org.directwebremoting.extend.EnginePrivate Maven / Gradle / Ivy
/*
* 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.extend;
import java.io.IOException;
import org.directwebremoting.ScriptBuffer;
import org.directwebremoting.dwrp.ProtocolConstants;
import org.directwebremoting.impl.DefaultRemoter;
import org.directwebremoting.proxy.ScriptProxy;
import org.directwebremoting.util.JavascriptUtil;
import org.directwebremoting.util.Logger;
/**
* An abstraction of the DWREngine Javascript class for use by
* {@link org.directwebremoting.dwrp.BaseCallMarshaller},
* {@link org.directwebremoting.dwrp.PollHandler} and a few others that need
* to call internal functions in engine.js
* @author Joe Walker [joe at getahead dot ltd dot uk]
*/
public class EnginePrivate extends ScriptProxy
{
/**
* Call the dwr.engine._remoteHandleResponse() in the browser
* @param conduit The browser pipe to write to
* @param batchId The identifier of the batch that we are handling a response for
* @param callId The identifier of the call that we are handling a response for
* @param data The data to pass to the callback function
* @throws IOException If writing fails.
* @throws MarshallException If objects in the script can not be marshalled
*/
public static void remoteHandleCallback(ScriptConduit conduit, String batchId, String callId, Object data) throws IOException, MarshallException
{
ScriptBuffer script = new ScriptBuffer();
script.appendScript("dwr.engine._remoteHandleCallback(\'")
.appendScript(batchId)
.appendScript("\',\'")
.appendScript(callId)
.appendScript("\',")
.appendData(data)
.appendScript(");");
conduit.addScript(script);
}
/**
* Call the dwr.engine._remoteHandleException() in the browser
* @param conduit The browser pipe to write to
* @param batchId The identifier of the batch that we are handling a response for
* @param callId The id of the call we are replying to
* @param ex The exception to throw on the remote end
* @throws IOException If writing fails.
*/
public static void remoteHandleMarshallException(ScriptConduit conduit, String batchId, String callId, MarshallException ex) throws IOException
{
try
{
ScriptBuffer script = new ScriptBuffer();
script.appendScript("dwr.engine._remoteHandleException(\'")
.appendScript(batchId)
.appendScript("\',\'")
.appendScript(callId)
.appendScript("\',")
.appendData(ex)
.appendScript(");");
conduit.addScript(script);
}
catch (MarshallException mex)
{
ScriptBuffer script = new ScriptBuffer();
script.appendScript("dwr.engine._remoteHandleException(\'")
.appendScript(batchId)
.appendScript("\',\'")
.appendScript(callId)
.appendScript("\',")
.appendData(mex)
.appendScript(");");
addScriptWithoutException(conduit, script);
}
}
/**
* Call the dwr.engine._remoteHandleException() in the browser
* @param conduit The browser pipe to write to
* @param batchId The identifier of the batch that we are handling a response for
* @param callId The id of the call we are replying to
* @param ex The exception to throw on the remote end
* @throws IOException If writing fails.
*/
public static void remoteHandleException(ScriptConduit conduit, String batchId, String callId, Throwable ex) throws IOException
{
try
{
ScriptBuffer script = new ScriptBuffer();
script.appendScript("dwr.engine._remoteHandleException(\'")
.appendScript(batchId)
.appendScript("\',\'")
.appendScript(callId)
.appendScript("\',")
.appendData(ex)
.appendScript(");");
conduit.addScript(script);
}
catch (MarshallException mex)
{
ScriptBuffer script = new ScriptBuffer();
script.appendScript("dwr.engine._remoteHandleException(\'")
.appendScript(batchId)
.appendScript("\',\'")
.appendScript(callId)
.appendScript("\',")
.appendData(mex)
.appendScript(");");
addScriptWithoutException(conduit, script);
}
}
/**
* Call the dwr.engine._remoteHandleServerException() in the browser
* @param batchId The identifier of the batch that we are handling a response for
* @param ex The execption from which we make a reply
* @return The string that calls dwr.engine._remoteHandleServerException()
*/
public static String getRemoteHandleBatchExceptionScript(String batchId, Exception ex)
{
StringBuffer reply = new StringBuffer();
String output = JavascriptUtil.escapeJavaScript(ex.getMessage());
String params = "{ name:'" + ex.getClass().getName() + "', message:'" + output + "' }";
if (batchId != null)
{
params += ", '" + batchId + "'";
}
reply.append(ProtocolConstants.SCRIPT_CALL_REPLY).append("\r\n");
reply.append("if (window.dwr) dwr.engine._remoteHandleBatchException(").append(params).append(");\r\n");
