/*
* Copyright 2002-2016 the original author or authors.
*
* 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 org.springframework.web.servlet.mvc.condition;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.servlet.http.HttpServletRequest;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.cors.CorsUtils;
/**
* A logical conjunction (' && ') request condition that matches a request against
* a set of header expressions with syntax defined in {@link RequestMapping#headers()}.
*
* <p>Expressions passed to the constructor with header names 'Accept' or
* 'Content-Type' are ignored. See {@link ConsumesRequestCondition} and
* {@link ProducesRequestCondition} for those.
*
* @author Arjen Poutsma
* @author Rossen Stoyanchev
* @since 3.1
*/
public final class HeadersRequestCondition extends AbstractRequestCondition<HeadersRequestCondition> {
private final static HeadersRequestCondition PRE_FLIGHT_MATCH = new HeadersRequestCondition();
private final Set<HeaderExpression> expressions;
/**
* Create a new instance from the given header expressions. Expressions with
* header names 'Accept' or 'Content-Type' are ignored. See {@link ConsumesRequestCondition}
* and {@link ProducesRequestCondition} for those.
* @param headers media type expressions with syntax defined in {@link RequestMapping#headers()};
* if 0, the condition will match to every request
*/
public HeadersRequestCondition(String... headers) {
this(parseExpressions(headers));
}
private HeadersRequestCondition(Collection<HeaderExpression> conditions) {
this.expressions = Collections.unmodifiableSet(new LinkedHashSet<>(conditions));
}
private static Collection<HeaderExpression> parseExpressions(String... headers) {
Set<HeaderExpression> expressions = new LinkedHashSet<>();
if (headers != null) {
for (String header : headers) {
HeaderExpression expr = new HeaderExpression(header);
if ("Accept".equalsIgnoreCase(expr.name) || "Content-Type".equalsIgnoreCase(expr.name)) {
continue;
}
expressions.add(expr);
}
}
return expressions;
}
/**
* Return the contained request header expressions.
*/
public Set<NameValueExpression<String>> getExpressions() {
return new LinkedHashSet<>(this.expressions);
}
@Override
protected Collection<HeaderExpression> getContent() {
return this.expressions;
}
@Override
protected String getToStringInfix() {
return " && ";
}
/**
* Returns a new instance with the union of the header expressions
* from "this" and the "other" instance.
*/
@Override
public HeadersRequestCondition combine(HeadersRequestCondition other) {
Set<HeaderExpression> set = new LinkedHashSet<>(this.expressions);
set.addAll(other.expressions);
return new HeadersRequestCondition(set);
}
/**
* Returns "this" instance if the request matches all expressions;
* or {@code null} otherwise.
*/
@Override
public HeadersRequestCondition getMatchingCondition(HttpServletRequest request) {
if (CorsUtils.isPreFlightRequest(request)) {
return PRE_FLIGHT_MATCH;
}
for (HeaderExpression expression : expressions) {
if (!expression.match(request)) {
return null;
}
}
return this;
}
/**
* Returns:
* <ul>
* <li>0 if the two conditions have the same number of header expressions
* <li>Less than 0 if "this" instance has more header expressions
* <li>Greater than 0 if the "other" instance has more header expressions
* </ul>
* <p>It is assumed that both instances have been obtained via
* {@link #getMatchingCondition(HttpServletRequest)} and each instance
* contains the matching header expression only or is otherwise empty.
*/
@Override
public int compareTo(HeadersRequestCondition other, HttpServletRequest request) {
return other.expressions.size() - this.expressions.size();
}
/**
* Parses and matches a single header expression to a request.
*/
static class HeaderExpression extends AbstractNameValueExpression<String> {
public HeaderExpression(String expression) {
super(expression);
}
@Override
protected boolean isCaseSensitiveName() {
return false;
}
@Override
protected String parseValue(String valueExpression) {
return valueExpression;
}
@Override
protected boolean matchName(HttpServletRequest request) {
return request.getHeader(name) != null;
}
@Override
protected boolean matchValue(HttpServletRequest request) {
return value.equals(request.getHeader(name));
}
}
}