001/*
002 * Copyright 2002-2017 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.http.converter.feed;
018
019import java.io.IOException;
020import java.io.InputStreamReader;
021import java.io.OutputStreamWriter;
022import java.io.Reader;
023import java.io.Writer;
024import java.nio.charset.Charset;
025
026import com.rometools.rome.feed.WireFeed;
027import com.rometools.rome.io.FeedException;
028import com.rometools.rome.io.WireFeedInput;
029import com.rometools.rome.io.WireFeedOutput;
030
031import org.springframework.http.HttpInputMessage;
032import org.springframework.http.HttpOutputMessage;
033import org.springframework.http.MediaType;
034import org.springframework.http.converter.AbstractHttpMessageConverter;
035import org.springframework.http.converter.HttpMessageNotReadableException;
036import org.springframework.http.converter.HttpMessageNotWritableException;
037import org.springframework.util.StringUtils;
038
039/**
040 * Abstract base class for Atom and RSS Feed message converters, using the
041 * <a href="https://github.com/rometools/rome">ROME tools</a> project.
042 *
043 * <p>><b>NOTE: As of Spring 4.1, this is based on the {@code com.rometools}
044 * variant of ROME, version 1.5. Please upgrade your build dependency.</b>
045 *
046 * @author Arjen Poutsma
047 * @since 3.0.2
048 * @see AtomFeedHttpMessageConverter
049 * @see RssChannelHttpMessageConverter
050 */
051public abstract class AbstractWireFeedHttpMessageConverter<T extends WireFeed> extends AbstractHttpMessageConverter<T> {
052
053        public static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8");
054
055
056        protected AbstractWireFeedHttpMessageConverter(MediaType supportedMediaType) {
057                super(supportedMediaType);
058        }
059
060
061        @Override
062        @SuppressWarnings("unchecked")
063        protected T readInternal(Class<? extends T> clazz, HttpInputMessage inputMessage)
064                        throws IOException, HttpMessageNotReadableException {
065
066                WireFeedInput feedInput = new WireFeedInput();
067                MediaType contentType = inputMessage.getHeaders().getContentType();
068                Charset charset = (contentType != null && contentType.getCharset() != null ?
069                                contentType.getCharset() : DEFAULT_CHARSET);
070                try {
071                        Reader reader = new InputStreamReader(inputMessage.getBody(), charset);
072                        return (T) feedInput.build(reader);
073                }
074                catch (FeedException ex) {
075                        throw new HttpMessageNotReadableException("Could not read WireFeed: " + ex.getMessage(), ex);
076                }
077        }
078
079        @Override
080        protected void writeInternal(T wireFeed, HttpOutputMessage outputMessage)
081                        throws IOException, HttpMessageNotWritableException {
082
083                Charset charset = (StringUtils.hasLength(wireFeed.getEncoding()) ?
084                                Charset.forName(wireFeed.getEncoding()) : DEFAULT_CHARSET);
085                MediaType contentType = outputMessage.getHeaders().getContentType();
086                if (contentType != null) {
087                        contentType = new MediaType(contentType.getType(), contentType.getSubtype(), charset);
088                        outputMessage.getHeaders().setContentType(contentType);
089                }
090
091                WireFeedOutput feedOutput = new WireFeedOutput();
092                try {
093                        Writer writer = new OutputStreamWriter(outputMessage.getBody(), charset);
094                        feedOutput.output(wireFeed, writer);
095                }
096                catch (FeedException ex) {
097                        throw new HttpMessageNotWritableException("Could not write WireFeed: " + ex.getMessage(), ex);
098                }
099        }
100
101}