is there any way how to return generic describing entity type with the JAX-RS Response? Something like REST-Easy ClientReponse but JAX-RS standard and not implementation-specific class.
The thing is I want to call my REST service via its shared interface (created by some proxy provider) and returning only object does not allow add information I need. E.g. for creating resource via POST, I would like to return also URL to newly created resource and so on. Returing simple Response does not show what type of entity is stored within such response.
Response<MyObject> getMyObject(#PathParam("id" Integer id)
So far it seems that I will have to return simple Response and then create adapter which will simply call Response.getEntity(.class)
There is probably no such option...
GenericEntity allows you to return a generic. The actual type is held at runtime by GenericEntity, allowing the object to be serialized.
Here's a contrived example of how it can be used.
GenericEntity entity = new GenericEntity<Employee>(new Employee());
return Response.ok(entity).build();
Related
I am developing a rest api on .Net core 2.2 following MVC pattern.
I have a controller with a post method like this...
// POST: api/Todo
[HttpPost]
public async Task<ActionResult<TodoItem>> PostTodoItem(string param, [FromBody] TodoItem item)
{
// some work...
return CreatedAtAction(nameof(GetTodoItem), new { id = item.Id }, item);
}
And it works fine.
The customer asked to have an api on the same route, but the Json body could have 2 different structures, bearing the same data on different schemas.
I considered using
PostTodoItem(string param, [FromBody] Object item)
{
// TryCast item to one of the possible POCO classes then work with the correct one.
}
Do you know a better way, maybe with some advanced routing and filtering option?
This is not really possible nor desirable. Pretty much the core tenant of REST is a URI uniquely represents a particular resource. If you've got a URI like POST /todo, then the post body should be a "todo" and it should create a new "todo" based on that. Here, that is a TodoItem, so that is all that should ever be posted.
REST aside, this just won't work. When your action is activated, the modelbinder attempts to bind the post body to the param(s) that the action accepts. It basically just news up whatever type the param is, and then attempts to find something from the post body to bind to the various properties on that type. This is an intentionally simplistic description of what's happening; the important part is that the type of the param informs how the post body is bound. If you bind to an object (which has no members) or even a base type, then the only members of the post body that will be bound are those that are present on that type, not derived types thereof. Anything that cannot be bound is discarded.
Long and short, you need a unique route for each type of thing you're working with. Under the hood, you can share or otherwise reuse code by factoring out common functionality into private methods, employing inheritance, etc., but you need a distinct action and route to handle each case.
I want to append the query parameters list of a received UriInfo in a Rest service. The query comes from the client with some parameters and I need to add some more in server side.
I tried with:
uriInfo.getQueryParameters().add("Param", "value");
but when I display the URI, it doesn't has the new parameter.
On the other hand, if I do it like this:
URI uri = uriInfo.getRequestUriBuilder().queryParam("Param", "value").build();
when I display the URI, it contains the new parameter. The problem in this second case is to reconstruct a UriInfo object to give to the next functions, they require it.
I've seen that it cannot be instantiated, it has no constructors, it has to be added with #Context, its value can be updated by another UriInfo... but how to create this UriInfo with the URI I modified?
It is not possible to modify a UriInfo, there are no methods defined for that. The only option is to recreate it using one implementation of the interface. The only implementation available is org.jboss.resteasy.spi.ResteasyUriInfo.
The problem is that when deployed, and the function using it is called, it throws a ClassDefNotFound exception; even with a dependency in the manifest pointing to resteasy-jaxrs-2.3.2.Final.jar
So, the only option is to make our own implementation of the interface.
I am trying to convert an existing wcf rest api to ServiceStack, and having issues right out of the gate:
[Route("foo/{userId}","POST")]
public class MyInputModel : IReturnVoid
{
public string userId { get; set; }
public SomeOtherObject properties { get; set; }
}
The intention here is that I would provide the userId in the url, and an instance of SomeOtherObject in the post body. The error I get is
<Message>Could not deserialize 'application/xml' request using MyInputModel'
Error: System.Runtime.Serialization.SerializationException:
Error in line 1 position 42. Expecting element 'MyInputModel'
from namespace 'blahblahblah'.. Encountered 'Element' with name
'SomeOtherObject', namespace 'http://blahblahblah'.
The only things I can think of are to wrap my xml in a MyInputModel to make the serializer happy. This is not really an option for backwards compatibility.
I could also modify SomeOtherObject to be the top level input model, and put a UserId property in there, but this also feels suboptimal since it is an object used throughout the api, and is really not tied to a user id. It is also already published independently, so it would be painful to make changes there.
Is there any way to indicate that the root element of the posted data will be a SomeOtherObject insted of a MyInputModel? In WebApi this would be with the [FromBody] attributes and whatnot. Does servicestack have anything similar?
