Say I have this class:
public class Account
{
public int AccountID { get; set; }
public Enterprise Enterprise { get; set; }
public List<User> UserList { get; set; }
}
When I use AutoMapper to map the Account class, I would also like it to map the Enterprise class, and the list of users (UserList) in the returned object. How can I get AutoMapper to do this?
Thanks!
AutoMapper does that out of-the-box if you provide a configuration for the Enterprise and User type.
Configuration looks like this:
Mapper.CreateMap<Account, AccountDto>();
Mapper.CreateMap<Enterprise, EnterpriseDto>();
Mapper.CreateMap<User, UserDto>();
This shows how to how collections get mapped:
http://automapper.codeplex.com/wikipage?title=Lists%20and%20Arrays&referringTitle=Home
You need to create a mapping for each pair of types you would like mapped.
Mapper.CreateMap<Account, AccountDto>();
Mapper.CreateMap<Enterprise, EnterpriseDto>();
Mapper.CreateMap<User, UserDto>();
Order is not important.
Related
I am a bit confused with ServiceStack 'old' and 'new' API and need some clarification and best practices, especially with Request / Response DTO's and routing. I watched some courses on Pluralsight and have the first three books listet on servicestack.net in my electronic bookshelf.
I like to 'restify' an existing application which is built using DDD patterns which means I have a high level of abstraction. The client is WPF and follows the MVVM pattern. I have 'client side service', 'server side service' and repository classes (and some aggregates too). I use NHibernate 4 (with fluent API and a code-first approach) as ORM. Only my repository classes know about the ORM. I have DTO's for all my Entity objects and in my WPF client I only work with those DTOs in the ViewModel classes. I heavily use AutoMapper to 'transfer' Entity objects to my DTO's and vice versa.
My confusion starts exactly with these DTO's and the Request / Response DTOs used in ServiceStack. Here is a very much simplified example of an Address Entity which illustrates the problem:
All my Entity Objects derive from EntityBase which contains basic properties used in all Entities:
public abstract class EntityBase : IEntity
{
public virtual Guid Id { get; protected set; }
public virtual DateTime CDate { get; set; } //creation date
public virtual string CUser { get; set; } //creation user
public virtual DateTime MDate { get; set; } //last modification date
public virtual string MUser { get; set; } //last modification user
//
// some operators and helper methods irrelevant for the question
// ....
}
public class Address : EntityBase
{
public string Street { get; private set; }
public string AdrInfo1 { get; private set; }
public string AdrInfo2 { get; private set; }
public string ZipCode { get; private set; }
public string City { get; private set; }
public string Country { get; private set; }
}
Of course there are collections and references to related objects which are ignored here as well as database mappers, naming conventions etc. The DTO I have looks like this:
public class AddressDto
{
public Guid Id { get; set; } // NHibernate GUID.comb, NO autoincrement ints!!
public DateTime CDate { get; set; }
public string CUser { get; set; }
public DateTime MDate { get; set; }
public string MUser { get; set; }
public string Street { get; private set; }
public string AdrInfo1 { get; private set; }
public string AdrInfo2 { get; private set; }
public string ZipCode { get; private set; }
public string City { get; private set; }
public string Country { get; private set; }
}
To use this with ServiceStack I need to support the following:
CRUD functionality
Filter / search functionality
So my 'Address service' should have the following methods:
GetAddresses (ALL, ById, ByZip, ByCountry, ByCity)
AddAddress (Complete AddressDTO without Id. CDate, CUser are filled automatically without user input)
UpdateAddress (Complete AddressDTO without CUser and CDate, MDate and MUser filled automatically without user input)
DeleteAddress (Just the Id)
For me it is pretty clear, that all Requests return either a single AddressDto or a List<AddressDto> as ResponseDTO except for the delete which should just return a status object.
But how to define all those RequestDTO's? Do I really have to define one DTO for EACH scenario?? In the books I only saw samples like:
[Route("/addresses", "GET")]
public class GetAddresses : IReturn<AddressesResponse> { }
[Route("/addresses/{Id}", "GET")]
public class GetAddressById : IReturn<AddressResponse>
{
public Guid Id { get; set; }
}
[Route("/addresses/{City}", "GET")]
public class GetAddressByCity : IReturn<AddressResponse>
{
public string City { get; set; }
}
// .... etc.
This is a lot of boilerplate code and remembers me a lot of old IDL compilers I used in C++ and CORBA.....
Especially for Create and Update I should be able to 'share' one DTO or even better reuse my existing DTO... For delete there is probably not much choice....
And then the filters. I have other DTOs with a lot more properties. A function approach like used in WCF, RPC etc is hell to code...
In my repositories I pass an entire DTO and use a predicate builder class which composes the LINQ where clause depending on the properties filled. This looks something like this:
List<AddressDto> addresses;
Expression<Func<Address, bool>> filter = PredicateBuilder.True<Address>();
if (!string.IsNullOrEmpty(address.Zip))
filter = filter.And(s => s.Zip == address.Zip);
// .... etc check all properties and dynamically build the filter
addresses = NhSession.Query<Address>()
.Where(filter)
.Select(a => new AddressDto
{
Id = a.Id,
CDate = a.CDate,
//.... etc
}).ToList();
Is there anything similar I could do with my RequestDTO and how should the routing be defined?
