/*
* Copyright 2014 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 ratpack.sse.internal;
import com.google.common.collect.Lists;
import com.google.common.reflect.TypeToken;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.handler.codec.http.HttpHeaders;
import ratpack.func.Function;
import ratpack.handling.Context;
import ratpack.http.Response;
import ratpack.http.internal.HttpHeaderConstants;
import ratpack.render.Renderer;
import ratpack.render.RendererSupport;
import ratpack.sse.ServerSentEvent;
import ratpack.sse.ServerSentEvents;
import ratpack.stream.Streams;
import ratpack.util.internal.ByteBufWriteThroughOutputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import static io.netty.util.CharsetUtil.UTF_8;
public class ServerSentEventsRenderer extends RendererSupport<ServerSentEvents> {
public static final TypeToken<Renderer<ServerSentEvents>> TYPE = new TypeToken<Renderer<ServerSentEvents>>() {};
private static final byte[] EVENT_TYPE_PREFIX = "event: ".getBytes(UTF_8);
private static final byte[] EVENT_DATA_PREFIX = "data: ".getBytes(UTF_8);
private static final byte[] EVENT_ID_PREFIX = "id: ".getBytes(UTF_8);
private static final byte[] NEWLINE = "\n".getBytes(UTF_8);
private static final CharSequence TEXT_EVENT_STREAM_CHARSET_UTF_8 = HttpHeaders.newEntity("text/event-stream;charset=UTF-8");
private final Encoder encoder;
public ServerSentEventsRenderer(ByteBufAllocator bufferAllocator) {
this.encoder = new Encoder(bufferAllocator);
}
@Override
public void render(Context context, ServerSentEvents object) throws Exception {
Response response = context.getResponse();
response.getHeaders().add(HttpHeaderConstants.CONTENT_TYPE, TEXT_EVENT_STREAM_CHARSET_UTF_8);
response.getHeaders().add(HttpHeaderConstants.CACHE_CONTROL, HttpHeaderConstants.NO_CACHE_FULL);
response.getHeaders().add(HttpHeaderConstants.PRAGMA, HttpHeaderConstants.NO_CACHE);
response.sendStream(Streams.map(object.getPublisher(), encoder));
}
public static class Encoder implements Function<ServerSentEvent, ByteBuf> {
private final ByteBufAllocator bufferAllocator;
public Encoder(ByteBufAllocator bufferAllocator) {
this.bufferAllocator = bufferAllocator;
}
@Override
public ByteBuf apply(ServerSentEvent serverSentEvent) throws Exception {
ByteBuf buffer = bufferAllocator.buffer();
OutputStream outputStream = new ByteBufWriteThroughOutputStream(buffer);
Writer writer = new OutputStreamWriter(outputStream, UTF_8);
String eventType = serverSentEvent.getEventType();
if (eventType != null) {
outputStream.write(EVENT_TYPE_PREFIX);
writer.append(eventType).flush();
outputStream.write(NEWLINE);
}
String eventData = serverSentEvent.getEventData();
if (eventData != null) {
outputStream.write(EVENT_DATA_PREFIX);
for (Character character : Lists.charactersOf(eventData)) {
if (character == '\n') {
outputStream.write(NEWLINE);
outputStream.write(EVENT_DATA_PREFIX);
} else {
writer.append(character).flush();
}
}
outputStream.write(NEWLINE);
}
String eventId = serverSentEvent.getEventId();
if (eventId != null) {
outputStream.write(EVENT_ID_PREFIX);
writer.append(eventId).flush();
outputStream.write(NEWLINE);
}
outputStream.write(NEWLINE);
writer.flush();
writer.close();
return buffer;
}
}
}