Routing in ASP.NET MVC Creating a RESTful interface to your site
Remember, browsers make HTTP requests
HTTP requests use a verb to communicate their intent
� GET � POST � PUT � DELETE
� asdf
Alright. Got that out of the way. Now back to our regularly-scheduled lecture.
Which is better? This …
http://tic.com/Report.aspx?
t=Sales&y=2013&m=07!
… or this …
http://tic.com/Sales/2013/7!
Why?
Reasons � SEO � Easy to type � Easy to remember � Hides implementation stack � URLs don’t have to change when the site
changes. � Hackable
URLs point to resources. � Uniform ________________ locator � They don’t point to pages � So RESTful URLs are more accurate,
actually
that reduces coupling
in a stateless environment …
an architectural style … REST is ...
HI, I'm Roy Fielding, the
inventor of REST.
for addressing resources …
A RESTful URL is one that conforms to all of the constraints � Separation between client and server � Stateless communication � Cacheable � A layered system � A uniform interface
A layered system has predictable parts
The usual method
Category
Thing
Action
ID
Properly RESTful url
Category
Thing
ID
(Use HTTP method as action)
Use the HTTP requests to specify the action
� GET � POST � PUT � DELETE
The URL should act as an API
� http://tic.com/Customer/List � http://tic.com/Customer/Create � http://tic.com/Customer/Details/71 � http://tic.com/Customer/Edit/71 � http://tic.com/Customer/Delete/71 � http://tic.com/Department � http://tic.com/Employee � http://tic.com/AddToCart/17
Or better yet ...
� GET http://tic.com/Customer � POST http://tic.com/Customer � GET http://tic.com/Customer/71 � PUT http://tic.com/Customer/71 � DELETE http://tic.com/Customer/71 � GET http://tic.com/Department � GET http://tic.com/Employee � POST http://tic.com/AddToCart/17
There are certain things you can do to make a URL RESTful � Give every “thing” an ID � Link things together � Use standard methods � Communicate statelessly � Provide multiple representations
Resources with multiple representations
� HTML � XML � VCard � RSS
Okay, I'm sold on RESTful urls. How do I get them into MVC?
Registering routes tells IIS that if a user asks for X, send them to Y
We use the MapRoute() method to create these routes MyRoutes.MapRoute(! string RouteName,! string UrlPattern,! object Defaults);!� Says when an url matching UrlPattern
comes through, what do we do with it?
Routing in ASP.NET MVC are set in Application_Start � Pulled out into a static method by default. public static void RegisterRoutes(RouteCollection routes)!{! routes.IgnoreRoute("{resource}.axd/{*pathInfo}");! routes.MapRoute(! "Default", // Route name! "{controller}/{action}/{id}", // URL with parms! new { controller = "Home", action = "Index", ! id = UrlParameter.Optional } // defaults! );!}!
Routes are matched in order that they appear
Hardcoded routes are easy routes.MapRoute(! "ListAllProducts",! "Product/List",! new { ! controller="Home", ! action="ShowProducts"! }!);!
Hands-on literal routes
Can receive arguments by putting them in curly braces � aka. URL Parameters
Examples Route definition Example of matching url
{controller}/{action}/{category} Product/show/beverage
{table}/details.aspx Products/Details.aspx
blog/{action}/{entry} blog/read/1234
blog/{entry}-{SEOString} blog/2234-Why-string-theory-is-flawed
{reportType}/{year}/{month}/{day} sales/2012/7/15
{locale}/{action} en-US/show
Hands-on matching routes
Optional parameters can save you from creating a lot of routes � Example: you want to match
� Clients/Miller � Clients/Miller/Harold � Clients/Miller/Harold/Dr
… with the same route � Simply make first name and title optional with: new { FirstName = UrlParameter.Optional, Title = UrlParameter.Optional }!
Hands-on optional parameters
Hands-on default values
Regular expression constraints routes.MapRoute(! "BlogArchive",! "Archive/{entryDate}",! new { controller="Blog", action="Archive" }, ! new { entryDate=@"\d{2}-\d{2}-\d{4}" }!);!
Hands-on constraints
Conclusion
� RESTful urls are easier to use, therefore better � MVC lends itself well to REST; in fact REST is pretty
much required to get to controllers and actions � Routes are set up using RegisterRoutes()
Oh! And one more thing ... These routes work for WebForms also � They're exactly the same.