Add url parser

close #6

environs.py

@@ -5,6 +5,11 @@
 import json as pyjson
 import os
 import re
+try:
+    import urllib.parse as urlparse
+except ImportError:
+    # Python 2
+    import urlparse
 
 import marshmallow as ma
 from read_env import read_env as _read_env
@@ -94,6 +99,16 @@ def _preprocess_dict(value, **kwargs):
 def _preprocess_json(value, **kwargs):
     return pyjson.loads(value)
 
+class URLField(ma.fields.URL):
+    def _serialize(self, value, attr, obj):
+        return value.geturl()
+
+    # Override deserialize rather than _deserialize because we need
+    # to call urlparse *after* validation has occurred
+    def deserialize(self, value, attr=None, data=None):
+        ret = super(URLField, self).deserialize(value, attr, data)
+        return urlparse.urlparse(ret)
+
 class Env(object):
     """An environment variable reader."""
     __call__ = _field2method(ma.fields.Field, '__call__')
@@ -115,6 +130,7 @@ def __init__(self):
             date=_field2method(ma.fields.Date, 'date'),
             timedelta=_field2method(ma.fields.TimeDelta, 'timedelta'),
             uuid=_field2method(ma.fields.UUID, 'uuid'),
+            url=_field2method(URLField, 'url'),
         )
 
     def __repr__(self):

tests/test_environs.py

@@ -3,6 +3,11 @@
 import uuid
 from decimal import Decimal
 import datetime as dt
+try:
+    import urllib.parse as urlparse
+except ImportError:
+    # Python 2
+    import urlparse
 
 import pytest
 from marshmallow import fields, validate
@@ -17,7 +22,7 @@ def _set_env(envvars):
     return _set_env
 
 
-@pytest.fixture
+@pytest.fixture(scope='function')
 def env():
     return environs.Env()
 
@@ -44,7 +49,7 @@ def test_int_cast(self, set_env, env):
     def test_invalid_int(self, set_env, env):
         set_env({'INT': 'invalid'})
         with pytest.raises(environs.EnvError) as excinfo:
-            env.int('INT') == 42
+            env.int('INT')
         assert 'Environment variable "INT" invalid' in excinfo.value.args[0]
 
     def test_float_cast(self, set_env, env):
@@ -122,6 +127,23 @@ def test_uuid_cast(self, set_env, env):
         set_env({'UUID': str(uid)})
         assert env.uuid('UUID') == uid
 
+    def test_url_cast(self, set_env, env):
+        set_env({'URL': 'http://stevenloria.com/projects/?foo=42'})
+        res = env.url('URL')
+        assert isinstance(res, urlparse.ParseResult)
+
+    @pytest.mark.parametrize('url',
+    [
+        'foo',
+        '42',
+        'foo@bar',
+    ])
+    def test_invalid_url(self, url, set_env, env):
+        set_env({'URL': url})
+        with pytest.raises(environs.EnvError) as excinfo:
+            env.url('URL')
+        assert 'Environment variable "URL" invalid' in excinfo.value.args[0]
+
 
 class TestProxiedVariables:
 
@@ -248,17 +270,25 @@ def _deserialize(self, value, *args, **kwargs):
 class TestDumping:
     def test_dump(self, set_env, env):
         dtime = dt.datetime.utcnow()
-        set_env({'STR': 'foo', 'INT': '42', 'DTIME': dtime.isoformat()})
+        set_env({
+            'STR': 'foo',
+            'INT': '42',
+            'DTIME': dtime.isoformat(),
+            'URLPARSE': 'http://stevenloria.com/projects/?foo=42',
+        })
 
         env.str('STR')
         env.int('INT')
         env.datetime('DTIME')
+        env.url('URLPARSE')
 
         result = env.dump()
         assert result['STR'] == 'foo'
         assert result['INT'] == 42
         assert 'DTIME' in result
         assert type(result['DTIME']) is str
+        assert type(result['URLPARSE']) is str
+        assert result['URLPARSE'] == 'http://stevenloria.com/projects/?foo=42'
 
     def test_env_with_custom_parser(self, set_env, env):
         @env.parser_for('url')