AutoQuery insight needed - servicestack

So, I'm working with ServiceStack and love what it offers. We've come to a point where I'm needing to implement a queryable data API... prior to my coming to this project, a half backed OData implementation was done. I'd rather not try and weed through that to make it work.
Which brings me to AutoQuery. I'd like to try it with our SQL Server database. I'm looking at the examples at http://docs.servicestack.net/autoquery-rdbms - but I cannot for the life of me get this to work. Is there something I'm missing here?
I'm using ORMLite to query SQL, and my integration tests I've written show it to be working as I would expect. I have registered the OrmLiteConnectionFactory in the container, as well as my repository which uses it by way of dependency injection.
Specific to code so far, I have a type, and a message that is based on QueryDb:
public class Detail
{
public string Div { get; set; }
public string Reg { get; set; }
}
[Route("/report/detail")]
public class DetailQuery : QueryDb<Detail>
{
public string[] Div { get; set; }
public string[] Reg { get; set; }
}
The message, DetailQuery, is used by my service:
public class ReportService : Service
{
public object Get(DetailQuery dq)
{
// not sure what to put here?
}
}
With all of that, I am able to see the AutoQuery service instance in the admin interface. When I play with the query interface, I hit my service endpoint, and I see the data I expect - filter values in the 'Div' and 'Reg' collections. What am I missing for this to 'just work' here? I have done plenty in ServiceStack accessing my repositories from the Service itself, but I'm trying to gain some insight into what AutoQuery brings to the table here. I have yet to see a 'straight forward' example of how this works... or am I looking for a pot of gold that just isn't there?

AutoQuery works with just the Request DTO i.e. it doesn't need any Service implementation, so your query:
[Route("/report/detail")]
public class DetailQuery : QueryDb<Detail>
{
public string[] Div { get; set; }
public string[] Reg { get; set; }
}
When called from /report/detail will query the Detail RDBMS Table. But your properties here either need to match a column on the Detail table (e.g. Div or Reg) in order to have an exact match (default), however exact matches aren't normally done with arrays they're done with scalar values like a string, e.g:
public string Div { get; set; }
public string Reg { get; set; }
If you're querying a collection you'd be instead making an IN Query where the values would contain list of values, in which case they're normally pluralized:
public string[] Divs { get; set; }
public string[] Regs { get; set; }
and can be called with:
/report/detail?Divs=A,B&Regs=C,D
Which will perform a query similar to:
SELECT * FROM Detail WHERE Div IN ('A','B') AND Rev IN ('C','D')
If that's not the behavior you want it needs to match an implicit convention, e.g:
public string[] DivBetween { get; set; }
Which will then query:
SELECT * FROM Detail WHERE Div BETWEEN 'A' AND 'B'
If you wanted to you could override the AutoQuery service with a custom implementation, e.g:
public class MyQueryServices : Service
{
public IAutoQueryDb AutoQuery { get; set; }
//Override with custom implementation
public object Any(DetailQuery query)
{
var q = AutoQuery.CreateQuery(query, base.Request);
return AutoQuery.Execute(request, q);
}
}
But you'd only need to do that when you want to customize the default behavior, e.g. add an extra filter to the populated SqlExpression.

Related

How AutoQuery Parameters work when supplied

I've been reviewing servicestack and the documentation. In regards to autoquery documentation the pre-autoquery and post auto query design is shown below. Where the DTO does not include the parameter "BookedAfter". It is my understanding in a non-Auto Query scenario that a Get would provide these parameters for the obvious query input options. For Auto Query I have a few questions. First, it would appear to me that if you only provide specific parameters (instead of leaving it wide open) that only those would be allowed for filtering (assuming DTO specific fields)? Is this out of the box or would one need to override the Auto Query implementation? Similarly with below, the code utilized a custom "BookedAfter" parameter. Would one override the implementation, map the more specific parameter wording to a DTO field query scenario? And what would it take to allow additional querying capabilities that came out of the box? I have not been able to find an example from documentation or the community.
[Route("/bookings/search")]
public class SeachBookings : IReturn<SeachBookingsResponse>
{
public DateTime BookedAfter { get; set; }
}
[Route("/bookings/search")]
public class SeachBookings : QueryDb<Booking>
{
public DateTime BookedAfter { get; set; }
}
// Types
public class Booking
{
public int Id { get; set; }
public int ShiftId { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public int Limit { get; set; }
}
Auto Query parameters simply match the rules in the configured Implicit Conventions, it's irrelevant if the property is defined on the DTO or not unless you restrict it with EnableUntypedQueries=false in which case it will only look at the conventions from explicit DTO properties.
Your BookedAfter matches the Implicit Convention:
{"%After%", GreaterThanFormat},
You're not limited to the pre-configured conventions and can add/remove your own rules.

