Java example source code file (HttpCorsServerInitializer.java)

This example Java source code file (HttpCorsServerInitializer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

channelinitializer, channelpipeline, chunkedwritehandler, corsconfig, corshandler, httpcorsserverinitializer, httpobjectaggregator, httprequestdecoder, httpresponseencoder, okresponsehandler, override, sslcontext

The HttpCorsServerInitializer.java Java example source code

/*
 * Copyright 2012 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.example.http.cors;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpRequestDecoder;
import io.netty.handler.codec.http.HttpResponseEncoder;
import io.netty.handler.codec.http.cors.CorsConfig;
import io.netty.handler.codec.http.cors.CorsConfigBuilder;
import io.netty.handler.codec.http.cors.CorsHandler;
import io.netty.handler.ssl.SslContext;
import io.netty.handler.stream.ChunkedWriteHandler;

/**
 * Please refer to the {@link CorsConfig} javadocs for information about all the
 * configuration options available.
 *
 * Below are some of configuration discussed in this example:
 * <h3>Support only a specific origin
 * To support a single origin instead of the wildcard use the following:
 * <pre>
 * CorsConfig corsConfig = CorsConfig.withOrigin("http://domain1.com")
 * </pre>
 *
 * <h3>Enable loading from the file system
 * To enable the server to handle an origin specified as 'null', which happens
 * when a web browser loads a file from the local file system use the following:
 * <pre>
 * corsConfig.isNullOriginAllowed()
 * </pre>
 *
 * <h3>Enable request headers
 * To enable additional request headers:
 * <pre>
 * corsConfig.allowedRequestHeaders("custom-request-header")
 * </pre>
 *
 * <h3>Expose response headers
 * By default a browser only exposes the following simple header:
 * <ul>
 * <li>Cache-Control
 * <li>Content-Language
 * <li>Content-Type
 * <li>Expires
 * <li>Last-Modified
 * <li>Pragma
 * </ul>
 * Any of the above response headers can be retreived by:
 * <pre>
 * xhr.getResponseHeader("Content-Type");
 * </pre>
 * If you need to get access to other headers this must be enabled by the server, for example:
 * <pre>
 * corsConfig.exposedHeaders("custom-response-header");
 * </pre>
 */
public class HttpCorsServerInitializer extends ChannelInitializer<SocketChannel> {

    private final SslContext sslCtx;

    public HttpCorsServerInitializer(SslContext sslCtx) {
        this.sslCtx = sslCtx;
    }

    @Override
    public void initChannel(SocketChannel ch) {
        CorsConfig corsConfig = CorsConfigBuilder.forAnyOrigin().allowNullOrigin().allowCredentials().build();
        ChannelPipeline pipeline = ch.pipeline();
        if (sslCtx != null) {
            pipeline.addLast(sslCtx.newHandler(ch.alloc()));
        }
        pipeline.addLast(new HttpResponseEncoder());
        pipeline.addLast(new HttpRequestDecoder());
        pipeline.addLast(new HttpObjectAggregator(65536));
        pipeline.addLast(new ChunkedWriteHandler());
        pipeline.addLast(new CorsHandler(corsConfig));
        pipeline.addLast(new OkResponseHandler());
    }

}