ratpack.http.ResponseChunks Maven / Gradle / Ivy
/*
* 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.http;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufAllocator;
import io.netty.buffer.ByteBufUtil;
import io.netty.util.CharsetUtil;
import org.reactivestreams.Publisher;
import ratpack.func.Function;
import ratpack.handling.Context;
import ratpack.http.internal.HttpHeaderConstants;
import ratpack.render.Renderable;
import ratpack.stream.Streams;
import ratpack.util.Exceptions;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
/**
* A {@link ratpack.handling.Context#render(Object) renderable} object for streaming data with HTTP chunked transfer-encoding.
*
* A {@link ratpack.render.Renderer renderer} for this type is implicitly provided by Ratpack core.
*
* Example usage:
*
{@code
* import org.reactivestreams.Publisher;
* import ratpack.stream.Streams;
* import ratpack.test.embed.EmbeddedApp;
*
* import java.time.Duration;
*
* import static ratpack.http.ResponseChunks.stringChunks;
*
* import static org.junit.Assert.assertEquals;
*
* public class Example {
* public static void main(String[] args) throws Exception {
* EmbeddedApp.fromHandler(ctx -> {
* Publisher strings = Streams.periodically(ctx, Duration.ofMillis(5),
* i -> i < 5 ? i.toString() : null
* );
*
* ctx.render(stringChunks(strings));
* }).test(httpClient -> {
* assertEquals("01234", httpClient.getText());
* });
* }
* }
* }
*
* @see Response#sendStream(org.reactivestreams.Publisher)
* @see Wikipedia - Chunked transfer encoding
*/
public class ResponseChunks implements Renderable {
/**
* Transmit each string emitted by the publisher as a chunk.
*
* The content type of the response is set to {@code text/plain;charset=UTF-8} and each string is decoded as UTF-8.
*
* @param publisher a publisher of strings
* @return a renderable object
*/
public static ResponseChunks stringChunks(Publisher publisher) {
return stringChunks(HttpHeaderConstants.PLAIN_TEXT_UTF8, CharsetUtil.UTF_8, publisher);
}
/**
* Transmit each string emitted by the publisher as a chunk.
*
* The content type of the response is set to the given content type and each string is decoded as UTF-8.
*
* @param contentType the value for the content-type header
* @param publisher a publisher of strings
* @return a renderable object
*/
public static ResponseChunks stringChunks(CharSequence contentType, Publisher publisher) {
return stringChunks(contentType, CharsetUtil.UTF_8, publisher);
}
/**
* Transmit each string emitted by the publisher as a chunk.
*
* The content type of the response is set to the given content type and each string is decoded as the given charset.
*
* @param contentType the value for the content-type header
* @param charset the charset to use to decode each string chunk
* @param publisher a publisher of strings
* @return a renderable object
*/
public static ResponseChunks stringChunks(CharSequence contentType, Charset charset, Publisher publisher) {
return new ResponseChunks(contentType, allocator ->
Streams.map(publisher, charSequence ->
ByteBufUtil.encodeString(allocator, CharBuffer.wrap(charSequence), charset)
)
);
}
/**
* Transmit each set of bytes emitted by the publisher as a chunk.
*
* The content type of the response is set to the given content type.
*
* @param contentType the value for the content-type header
* @param publisher a publisher of byte buffers
* @return a renderable object
*/
public static ResponseChunks bufferChunks(CharSequence contentType, Publisher publisher) {
return new ResponseChunks(contentType, byteBufAllocator -> publisher);
}
private final Function> publisherFactory;
private final CharSequence contentType;
private ResponseChunks(CharSequence contentType, Function> publisherFactory) {
this.publisherFactory = publisherFactory;
this.contentType = contentType;
}
/**
* Returns the chunk publisher.
*
* This method is called internally by the renderer for this type.
*
* @param byteBufAllocator a byte buf allocator that can be used if necessary to allocate byte buffers
* @return a publisher of byte buffers
*/
public Publisher publisher(ByteBufAllocator byteBufAllocator) {
return Exceptions.uncheck(() -> publisherFactory.apply(byteBufAllocator));
}
/**
* The intended value of the content-type header.
*
* @return the intended value of the content-type header.
*/
public CharSequence getContentType() {
return contentType;
}
/**
* {@inheritDoc}
*/
@Override
public void render(Context context) throws Exception {
Response response = context.getResponse();
response.getHeaders().add(HttpHeaderConstants.TRANSFER_ENCODING, HttpHeaderConstants.CHUNKED);
response.getHeaders().set(HttpHeaderConstants.CONTENT_TYPE, getContentType());
Publisher publisher = publisher(context.get(ByteBufAllocator.class));
response.sendStream(publisher);
}
}