C# Asp.net WebApi how to not populate ID field for the Entity when post in CRUD

I am creating simple webapi with CRUD functionality.
I have an entity say for eg: Product.
I am using FluentNHibernate to map the tables. The Id is generated by sequence.
public ProductMap()
{
Table("PRODUCT");
Id(x => x.Id).GeneratedBy.Sequence("SEQ_REC_SCH_INFO").Column("SCH_ID");
Map(x => x.Name, "Name");
Map(x => x.Category, "Category");
Map(x=>x.Price,"Price");
}
So I dont want the Id parameter of the Product to be populated when i post the data.
public class Product
{
public int Id { get; set; }
public string Name { get; set; }
public string Category { get; set; }
public decimal Price { get; set; }
}
How to make other fields passed to the api controller except Id field?
Thanks
The best way to pass models between systems is ViewModels, with this approach you can ignore some properties in certain cases and include them in other cases, but if you want to ignore this property in all cases you can use JsonIgnore attribute to prevent these properties from serializing.

ServiceStack - [Reference] or [Ignore]?

We have a DTO - Employee - with many (> 20) related DTOs and DTO collections. For "size of returned JSON" reasons, we have marked those relationships as [Ignore]. It is then up to the client to populate any related DTOs that they would like using other REST calls.
We have tried a couple of things to satisfy clients' desire to have some related Employee info but not all:
We created a new DTO - EmployeeLite - which has the most-requested fields defined with "RelatedTableNameRelatedFieldName" approach and used the QueryBase overload and that has worked well.
We've also tried adding a property to a request DTO - "References" - which is a comma-separated list of related DTOs that the client would like populated. We then iterate the response and populate each Employee with the related DTO or List. The concern there is performance when iterating a large List.
We're wondering if there a suggested approach to what we're trying to do?
Thanks for any suggestions you may have.
UPDATE:
Here is a portion of our request DTO:
[Route("/employees", "GET")]
public class FindEmployeesRequest : QueryDb<Employee> {
public int? ID { get; set; }
public int[] IDs { get; set; }
public string UserID { get; set; }
public string LastNameStartsWith { get; set; }
public DateTime[] DateOfBirthBetween { get; set; }
public DateTime[] HireDateBetween { get; set; }
public bool? IsActive { get; set; }
}
There is no code for the service (automagical with QueryDb), so I added some to try the "merge" approach:
public object Get(FindEmployeesRequest request) {
var query = AutoQuery.CreateQuery(request, Request.GetRequestParams());
QueryResponse<Employee> response = AutoQuery.Execute(request, query);
if (response.Total > 0) {
List<Clerkship> clerkships = Db.Select<Clerkship>();
response.Results.Merge(clerkships);
}
return response;
}
This fails with Could not find Child Reference for 'Clerkship' on Parent 'Employee'
because in Employee we have:
[Ignore]
public List<Clerkship> Clerkships { get; set; }
which we did because we don't want "Clerkships" with every request. If I change [Ignore] to [Reference] I don't need the code above in the service - the List comes automatically. So it seems that .Merge only works with [Reference] which we don't want to do.
I'm not sure how I would use the "Custom Load References" approach in an AutoQuery service. And, AFAIKT, the "Custom Fields" approach can't be use for related DTOs, only for fields in the base table.
UPDATE 2:
The LoadSelect with include[] is working well for us. We are now trying to cover the case where ?fields= is used in the query string but the client does not request the ID field of the related DTO:
public partial class Employee {
[PrimaryKey]
[AutoIncrement]
public int ID { get; set; }
.
.
.
[References(typeof(Department))]
public int DepartmentID { get; set; }
.
.
.
public class Department {
[PrimaryKey]
public int ID { get; set; }
public string Name { get; set; }
.
.
.
}
So, for the request
/employees?fields=id,departmentid
we will get the Department in the response. But for the request
/employees?fields=id
