Using regular expressions in URL rules_Yii Application Development Cookbook（Second Edition）-QQ阅读男生科幻网

上QQ阅读APP看书，第一时间看更新

Using regular expressions in URL rules

One of the hidden features of the Yii URL router is that you can use regular expressions that are pretty powerful when it comes to strings handling.

Getting ready

Create a fresh Yii application using yiic webapp as described in the official guide and find your protected/config/main.php file. It should contain the following:

// application components
'components'=>array(
   …
   // uncomment the following to enable URLs in path-format
   /*
   'urlManager'=>array(
      'urlFormat'=>'path',
      'rules'=>array(
         '<controller:\w+>/<id:\d+>'=>'<controller>/view',
         '<controller:\w+>/<action:\w+>/<id:\d+>'=>'<controller>/<action>',
          '<controller:\w+>/<action:\w+>'=>'<controller>/<action>',
      ),
   ),

Delete everything from rules as we are going to start from scratch.

In your protected/controllers directory, create PostController.php with the following code inside it:

class PostController extends CController
{
  public function actionView($alias)
  {
      echo "Showing post with alias $alias.";
  }

  public function actionIndex($order = 'DESC')
  {
      echo "Showing posts ordered $order.";
  }

  public function actionHello($name)
  {
   echo "Hello, $name!";
  }
}

This is our application controller that we are going to access using our custom URLs.

Configure your application server to use clean URLs. If you are using Apache with mod_rewrite and AllowOverride turned on, then you should add the following lines to the .htaccess file under your webroot folder:

Options +FollowSymLinks
IndexIgnore */*
RewriteEngine on

# if a directory or a file exists, use it directly
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

# otherwise forward it to index.php
RewriteRule . index.php

How to do it...

We want our PostController action to accept parameters according to some specified rules and give the 404 not found HTTP response for all parameters that do not match. In addition, post/index should have an alias URL, archive.

Let's use regular expressions in the configuration file to achieve this:

'post/<alias:[-a-z]+>' => 'post/view',
'(posts|archive)' => 'post/index',
'(posts|archive)/<order:(DESC|ASC)>' => 'post/index',
'sayhello/<name>' => 'post/hello',

The following URLs will be successful:

http://example.com/post/test-post
http://example.com/posts
http://example.com/archive
http://example.com/posts/ASC
http://example.com/sayhello/Александр

The following URLs will fail:

http://example.com/archive/test
http://example.com/post/another_post

The following screenshot shows that the URL http://example.com/post/test-post has run successfully:

The following screenshot shows that the URL http://example.com/archive/test did not run successfully and encountered an error:

How it works...

You can use regular expressions in both parameter definition and the rest of the rule. Let's read our rules one by one.

'post/<alias:[-a-z]+>' => 'post/view',

The alias parameter should contain one or more English letters or a dash. No other symbols are allowed.

'(posts|archive)' => 'post/index',

Both posts and archive lead to post/index.

'(posts|archive)/<order:(DESC|ASC)>' => 'post/index',

Both posts and archive lead to post/index. The order parameter can only accept two values: DESC and ASC.

'sayhello/<name>' => 'post/hello',

You should specify the name part but there are no restrictions on what characters are allowed.

Note that regardless of the rule used, the developer should never assume that input data is safe.

There's more...

To learn more about regular expressions, you can use the following sources:

http://www.php.net/manual/en/reference.pcre.pattern.syntax.php
Mastering Regular Expressions, Jeffrey Friedl available at http://regex.info/