util.HashingStrategy;
import io.netty.util.internal.StringUtil;

import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import static io.netty.util.AsciiString.CASE_INSENSITIVE_HASHER;
import static io.netty.util.internal.StringUtil.COMMA;
import static io.netty.util.internal.StringUtil.unescapeCsvFields;

Will add multiple values for the same header as single header with a comma separated list of values.

Please refer to section RFC 7230, 3.2.2.

/** * Will add multiple values for the same header as single header with a comma separated list of values. * <p> * Please refer to section <a href="https://tools.ietf.org/html/rfc7230#section-3.2.2">RFC 7230, 3.2.2</a>. */
public class CombinedHttpHeaders extends DefaultHttpHeaders { public CombinedHttpHeaders(boolean validate) { super(new CombinedHttpHeadersImpl(CASE_INSENSITIVE_HASHER, valueConverter(validate), nameValidator(validate))); } @Override public boolean containsValue(CharSequence name, CharSequence value, boolean ignoreCase) { return super.containsValue(name, StringUtil.trimOws(value), ignoreCase); } private static final class CombinedHttpHeadersImpl extends DefaultHeaders<CharSequence, CharSequence, CombinedHttpHeadersImpl> {
An estimate of the size of a header value.
/** * An estimate of the size of a header value. */
private static final int VALUE_LENGTH_ESTIMATE = 10; private CsvValueEscaper<Object> objectEscaper; private CsvValueEscaper<CharSequence> charSequenceEscaper; private CsvValueEscaper<Object> objectEscaper() { if (objectEscaper == null) { objectEscaper = new CsvValueEscaper<Object>() { @Override public CharSequence escape(Object value) { return StringUtil.escapeCsv(valueConverter().convertObject(value), true); } }; } return objectEscaper; } private CsvValueEscaper<CharSequence> charSequenceEscaper() { if (charSequenceEscaper == null) { charSequenceEscaper = new CsvValueEscaper<CharSequence>() { @Override public CharSequence escape(CharSequence value) { return StringUtil.escapeCsv(value, true); } }; } return charSequenceEscaper; } public CombinedHttpHeadersImpl(HashingStrategy<CharSequence> nameHashingStrategy, ValueConverter<CharSequence> valueConverter, io.netty.handler.codec.DefaultHeaders.NameValidator<CharSequence> nameValidator) { super(nameHashingStrategy, valueConverter, nameValidator); } @Override public Iterator<CharSequence> valueIterator(CharSequence name) { Iterator<CharSequence> itr = super.valueIterator(name); if (!itr.hasNext()) { return itr; } Iterator<CharSequence> unescapedItr = unescapeCsvFields(itr.next()).iterator(); if (itr.hasNext()) { throw new IllegalStateException("CombinedHttpHeaders should only have one value"); } return unescapedItr; } @Override public List<CharSequence> getAll(CharSequence name) { List<CharSequence> values = super.getAll(name); if (values.isEmpty()) { return values; } if (values.size() != 1) { throw new IllegalStateException("CombinedHttpHeaders should only have one value"); } return unescapeCsvFields(values.get(0)); } @Override public CombinedHttpHeadersImpl add(Headers<? extends CharSequence, ? extends CharSequence, ?> headers) { // Override the fast-copy mechanism used by DefaultHeaders if (headers == this) { throw new IllegalArgumentException("can't add to itself."); } if (headers instanceof CombinedHttpHeadersImpl) { if (isEmpty()) { // Can use the fast underlying copy addImpl(headers); } else { // Values are already escaped so don't escape again for (Map.Entry<? extends CharSequence, ? extends CharSequence> header : headers) { addEscapedValue(header.getKey(), header.getValue()); } } } else { for (Map.Entry<? extends CharSequence, ? extends CharSequence> header : headers) { add(header.getKey(), header.getValue()); } } return this; } @Override public CombinedHttpHeadersImpl set(Headers<? extends CharSequence, ? extends CharSequence, ?> headers) { if (headers == this) { return this; } clear(); return add(headers); } @Override public CombinedHttpHeadersImpl setAll(Headers<? extends CharSequence, ? extends CharSequence, ?