The purpose of a DTO is to auto-generate the wire format which is why ServiceStack requires the Request DTO to match the shape of the incoming request. Part of what makes ServiceStack so productive is that it's a code-first web service framework which encourages starting from C# and projecting out, i.e. your clients should bind to your web service outputs and not the other way round of mapping code-first models to existing schema inputs.
Having said that, the Serialization / Deserialization wiki page lists the different ways to override ServiceStack's default request binding with your own.
Access HTTP Request variables in any Service or Filter
Not everything needs to be mapped to a DTO as any HTTP Variable can still be accessed from the IHttpRequest available from any service or filter, i.e:
base.Request.QueryString
base.Request.FormData
base.Request.Headers[name]
base.Request.PathInfo
base.Request.AbsoluteUri
Let's say the Action below is exposed via REST service and is called from a different appliation how would it handle the posted data/object?
Should I use Create(FormCollection collection) here?
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(Member member)
{
....
}
I'd suggest using a model, but one in which all of the parameters are nullable and use the RequiredAttribute for actual, required parameters. This would allow your method to accept invalid requests -- with missing or extra data -- yet have valid data bound to the model. For invalid data, you can supply error returns instead of presuming default values for non-nullable properties. Using the model binding validation architecture provides a convenient way to make sure that the request is legal. It would be up to you how you want to handle "extra" data supplied by the request -- I'd say ignore it.
My EF model was generated from my SQL Server database. I then generated a DomainService for RIAServices against the EF model. One of the entities is called "EntryCategories". The DomainService created this method:
public IQueryable<EntryCategories> GetEntryCategoriesSet()
{
return this.Context.EntryCategoriesSet;
}
Since my user interface display model looks quite different from the physical model, I decided to write my own DomainService for that and related entities. Yes, I know we are meant to modify the generated one but it has so much stuff in there and I wanted to focus on a small thing.
I removed the EnableClientAccess attribute from the generated DomainService and added a new class called ClientDomainService, and encapsulated in it the generated DomainService:
[EnableClientAccess()]
public class ClientDomainService : DomainService
{
// the generated domain service encapsulated in my new one.
private DataDomainService _dcds = new DataDomainService();
// reimplement one of the DataDomainService methods
public IQueryable<EntryCategories> GetEntryCategories()
{
return (from t in _dcds.GetEntryCategoriesSet() where t.EntryCategoriesVersions.EntryCategoriesVersionId == datahead.EntryCategoriesVersions.EntryCategoriesVersionId orderby t.DisplayOrder select t);
}
}
The very fist thing I tried is to reimplement the GetCateogoriesSet method but with the underlying data filtered based on another entity in my class (not shown). But when I build this, an error shows up:
Entity 'DataProject.Web.EntryCategories' has a property 'EntryCategoriesVersionsReference' with an unsupported type
If I comment out my CientDomainService, replace the EnableClientAccess attribute on the generated DomainService, and place the analagous linq filtering in the original GetEntryCategoriesSet method, the project compiles with no errors.
What is so special about the generated DomainService that my new one doesn't have? Is it that metadata.cs file?
What's special about the generated domain service is not the .metadata.cs file (you can keep it, and use it, but it doesn't solve your problem).
The problem appears somehow because RIA services (?) needs a 'domain service description provider' for the exposed Linq to EF entities. The LinqToEntitiesDomainService class has the LinqToEntitiesDomainServiceDescriptionProviderAttribute, already applied, so the generated domain services which inherit from it also inherit the provider.
When you build your own custom domain service, derived from DomainService, and expose entities through it, you need to apply this attribute yourself. Furthermore, since the provider cannot infer the object context type from the domain service base class (which it can and does if the base class is LinqToEntitiesDomainService), you need to specify the object context type in the attribute constructor, like this:
[EnableClientAccess()]
[LinqToEntitiesDomainServiceDescriptionProvider(
typeof(YourObjectContextType))]
public class ClientDomainService : DomainService
{
...
}
That should fix it.
Note that this means if you had hoped to abstract your object context away from your domain service, you'll be disappointed. I had opted for the seemingly popular repository model where all code that operates on the object context goes into a provider used by the domain service. This facilitates unit testing, but evidently doesn't remove the domain service's dependency on the object context. The context is required for RIA Services to make sense of your entites, or at least those referenced by the domain entity (such as EntryCategoriesVersions in your case).
If you want to expose a specific entity on a domain service you will have to provde at least one query method for it. This is also required when the entity is only accessed as a child of another entity.
In this case you need to add the EntryCategoriesVersions entityset to the domain service, to get the scenario working correctly.
What type is EntryCategoriesVersionsReference ? Try adding a [DataContract] annotation against the type, and appropriate [Key] and [DataMember]. It should help with marshalling.
For me, the fix for this error was to add a default constructor to the return type.
In OP's example, the property 'EntryCategories.EntryCategoriesVersionsReference' needs to be of a type with a default constructor.