AutoQueryable add auto querying functionality like OData on top of IQueryable with best url practices. It help you to make requests like http://baseurl/api/products?nameContains=frame&color=red,black with no effort.

With this url: /products?select=productId,name,color,productCategory.name,salesOrderDetail,salesOrderDetail.product

You will get result like:

[
    {
        "productId": 1,
        "name": "Product 0",
        "color": "red",
        "productCategory": {
            "name": "red"
        },
        "salesOrderDetail": [
            {
                "product": {
                    "productId": 1,
                    "name": "Product 0",
                    "productNumber": "24bb9446-d540-4513-a3c6-be4323984112",
                    ...
                    "modifiedDate": "0001-01-01T00:00:00",
                    "salesOrderDetail": []
                },
                "salesOrderId": 0,
                "salesOrderDetailId": 1,
                ...
            },
            ...
        ]
    },
    ...
]

Package	NuGet
Install-Package AutoQueryable		Install without filters
AutoQueryable.AspNetCore.Filter		Install for AspNet Core
AutoQueryable.AspNetCore.Swagger		Install for AspNet Core
AutoQueryable.Extensions.DependencyInjection		Install for AspNet Core
AutoQueryable.AspNet.Filter		Install for Web api 2
AutoQueryable.AspNet		Install for Web api 2
AutoQueryable.Extensions.Autofac		Install for Web api 2
AutoQueryable.Nancy.Filter (old version)		Install for Nancy

Other web framework? You could made your own attribute, see Use AutoQueryable without attribute section.

Install the DI package: AutoQueryable.Extensions.DependencyInjection and register AutoQueryable dependencies with your favorite DI framework

public void ConfigureServices(IServiceCollection services)
{
    ...
    services.AddAutoQueryable();
}

Install the DI package: AutoQueryable.Extensions.Autofac and register AutoQueryable dependencies

protected void Application_Start()
{
    var builder = new ContainerBuilder();
    ...
    builder.RegisterAutoQueryable();
    GlobalConfiguration.Configuration.DependencyResolver = new AutofacWebApiDependencyResolver(builder.Build())
}

you can configure the default AutoQueryable settings. For example get only 10 results :

services.AddAutoQueryable(settings => settings.DefaultToTake = 10)

builder.RegisterAutoQueryable(settings => settings.DefaultToTake = 10);

Ensure your API actions are decorated with AutoQueryable attribute and let the magic begin.

[HttpGet, AutoQueryable]
public IQueryable<Product> Get([FromServices] MyDbContext dbContext)
{
    return dbContext.Product;
}

AQ settings can be overriden in attribute too

[AutoQueryable(DefaultToTake = 50, UnselectableProperties = new [] {"Id", "Password"})]
...

Note that you can use AQ without attribute, see Use AutoQueryable without attribute section

• Selectable columns: /products?select=name,color,toto
• Top/Take, Skip: /products?take=5&skip=5
• First, Last: /products?first=true
• OrderBy, OrderByDesc: /products?orderby=price,id
• Wrap with: /products?wrapwith=count,total-count,next-link
• Filtering: /products?nameContains=frame&color=red,black
• Paging: /products?page=2&pagesize=10

• In a single filter, properties are managed with OR, eg prop1=a,b,c
• If you want single filter with AND you need to add the same filter, eg prop1=a&prop1=b&prop1=c
• If multiple filters are provided, there are managed with AND, eg prop1=a&prop2=a&prop3Contains=b
• If you want multiple filters with OR, you must provide all filters before the =, eg prop1StartsWith,prop2:i,prop3Contains:i=a,b,c

• Select all properties of level zero without relations: /products?select=_
• Select all properties of level zero with relations: /products?select=*
• Select an object with all its value types: /products?select=productcategory
• Select an object with all its values including navigation properties on the first level: /products?select=productcategory.*

You can use projection in select & filters clauses with navigation properties (objects or collection of object)

• Select projection: /products?select=name,color,toto,productcategory.name
• Filter projection: /products?salesorderdetail.product.productid=1

You can still use dto projection and query over your dto with defined type:

[HttpGet]
[AutoQueryable]
public IQueryable Get([FromServices] AdventureWorksContext adventureWorksContext)
{
    return adventureWorksContext.Product.Select(p => new ProductProjection
    {
        Name = p.Name,
        ProductColor = p.Color,
        FinalPrice = p.price
    });
}

Or anonymous type:

[HttpGet]
[AutoQueryable]
public IQueryable Get([FromServices] AdventureWorksContext adventureWorksContext)
{
    return adventureWorksContext.Product.Select(p => new
    {
        p.Name,
        p.Color,
        FinalPrice = p.Price
    });
}

If you want some properties to be unselectable (eg: Id, Password, ...)

