When I send back a Class, it ignores the DataContract - DataMember attributes and serializes all members of the class as well as sends the class name in the "__type" flag as well. How can I make it respect the DataMember attributes?
WebMethods use the legacy "ASMX Web Service" technology. DataContract is part of WCF.
They are totally unrelated technologies.
Related
As far as i understand it right JMSSerializerBundle's deserialisation does the same same as the symfony form component when a controller gets an post/put/patch request?
So either i create a symfony custom formType for e.g. an UserType and when i get a request i do something like $form->handleRequest($request) or i use JMSSerializerBundle to unserialize the request to a document/entity which gets finally stored.
Does anyone have experience with both methods? Currently i'm only familiar with the form way... Which one should i choose?
The Application i'm talking about is purely Restful, there are no twig html templates and FOSRestbundle is doing all the RESTful routing.
In our restfull API we usually use the Symfony Serializer component to handle the deserialization of entities, then the Symfony Validator component to ensure that the entities fulfill all the required conditions before pushing/updating them in database. Works pretty well, lighter than the form component.
Anyway The Form component would not be able to deserialize the json/xml so you'll have to use a serializer.
The benefit of the Symfony\Form component over the JMS Serializer is that the validation is done before deserialization which fits into PHP 7 strict typing. Example case - you pass an array instead of a string, JMS creates and object and the getter raises a \TypeError instead of a validation error from the validator.
I have recently created a pretty robust API built around Entity Framework's DbContext. I am using a lot of metadata programming and taking advantage of the fact that I can get my data with a call like DbContext.Set(typeof(Customer)). Only, in my API I do not know at compile time what type I will be passing to the Set method. This is working very well with EntityFramework and I would like to add another layer abstraction and have it work with both EntityFramework or DataServiceContext. So, I really have two questions.
Firstly, and more specifically, is there a DataServiceContext (i.e. odata/wcf) equivalent to the DbContext.Set(type) method?
Secondly, and more generally, is there a good resource that compares the APIs provided by DbContext with DataServiceContext?
EntityFramework and DataServices client API should not be mixed. Even though they look similar they are not. DbSet represents entity set. I don't think there is a strong contract around entity sets in DataServiceContext. Instead the name of the entity set is passed to methods that need to know this (e.g. look at DataServiceContext.AddObject() or DataServiceContext.CreateQuery() methods) as strings. In some sense it makes it much easier to program the DataServiceContext dynamically. On the other hand you still need to know what is on the other side of the pipe (i.e. the server). As said above WCF Data Services and EntityFramework are different technologies (even though they can work together) and their APIs, though similar, serve different purposes. Therefore comparing them would be like comparing apples to oranges.
The DbContext API in the client side is not the same from DbContext on server side. The main goal is to expose the data and model, which can be done pretty well. I think you may be overengeneering your app, since WCF Data Services can provide enough funcionalities.
Here is a link from Ladislav Mrnka, who is very good at entity framework, he shows how you could expose your robust api with WCF Data Services.
Implement WCF Data Service using the Repository Pattern
I must admit that I'm new to Web services. When I create a Web service using CXF or Axis, even with custom beans being used to communicate information between the client and the service, the objects are automatically marshalled and unmarshalled for me (I mean CXF or Axis create all the necessary files and classes). So, even though I know JAXB is used by the stack to marshal, and unmarshal objects, but I don't directly need to work with JAXB.
Now, my question is whether I need to work with JAXB directly, as far as Web services are concerned, or that marshaling and unmarshalling will always be handled for me?
When creating a JAX-WS (SOAP) or JAX-RS (RESTful) Web Service, JAXB is used as the binding layer to convert objects to/from XML (and sometimes JSON). This marshalling/unmarshalling is triggered automatically for you. Where you interact with JAXB is by adding annotations to your domain model to control how the XML looks. Below are a couple of examples that you may find useful:
http://blog.bdoughan.com/2011/12/eclipselink-moxy-is-jaxb-provider-in.html (JAX-WS example)
http://blog.bdoughan.com/2010/08/creating-restful-web-service-part-35.html (JAX-RS example)
When we are using EF (f.e.) via MVC, we can use ModelState.IsValid to detect a model can pass DataAnnotations metadata or not. But how can I use DataAnnotations metadata in a desktop (win-forms / wpf) application?
