Overview of URL Routing

Before we move on, let's recap what we've covered so far. 0:00 We created an NBC website using Visual Studio. 0:04 Once we created our website, we learned how to run it so 0:08 that we could preview it in a browser. 0:11 Then we looked at how our project is put together. 0:13 We've covered a lot of ground. 0:16 Give yourself a part on the back. 0:18 Now let's build upon that base by learning how to add a new page to our website. 0:20 But before we do that let's take a bit of a tangent and 0:25 take a closer look at the U.R.L.'s for the existing pages on our website. 0:28 Chrome by default won't display the full U.R.L. in the address bar. 0:33 So I'm going to select Internet Explorer for my browser, 0:37 then click the play button, or the FI function key to start running our website. 0:41 Sometimes Visual Studio won't bring the selected browser to the foreground. 0:47 So if you're not seeing your browser, go ahead and bring it to the foreground. 0:51 Looking in the address bar, our current URL is HTTP 0:54 colon slash slash local host colon 50356 slash. 1:00 Let's break this down in URL. 1:05 HTTP is the protocol and local host is our host name. 1:09 Typically, the host name is the domain name of the website. 1:13 So for example www.teamtreehouse.com or www.google.com. 1:16 Since we're running our website locally the special name local host is used. 1:21 The number following the colon after the host's name is our port number, 1:27 which in my case is 50356. 1:31 Your report number might be different as Visual Studio assigns a random number 1:35 when creating ASP.NET projects. 1:39 Using a different explicit port number allows each project to be ran locally 1:42 at the same time even though they're all using the same host name local host. 1:47 If the terms URL, protocol, hostname, or 1:52 port are unfamiliar to you check the teacher's notes for 1:55 links to resources that will explain these concepts in detail. 1:58 You'll notice that as we browse around our website the protocol, hostname and 2:02 port number won't change. 2:06 Given that, as we talk further about URLs I'm only gonna focus on the part of 2:08 the URL to the right of the port number, which is often referred to as the path. 2:12 If we click on the about menu item to browse to the about page 2:18 the URL changes to home slash about. 2:22 And if we click the contact menu item to browse to the a contact page the URL path 2:26 changes to home/contact when browsing to pages in our website the N.P.C. 2:31 framework will look for a controller and action to handle that request. 2:36 So how does this work whenever in V.C. process is a request for a U.R.L., 2:41 it uses simple pattern matching to determine the name of the controller and 2:47 action in the form of controller slash action. 2:51 So the URL path home/about would map to a controller named home and 2:55 an action named about. 3:00 And home/contact would map to a controller named home and an action named contact. 3:02 Go ahead and switch back to Visual Studio and 3:09 click the stop button to stop running our website. 3:12 Now let's see if we can find the Home Controller in the Solution Explorer panel. 3:15 Remember, all of our controllers are located in the controllers folder. 3:20 If the folder isn't expanded, double-click the folder name to display its contents. 3:24 Here's a file named HomeController.cs. 3:30 That looks promising. 3:32 Go ahead and double-click it to open it. 3:34 Here's our home controller. 3:37 We can see that the home controller class has three methods index, about, 3:39 and if we scroll down a little bit, contact. 3:44 That's interesting. 3:47 The about and contact methods match the action names for our about and 3:50 contact pages. 3:54 That's not a coincidence. 3:55 These methods are special methods called action methods. 3:57 When we browse to the about or contact pages, the NPC framework will find 4:01 the home controller and call the about method if we're viewing the about 4:05 page or the contact method if we're viewing the contact page. 4:10 So what about the index method? 4:15 We don't have an index page on our website. 4:19 So when would this method get called? 4:21 To answer this question, let's start our website again and look at the URL for 4:23 the homepage. 4:28 The URL is http://localhost, 4:28 followed by our port number, which doesn't include a path. 4:33 So if the control or action name is not supplied in the URL path, 4:38 how does NPC know which controller and action to use? 4:42 When we make requests for 4:45 pages on our website, it turns out we don't have to supply an action name. 4:46 When we don't, index is used by default, so browsing to the URL home 4:51 would result in the home controllers index method being called. 4:56 We also don't need to provide a controller name. 5:00 If we don't the home is used by default. 5:03 This allows us to browse to our home page using nothing but our host name, and 5:05 in our case the port number. 5:10 So what happens if we try to browse to a page that 5:13 doesn't have a matching control or action. 5:15 Let's try it and see. 5:18 In the address bar, let's type the URL home/new and 5:19 press the enter key.Ah we get an error page. 5:25 Specifically the error message the resource cannot be found. 5:30 Let's go ahead and change new to about and press the enter key. 5:34 Now we're back at our about page. 5:42 In ASP.NET NVC, the process of matching no URL to a controller an action 5:45 is called URL routing. 5:50 We're just scratching the surface of what URL routing is capable, but for 5:52 now, these basic concepts are just what we need to know, 5:56 in order to add a new page to our website. 5:59