Static pages¶
Note: This tutorial assumes you've downloaded CodeIgniter and installed the framework in your development environment.
The first thing you're going to do is set up a controller to handle static pages. A controller is simply a class that helps delegate work. It is the glue of your web application.
For example, when a call is made to:
http://example.com/news/latest/10
We might imagine that there is a controller named "news". The method being called on news would be "latest". The news method's job could be to grab 10 news items, and render them on the page. Very often in MVC, you'll see URL patterns that match:
http://example.com/[controller-class]/[controller-method]/[arguments]
As URL schemes become more complex, this may change. But for now, this is all we will need to know.
Let's make our first controller¶
Create a file at app/Controllers/Pages.php with the following code.
<?php namespace App\Controllers;
use CodeIgniter\Controller;
class Pages extends Controller {
public function index()
{
return view('welcome_message');
}
public function showme($page = 'home')
{
}
}
You have created a class named Pages
, with a showme
method that accepts
one argument named $page
. It also has an index()
method, the same
as the default controller found in app/Controllers/Home.php; that method
displays the CodeIgniter welcome page.
The Pages
class is extending the
CodeIgniter\Controller
class. This means that the new Pages class can access the
methods and variables defined in the CodeIgniter\Controller
class
(system/Controller.php).
The controller is what will become the center of every request to
your web application. Like any php class, you refer to
it within your controllers as $this
.
Now that you've created your first method, it's time to make some basic page templates. We will be creating two "views" (page templates) that act as our page footer and header.
Create the header at app/Views/templates/header.php and add the following code:
<!doctype html>
<html>
<head>
<title>CodeIgniter Tutorial</title>
</head>
<body>
<h1><?= $title; ?></h1>
The header contains the basic HTML code that you'll want to display
before loading the main view, together with a heading. It will also
output the $title
variable, which we'll define later in the controller.
Now, create a footer at app/Views/templates/footer.php that
includes the following code:
<em>© 2019</em>
</body>
</html>
Adding logic to the controller¶
Earlier you set up a controller with a showme()
method. The method
accepts one parameter, which is the name of the page to be loaded. The
static page bodies will be located in the app/Views/pages/
directory.
In that directory, create two files named home.php and about.php. Within those files, type some text − anything you'd like − and save them. If you like to be particularly un-original, try "Hello World!".
In order to load those pages, you'll have to check whether the requested
page actually exists. This will be the body of the showme()
method
in the Pages
controller created above:
public function showme($page = 'home')
{
if ( ! is_file(APPPATH.'/Views/pages/'.$page.'.php'))
{
// Whoops, we don't have a page for that!
throw new \CodeIgniter\Exceptions\PageNotFoundException($page);
}
$data['title'] = ucfirst($page); // Capitalize the first letter
echo view('templates/header', $data);
echo view('pages/'.$page, $data);
echo view('templates/footer', $data);
}
Now, when the requested page does exist, it is loaded, including the header and footer, and displayed to the user. If the requested page doesn't exist, a "404 Page not found" error is shown.
The first line in this method checks whether the page actually exists.
PHP's native is_file()
function is used to check whether the file
is where it's expected to be. The PageNotFoundException
is a CodeIgniter
exception that causes the default error page to show.
In the header template, the $title
variable was used to customize the
page title. The value of title is defined in this method, but instead of
assigning the value to a variable, it is assigned to the title element
in the $data
array.
The last thing that has to be done is loading the views in the order
they should be displayed. The view()
method built-in to
CodeIgniter will be used to do this. The second parameter in the view()
method is
used to pass values to the view. Each value in the $data
array is
assigned to a variable with the name of its key. So the value of
$data['title']
in the controller is equivalent to $title
in the
view.
注釈
Any files and directory names passed into the view() function MUST match the case of the actual directory and file itself or the system will throw errors on case-sensitive platforms.
Running the App¶
Ready to test? You cannot run the app using PHP's built-in server,
since it will not properly process the .htaccess
rules that are provided in
public
, and which eliminate the need to specify "index.php/"
as part of a URL. CodeIgniter has its own command that you can use though.
From the command line, at the root of your project:
php spark serve
will start a web server, accessible on port 8080. If you set the location field
in your browser to localhost:8080
, you should see the CodeIgniter welcome page.
You can now try several URLs in the browser location field, to see what the Pages controller you made above produces...
localhost:8080/pages
will show the results from the index method inside our Pages controller, which is to display the CodeIgniter "welcome" page, because "index" is the default controller methodlocalhost:8080/pages/index
will also show the CodeIgniter "welcome" page, because we explicitly asked for the "index" methodlocalhost:8080/pages/showme
will show the "home" page that you made above, because it is the default "page" parameter to the showme() method.localhost:8080/pages/showme/home
will also show the "home" page that you made above, because we explicitly asked for itlocalhost:8080/pages/showme/about
will show the "about" page that you made above, because we explicitly asked for itlocalhost:8080/pages/showme/shop
will show a "404 - File Not Found" error page, because there is no app/Views/pages/shop.php
Routing¶
The controller is now functioning!
Using custom routing rules, you have the power to map any URI to any
controller and method, and break free from the normal convention:
http://example.com/[controller-class]/[controller-method]/[arguments]
Let's do that. Open the routing file located at app/Config/Routes.php and look for the "Route Definitions" section of the configuration file.
The only uncommented line there to start with should be::
$routes->get('/', 'Home::index');
This directive says that any incoming request without any content
specified should be handled by the index
method inside the Home
controller.
Add the following line, after the route directive for '/'.
$routes->get('(:any)', 'Pages::showme/$1');
CodeIgniter reads its routing rules from top to bottom and routes the request to the first matching rule. Each rule is a regular expression (left-side) mapped to a controller and method name separated by slashes (right-side). When a request comes in, CodeIgniter looks for the first match, and calls the appropriate controller and method, possibly with arguments.
More information about routing can be found in the URI Routing documentation.
Here, the second rule in the $routes
array matches any request
using the wildcard string (:any)
. and passes the parameter to the
view()
method of the Pages
class.
Now visit home
. Did it get routed correctly to the showme()
method in the pages controller? Awesome!
You should see something like the following: