Asp.net Web api routing

1. Web API Routing
Eyal Vardi
CEO E4D Solutions LTD
Microsoft MVP Visual C#
blog: www.eVardi.com

2. Expert Days 2012

© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

3. Routing Has Three Main Phases
1. Matching the URI to a route template.
2. Selecting a controller.
3. Selecting an action.
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4. Routing Tables
routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
constraints: new { id = @"d+" }
);
Action HTTP method Relative URI
Get a list of all products GET /api/products
Get a product by ID GET /api/products/id
Get a product by category GET /api/products?category=1
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5. Action Mapping
public class ProductsController : ApiController
{
public void GetAllProducts() { }
public IEnumerable<Product> GetProductById(int id) { }
public HttpResponseMessage DeleteProduct(int id) { }
}
Method URI Path Action Parameter
GET api/products GetAllProducts (none)
GET api/products/4 GetProductById 4
DELETE api/products/4 DeleteProduct 4
POST api/products (no match)
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6. Routing by Action Name
routes.MapHttpRoute(
name: "ActionApi",
routeTemplate: "api/{controller}/{action}/{id}",
defaults: new { id = RouteParameter.Optional }
);
public class ProductsController : ApiController
{
[AcceptVerbs("GET", "HEAD")]
public Product FindProduct(id) { }
// WebDAV method
[AcceptVerbs("MKCOL")]
public void MakeCollection() { }
}
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

7. Web API Routing
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

8. Paging and Querying (OData)
 ASP.NET Web API provides built-in support
for OData query parameters.
 $filter, $orderby, $skip & $top
 Examples
 /api/products?$filter=substringof(Name, 'Ed') eq true
 api/products?$skip=2
 api/products?$top=3&$orderby=Name
[Queryable(ResultLimit=20)]
public IQueryable<Product> GetAllProducts()
{
return repository.GetAll().AsQueryable();
}
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

9. Query string options
 $Expand
 /Customers(ALFKI)?$expand=Orders.Employees
 $Orderby
 /Customers?$orderby=City desc, CompanyName
 $Skip
 /Customers?$skip=10
 $Top
 /Orders?$orderby=TotalDue&$top=5
 $Filter
 /Customers?$filter=City eq ‘London’
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10. Expression Syntax
Operator Description Example
Logical Operators
eq Equal /Customers?filter = City eq 'London'
ne Not equal /Customers?filter = City ne 'London'
gt Greater than /Product?$filter = UnitPrice gt 20
gteq Greater than or equal /Orders?$filter = Freight gteq 800
lt Less than /Orders?$filter = Freight lt 1
lteq Less than or equal /Product?$filter = UnitPrice lteq 20
and Logical and /Product?filter=UnitPrice lteq 20 and UnitPrice gt 10
or Logical or /Product?filter=UnitPrice lteq 20 or UnitPrice gt 10
not Logical negation /Orders?$ ?$filter=not endswith(ShipPostalCode,'100')
Arithmetic Operators
add Addition /Product?filter = UnitPrice add 5 gt 10
sub Subtraction /Product?filter = UnitPrice sub 5 gt 10
mul Multiplication /Orders?$filter = Freight mul 800 gt 2000
div Division /Orders?$filter = Freight div 10 eq 4
mod Modulo /Orders?$filter = Freight mod 10 eq 0
Grouping Operators
( ) Precedence grouping /Product?filter = (UnitPrice sub 5) gt 10
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11. Expression Syntax Cont.
String Functions Date Functions
bool contains(string p0, string p1) int day(DateTime p0)
bool endswith(string p0, string p1) int hour(DateTime p0)
bool startswith(string p0, string p1) int minute(DateTime p0)
int length(string p0) int month(DateTime p0)
int indexof(string arg) int second(DateTime p0)
string insert(string p0, int pos, string p1) int year(DateTime p0)
string remove(string p0, int pos)
string remove(string p0, int pos, int length)
string replace(string p0, string find, string replace) Math Functions
string substring(string p0, int pos) double round(double p0)
string substring(string p0, int pos, int length) decimal round(decimal p0)
string tolower(string p0) double floor(double p0)
string toupper(string p0) decimal floor(decimal p0)
string trim(string p0) double ceiling(double p0)
string concat(string p0, string p1) decimal ceiling(decimal p)
Type Functions
bool IsOf(type p0)
bool IsOf(expression p0, type p1)
<p0> Cast(type p0)
<p1> Cast(expression p0, type p1)
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12. Data Services
URL Syntax
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