b1cb059540
It is generally useful to have origin http servers respond to "expect: continue-100" as soon as possible but applications without a HttpObjectAggregator in their pipelines must use boiler plate to do so. Modifications: Introduce the HttpServerExpectContinueHandler handler to make it easier. Result: Less boiler plate for http application authors.
98 lines
4.0 KiB
Java
98 lines
4.0 KiB
Java
/*
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* Copyright 2017 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.handler.codec.http;
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import io.netty.buffer.Unpooled;
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import io.netty.channel.ChannelFutureListener;
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import io.netty.channel.ChannelHandlerContext;
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import io.netty.channel.ChannelInboundHandlerAdapter;
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import io.netty.util.ReferenceCountUtil;
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import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_LENGTH;
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import static io.netty.handler.codec.http.HttpResponseStatus.CONTINUE;
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import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1;
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/**
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* Sends a <a href="https://www.w3.org/Protocols/rfc2616/rfc2616-sec8.html#sec8.2.3">100 CONTINUE</a>
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* {@link HttpResponse} to {@link HttpRequest}s which contain a 'expect: 100-continue' header. It
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* should only be used for applications which do <b>not</b> install the {@link HttpObjectAggregator}.
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* <p>
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* By default it accepts all expectations.
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* <p>
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* Since {@link HttpServerExpectContinueHandler} expects {@link HttpRequest}s it should be added after {@link
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* HttpServerCodec} but before any other handlers that might send a {@link HttpResponse}. <blockquote>
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* <pre>
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* {@link io.netty.channel.ChannelPipeline} p = ...;
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* ...
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* p.addLast("serverCodec", new {@link HttpServerCodec}());
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* p.addLast("respondExpectContinue", <b>new {@link HttpServerExpectContinueHandler}()</b>);
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* ...
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* p.addLast("handler", new HttpRequestHandler());
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* </pre>
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* </blockquote>
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*/
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public class HttpServerExpectContinueHandler extends ChannelInboundHandlerAdapter {
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private static final FullHttpResponse EXPECTATION_FAILED = new DefaultFullHttpResponse(
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HTTP_1_1, HttpResponseStatus.EXPECTATION_FAILED, Unpooled.EMPTY_BUFFER);
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private static final FullHttpResponse ACCEPT = new DefaultFullHttpResponse(
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HTTP_1_1, CONTINUE, Unpooled.EMPTY_BUFFER);
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static {
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EXPECTATION_FAILED.headers().set(CONTENT_LENGTH, 0);
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ACCEPT.headers().set(CONTENT_LENGTH, 0);
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}
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/**
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* Produces a {@link HttpResponse} for {@link HttpRequest}s which define an expectation. Returns {@code null} if the
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* request should be rejected. See {@link #rejectResponse(HttpRequest)}.
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*/
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protected HttpResponse acceptMessage(@SuppressWarnings("unused") HttpRequest request) {
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return ACCEPT.retainedDuplicate();
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}
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/**
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* Returns the appropriate 4XX {@link HttpResponse} for the given {@link HttpRequest}.
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*/
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protected HttpResponse rejectResponse(@SuppressWarnings("unused") HttpRequest request) {
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return EXPECTATION_FAILED.retainedDuplicate();
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}
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@Override
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public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
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if (msg instanceof HttpRequest) {
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HttpRequest req = (HttpRequest) msg;
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if (HttpUtil.is100ContinueExpected(req)) {
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HttpResponse accept = acceptMessage(req);
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if (accept == null) {
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// the expectation failed so we refuse the request.
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HttpResponse rejection = rejectResponse(req);
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ReferenceCountUtil.release(msg);
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ctx.writeAndFlush(rejection).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
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return;
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}
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ctx.writeAndFlush(accept).addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
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req.headers().remove(HttpHeaderNames.EXPECT);
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}
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}
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super.channelRead(ctx, msg);
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}
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}
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