we won't get the Department in the response.
We're trying to "quietly fix" this for the requester by modifying the query.SelectExpression and adding , "Employee"."DepartmentID" to the SELECT before doing the Db.LoadSelect. Debugging shows that query.SelectExpression is being modified, but according to SQL Profiler, "Employee"."DepartmentID" is not being selected.
Is there something else we should be doing to get "Employee"."DepartmentID" added to the SELECT?
Thanks.
UPDATE 3:
The Employee table has three 1:1 relationships - EmployeeType, Department and Title:
public partial class Employee {
[PrimaryKey]
[AutoIncrement]
public int ID { get; set; }
[References(typeof(EmployeeType))]
public int EmployeeTypeID { get; set; }
[References(typeof(Department))]
public int DepartmentID { get; set; }
[References(typeof(Title))]
public int TitleID { get; set; }
.
.
.
}
public class EmployeeType {
[PrimaryKey]
public int ID { get; set; }
public string Name { get; set; }
}
public class Department {
[PrimaryKey]
public int ID { get; set; }
public string Name { get; set; }
[Reference]
public List<Title> Titles { get; set; }
}
public class Title {
[PrimaryKey]
public int ID { get; set; }
[References(typeof(Department))]
public int DepartmentID { get; set; }
public string Name { get; set; }
}
The latest update to 4.0.55 allows this:
/employees?fields=employeetype,department,title
I get back all the Employee table fields plus the three related DTOs - with one strange thing - the Employee's ID field is populated with the Employee's TitleID values (I think we saw this before?).
This request fixes that anomaly:
/employees?fields=id,employeetypeid,employeetype,departmentid,department,titleid,title
but I lose all of the other Employee fields.
This sounds like a "have your cake and eat it too" request, but is there a way that I can get all of the Employee fields and selective related DTOs? Something like:
/employees?fields=*,employeetype,department,title
AutoQuery Customizable Fields
Not sure if this is Relevant but AutoQuery has built-in support for Customizing which fields to return with the ?fields=Field1,Field2 option.
Merge disconnected POCO Results
As you've not provided any source code it's not clear what you're trying to achieve or where the inefficiency with the existing solution lies, but you don't want to be doing any N+1 SELECT queries. If you are, have a look at how you can merge disconnected POCO results together which will let you merge results from separate queries based on the relationships defined using OrmLite references, e.g the example below uses 2 distinct queries to join Customers with their orders:
//Select Customers who've had orders with Quantities of 10 or more
List<Customer> customers = db.Select<Customer>(q =>
q.Join<Order>()
.Where<Order>(o => o.Qty >= 10)
.SelectDistinct());
//Select Orders with Quantities of 10 or more
List<Order> orders = db.Select<Order>(o => o.Qty >= 10);
customers.Merge(orders); // Merge disconnected Orders with their related Customers
Custom Load References
You can selectively control which references OrmLite should load by specifying them when you call OrmLite's Load* API's, e.g:
var customerWithAddress = db.LoadSingleById<Customer>(customer.Id,
include: new[] { "PrimaryAddress" });
Using Custom Load References in AutoQuery
You can customize an AutoQuery Request to not return any references by using Db.Select instead of Db.LoadSelect in your custom AutoQuery implementation, e.g:
public object Get(FindEmployeesRequest request)
{
var q = AutoQuery.CreateQuery(request, Request);
var response = new QueryResponse<Employee>
{
Offset = q.Offset.GetValueOrDefault(0),
Results = Db.Select(q),
Total = (int)Db.Count(q),
};
return response;
}
Likewise if you only want to selectively load 1 or more references you can change LoadSelect to pass in an include: array with only the reference fields you want included, e.g:
public object Get(FindEmployeesRequest request)
{
var q = AutoQuery.CreateQuery(request, Request);
var response = new QueryResponse<Employee>
{
Offset = q.Offset.GetValueOrDefault(0),
Results = Db.LoadSelect(q, include:new []{ "Clerkships" }),
Total = (int)Db.Count(q),
};
return response;
}

