com.wl4g.infra.common.remoting.parse.HttpMessageParserExtractor Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of infra-common Show documentation
A Infra Common.
There is a newer version: 3.1.72
/*
 * Copyright 2017 ~ 2025 the original author or authors. James Wong 
 *
 * 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 com.wl4g.infra.common.remoting.parse;

import java.io.IOException;
import java.lang.reflect.Type;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import javax.annotation.Nullable;
import com.wl4g.infra.common.lang.Assert2;
import com.wl4g.infra.common.reflect.ResolvableType;
import com.wl4g.infra.common.remoting.ClientHttpResponse;
import com.wl4g.infra.common.remoting.RestClient.ResponseProcessor;
import com.wl4g.infra.common.remoting.exception.RestClientException;
import com.wl4g.infra.common.remoting.standard.HttpMediaType;

/**
 * Response extractor that uses the given {@linkplain HttpMessageParser entity
 * converters} to convert the response into a type {@code T}.
 *
 * @param 
 *            the data type
 * @see RestTemplate
 */
public class HttpMessageParserExtractor implements ResponseProcessor {

    private final Type responseType;

    @Nullable
    private final Class responseClass;

    private final List> messageParsers;

    private final Log log;

    /**
     * Create a new instance of the {@code HttpMessageParserExtractor} with the
     * given response type and message converters. The given converters must
     * support the response type.
     */
    public HttpMessageParserExtractor(Class responseType, List> messageConverters) {
        this((Type) responseType, messageConverters);
    }

    /**
     * Creates a new instance of the {@code HttpMessageParserExtractor} with the
     * given response type and message converters. The given converters must
     * support the response type.
     */
    public HttpMessageParserExtractor(Type responseType, List> messageConverters) {
        this(responseType, messageConverters, LogFactory.getLog(HttpMessageParserExtractor.class));
    }

    @SuppressWarnings("unchecked")
    public HttpMessageParserExtractor(Type responseType, List> messageConverters, Log logger) {
        Assert2.notNull(responseType, "'responseType' must not be null");
        Assert2.notEmpty(messageConverters, "'messageConverters' must not be empty");
        this.responseType = responseType;
        this.responseClass = (responseType instanceof Class ? (Class) responseType : null);
        this.messageParsers = messageConverters;
        this.log = logger;
    }

    @Override
    @SuppressWarnings({ "unchecked", "rawtypes", "resource" })
    public T extractData(ClientHttpResponse response) throws IOException {
        MessageBodyClientHttpResponseWrapper wrapper = new MessageBodyClientHttpResponseWrapper(response);
        if (!wrapper.hasMessageBody() || wrapper.hasEmptyMessageBody()) {
            return null;
        }
        HttpMediaType contentType = getContentType(wrapper);

        try {
            for (HttpMessageParser parser : messageParsers) {
                if (parser instanceof GenericHttpMessageParser) {
                    GenericHttpMessageParser genericMessageConverter = (GenericHttpMessageParser) parser;
                    if (genericMessageConverter.canRead(responseType, null, contentType)) {
                        if (log.isDebugEnabled()) {
                            ResolvableType type = ResolvableType.forType(responseType);
                            log.debug("Reading to [" + type + "]");
                        }
                        return (T) genericMessageConverter.read(responseType, null, wrapper);
                    }
                }
                if (responseClass != null) {
                    if (parser.canRead(responseClass, contentType)) {
                        if (log.isDebugEnabled()) {
                            String className = responseClass.getName();
                            log.debug("Reading to [" + className + "] as \"" + contentType + "\"");
                        }
                        return (T) parser.read((Class) responseClass, wrapper);
                    }
                }
            }
        } catch (IOException | HttpMessageNotReadableException ex) {
            throw new RestClientException(
                    "Error while extracting response for type [" + responseType + "] and content type [" + contentType + "]", ex);
        }

        throw new RestClientException("Could not extract response: no suitable HttpMessageParser found " + "for response type ["
                + responseType + "] and content type [" + contentType + "]");
    }

    /**
     * Determine the Content-Type of the response based on the "Content-Type"
     * header or otherwise default to
     * {@link HttpMediaType#APPLICATION_OCTET_STREAM}.
     * 
     * @param response
     *            the response
     * @return the HttpMediaType, possibly {@code null}.
     */
    @Nullable
    protected HttpMediaType getContentType(MessageBodyClientHttpResponseWrapper response) {
        HttpMediaType contentType = response.getHeaders().getContentType();
        if (contentType == null) {
            if (log.isTraceEnabled()) {
                log.trace("No content-type, using 'application/octet-stream'");
            }
            contentType = HttpMediaType.APPLICATION_OCTET_STREAM;
        }
        return contentType;
    }

}