FlowHandler.handleException question

[lumpynose]

I'm still stumbling around in the dark trying to figure out how to handle NoSuchFlowExecutionException.

If my FlowHandler.handleException() returns null my browser is sent to

/swf-example/addUser

If my FlowHandler.handleException() returns the empty string my browser is sent to

/swf-example/addUser.zug/

or, whatever string it returns is appended to the above.

addUser is the flow identifier. addUser.zug is the start of the flow;

    <beans:bean id="flowUrlMappings"
            class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <beans:property name="mappings">
            <beans:value>
                /addUser.zug=addUserFlowHandler
            </beans:value>
        </beans:property>
    </beans:bean>

And in my web.xml the servlet-mapping section has *.zug for the url-pattern.

Question 1: why the difference in behavior?

Question 2: Given this behavior I still don't see how I can display a specific view from the NoSuchFlowExecutionException when the user uses the back button after the flow has finished (or any other exception under other conditions).

[michaelcourcy]

I have exactly the same problem

My flow mapping

/back/product/searchProduct.html=flowController

And in my web.xml the servlet-mapping section has *.html for the url-pattern

But when a NoSuchFlowExecutionException is fired the browser is sent to

/back/product/searchProduct

instead of

/back/product/searchProduct.html

[Keith Donald]

Did you guys see the JavaDoc for the String returned from handleExecutionOutcome and handleException?

	 * The following prefixes are supported for qualifying the returned location string:
	 * <ul>
	 * <li>servletRelative: - the location is relative to the current servlet</li>
	 * <li>contextRelative: - the location is relative to the current web application</li>
	 * <li>serverRelative: - the location is relative to the server root</li>
	 * </ul>
	 * If the returned location is a path with no prefix, for example "/hotels/index", it is treated as relative to the
	 * current servlet by default. Fully qualified URLs beginning with http:// or https:// may also be returned.
	 * <p>
	 * For servlet-relative, context-relative, and server-relative URLs, a leading slash is optional.

With that said, it's quite possible there is an issue with *.htm mappings and generating flow definition urls using the available FlowUrlHandlers. These days, we do not generally recommend that style of extension based mapping, but a path-based mapping instead. However, we still should make sure *.htm mappings work completely.

Have a look at the DefaultFlowUrlHandler or the WebFlow1UrlHandler code if you are using it to see what I mean. You could plug in a custom extension to one of these classes for the time being.

Keith

[michaelcourcy]

Ok thanks

Here is a fix for flowController mapped to extension :

package com.netapsys.shop.flow.handler;

import javax.servlet.http.HttpServletRequest;

import org.springframework.webflow.context.servlet.DefaultFlowUrlHandler;
import org.springframework.webflow.core.collection.AttributeMap;

/**
 * An extension of {@link DefaultFlowUrlHandler} to handle
 * the relaunch of flow mapped with extension such "*.html". 
 * 
 * When the swf send a redirect to the browser for an expired flow  
 * the url is simply the id of the flow.
 * 
 * Thus this class is a quick fix and should be deprecated soon.
 * 
 * How to use it ?
 * 
 * In Your dispatcher config :
 *   <bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController">
 *       <constructor-arg ref="flowExecutor" />
 *       <property name="flowUrlHandler" ref="urlHandler" />
 *   </bean> 
 *   <bean id="urlHandler" class="com.netapsys.shop.flow.handler.SimpleExtensionUrlHandler">
 *       <property name="extension" value="html" />
 *   </bean>
 * 
 * @author Michael Courcy
 * @date 4 mai 08
 * @version $Revision$ $Date$
 * 
 */
public class SimpleExtensionUrlHandler
    extends DefaultFlowUrlHandler
{

    /**
     * The extension we must add at the end of the url when the a redicect is
     * sent to the browser.
     */
    private String extension = "";

    /**
     * {@inheritDoc}
     * 
     * @see org.springframework.webflow.context.servlet.DefaultFlowUrlHandler
     * #createFlowDefinitionUrl(java.lang.String,
     * org.springframework.webflow.core.collection.AttributeMap,
     * javax.servlet.http.HttpServletRequest)
     */
    public String createFlowDefinitionUrl(final String flowId,
            final AttributeMap input, final HttpServletRequest request)
    {
        final String initialUrl = super.createFlowDefinitionUrl(flowId, input,
                request);
        if ("".equals(extension)) {
            return initialUrl;
        }
        else {
            final String urlWithExtension = addExtenstionToUrl(initialUrl,
                    extension);
            return urlWithExtension;
        }

    }

    /**
     * Add an extension to the url.
     * 
     * @param initialUrl the url we must change with an extra extension
     * @param ext the value of the extension, you have to set this extension
     * with {@link #setExtension(String)}
     * @return the url modified
     */
    public String addExtenstionToUrl(final String initialUrl, final String ext)
    {
        final int posQuestionMark = initialUrl.indexOf("?");
        if (posQuestionMark == -1) {
            return initialUrl + "." + ext;
        }
        else {
            final String firstPartUrl = initialUrl.substring(0, posQuestionMark);
            final String secondPartUrl = initialUrl.substring(posQuestionMark);
            return firstPartUrl + "." + ext + secondPartUrl;
        }
    }

    /**
     * Getter for <code>extension</code>.
     * 
     * @return the value of extension.
     */
    public String getExtension()
    {
        return extension;
    }

    /**
     * Setter for <code>extension</code>.
     * 
     * @param extension : the value to set in extension.
     */
    public void setExtension(final String extension)
    {
        this.extension = extension;
    }

}

in your dispatcher config :

<bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController">
		<constructor-arg ref="flowExecutor" />
		<property name="flowUrlHandler" ref="urlHandler" />
	</bean>	
	<bean id="urlHandler" class="com.netapsys.shop.flow.handler.SimpleExtensionUrlHandler">
		<property name="extension" value="html" />
	</bean>

For you lumpynose yo will use "zug" instead of "html".

Do you want me to propose a fix directly in DefaultFlowUrlHandler ?