Option for Include to only return foreign keys

Does Entity Framework provide an option to retrieve child objects that are only populated with fields that are foreign keys to the parent object?
Sample code might illustrate this better.
Assuming you have the following POCO classes...
public abstract class Base
{
public Guid Id { get; set; }
}
public class User : Base
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
public class Photo : Base
{
public string Description { get; set; }
public User UploadedBy { get; set; }
}
... and assuming you've configured a DbContext correctly, how do you query for a list of all Photos including the UploadedBy object, but where that UploadedBy object only contains the Id property?
I know I can do this...
return await _dbContext.Photos.Include(p => p.UploadedBy).ToListAsync();
... but that returns the entire User object.
I'd like to do something like this...
return await _dbContext.Photos.Include(p => p.UploadedBy.Id).ToListAsync();
... to indicate that I only want the Id property back.
If we could chain those includes we would be able to pick each property on the child object that we want returned.
Or even better, I'd love to be able to configure a setting at a more global level that would make it so that anytime I ask for Photos, give me all members of photos, even child objects, but only populate their foreign keys and nothing more.
The last request is less important though because I could just create the following extension method for each POCO object...
public static IQueryable<Photo> IncludeForigenKeys(this PhotoAlbumDbContext context){
return context.Photos
.Include(photo => photo.UploadedBy.Id);
}
As far as I understand there is no way to partially load a Navigation Property.
However for foreign keys the standard way of accessing these without loading the Nav property is to include the actual key in your model. Eg:
public class Photo : Base
{
public string Description { get; set; }
public int UploadedById { get; set; }
public User UploadedBy { get; set; }
}
This id will be populated even if you don't actually load the whole navigation property.
In the case where you load both you can update either the value on the local or remote end of the nav property and that update will be persisted to the database on save. In my experience EF is very clever around this. The only scenario where it becomes a little more tricky is in unit tests where EF is not maintaining this state.

REST Routing in ServiceStack

I just start to learn REST and ServiceStack and there's something about Route that I just can't quite understand. For example if we take the very basic HelloWorld example from GitHub tutorial and re-write it to return collection of User objects. Here is example:
public User
{
public string Name;
public string Address;
public int Age;
}
// Hello - request object without [Route] attribute
public class Hello
{
public string Name { get; set; }
}
public class HelloResponse
{
public IEnumerable<User> Result {get;set;}
}
public class HelloService : Service
{
public object Any(Hello request)
{
return new HelloResponse { // Collection of User object };
}
}
now everything working right and no problems here. But now I want to add another routing url like: /Hello/{name}/Address
Actually this call (GET) to this url will return a single User selected by Age parameter. How I can do this ? Should I add another Service ? And if the url will be:
/Hello/{name}/{age}/Address
It seems I don't understand something.....
See this earlier answer for details about Routing in ServiceStack. The Smart Routing section in ServiceStack's New API explains further options and different precedence.
There are a few problems with your example. First ServiceStack text serializers only support public properties so you need to change your User Model to use public properties instead of fields, e.g:
public User
{
public string Name { get; set; }
public string Address { get; set; }
public int Age { get; set; }
}
Next, Interfaces on DTOs are a bad idea as there's no good reason for it. They're still supported but you can end up with undesirable results. Use a concrete collection like a List<T> which provides more utility, e.g:
public class HelloResponse
{
public List<User> Results { get; set; }
}
Also the routes should match the property names on your DTO exactly, they are case-insensitive when matching against the Request Path, but they need to map to an exact property name, e.g:
/Hello/{Name}/{Age}/Address

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