reply.append("else if (window.parent.dwr) window.parent.dwr.engine._remoteHandleBatchException(").append(params).append(");\r\n");
return reply.toString();
}
/**
* Call the dwr.engine._remotePollCometDisabled() in the browser
* @param batchId The identifier of the batch that we are handling a response for
* @return The string that calls dwr.engine._remoteHandleServerException()
*/
public static String getRemotePollCometDisabledScript(String batchId)
{
StringBuffer reply = new StringBuffer();
String params = "{ name:'dwr.engine.pollAndCometDisabled', message:'Polling and Comet are disabled. See the server logs.' }";
if (batchId != null)
{
params += ", '" + batchId + "'";
}
reply.append(ProtocolConstants.SCRIPT_CALL_REPLY).append("\r\n");
reply.append("if (window.dwr) dwr.engine._remotePollCometDisabled(").append(params).append(");\r\n");
reply.append("else if (window.parent.dwr) window.parent.dwr.engine._remotePollCometDisabled(").append(params).append(");\r\n");
return reply.toString();
}
/**
* Take an XML string, and convert it into some Javascript that when
* executed will return a DOM object that represents the same XML object
* @param xml The XML string to convert
* @return The Javascript
*/
public static String xmlStringToJavascriptDom(String xml)
{
String xmlout = JavascriptUtil.escapeJavaScript(xml);
return "dwr.engine._unserializeDocument(\"" + xmlout + "\")";
}
/**
* Get a string which will initialize a dwr.engine object
* @return A dwr.engine init script
*/
public static String getEngineInitScript()
{
return "// Provide a default path to dwr.engine\n" +
"if (dwr == null) var dwr = {};\n" +
"if (dwr.engine == null) dwr.engine = {};\n" +
"if (DWREngine == null) var DWREngine = dwr.engine;\n" +
'\n';
}
/**
* {@link DefaultRemoter} needs to know the name of the execute function
* @return The execute function name
*/
public static String getExecuteFunctionName()
{
return "dwr.engine._execute";
}
/**
* A script to send at the beginning of an iframe response
* @param batchId The id of the current batch
* @param useWindowParent Will the exec happen from a child iframe which is
* the case for normal iframe based calls, or from the main window, which is
* the case for iframe streamed polling.
* @return A script to init the environment
*/
public static String remoteBeginIFrameResponse(String batchId, boolean useWindowParent)
{
String script = "dwr.engine._remoteBeginIFrameResponse(this.frameElement"+(batchId == null?"":", '" + batchId+"'") + ");";
if (useWindowParent)
{
script = addWindowParent(script);
}
return script;
}
/**
* A script to send at the end of an iframe response
* @param batchId The id of the current batch
* @param useWindowParent Will the exec happen from a child iframe which is
* the case for normal iframe based calls, or from the main window, which is
* the case for iframe streamed polling.
* @return A script to tidy up the environment
*/
public static String remoteEndIFrameResponse(String batchId, boolean useWindowParent)
{
String script = "dwr.engine._remoteEndIFrameResponse("+(batchId == null?"":"'" + batchId+"'")+");";
if (useWindowParent)
{
script = addWindowParent(script);
}
return script;
}
/**
* Prepare a script for execution in an iframe environment
* @param script The script to modify
* @return The modified script
*/
public static String remoteEval(String script)
{
String script2 = "dwr.engine._eval(\"" + JavascriptUtil.escapeJavaScript(script) + "\");";
return addWindowParent(script2);
}
/**
* A Utility to add a try/catch block to get rid of the infamous IE
* "Can't execute code from a freed script" errors
* @param script The script to wrap in a try/catch
* @return The wrapped script
*/
private static String addWindowParent(String script)
{
return "try { window.parent." + script + " } catch(ex) { if (!(ex.number && ex.number == -2146823277)) { throw ex; }}";
}
/**
* Calling {@link ScriptConduit#addScript(ScriptBuffer)} throws a
* {@link MarshallException} which we want to ignore since it almost
* certainly can't happen for real.
* @param conduit The browser pipe to write to
* @param script The buffer to add to the current {@link ScriptConduit}
* @throws IOException If the write process fails
*/
private static void addScriptWithoutException(ScriptConduit conduit, ScriptBuffer script) throws IOException
{
try
{
conduit.addScript(script);
}
catch (MarshallException ex)
{
log.warn("This exception can't happen", ex);
}
}
/**
* The log stream
*/
private static final Logger log = Logger.getLogger(EnginePrivate.class);
}
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