A lot of questions raised here have been covered in existing linked answers below. The Request / Response DTOs are what you use to define your Service Contract, i.e. instead of using RPC method signatures, you define your contract with messages that your Service accepts (Request DTO) and returns (Response DTO). This previous example also walks through guidelines on designing HTTP APIs with ServicesStack.
Use of well-defined DTOs have a very important role in Services:
You want to ensure all types your Services return are in DTOs since this, along with the base url of where your Services are hosted is all that's required for your Service Consumers to know in order to consume your Services. Which they can use with any of the .NET Service Clients to get an end-to-end Typed API without code-gen, tooling or any other artificial machinery.
DTOs are what defines your Services contract, keeping them isolated from any Server implementation is how your Service is able to encapsulate its capabilities (which can be of unbounded complexity) and make them available behind a remote facade. It separates what your Service provides from the complexity in how it realizes it. It defines the API for your Service and tells Service Consumers the minimum info they need to know to discover what functionality your Services provide and how to consume them (maintaining a similar role to Header files in C/C++ source code). Well-defined Service contracts decoupled from implementation, enforces interoperability ensuring that your Services don't mandate specific client implementations, ensuring they can be consumed by any HTTP Client on any platform. DTOs also define the shape and structure of your Services wire-format, ensuring they can be cleanly deserialized into native data structures, eliminating the effort in manually parsing Service Responses.
Auto Queryable Services
If you're doing a lot of data driven Services I recommend taking a look at AutoQuery which lets you define fully queryable Services without an implementation using just your Services Request DTO definition.
In my example I have the following database structure. Order has many OrderLine, which has one Product.
I am trying to return the following DTO:
public class OrderLineDto {
public int Id { get; set; }
public int Quantity { get; set; }
public string OrderType { get; set; }
public string ProductName { get; set; }
}
This should be possible by use of the following Query Route:
[Route("/orderlines")]
public class FindOrderLines : QueryBase<OrderLine, OrderLineDto>,
IJoin<OrderLine, Order>,
IJoin<OrderLine, Product>
{ }
What I am trying to do here is join OrderLine in both directions to bring in Type from Order, and Name from Product and return it in an OrderLineDto.
I am able to do these things individually by only using one IJoin, however AutoQuery appears only to use the first IJoin interface declaration, and does not perform the second join.
If I attempt to do a join like this: IJoin<OrderLine, Order, Product>
I get the following exception: Could not infer relationship between Order and Product
Is it possible to achieve what I am trying to do here with auto query or should I go back to writing standard REST services, abandoning AutoQuery?
I have submitted a pull request to ServiceStack which will now allow this behavior.
https://github.com/ServiceStack/ServiceStack/pull/955
BACKGROUND: I have a Person domain object. It is an aggregate root. I have included a portion of the class below.
I am exposing methods to perform the objects behaviors. For instance, to add a BankAccount I have the AddBankAccount() method. I have not included all the methods of the class but suffice to say that any public property must be updated using a method.
I am going to create an IPerson repository to handle the CRUD operations.
public interface IPersonRepository
{
void Save(Person p);
//...other methods
}
QUESTION: How do I tell the repository which fields need to be updated when we are updating an existing person? For example, If I add a bank account to an existing person how do I communicate this information to the repository when repository.Save() is called?
In the repository it is easy to determine when a new person is created, but when an existing person exists and you update fields on that person, i'm not sure how to communicate this to the repository.
I don't want to pollute my Person object with information about which fields are updated.
I could have separate methods on the repository like .UpdateEmail(), AddBankAccount() but that feels like overkill. I would like a simple .Save() method on the repository and it determines what needs to update in some manner.
How have others handled this situation?
I have searched the web and stackoverflow but haven't found anything. I must not be searching correctly because this seems like something simple when it comes to persistence within the DDD paradigm. I could also be way off on my understanding of DDD :-)
public class Person : DomainObject
{
public Person(int Id, string FirstName, string LastName,
string Name, string Email)
{
this.Id = Id;
this.CreditCards = new List<CreditCard>();
this.BankAccounts = new List<BankAccount>();
this.PhoneNumbers = new List<PhoneNumber>();
this.Sponsorships = new List<Sponsorship>();
}
public string FirstName { get; private set; }
public string LastName { get; private set; }
public string Name{ get; private set; }
public string Email { get; private set; }
public string LoginName { get; private set; }
public ICollection<CreditCard> CreditCards { get; private set; }
public ICollection<BankAccount> BankAccounts { get; private set; }
public ICollection<PhoneNumber> PhoneNumbers { get; private set; }
public void AddBankAccount(BankAccount accountToAdd, IBankAccountValidator bankAccountValidator)
{
bankAccountValidator.Validate(accountToAdd);
this.BankAccounts.Add(accountToAdd);
}
public void AddCreditCard(CreditCard creditCardToAdd, ICreditCardValidator ccValidator)
{
ccValidator.Validate(creditCardToAdd);
this.CreditCards.Add(creditCardToAdd);
}
public void UpdateEmail(string NewEmail)
{
this.Email = NewEmail;
}
There is an example of Repository interface from S#arp Architecture project. It is similar to PoEAA Data Mapper because it used to CRUD operations also.
