/*
* Copyright 2002-2008 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 org.springframework.remoting.httpinvoker;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.rmi.RemoteException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.remoting.rmi.CodebaseAwareObjectInputStream;
import org.springframework.remoting.support.RemoteInvocation;
import org.springframework.remoting.support.RemoteInvocationResult;
import org.springframework.util.Assert;
/**
* Abstract base implementation of the HttpInvokerRequestExecutor interface.
*
* <p>Pre-implements serialization of RemoteInvocation objects and
* deserialization of RemoteInvocationResults objects.
*
* @author Juergen Hoeller
* @since 1.1
* @see #doExecuteRequest
*/
public abstract class AbstractHttpInvokerRequestExecutor
implements HttpInvokerRequestExecutor, BeanClassLoaderAware {
/**
* Default content type: "application/x-java-serialized-object"
*/
public static final String CONTENT_TYPE_SERIALIZED_OBJECT = "application/x-java-serialized-object";
protected static final String HTTP_METHOD_POST = "POST";
protected static final String HTTP_HEADER_ACCEPT_LANGUAGE = "Accept-Language";
protected static final String HTTP_HEADER_ACCEPT_ENCODING = "Accept-Encoding";
protected static final String HTTP_HEADER_CONTENT_ENCODING = "Content-Encoding";
protected static final String HTTP_HEADER_CONTENT_TYPE = "Content-Type";
protected static final String HTTP_HEADER_CONTENT_LENGTH = "Content-Length";
protected static final String ENCODING_GZIP = "gzip";
private static final int SERIALIZED_INVOCATION_BYTE_ARRAY_INITIAL_SIZE = 1024;
protected final Log logger = LogFactory.getLog(getClass());
private String contentType = CONTENT_TYPE_SERIALIZED_OBJECT;
private boolean acceptGzipEncoding = true;
private ClassLoader beanClassLoader;
/**
* Specify the content type to use for sending HTTP invoker requests.
* <p>Default is "application/x-java-serialized-object".
*/
public void setContentType(String contentType) {
Assert.notNull(contentType, "'contentType' must not be null");
this.contentType = contentType;
}
/**
* Return the content type to use for sending HTTP invoker requests.
*/
public String getContentType() {
return this.contentType;
}
/**
* Set whether to accept GZIP encoding, that is, whether to
* send the HTTP "Accept-Encoding" header with "gzip" as value.
* <p>Default is "true". Turn this flag off if you do not want
* GZIP response compression even if enabled on the HTTP server.
*/
public void setAcceptGzipEncoding(boolean acceptGzipEncoding) {
this.acceptGzipEncoding = acceptGzipEncoding;
}
/**
* Return whether to accept GZIP encoding, that is, whether to
* send the HTTP "Accept-Encoding" header with "gzip" as value.
*/
public boolean isAcceptGzipEncoding() {
return this.acceptGzipEncoding;
}
public void setBeanClassLoader(ClassLoader classLoader) {
this.beanClassLoader = classLoader;
}
/**
* Return the bean ClassLoader that this executor is supposed to use.
*/
protected ClassLoader getBeanClassLoader() {
return this.beanClassLoader;
}
public final RemoteInvocationResult executeRequest(
HttpInvokerClientConfiguration config, RemoteInvocation invocation) throws Exception {
ByteArrayOutputStream baos = getByteArrayOutputStream(invocation);
if (logger.isDebugEnabled()) {
logger.debug("Sending HTTP invoker request for service at [" + config.getServiceUrl() +
"], with size " + baos.size());
}
return doExecuteRequest(config, baos);
}
/**
* Serialize the given RemoteInvocation into a ByteArrayOutputStream.
* @param invocation the RemoteInvocation object
* @return a ByteArrayOutputStream with the serialized RemoteInvocation
* @throws IOException if thrown by I/O methods
*/
protected ByteArrayOutputStream getByteArrayOutputStream(RemoteInvocation invocation) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream(SERIALIZED_INVOCATION_BYTE_ARRAY_INITIAL_SIZE);
writeRemoteInvocation(invocation, baos);
return baos;
}
/**
* Serialize the given RemoteInvocation to the given OutputStream.
* <p>The default implementation gives <code>decorateOutputStream</code> a chance
* to decorate the stream first (for example, for custom encryption or compression).
* Creates an <code>ObjectOutputStream</code> for the final stream and calls
* <code>doWriteRemoteInvocation</code> to actually write the object.
* <p>Can be overridden for custom serialization of the invocation.
* @param invocation the RemoteInvocation object
* @param os the OutputStream to write to
* @throws IOException if thrown by I/O methods
* @see #decorateOutputStream
* @see #doWriteRemoteInvocation
*/
protected void writeRemoteInvocation(RemoteInvocation invocation, OutputStream os) throws IOException {
ObjectOutputStream oos = new ObjectOutputStream(decorateOutputStream(os));
try {
doWriteRemoteInvocation(invocation, oos);
oos.flush();
}
finally {
oos.close();
}
}
/**
* Return the OutputStream to use for writing remote invocations,
* potentially decorating the given original OutputStream.
