Close #1360 url: Allow _ in hostnames.

lib/url.js

@@ -44,8 +44,8 @@ var protocolPattern = /^([a-z0-9]+:)/i,
       .concat(unwise).concat(autoEscape),
     nonAuthChars = ['/', '@', '?', '#'].concat(delims),
     hostnameMaxLen = 255,
-    hostnamePartPattern = /^[a-zA-Z0-9][a-z0-9A-Z-]{0,62}$/,
+    hostnamePartPattern = /^[a-zA-Z0-9][a-z0-9A-Z_-]{0,62}$/,
-    hostnamePartStart = /^([a-zA-Z0-9][a-z0-9A-Z-]{0,62})(.*)$/,
+    hostnamePartStart = /^([a-zA-Z0-9][a-z0-9A-Z_-]{0,62})(.*)$/,
     // protocols that can allow "unsafe" and "unwise" chars.
     unsafeProtocol = {
       'javascript': true,

test/simple/test-url.js

@@ -274,8 +274,17 @@ var parseTests = {
     'search' : '?search=foo',
     'query' : 'search=foo',
     'hash' : '#bar'
+  },
+  'http://bucket_name.s3.amazonaws.com/image.jpg': {
+    protocol: 'http:',
+    slashes: true,
+    host: 'bucket_name.s3.amazonaws.com',
+    hostname: 'bucket_name.s3.amazonaws.com',
+    pathname: '/image.jpg',
+    href: 'http://bucket_name.s3.amazonaws.com/image.jpg'
   }
 };
+
 for (var u in parseTests) {
   var actual = url.parse(u),
       expected = parseTests[u];