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* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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 org.elasticsearch.http.netty4.cors;
import io.netty.handler.codec.http.DefaultHttpHeaders;
import io.netty.handler.codec.http.EmptyHttpHeaders;
import io.netty.handler.codec.http.HttpHeaders;
import io.netty.handler.codec.http.HttpMethod;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.regex.Pattern;
/**
* Configuration for Cross-Origin Resource Sharing (CORS).
*
* This class was lifted from the Netty project:
* https://github.com/netty/netty
*/
public final class Netty4CorsConfig {
private final Optional<Set<String>> origins;
private final Optional<Pattern> pattern;
private final boolean anyOrigin;
private final boolean enabled;
private final boolean allowCredentials;
private final long maxAge;
private final Set<HttpMethod> allowedRequestMethods;
private final Set<String> allowedRequestHeaders;
private final boolean allowNullOrigin;
private final Map<CharSequence, Callable<?>> preflightHeaders;
private final boolean shortCircuit;
Netty4CorsConfig(final Netty4CorsConfigBuilder builder) {
origins = builder.origins.map(s -> new LinkedHashSet<>(s));
pattern = builder.pattern;
anyOrigin = builder.anyOrigin;
enabled = builder.enabled;
allowCredentials = builder.allowCredentials;
maxAge = builder.maxAge;
allowedRequestMethods = builder.requestMethods;
allowedRequestHeaders = builder.requestHeaders;
allowNullOrigin = builder.allowNullOrigin;
preflightHeaders = builder.preflightHeaders;
shortCircuit = builder.shortCircuit;
}
/**
* Determines if support for CORS is enabled.
*
* @return {@code true} if support for CORS is enabled, false otherwise.
*/
public boolean isCorsSupportEnabled() {
return enabled;
}
/**
* Determines whether a wildcard origin, '*', is supported.
*
* @return {@code boolean} true if any origin is allowed.
*/
public boolean isAnyOriginSupported() {
return anyOrigin;
}
/**
* Returns the set of allowed origins.
*
* @return {@code Set} the allowed origins.
*/
public Optional<Set<String>> origins() {
return origins;
}
/**
* Returns whether the input origin is allowed by this configuration.
*
* @return {@code true} if the origin is allowed, otherwise {@code false}
*/
public boolean isOriginAllowed(final String origin) {
if (origins.isPresent()) {
return origins.get().contains(origin);
} else if (pattern.isPresent()) {
return pattern.get().matcher(origin).matches();
}
return false;
}
/**
* Web browsers may set the 'Origin' request header to 'null' if a resource is loaded
* from the local file system.
*
* If isNullOriginAllowed is true then the server will response with the wildcard for the
* the CORS response header 'Access-Control-Allow-Origin'.
*
* @return {@code true} if a 'null' origin should be supported.
*/
public boolean isNullOriginAllowed() {
return allowNullOrigin;
}
/**
* Determines if cookies are supported for CORS requests.
*
* By default cookies are not included in CORS requests but if isCredentialsAllowed returns
* true cookies will be added to CORS requests. Setting this value to true will set the
* CORS 'Access-Control-Allow-Credentials' response header to true.
*
* Please note that cookie support needs to be enabled on the client side as well.
* The client needs to opt-in to send cookies by calling:
* <pre>
* xhr.withCredentials = true;
* </pre>
* The default value for 'withCredentials' is false in which case no cookies are sent.
* Setting this to true will included cookies in cross origin requests.
*
* @return {@code true} if cookies are supported.
*/
public boolean isCredentialsAllowed() {
return allowCredentials;
}
/**
* Gets the maxAge setting.
*
* When making a preflight request the client has to perform two request with can be inefficient.
* This setting will set the CORS 'Access-Control-Max-Age' response header and enables the
* caching of the preflight response for the specified time. During this time no preflight
* request will be made.
*
* @return {@code long} the time in seconds that a preflight request may be cached.
*/
public long maxAge() {
return maxAge;
}
/**
* Returns the allowed set of Request Methods. The Http methods that should be returned in the
* CORS 'Access-Control-Request-Method' response header.
*
* @return {@code Set} of {@link HttpMethod}s that represent the allowed Request Methods.
*/
public Set<HttpMethod> allowedRequestMethods() {
return Collections.unmodifiableSet(allowedRequestMethods);
}
/**
* Returns the allowed set of Request Headers.
*
* The header names returned from this method will be used to set the CORS
* 'Access-Control-Allow-Headers' response header.
*
* @return {@code Set<String>} of strings that represent the allowed Request Headers.
*/
public Set<String> allowedRequestHeaders() {
return Collections.unmodifiableSet(allowedRequestHeaders);
}
/**
* Returns HTTP response headers that should be added to a CORS preflight response.
*
* @return {@link HttpHeaders} the HTTP response headers to be added.
*/
public HttpHeaders preflightResponseHeaders() {
if (preflightHeaders.isEmpty()) {
return EmptyHttpHeaders.INSTANCE;
}
final HttpHeaders preflightHeaders = new DefaultHttpHeaders();
for (Map.Entry<CharSequence, Callable<?>> entry : this.preflightHeaders.entrySet()) {
final Object value = getValue(entry.getValue());
if (value instanceof Iterable) {
preflightHeaders.add(entry.getKey().toString(), (Iterable<?>) value);
} else {
preflightHeaders.add(entry.getKey().toString(), value);
}
}
return preflightHeaders;
}
/**
* Determines whether a CORS request should be rejected if it's invalid before being
* further processing.
*
* CORS headers are set after a request is processed. This may not always be desired
* and this setting will check that the Origin is valid and if it is not valid no
* further processing will take place, and a error will be returned to the calling client.
*
* @return {@code true} if a CORS request should short-circuit upon receiving an invalid Origin header.
*/
public boolean isShortCircuit() {
return shortCircuit;
}
private static <T> T getValue(final Callable<T> callable) {
try {
return callable.call();
} catch (final Exception e) {
throw new IllegalStateException("Could not generate value for callable [" + callable + ']', e);
}
}
@Override
public String toString() {
return "CorsConfig[enabled=" + enabled +
", origins=" + origins +
", anyOrigin=" + anyOrigin +
", isCredentialsAllowed=" + allowCredentials +
", maxAge=" + maxAge +
", allowedRequestMethods=" + allowedRequestMethods +
", allowedRequestHeaders=" + allowedRequestHeaders +
", preflightHeaders=" + preflightHeaders + ']';
}
}