More:
In fact, I want to create an object same as ModelState (a dictionary that can save properties and messages associated with each). Then, wrap the DAL by a validation-layer, in VL use metadata to validate models, that the VL can be used in any project. I know I should use reflector, but I haven't any experience. Thanks to any help and suggestion.
If you are using EF 4.1/4.1 dbcontext, it has a built in validation API that can check Data Annotation rules as well as IValidatableObject.Validate. I'm not quite sure that I understand your goal, but if it is to have the validation in the data layer then you can just use what's built in. (Here's an overview http://msdn.microsoft.com/en-us/data/gg193959).
If you want your own validator that is separate from the data layer, then look at the System.ComponentModel.DataAnnotations namespace for methods and other logic you can leverage to do your own validation.
Still wresting with GWT and App Engine, and I have come to this problem:
I have an app engine populated with various data, which I would like to present on the client using a GWT RPC.
I have found out the hard way that, because my Model objects are annotated with JDO, i can't just send them back to the client because they aren't serializable. This means I'm going to have to create a layer of intermediate classes to extract data from my model objects, and send it back to the client to use asynchronously.
I am wondering though, it is possible to construct a GWT object in a servlet and send it back to be used? For example, the servlet would be receive my asynchronous request, pull out the data i want from the database, create a GWT VerticalPanel() with appropriate child elements for the data, and send that VerticalPanel back to the client to be injected.
My understanding of the Java / Javascript interaction that is going on here is still foggy, and I'm thinking that sending a Java object that is not compiled to Javascript after the application is deplyed will not work. Can anybody clarify this for me?
No the server can't create GWT UI objects (like vertical panels) to be used in the presentation layer, nor should it, that's why it's called a 'server' and a 'presentation layer' one serves the data and handles all the business logic, the other displays things on a screen and allows a user to interact with them.
You can however send your JPA annotated POJO's to the front end just fine (we do it in all our applications). You simply need to include the source code for the annotations themselves so that GWT knows how to compile them. You also need to make sure your POJOs's are in a package that is referenced by a NameOfXmlFile.gwt.xml file, eg:
<module>
<inherits name='com.google.gwt.user.User'/>
<source path="domain" />
</module>
This file in my case is in a folder above a package called 'domain' where all my JPA annotated POJO's live. Then in your client side you tell it to inherit that .gwt.xml file:
<module>
<inherits name='com.google.gwt.user.User'/>
<!-- Domain layer references -->
<inherits name='your.package.structure.NameOfXmlFile'/>
</module>
There are restrictions on what you can put in those classes (like for example BigDecimal is not supported, etc) but anything that can be compiled by the GWT compiler (and JPA annotations certainly can be) can be sent without needing any kind of transfer objects. This is one of the real strengths of GWT, that you can use the same JPA Pojos in your entire application, without ever needing to create any other similar object.
Edit: I just noticed you said JDO and not JPA. I assume the same applies there as well though if they are just annotations?
I've seen good answers, so I won't repeat them myself..
Anyway my simple but vital suggestion is: the only way to go is through POJO objects.. BUT IMHO to avoid problems, remember that your POJO objects SHOULD be really PLAIN
Anyway, I can suggest you also a little framework I recently did (few hours of work, so don't expect a rocket!).
It is pojo-injector: http://code.google.com/p/pojo-injector
It helps you in translating your data models to POJO and back... It's based on annotations (only on the POJO side!).
I hope it can help.
This is (imho) one of the problems with GWT.
Basically in Java Web applications it's pretty common to have data or domain objects (which would be your JDO objects) and presentation objects, which are sent to the view. Some go much further than this and can have many more layers of abstraction ("go ahead, add one more layer").
I can see the argument for this but it adds a lot of boilerplate as you translate objects between layers.
Anyway, in GWT you need to do this if your domain objects are POJOs (and as with JPA, even though they claim to be POJOs, the annotations make them not so in reality).
GWT will do this for you on objects returned by your RPC interface but there are certain classes you can't use (eg BigDecimal) as there is no Javascript equivalent (so to use BigDecimals you pass Strings around to construct BigDecimals yourself on the serverside when you ened them and convert them back to Strings when you send them to the client).