tapestry-offline

Offline rendering of Tapestry pages and components without a HTTP servlet request

Usage

Pages and components can be rendered via the OfflineComponentRenderer which can be injected via Tapestry IOC

public class MyOfflineRenderer {
    @Inject
    private OfflineComponentRenderer offlineRenderer;

    @Inject
    private TypeCoercer typeCoercer;

    public String renderPageAsString() throws Exception {
        // setup the PageRenderRequestParameters
        String logicalPageName = ...;
        EventContext activationContext = new ArrayEventContext(typeCoercer, ...);
        boolean loopback = false;
        PageRenderRequestParameters params = new PageRenderRequestParameters(
            logicalPageName,
            activationContext,
            loopback
        );
    
        // setup the RequestContext
        Map<String, Object> session = new HashMap<String, Object>();
        session.put("foo", "bar");
        DefaultOfflineRequestContext requestContext = new DefaultOfflineRequestContext();
        requestContext.setSession(session);
        requestContext.setParameter("someParam", "paramValue");
        requestContext.setAttribute("someAttribute", "attributeValue");
        requestContext.setHeader("someHeader", "headerValue");

        // render the page offline
        StringWriter stringWriter = new StringWriter();
        PrintWriter printWriter = new PrintWriter(stringWriter);
        Future<?> future = offlineRenderer.renderPage(requestContext, params, printWriter);
        future.get();
        return stringWriter.toString();
    }

    public JSONObject renderComponentAsJSONObject() throws Exception {
        // setup the ComponentEventRequestParameters
        String activePageName = ...;
        String containingPageName = ...;
        String nestedComponentId = ...;
        String event = ...;
        EventContext pageActivationContext = new ArrayEventContext(typeCoercer, ...);
        EventContext eventContext = new ArrayEventContext(typeCoercer, ...);
        ComponentEventRequestParameters eventParams = new ComponentEventRequestParameters(
            activePageName,
            containingPageName,
            nestedComponentId, 
            event,
            pageActivationContext, 
            eventContext
        );

        // setup the RequestContext
        Map<String, Object> session = new HashMap<String, Object>();
        session.put("foo", "bar");
        DefaultOfflineRequestContext requestContext = new DefaultOfflineRequestContext();
        requestContext.setSession(session);
        requestContext.setXHR(true);
        requestContext.setParameter("someParam", "paramValue");
        requestContext.setAttribute("someAttribute", "attributeValue");
        requestContext.setHeader("someHeader", "headerValue");
    
        // render the component event offline
        Future<JSONObject> future = offlineRenderer.renderComponent(requestContext, eventParams);
        return future.get();
    }
}

Configuration

AppModule

Configure the offline request symbols in your IOC Module

/**
 * These are usually only required if generating links when rendering pages / components offline
 */
public static void contributeApplicationDefaults(MappedConfiguration<String, Object> config) {
    // the host name of the server to which the request was sent. It is the value of the part
    // before ":" in the Host header value, if any, or the resolved server name, or the 
    // server IP address.
    config.add("tapestry-offline.serverName", ...);

    //  the fully qualified name of the client or the last proxy that sent the request
    config.add("tapestry-offline.remoteHost", ...);
    
    // the Internet Protocol (IP) port number of the interface on which the request was received.
    config.add("tapestry-offline.localPort", ...);
    
    // the port number to which the request was sent.
    config.add("tapestry-offline.serverPort", ...);
}

ParallelExecutor

Configuration options listed here

Maven

Add the following to your pom.xml:

<dependencies>
    <dependency>
        <groupId>org.lazan</groupId>
        <artifactId>tapestry-offline</artifactId>
        <version>x.y.z</version> <!-- lookup latest version at https://github.com/uklance/releases -->
    </dependency>
</dependencies>

<repositories>
    <repository>
        <id>lazan-releases</id>
        <url>https://raw.github.com/uklance/releases/master</url>
    </repository>
</repositories>

How does it work?

First, a Request is constructed by combining the OfflineRequestContext parameter with the global OfflineRequestGlobals service. Next, a Response is created by combining the Writer / OutputStream parameter with the global OfflineResponseGlobals service. The core tapestry page / component rendering pipeline is then invoked on a seperate thread by the ParallelExecutor to prevent dirtying the current thread.