[Route("api/[controller]")]
public class UsersController : Controller
{
    [HttpGet]
    [AutoQueryable(UnselectableProperties = new []{ "Password", "Id" })]
    public IQueryable<User> Get([FromServices] myDbContext dbContext)
    {
        return dbContext.User;
    }
}

Note that Dto projection is the best way to limit selectable properties

By default filters are separated by AND (eg: color=red&color=black is translated by color == red AND color == black)

In a filter, comma separator is used for OR (eg: color=red,black is translated by color == red OR black)

• Equals '=': /products?color=red,black
• Not Equals '!=': /products?color!=green,blue
• Less Than, Greater Than '<', '>': /products?productCount<5
• Less Than or Equals, Greater Than or equals '<=' /products?productCount<=5
• Contains 'contains': /products?colorContains=bla,ed
• StartsWith, EndsWith 'startswith', 'endswith': /products?colorStartsWith=bla,re

String filters have a negate (NOT) variant:

• NotContains 'notcontains': /products?colorContains!=bla,ed
• NotStartsWith, NotEndsWith 'notstartswith', 'notendswith': /products?colorStartsWith!=bla,ed

Filter aliases are not case sensitive:

• Contains 'contains': /products?colorcontains=bla,ed

Note that filters works with primitive types, string, datetime & guid

AQ provide property modifiers to modify property before select or filter, modifiers are denoted with :

• DateInYear :year=: /products?selldate:year=1989
• NotDateInYear :year!=: /products?selldate:year!=2000

• :i (case insensitivity), ex. 'contains:i', 'startsWith:i!=': /products?colorContains:i=bla,ed

AQ uses dynamic types per default to ensure that the final flow will be as small as possible. In some cases you may not want to use dynamic types, there is a property for this:

[Route("api/[controller]")]
public class UsersController : Controller
{
    [HttpGet]
    [AutoQueryable(UseBaseType = true)]
    public IQueryable<User> Get([FromServices] myDbContext dbContext)
    {
        return dbContext.User;
    }
}

Note that final flow will include null and default values but you can escape them with serializer settings for exemple

If you don't want to use autoqueryable attribute you could use AQ directry in your code by passing it the querystring. First install the Autoqueryable package

Install-Package AutoQueryable

[Route("api/[controller]")]
public class UsersController
{
    [HttpGet]
    public IActionResult Get([FromServices] myDbContext dbContext)
    {
        var resultSet = dbContext.Product.Select(p => new { ... }).AutoQueryable(queryString);
        return new OkObjectResult(new {
            foo = "",
            ....,
            Values = resultSet;
        })
    }
}

If you want to add AQ parameters to your swagger docs, just add AutoQueryable to the swagger conf.

Install-Package AutoQueryable.AspNetCore.Swagger

services.AddSwaggerGen(c =>
{
    c.SwaggerDoc("v1", new Info { Title = "My API", Version = "v1" });
    c.AddAutoQueryable(); // add this line
});

If you're using AQ without attribute .AutoQueryable(queryString) and want swagger parameters, you can add AutoQueryableSwagger attribute

[AutoQueryableSwagger]

If you are getting the error "Sequence contains no elements", you should use the package

Install-Package AutoMapper.Extensions.ExpressionMapping

and replace the

ProjectTo<T>()

with

.UseAsDataSource().For<T>()

AutoQueryable and AutoMapper do not work together when it comes to mapping entity relations from an Entity to a Dto. To fix this, use the AutoQueryable profile setting

profile.ToListBeforeSelect = true

This performs a ToList() using the AutoMapper mapping before using the select query parameters and selecting only the properties asked by the Querystring