basecallmarshaller.java

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/*
 * Copyright 2005 Joe Walker
 *
 * 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.directwebremoting.dwrp;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.WebContext;
import org.directwebremoting.WebContextFactory;
import org.directwebremoting.extend.AccessControl;
import org.directwebremoting.extend.Call;
import org.directwebremoting.extend.Calls;
import org.directwebremoting.extend.ConverterManager;
import org.directwebremoting.extend.Creator;
import org.directwebremoting.extend.CreatorManager;
import org.directwebremoting.extend.InboundContext;
import org.directwebremoting.extend.InboundVariable;
import org.directwebremoting.extend.MarshallException;
import org.directwebremoting.extend.Marshaller;
import org.directwebremoting.extend.PageNormalizer;
import org.directwebremoting.extend.RealScriptSession;
import org.directwebremoting.extend.EnginePrivate;
import org.directwebremoting.extend.Replies;
import org.directwebremoting.extend.Reply;
import org.directwebremoting.extend.ScriptBufferUtil;
import org.directwebremoting.extend.ScriptConduit;
import org.directwebremoting.extend.ServerException;
import org.directwebremoting.extend.TypeHintContext;
import org.directwebremoting.util.DebuggingPrintWriter;
import org.directwebremoting.util.Logger;
import org.directwebremoting.util.Messages;

/**
 * A Marshaller that output plain Javascript.
 * This marshaller can be tweaked to output Javascript in an HTML context.
 * This class works in concert with CallScriptConduit, they should be
 * considered closely related and it is important to understand what one does
 * while editing the other.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public abstract class BaseCallMarshaller implements Marshaller
{
    /* (non-Javadoc)
     * @see org.directwebremoting.extend.Marshaller#marshallInbound(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
    public Calls marshallInbound(HttpServletRequest request, HttpServletResponse response) throws IOException, ServerException
    {
        // We must parse the parameters before we setup the conduit because it's
        // only after doing this that we know the scriptSessionId

        WebContext webContext = WebContextFactory.get();
        Batch batch = (Batch) request.getAttribute(ATTRIBUTE_BATCH);
        if (batch == null)
        {
            batch = new Batch(request, crossDomainSessionSecurity, allowGetForSafariButMakeForgeryEasier, sessionCookieName);

            // Save calls for retry exception
            request.setAttribute(ATTRIBUTE_BATCH, batch);
        }

        // Various bits of the Batch need to be stashed away places
        storeParsedRequest(request, webContext, batch);

        Calls calls = batch.getCalls();

        // Debug the environment
        if (log.isDebugEnabled() && calls.getCallCount() > 0)
        {
            // We can just use 0 because they are all shared
            InboundContext inctx = (InboundContext) batch.getInboundContexts().get(0);
            StringBuffer buffer = new StringBuffer();

            for (Iterator it = inctx.getInboundVariableNames(); it.hasNext();)
            {
                String key = (String) it.next();
                InboundVariable value = inctx.getInboundVariable(key);
                if (key.startsWith(ProtocolConstants.INBOUND_CALLNUM_PREFIX) &&
                    key.indexOf(ProtocolConstants.INBOUND_CALLNUM_SUFFIX + ProtocolConstants.INBOUND_KEY_ENV) != -1)
                {
                    buffer.append(key);
                    buffer.append('=');
                    buffer.append(value.toString());
                    buffer.append(", ");
                }
            }

            if (buffer.length() > 0)
            {
                log.debug("Environment:  " + buffer.toString());
            }
        }

        callLoop:
        for (int callNum = 0; callNum < calls.getCallCount(); callNum++)
        {
            Call call = calls.getCall(callNum);
            InboundContext inctx = (InboundContext) batch.getInboundContexts().get(callNum);

            // Get a list of the available matching methods with the coerced
            // parameters that we will use to call it if we choose to use
            // that method.
            Creator creator = creatorManager.getCreator(call.getScriptName());

            // Which method are we using?
            Method method = findMethod(call, inctx);
            if (method == null)
            {
                String name = call.getScriptName() + '.' + call.getMethodName();
                String error = Messages.getString("BaseCallMarshaller.UnknownMethod", name);
                log.warn("Marshalling exception: " + error);

                call.setMethod(null);
                call.setParameters(null);
                call.setException(new IllegalArgumentException(error));

                continue callLoop;
            }

            call.setMethod(method);

