add request.hostname(getter), fixed #224

make request.host and request.hostname work as node url lib
http://nodejs.org/api/url.html#url_url
this commit will change older request.host(getter)

lib/context.js

@@ -179,6 +179,7 @@ delegate(proto, 'request')
   .access('url')
   .getter('subdomains')
   .getter('protocol')
+  .getter('hostname')
   .getter('header')
   .getter('secure')
   .getter('stale')

lib/request.js

@@ -173,11 +173,11 @@ module.exports = {
   },
 
   /**
-   * Parse the "Host" header field hostname
+   * Parse the "Host" header field host
    * and support X-Forwarded-Host when a
    * proxy is enabled.
    *
-   * @return {String}
+   * @return {String} hostname:port
    * @api public
    */
 
@@ -186,7 +186,7 @@ module.exports = {
     var host = proxy && this.get('X-Forwarded-Host');
     host = host || this.get('Host');
     if (!host) return;
-    return host.split(/\s*,\s*/)[0].split(':')[0];
+    return host.split(/\s*,\s*/)[0];
   },
 
   /**
@@ -200,6 +200,21 @@ module.exports = {
     this.req.headers.host = val;
   },
 
+  /**
+   * Parse the "Host" header field hostname
+   * and support X-Forwarded-Host when a
+   * proxy is enabled.
+   *
+   * @return {String} hostname
+   * @api public
+   */
+
+  get hostname() {
+    var host = this.host;
+    if (!host) return;
+    return host.split(':')[0];
+  },
+
   /**
    * Check if the request is fresh, aka
    * Last-Modified and/or the ETag
@@ -579,4 +594,4 @@ module.exports = {
       header: this.header
     }
   }
-};
+};

test/request/host.js

@@ -2,10 +2,10 @@
 var request = require('../context').request;
 
 describe('req.host', function(){
-  it('should return host void of port', function(){
+  it('should return host with port', function(){
     var req = request();
     req.header.host = 'foo.com:3000';
-    req.host.should.equal('foo.com');
+    req.host.should.equal('foo.com:3000');
   })
 
   describe('when X-Forwarded-Host is present', function(){

test/request/hostname.js

@@ -0,0 +1,31 @@
+
+var request = require('../context').request;
+
+describe('req.hostname', function(){
+  it('should return hostname void of port', function(){
+    var req = request();
+    req.header.host = 'foo.com:3000';
+    req.hostname.should.equal('foo.com');
+  })
+
+  describe('when X-Forwarded-Host is present', function(){
+    describe('and proxy is not trusted', function(){
+      it('should be ignored', function(){
+        var req = request();
+        req.header['x-forwarded-host'] = 'bar.com';
+        req.header['host'] = 'foo.com';
+        req.hostname.should.equal('foo.com')
+      })
+    })
+
+    describe('and proxy is trusted', function(){
+      it('should be used', function(){
+        var req = request();
+        req.app.proxy = true;
+        req.header['x-forwarded-host'] = 'bar.com, baz.com';
+        req.header['host'] = 'foo.com';
+        req.hostname.should.equal('bar.com')
+      })
+    })
+  })
+})