public interface IRepositoryWithTypedId<T, IdT>
{
T Get(IdT id);
IList<T> GetAll();
IList<T> FindAll(IDictionary<string, object> propertyValuePairs);
T FindOne(IDictionary<string, object> propertyValuePairs);
T SaveOrUpdate(T entity);
void Delete(T entity);
IDbContext DbContext { get; }
}
As you can see, there is no update method for specific properties of an entity. The whole entity is provided as an argument into the method SaveOrUpdate.
When properties of your domain entity are being updated you should tell your Unit of Work that entity is 'dirty' and should be saved into storage (e.g. database)
You should not pollute your Person object with information about updated fields but it is needed to track information if entity is updated.
There might be methods of the class DomainObject which tell 'Unit of Work' if entity is 'new', 'dirty' or 'deleted'. And then your UoW itself might invoke proper repository methods - 'SaveOrUpdate' or 'Delete'.
Despite the fact that modern ORM Frameworks like NHibernate or EntityFramework have their own implementations of 'Unit of Work', people tend to write their own wrappers/ abstractions for them.
What I'm doing to solve this problem, is adding an interface to my domain objects:
interface IDirtyTracker {
bool IsDirty {get;}
void MarkClean();
void MarkDirty();
}
The base DomainObject class could implement IDirtyTracker, and then repositories etc. could use IsDirty to check if it's dirty or clean.
In each setter that makes a change:
void SetValue() {
this._value = newValue;
this.MarkDirty();
}
This does not give you fine grain checking, but it's a simple way to avoid some unnecessary updates at the repository level.
To make this a little easier, a GetPropertiesToIncludeInDirtyCheck method could be added, which would retrieve a list of properties which need to be checked.
interface IDirtyTracker {
IENumerable<Object> GetPropertiesToIncludeInDirtyCheck();
}
here are my entities:
public abstract class ResourceBase
{
[Key]
int Id { get; set; }
[ForeignKey("Resource")]
public Guid ResourceId { get; set; }
public virtual Resource Resource { get; set; }
}
public class Resource
{
[Key]
public Guid Id { get; set; }
public string Type { get; set; }
}
public class Message : ResourceBase
{
[MaxLength(300)]
public string Text { get; set; }
}
And then my query is something like this:
var msgs = messages.Where(x=>x.Id == someRangeOfIds).Include(m=>m.Resource).Select(x => new
{
message = x,
replyCount = msgs.Count(msg => msg.Id = magicNumber)
});
I am running this with proxy creation disabled, and the result is all the messages BUT with all the Resource properties as NULL. I checked the database and the Resources with matching Guids are there.
I drastically simplified my real life scenario for illustration purposes, but I think you'll find you can reproduce the issue with just this.
Entity Framework 5 handles inherited properties well (by flattening the inheritence tree and including all the properties as columns for the entity table).
The reason this query didn't work was due to the projection after the include. Unfortunately, the include statement only really works when you are returning entities. Although, I did see mention of a solution which is tricky and involves invoking the "include" after the shape of the return data is specified... If anyone has more information on this please reply.
The solution I came up with was to just rephrase the query so I get all messages in one query, and then in another trip to the database another query that gets all the reply counts.
2 round trips when it really should only be 1.
I have the following class:
public class Account
{
public int AccountID { get; set; }
public Enterprise Enterprise { get; set; }
public List<User> UserList { get; set; }
}
And I have the following method fragment:
Entities.Account accountDto = new Entities.Account();
DAL.Entities.Account account;
Mapper.CreateMap<DAL.Entities.Account, Entities.Account>();
Mapper.CreateMap<DAL.Entities.User, Entities.User>();
account = DAL.Account.GetByPrimaryKey(this.Database, primaryKey, withChildren);
Mapper.Map(account,accountDto);
return accountDto;
When the method is called, the Account class gets mapped correctly but the list of users in the Account class does not (it is NULL). There are four User entities in the List that should get mapped. Could someone tell me what might be wrong?
Try not passing in the accountDto, and let AutoMapper create it for you. When you map to an existing destination object, AutoMapper makes a few assumptions, that you won't have any already-null destination collections for one. Instead, do:
var accountDto = Mapper.Map<DAL.Entities.Account, Entities.Account>(account);
The last thing you should check is that your configuration is valid, so you can try:
Mapper.AssertConfigurationIsValid();
After those CreateMap calls. This checks to make sure everything lines up properly on the destination type side of things.