> headers) { if (headers == this) { return this; } for (CharSequence key : headers.names()) { remove(key); } return add(headers); } @Override public CombinedHttpHeadersImpl add(CharSequence name, CharSequence value) { return addEscapedValue(name, charSequenceEscaper().escape(value)); } @Override public CombinedHttpHeadersImpl add(CharSequence name, CharSequence... values) { return addEscapedValue(name, commaSeparate(charSequenceEscaper(), values)); } @Override public CombinedHttpHeadersImpl add(CharSequence name, Iterable<? extends CharSequence> values) { return addEscapedValue(name, commaSeparate(charSequenceEscaper(), values)); } @Override public CombinedHttpHeadersImpl addObject(CharSequence name, Object value) { return addEscapedValue(name, commaSeparate(objectEscaper(), value)); } @Override public CombinedHttpHeadersImpl addObject(CharSequence name, Iterable<?> values) { return addEscapedValue(name, commaSeparate(objectEscaper(), values)); } @Override public CombinedHttpHeadersImpl addObject(CharSequence name, Object... values) { return addEscapedValue(name, commaSeparate(objectEscaper(), values)); } @Override public CombinedHttpHeadersImpl set(CharSequence name, CharSequence... values) { super.set(name, commaSeparate(charSequenceEscaper(), values)); return this; } @Override public CombinedHttpHeadersImpl set(CharSequence name, Iterable<? extends CharSequence> values) { super.set(name, commaSeparate(charSequenceEscaper(), values)); return this; } @Override public CombinedHttpHeadersImpl setObject(CharSequence name, Object value) { super.set(name, commaSeparate(objectEscaper(), value)); return this; } @Override public CombinedHttpHeadersImpl setObject(CharSequence name, Object... values) { super.set(name, commaSeparate(objectEscaper(), values)); return this; } @Override public CombinedHttpHeadersImpl setObject(CharSequence name, Iterable<?> values) { super.set(name, commaSeparate(objectEscaper(), values)); return this; } private CombinedHttpHeadersImpl addEscapedValue(CharSequence name, CharSequence escapedValue) { CharSequence currentValue = super.get(name); if (currentValue == null) { super.add(name, escapedValue); } else { super.set(name, commaSeparateEscapedValues(currentValue, escapedValue)); } return this; } private static <T> CharSequence commaSeparate(CsvValueEscaper<T> escaper, T... values) { StringBuilder sb = new StringBuilder(values.length * VALUE_LENGTH_ESTIMATE); if (values.length > 0) { int end = values.length - 1; for (int i = 0; i < end; i++) { sb.append(escaper.escape(values[i])).append(COMMA); } sb.append(escaper.escape(values[end])); } return sb; } private static <T> CharSequence commaSeparate(CsvValueEscaper<T> escaper, Iterable<? extends T> values) { @SuppressWarnings("rawtypes") final StringBuilder sb = values instanceof Collection ? new StringBuilder(((Collection) values).size() * VALUE_LENGTH_ESTIMATE) : new StringBuilder(); Iterator<? extends T> iterator = values.iterator(); if (iterator.hasNext()) { T next = iterator.next(); while (iterator.hasNext()) { sb.append(escaper.escape(next)).append(COMMA); next = iterator.next(); } sb.append(escaper.escape(next)); } return sb; } private static CharSequence commaSeparateEscapedValues(CharSequence currentValue, CharSequence value) { return new StringBuilder(currentValue.length() + 1 + value.length()) .append(currentValue) .append(COMMA) .append(value); }
Escapes comma separated values (CSV).
Type parameters:
  • <T> – The type that a concrete implementation handles
/** * Escapes comma separated values (CSV). * * @param <T> The type that a concrete implementation handles */
private interface CsvValueEscaper<T> {
Appends the value to the specified StringBuilder, escaping if necessary.
Params:
  • value – the value to be appended, escaped if necessary
/** * Appends the value to the specified {@link StringBuilder}, escaping if necessary. * * @param value the value to be appended, escaped if necessary */
CharSequence escape(T value); } } }