RESTful url may contain the content type with in the url string. For example: http://host/action/xml/bookmark. Here “xml” is content type, this content type can be changed to “text, json” or etc…
So following urls are valid too. http://host/action/text/bookmark, http://host/action/json/bookmark etc…
these days I am playing with “Stripes” web framework a lot. Those who didn’t get in touch with “Stripes” have a look on the following URL – http://stripes.mc4j.org, hope you will enjoy it.
stripes has fantastic flexibility, it enables a lot of customization. Now my tutorial will demonstrate how you can enable this url pattern, where your single “ActionBean” will be invoked on the following url patterns:
http://host/action/xml/bookmark, http://host/action/text/bookmark, http://host/action/json/bookmark etc…
My target audience:
Who has already been introduced with Stripes or those who are interested on stripes framework.
Routing plan:
Request Dispatch
[visitor] — > http://host/action/xml/bookmark — > [web server] — > [Stripe servlet] — > [Custom Action resolver] — > [remove user defined content type “xml” and retrieve action bean]
Response Dispatch
[clean url (after removing content type)] — > http://host/action/bookmark — > [BookmarkActionBean] — > [Resolution] — >
Pre requisite:
Stripes servlet is configured and web context is up and running.
ActionBean code:
* create an ActionBean, for example “BookmarkActionBean”
@UrlBinding(“/action/bookmark”)
public class BookmarkAction implements ActionBean {
private final Log LOG = LogFactory.getLog(getClass());
private ActionBeanContext mActionBeanContext;
private String mContentType = “text/xml”;
public void setContext(ActionBeanContext actionBeanContext) {
mActionBeanContext = actionBeanContext;
// retrieve user requested content type constant for example “text,json, xml”
// convert consts to mime type “text, text/xml, application/JSON”
mContentType = URLHelper.getMimeType(URLHelper.getContentType(getContext().getRequest().getPathInfo()));
}
public ActionBeanContext getContext() {
return mActionBeanContext;
}
@DefaultHandler
public Resolution save() {
if (LOG.isDebugEnabled())
LOG.debug( “storing bookmark object on the data store, ” +
“response content type is requested – ” + mContentType );
return new StreamingResolution( mContentType, new StringReader(“”) );
}
}
Description:
Here i have set our action on “/action/bookmark” url, but our user requested url pattern is “/action//actionBean”
Look on the “setContext” method, I have added an extra line
mContentType = URLHelper.getMimeType(URLHelper.getContentType(getContext().getRequest().getPathInfo()));
now have a look on the URLHelper class.
public static String getContentType( String pRequestedUrl ) {
String contentType = CACHED_URL_CONTENT_TYPE.get(pRequestedUrl);
if (contentType == null) {
contentType = DEFAULT_CONTENT_TYPE;
Perl5Util util = new Perl5Util();
if (util.match( REGEX_ACTION_CONTENT_TYPE, pRequestedUrl ))
contentType = util.group(1)+”";
CACHED_URL_CONTENT_TYPE.put( pRequestedUrl, contentType );
}
return contentType;
}
This method is responsible to retrieve user requested content type constants.
for example “text, xml, json”
public static String getMimeType( String pContentType ) {
// convert content type to MIME Type
if (pContentType.equalsIgnoreCase(CONTENT_TYPE_CONST_XML))
pContentType = CONTENT_TYPE_XML;
else if (pContentType.equalsIgnoreCase(CONTENT_TYPE_CONST_JSON))
pContentType = CONTENT_TYPE_JSON;
return pContentType;
}
This method is also converting constant to MIME content type.
For example “xml –> text/xml”
Now return to my base action bean. I have added the following method, which is defined as default handler.
@DefaultHandler
public Resolution save() {….
return new StreamingResolution( mContentType, new StringReader(“”) );
}
Here “mContentType” is repopulate when “setContext” is invoked.
ActionResolver code:
This is my action resolver.
public class NBookmarkSystemActionResolver extends NameBasedActionResolver {
// ………
@Override
public ActionBean getActionBean(ActionBeanContext pActionBeanContext, String pRequestedUrl) throws StripesServletException {
String cleanUrl = URLHelper.getCleanUrl(pRequestedUrl);
if (LOG.isDebugEnabled())
LOG.debug( “user requested url – ” + pRequestedUrl + ” clean url – ” + cleanUrl);
return super.getActionBean(actionBeanContext, cleanUrl);
}
}
Now let’s have a look on “getCleanUrl” method.
public static String getCleanUrl( String pRequestedUrl ) {
return pRequestedUrl.replaceAll(“/”+getContentType(pRequestedUrl),”");
}
Custom ActionResolver configuration:
Stripes Filter
StripesFilter
net.sourceforge.stripes.controller.StripesFilter
ActionResolver.UrlFilters
/WEB-INF/classes/
ActionResolver.PackageFilters
com.we4tech.nBookmarkSystem.service.webService/*
ActionResolver.Class
com.we4tech.nBookmarkSystem.configuration.NBookmarkSystemActionResolver
That’s all for today,
Hope you will enjoy stripes. Best of luck…
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