Adding methods to get host, domain and subdomains for a request.

Tests added.

cake/libs/cake_request.php

@@ -561,6 +561,38 @@ class CakeRequest implements ArrayAccess {
 		return env('REQUEST_METHOD');
 	}
 
+/**
+ * Get the host that the request was handled on.
+ *
+ * @return void
+ */
+	public function host() {
+		return env('HTTP_HOST');
+	}
+
+/**
+ * Get the domain name and include $tldLength segments of the tld.
+ *
+ * @param int $tldLength Number of segments your tld contains
+ * @return string Domain name without subdomains.
+ */
+	function domain($tldLength = 1) {
+		$segments = explode('.', $this->host());
+		$domain = array_slice($segments, -1 * ($tldLength + 1));
+		return implode('.', $domain);
+	}
+
+/**
+ * Get the subdomains for a host.
+ *
+ * @param int $tldLength Number of segments your tld contains.
+ * @return array of subdomains.
+ */
+	function subdomains($tldLength = 1) {
+		$segments = explode('.', $this->host());
+		return array_slice($segments, 0, -1 * ($tldLength + 1));
+	}
+
 /**
  * Find out which content types the client accepts or check if they accept a 
  * particular type of content.

cake/tests/cases/libs/cake_request.test.php

@@ -512,6 +512,51 @@ class CakeRequestTestCase extends CakeTestCase {
 		$this->assertEquals('delete', $request->method());
 	}
 
+/**
+ * test host retrieval.
+ *
+ * @return void
+ */
+	function testHost() {
+		$_SERVER['HTTP_HOST'] = 'localhost';
+		$request = new CakeRequest('some/path');
+		
+		$this->assertEquals('localhost', $request->host());
+	}
+
+/**
+ * test domain retrieval.
+ *
+ * @return void
+ */
+	function testDomain() {
+		$_SERVER['HTTP_HOST'] = 'something.example.com';
+		$request = new CakeRequest('some/path');
+
+		$this->assertEquals('example.com', $request->domain());
+
+		$_SERVER['HTTP_HOST'] = 'something.example.co.uk';
+		$this->assertEquals('example.co.uk', $request->domain(2));
+	}
+
+/**
+ * test getting subdomains for a host.
+ *
+ * @return void
+ */
+	function testSubdomain() {
+		$_SERVER['HTTP_HOST'] = 'something.example.com';
+		$request = new CakeRequest('some/path');
+
+		$this->assertEquals(array('something'), $request->subdomains());
+
+		$_SERVER['HTTP_HOST'] = 'www.something.example.com';
+		$this->assertEquals(array('www', 'something'), $request->subdomains());
+
+		$_SERVER['HTTP_HOST'] = 'www.something.example.co.uk';
+		$this->assertEquals(array('www', 'something'), $request->subdomains(2));
+	}
+
 /**
  * test ajax, flash and friends
  *