com.amazonaws.http.XmlRxNettyErrorResponseHandler.java Source code

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Here is the source code for com.amazonaws.http.XmlRxNettyErrorResponseHandler.java

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/*
 * Copyright 2014-2017 Netflix, Inc.
 *
 * 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.amazonaws.http;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Node;

import com.amazonaws.AmazonClientException;
import com.amazonaws.AmazonServiceException;
import com.amazonaws.transform.Unmarshaller;
import com.amazonaws.util.IOUtils;
import com.amazonaws.util.XpathUtils;
import com.amazonaws.util.RxSchedulers;

import rx.Observable;
import rx.functions.*;
import io.netty.buffer.ByteBuf;
import io.netty.util.ReferenceCountUtil;
import iep.io.reactivex.netty.protocol.http.client.HttpClientResponse;

/**
 * Implementation of HttpResponseHandler that handles only error responses from
 * Amazon Web Services. A list of unmarshallers is passed into the constructor,
 * and while handling a response, each unmarshaller is tried, in order, until
 * one is found that can successfully unmarshall the error response.  If no
 * unmarshaller is found that can unmarshall the error response, a generic
 * AmazonServiceException is created and populated with the AWS error response
 * information (error message, AWS error code, AWS request ID, etc).
 */
public class XmlRxNettyErrorResponseHandler implements RxNettyResponseHandler<AmazonServiceException> {
    private static final Log log = LogFactory.getLog(XmlRxNettyErrorResponseHandler.class);

    /**
     * The list of error response unmarshallers to try to apply to error
     * responses.
     */
    private List<Unmarshaller<AmazonServiceException, Node>> unmarshallerList;

    /**
     * Constructs a new XmlRxNettyErrorResponseHandler that will handle error
     * responses from Amazon services using the specified list of unmarshallers.
     * Each unmarshaller will be tried, in order, until one is found that can
     * unmarshall the error response.
     *
     * @param unmarshallerList
     *            The list of unmarshallers to try using when handling an error
     *            response.
     */
    public XmlRxNettyErrorResponseHandler(List<Unmarshaller<AmazonServiceException, Node>> unmarshallerList) {
        this.unmarshallerList = unmarshallerList;
    }

    @Override
    public AmazonServiceException handle(HttpResponse response) throws Exception {
        throw new UnsupportedOperationException("appache response not supported");
    }

    @Override
    public Observable<AmazonServiceException> handle(HttpClientResponse<ByteBuf> response) throws Exception {
        // Try to read the error response
        return response.getContent().reduce(new ByteArrayOutputStream(),
                new Func2<ByteArrayOutputStream, ByteBuf, ByteArrayOutputStream>() {
                    @Override
                    public ByteArrayOutputStream call(ByteArrayOutputStream out, ByteBuf bb) {
                        try {
                            bb.readBytes(out, bb.readableBytes());
                            return out;
                        } catch (java.io.IOException e) {
                            throw newAmazonServiceException("Unable to unmarshall error response", response, e);
                        } finally {
                            ReferenceCountUtil.safeRelease(bb);
                        }
                    }
                }).observeOn(RxSchedulers.computation()).map(new Func1<ByteArrayOutputStream, Document>() {
                    @Override
                    public Document call(ByteArrayOutputStream out) {
                        String content = new String(out.toByteArray());
                        try {
                            return XpathUtils.documentFrom(content);
                        } catch (Exception e) {
                            throw newAmazonServiceException(
                                    String.format("Unable to unmarshall error response (%s)", content), response,
                                    e);
                        }
                    }
                }).map(new Func1<Document, AmazonServiceException>() {
                    @Override
                    public AmazonServiceException call(Document document) {
                        for (Unmarshaller<AmazonServiceException, Node> unmarshaller : unmarshallerList) {
                            try {
                                AmazonServiceException ase = unmarshaller.unmarshall(document);
                                if (ase != null) {
                                    ase.setStatusCode(response.getStatus().code());
                                    return ase;
                                }
                            } catch (Exception e) {
                            }
                        }
                        throw new AmazonClientException("Unable to unmarshall error response from service");
                    }
                }).onErrorResumeNext(new Func1<Throwable, Observable<AmazonServiceException>>() {
                    @Override
                    public Observable<AmazonServiceException> call(Throwable t) {
                        if (t instanceof AmazonServiceException)
                            return Observable.just((AmazonServiceException) t);
                        else
                            return Observable.error(t);
                    }
                });
    }

    /**
     * Used to create an {@link newAmazonServiceException} when we failed to
     * read the error response or parsed the error response as XML.
     */
    private AmazonServiceException newAmazonServiceException(String errmsg,
            HttpClientResponse<ByteBuf> httpResponse, Exception readFailure) {
        AmazonServiceException exception = new AmazonServiceException(errmsg, readFailure);
        final int statusCode = httpResponse.getStatus().code();
        exception.setErrorCode(statusCode + " " + httpResponse.getStatus().reasonPhrase());
        exception.setErrorType(AmazonServiceException.ErrorType.Unknown);
        exception.setStatusCode(statusCode);
        return exception;
    }

    /**
     * Since this response handler completely consumes all the data from the
     * underlying HTTP connection during the handle method, we don't need to
     * keep the HTTP connection open.
     *
     * @see com.amazonaws.http.HttpResponseHandler#needsConnectionLeftOpen()
     */
    public boolean needsConnectionLeftOpen() {
        return false;
    }

}