            // Check this method is accessible
            accessControl.assertExecutionIsPossible(creator, call.getScriptName(), method);

            // Convert all the parameters to the correct types
            Object[] params = new Object[method.getParameterTypes().length];
            for (int j = 0; j < method.getParameterTypes().length; j++)
            {
                try
                {
                    Class paramType = method.getParameterTypes()[j];
                    InboundVariable param = inctx.getParameter(callNum, j);
                    TypeHintContext incc = new TypeHintContext(converterManager, method, j);
                    params[j] = converterManager.convertInbound(paramType, param, inctx, incc);
                }
                catch (MarshallException ex)
                {
                    log.warn("Marshalling exception", ex);

                    call.setMethod(null);
                    call.setParameters(null);
                    call.setException(ex);

                    continue callLoop;
                }
            }

            call.setParameters(params);
        }

        return calls;
    }

    /**
     * Build a Batch and put it in the request
     * @param request Where we store the parsed data
     * @param webContext We need to notify others of some of the data we find
     * @param batch The parsed data to store
     */
    private void storeParsedRequest(HttpServletRequest request, WebContext webContext, Batch batch)
    {
        String normalizedPage = pageNormalizer.normalizePage(batch.getPage());
        webContext.setCurrentPageInformation(normalizedPage, batch.getScriptSessionId());

        // Remaining parameters get put into the request for later consumption
        Map paramMap = batch.getSpareParameters();
        if (paramMap.size() != 0)
        {
            for (Iterator it = paramMap.entrySet().iterator(); it.hasNext();)
            {
                Map.Entry entry = (Map.Entry) it.next();
                String key = (String) entry.getKey();
                String value = (String) entry.getValue();

                request.setAttribute(key, value);
                log.debug("Moved param to request: " + key + "=" + value);
            }
        }
    }

    /**
     * Find the method the best matches the method name and parameters
     * @param call The function call we are going to make
     * @param inctx The data conversion context
     * @return A matching method, or null if one was not found.
     */
    private Method findMethod(Call call, InboundContext inctx)
    {
        if (call.getScriptName() == null)
        {
            throw new IllegalArgumentException(Messages.getString("BaseCallMarshaller.MissingClassParam"));
        }

        if (call.getMethodName() == null)
        {
            throw new IllegalArgumentException(Messages.getString("BaseCallMarshaller.MissingMethodParam"));
        }

        Creator creator = creatorManager.getCreator(call.getScriptName());
        Method[] methods = creator.getType().getMethods();
        List available = new ArrayList();

        methods:
        for (int i = 0; i < methods.length; i++)
        {
            // Check method name and access
            if (methods[i].getName().equals(call.getMethodName()))
            {
                // Check number of parameters
                if (methods[i].getParameterTypes().length == inctx.getParameterCount())
                {
                    // Clear the previous conversion attempts (the param types
                    // will probably be different)
                    inctx.clearConverted();

                    // Check parameter types
                    for (int j = 0; j < methods[i].getParameterTypes().length; j++)
                    {
                        Class paramType = methods[i].getParameterTypes()[j];
                        if (!converterManager.isConvertable(paramType))
                        {
                            // Give up with this method and try the next
                            continue methods;
                        }
                    }

                    available.add(methods[i]);
                }
            }
        }

        // Pick a method to call
        if (available.size() > 1)
        {
            log.warn("Warning multiple matching methods. Using first match.");
        }

        if (available.isEmpty())
        {
            return null;
        }

        // At the moment we are just going to take the first match, for a
        // later increment we might pick the best implementation
        return (Method) available.get(0);
    }

    /* (non-Javadoc)
     * @see org.directwebremoting.Marshaller#marshallOutbound(org.directwebremoting.Replies, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
     */
    public void marshallOutbound(Replies replies, HttpServletRequest request, HttpServletResponse response) throws IOException
    {
        // Get the output stream and setup the mimetype
        response.setContentType(getOutboundMimeType());
        PrintWriter out;
        if (log.isDebugEnabled())
        {
            // This might be considered evil - altering the program flow
            // depending on the log status, however DebuggingPrintWriter is
            // very thin and only about logging
            out = new DebuggingPrintWriter("", response.getWriter());
        }
        else
        {
            out = response.getWriter();
        }

        // The conduit to pass on reverse ajax scripts