* <p>The default implementation returns the given stream as-is.
* Can be overridden, for example, for custom encryption or compression.
* @param os the original OutputStream
* @return the potentially decorated OutputStream
*/
protected OutputStream decorateOutputStream(OutputStream os) throws IOException {
return os;
}
/**
* Perform the actual writing of the given invocation object to the
* given ObjectOutputStream.
* <p>The default implementation simply calls <code>writeObject</code>.
* Can be overridden for serialization of a custom wrapper object rather
* than the plain invocation, for example an encryption-aware holder.
* @param invocation the RemoteInvocation object
* @param oos the ObjectOutputStream to write to
* @throws IOException if thrown by I/O methods
* @see java.io.ObjectOutputStream#writeObject
*/
protected void doWriteRemoteInvocation(RemoteInvocation invocation, ObjectOutputStream oos) throws IOException {
oos.writeObject(invocation);
}
/**
* Execute a request to send the given serialized remote invocation.
* <p>Implementations will usually call <code>readRemoteInvocationResult</code>
* to deserialize a returned RemoteInvocationResult object.
* @param config the HTTP invoker configuration that specifies the
* target service
* @param baos the ByteArrayOutputStream that contains the serialized
* RemoteInvocation object
* @return the RemoteInvocationResult object
* @throws IOException if thrown by I/O operations
* @throws ClassNotFoundException if thrown during deserialization
* @throws Exception in case of general errors
* @see #readRemoteInvocationResult(java.io.InputStream, String)
*/
protected abstract RemoteInvocationResult doExecuteRequest(
HttpInvokerClientConfiguration config, ByteArrayOutputStream baos)
throws Exception;
/**
* Deserialize a RemoteInvocationResult object from the given InputStream.
* <p>Gives <code>decorateInputStream</code> a chance to decorate the stream
* first (for example, for custom encryption or compression). Creates an
* <code>ObjectInputStream</code> via <code>createObjectInputStream</code> and
* calls <code>doReadRemoteInvocationResult</code> to actually read the object.
* <p>Can be overridden for custom serialization of the invocation.
* @param is the InputStream to read from
* @param codebaseUrl the codebase URL to load classes from if not found locally
* @return the RemoteInvocationResult object
* @throws IOException if thrown by I/O methods
* @throws ClassNotFoundException if thrown during deserialization
* @see #decorateInputStream
* @see #createObjectInputStream
* @see #doReadRemoteInvocationResult
*/
protected RemoteInvocationResult readRemoteInvocationResult(InputStream is, String codebaseUrl)
throws IOException, ClassNotFoundException {
ObjectInputStream ois = createObjectInputStream(decorateInputStream(is), codebaseUrl);
try {
return doReadRemoteInvocationResult(ois);
}
finally {
ois.close();
}
}
/**
* Return the InputStream to use for reading remote invocation results,
* potentially decorating the given original InputStream.
* <p>The default implementation returns the given stream as-is.
* Can be overridden, for example, for custom encryption or compression.
* @param is the original InputStream
* @return the potentially decorated InputStream
*/
protected InputStream decorateInputStream(InputStream is) throws IOException {
return is;
}
/**
* Create an ObjectInputStream for the given InputStream and codebase.
* The default implementation creates a CodebaseAwareObjectInputStream.
* @param is the InputStream to read from
* @param codebaseUrl the codebase URL to load classes from if not found locally
* (can be <code>null</code>)
* @return the new ObjectInputStream instance to use
* @throws IOException if creation of the ObjectInputStream failed
* @see org.springframework.remoting.rmi.CodebaseAwareObjectInputStream
*/
protected ObjectInputStream createObjectInputStream(InputStream is, String codebaseUrl) throws IOException {
return new CodebaseAwareObjectInputStream(is, getBeanClassLoader(), codebaseUrl);
}
/**
* Perform the actual reading of an invocation object from the
* given ObjectInputStream.
* <p>The default implementation simply calls <code>readObject</code>.
* Can be overridden for deserialization of a custom wrapper object rather
* than the plain invocation, for example an encryption-aware holder.
* @param ois the ObjectInputStream to read from
* @return the RemoteInvocationResult object
* @throws IOException if thrown by I/O methods
* @throws ClassNotFoundException if the class name of a serialized object
* couldn't get resolved
* @see java.io.ObjectOutputStream#writeObject
*/
protected RemoteInvocationResult doReadRemoteInvocationResult(ObjectInputStream ois)
throws IOException, ClassNotFoundException {
Object obj = ois.readObject();
if (!(obj instanceof RemoteInvocationResult)) {
throw new RemoteException("Deserialized object needs to be assignable to type [" +
RemoteInvocationResult.class.getName() + "]: " + obj);
}
return (RemoteInvocationResult) obj;
}
}