make shorthand parsing more robust, add unit tests and documentation

README.rst

@@ -121,7 +121,6 @@ See also ``http --help``.
 Examples
 --------
 
-
 Custom `HTTP method`_, `HTTP headers`_ and `JSON`_ data:
 
 .. code-block:: bash
@@ -226,6 +225,15 @@ The only information HTTPie needs to perform a request is a URL.
 The default scheme is, somewhat unsurprisingly, ``http://``,
 and can be omitted from the argument – ``http example.org`` works just fine.
 
+Additionally, curl-like shorthand for localhost is supported.
+This means that, for example ``:3000`` would expand to ``http://localhost:3000``
+If the port is omitted, then port 80 is assumed.
+
+.. code-block:: bash
+
+    $ http :/foo
+    $ http :3000/bar
+
 If find yourself manually constructing URLs with **querystring parameters**
 on the terminal, you may appreciate the ``param==value`` syntax for appending
 URL parameters so that you don't have to worry about escaping the ``&``

httpie/input.py

@@ -138,8 +138,15 @@ class Parser(ArgumentParser):
         if not (self.args.url.startswith((HTTP, HTTPS))):
             # Default to 'https://' if invoked as `https args`.
             scheme = HTTPS if self.env.progname == 'https' else HTTP
-            if self.args.url.startswith(':'):
+            # See if we're using curl style shorthand for localhost (:3000/foo)
-                self.args.url = scheme + 'localhost' + self.args.url
+            shorthand = re.match(r'^:(?!:)(\d*)(\/?.*)$', self.args.url)
+            if shorthand:
+                port = shorthand.group(1)
+                rest = shorthand.group(2)
+                self.args.url = scheme + 'localhost'
+                if port:
+                    self.args.url += ':' + port
+                self.args.url += rest
             else:
                 self.args.url = scheme + self.args.url
         self._process_auth()

tests/tests.py

@@ -64,6 +64,7 @@ sys.path.insert(0, os.path.realpath(os.path.join(TESTS_ROOT, '..')))
 
 from httpie import ExitStatus
 from httpie import input
+from httpie.cli import parser
 from httpie.models import Environment
 from httpie.core import main
 from httpie.output import BINARY_SUPPRESSED_NOTICE
@@ -1264,6 +1265,52 @@ class ItemParsingTest(BaseTestCase):
         self.assertEqual(files['file'][1].read().strip().decode('utf8'),
                          FILE_CONTENT)
 
+class CLIParserTestCase(unittest.TestCase):
+
+    def test_expand_localhost_shorthand(self):
+        args = parser.parse_args(args=[':'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost')
+
+    def test_expand_localhost_shorthand_with_slash(self):
+        args = parser.parse_args(args=[':/'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost/')
+
+    def test_expand_locahost_shorthand_with_port(self):
+        args = parser.parse_args(args=[':3000'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost:3000')
+
+    def test_expand_localhost_shorthand_with_path(self):
+        args = parser.parse_args(args=[':/path'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost/path')
+
+    def test_expand_localhost_shorthand_with_port_and_slash(self):
+        args = parser.parse_args(args=[':3000/'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost:3000/')
+
+    def test_expand_localhost_shorthand_with_port_and_path(self):
+        args = parser.parse_args(args=[':3000/path'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://localhost:3000/path')
+
+    def test_dont_expand_shorthand_ipv6_as_shorthand(self):
+        args = parser.parse_args(args=['::1'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://::1')
+
+    def test_dont_expand_longer_ipv6_as_shorthand(self):
+        args = parser.parse_args(args=['::ffff:c000:0280'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://::ffff:c000:0280')
+
+    def test_dont_expand_full_ipv6_as_shorthand(self):
+        args = parser.parse_args(args=['0000:0000:0000:0000:0000:0000:0000:0001'], env=TestEnvironment())
+
+        self.assertEqual(args.url, 'http://0000:0000:0000:0000:0000:0000:0000:0001')
 
 class ArgumentParserTestCase(unittest.TestCase):