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From what I understand, you are "manually" copying the properties from the Entity to the DTO. But this process is automated in GWT 2.1 So, I am not sending my entities directly, but the proxies as per the documentation : http://code.google.com/webtoolkit/doc/latest/DevGuideRequestFactory.html "An entity proxy is a client-side representation of an entity, otherwise known as a DTO (Data Transfer Object). With RequestFactory, entity proxies are interfaces that extend the EntityProxy interface, which is the hook used to indicate that an object can be managed by RequestFactory. RequestFactory automatically populates bean-style properties between entities on the server and the corresponding EntityProxy on the client, which simplifies using the DTO pattern. Furthermore, the EntityProxy interface enables RequestFactory to compute and send only changes ("deltas") to the server." "Entity proxies simply extend the EntityProxy interface and use the @ProxyFor annotation to reference the server-side entity being represented. It is not necessary to represent every property and method from the server-side entity in the EntityProxy, only getters and setters for properties that should be exposed to the client." The entity proxies are merely interfaces that are being populated by the new GWT 2.1 RequestFactory framework. I have no control over this copying process. Per definition, getters/setters of the real entity are injected into the EntityProxy whenever they are present; So my problem still stands : what about complex values like com.google.appengine.api.datastore.Email that are not known by the client side code ? How to transfer these complex values to the client.

When I copy my entities onto my dtos, some entity fields don't even make it into the dto. Others only have getters in the dto because they are read-only to the client. Those that do get into the dto get converted to native Java types. For instance, Text gets converted to String. Key gets encoded to a url friendly string. If I have Set fields on the entities to manager my relations (property lists), I remap those to ArrayList... First, don't serialize interfaces to GWT client, you'll get Javascript bloat. Then, Hashmap is costly to serialize because String.hashCode() is not the same on in Java and in Javascript. Hence, all the items need to be re-inserted into a client side map. Of course, in Web mode, performance is good enough... but in development mode, your data transfers will become really slow for somewhat big transfers.

Blobstore crash course It’ll be best if we gave a quick refresher course on the blobstore before we begin. Here’s the standard flow for a blobstore upload: Create a new blobstore session and generate an upload URL for a form to POST to. This is done using the createUploadUrl() method of BlobstoreService. Pass a callback URL to this method. This URL is where the user will be forwarded after the upload has completed. Present an upload form to the user. The action is the URL generated in step 1. Each URL must be unique: you cannot use the same URL for multiple sessions, as this will cause an error. After the URL has uploaded the file, the user is forwarded to the callback URL in your App Engine application specified in step 1. The key of the uploaded blob, a String blob key, is passed as an URL parameter. Save this URL and pass the user to their final destination

Yes, worker would be a servlet which can handle a request with POST parameters. If you want an asynchronous call from client's point of view then RPC is enough (from server's point of view it is still synchronous). If you want to do "delayed" jobs which don't talk to your client, you can use a task queue.

Instead of trying to create a thread (which is impossible in App Engine), this is a great way to asynchronously run tasks.

I figure it is going to take me at least four iterations to get this right. The first one will be building a GWT application with a simple UI that has no server logic behind it (just to learn how layout in GWT works). Step two will be adding a fake servlet backend (not app engine, just in memory). While not exactly App Engine yet, I should have a completely specified client-server API by the end of this process that I can subsequently implement on App Engine (iteration 3). Iteration four will handle deployment, CSS and whatever I may screw up in iterations one and two. I will log my notes of things I run into while I code.

This tutorial concerns using Google Accounts to maintain the existence of your users in a Google App Engine application. Google App Engine provides the class UserServiceFactory to facilitate that. UserServiceFactory is then used to generate UserService object, which in turn provides the following features createLoginURL createLogoutURL getCurrentUser isUserAdmin isUserLoggedIn You would use UserService object to generate the login URL for the browser. The browser would be directed/redirected to this URL. On reaching this URL, the Google log-in prompt would be displayed by Google's server.

Cold-start latency is determined by the time it takes to load all the classes needed to handle the request. If you upload a JAR file, but nothing references it, it won't be loaded, and thus won't affect your cold-start latency.

Only those jars under WEB-INF/lib will be uploaded to GAE. You can prevent GWT jars from being uploaded by not placing them under WEB-INF/lib, rather by externally linking to them in your project build path.

Have you tried these? for server-side (GAE) *com.google.appengine.repackaged.org.json.JSONObject.JSONObject(String arg0)* for client *com.google.gwt.json.client.JSONParser* I haven't tried japanese or chinese characters though, rather stuff like this: "Příliš žluťoučký kuň úpěl ďábělské ódy"

you can use the sample project that the google plugin for eclipse create for you. Then you can easily replace the generated java code by groovy / gaelyk code. Note that you need to add the jars in the war/WEB-INF/lib of your project, and add them in the project build path options.

've been able to accomplish what you're doing with Selenium testing. If you're using GWT, then your integration testing and user acceptance probably won't be that far from each other.

> My question is this. What's the best way to use LocalServiceTestHelper > so that I can use my app like it has a persistent store? There is no > 'setUp' and 'tearDown' hooks like a JUnit test and the app runs in a > separate process within the IDE. (And in any case, I'm looking to do > integration testing where I want the state to be consistent across a > number of page requests.)

You don't have to add each class individually to the black list. They are all regex patterns, so just do this: <extend-configuration-property name="rpc.blacklist" value="com.google.gwt.user.client.ui.*Collection"/> In my case I wanted even finer grained control over which collections get included, so I did this: <extend-configuration-property name="rpc.blacklist" value="-.*List"/> <extend-configuration-property name="rpc.blacklist" value="-.*Map"/> <extend-configuration-property name="rpc.blacklist" value="-.*Collection"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.HashMap"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.LinkedHashMap"/> <extend-configuration-property name="rpc.blacklist" value="+java.util.ArrayList"/>