Freemarker templates and java backed webscripts

Wondering about output to freemarker template from java backed webscript in Spring Surf? You’re on the right place, it’s simple so I’ll try to describe it on a few lines. For first I suppose some prerequisites you have:

Ok, let’s get it done quickly! Create new directory, for example webscripts. Go into it, fire up roo, create a new project, install surf extension into it and create an Eclipse project:

project --topLevelPackage cz.shmoula.webscripts
surf install
perform eclipse

Now you should have base skeleton of our future app (you can also download it here) and you can import it into SpringSource Tool Suite.

Webscripts are located in src/main/webapp/WEB-INF/webscripts folder, so open that folder and create two files: example.get.html.ftl (template) and example.get.desc.xml (description).

<p>logged user: ${userId}</p>
      <description>Sample java backed webscript</description>

Now we have to create our java source code. It’s not bad idea to put webscripts to their own package, for example webscript. In that package create a new class, which extends org.springframework.extensions.webscripts.AbstractWebScript – Example. By doing that we have to implement an execute method, which is called, when webscript is executed:

public void execute(WebScriptRequest req, WebScriptResponse res)
    throws IOException {

Let’s fill that method. We need a model map, which holds values as pair (String)key – (Object)value. For our desired function we also need to get HttpServletRequest:

Map<String, Object> model = new HashMap<String, Object>();
HttpServletRequest httpRequest = ServletUtil.getRequest();

Now to fill up model (aka our function). Let’s find out if there is logged in user and if so, write out it’s userId:

      model.put("userId", AuthenticationUtil.getUserId(httpRequest));
      model.put("userId", "guest");

Final step is to put out our model. We need to get writer and renderTemplate, which we specified by its path (and also flush and close our writer):

Writer writer = res.getWriter();
String templatePath = "webscripts/example.get.html.ftl";
renderTemplate(templatePath, createTemplateParameters(req, res, model), writer);


Last thing we have to do is to let Surf know about our shiny new webscript. You can add new bean directly inside applicationContext, but it’s not bad idea to keep them separately. So in src/main/webapp/WEB-INF/config create new Spring Bean Definition file – custom-webscripts-config.xml and put inside new bean definition:

<bean id="webscript.webscripts.example.get" class="cz.shmoula.webscript.Example" parent="webscript"/>

Now we have to import that new config: in the same directory is surf-config.xml file, so let’s add there new import:

<import resource="custom-webscripts-config.xml"/>

At this time we can run our project and visit http://localhost:8080/webscripts/example, which shows following page:

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It’s possible to login (if you have set up user factory) as an Alfresco user and after that another userId is shown. I’m planning to write new blogpost about custom user factory and stuff like that, so be patient please. Finally, you can download source code for this example at this link. Structure of project is shown at following screenshot (note that red dots – those are modified files):

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Finally, try to experiment with some examples from Alfresco wiki and look forward to next blogpost.

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