Add re type

CHANGELOG.rst

@@ -6,6 +6,13 @@ The format is *inspired* by `Keep a Changelog <http://keepachangelog.com/en/1.0.
 and this project adheres to `Semantic Versioning <http://semver.org/spec/v2.0.0.html>`_.
 
 
+`unreleased`_
+--------------------------
+Added
++++++
+  - New type: re
+
+
 `v0.4.5`_ - 25-June-2018
 --------------------------
 Added

README.rst

@@ -119,6 +119,7 @@ Supported types
 - dict (BAR=key=val,foo=bar) #environ.Env(BAR=(dict, {}))
 - dict (BAR=key=val;foo=1.1;baz=True) #environ.Env(BAR=(dict(value=unicode, cast=dict(foo=float,baz=bool)), {}))
 - url
+- re
 - path (environ.Path)
 - db_url
     -  PostgreSQL: postgres://, pgsql://, psql:// or postgresql://
@@ -207,7 +208,7 @@ Some settings such as Django's ``ADMINS`` make use of nested lists. You can use
 .. code-block:: python
 
     # DJANGO_ADMINS=John:john@admin.com,Jane:jane@admin.com
-    ADMINS = [x.split(':') for x in env.list('DJANGO_ADMINS')] 
+    ADMINS = [x.split(':') for x in env.list('DJANGO_ADMINS')]
 
     # or use more specific function
 

environ/environ.py

@@ -233,6 +233,20 @@ def path(self, var, default=NOTSET, **kwargs):
         """
         return Path(self.get_value(var, default=default), **kwargs)
 
+    def re(self, var, regex, default=EnvBase.NOTSET):
+        """Returns the string that satisfies the given regex.
+        If it's not satisfied returns the var as string
+
+        :param var: Name of variable.
+        :param regex: Regular expression to apply to var.
+        :param default: If var not present in environ, return this instead.
+
+        :returns: str
+        """
+        str_var = self.str(var, default)
+        re_obj = re.search(regex, str_var)
+        return re_obj.group(0) if re_obj else str_var
+
     def get_value(self, var, cast=None, default=NOTSET, parse_default=False):
         """Return value for given environment variable.
 
@@ -768,7 +782,7 @@ def __unicode__(self):
 
     def __getitem__(self, *args, **kwargs):
         return self.__str__().__getitem__(*args, **kwargs)
-    
+
     def __fspath__(self):
         return self.__str__()
 

environ/test.py

@@ -97,6 +97,11 @@ def test_str(self):
         self.assertTypeAndValue(str, 'foo\\nbar', self.env.str('MULTILINE_STR_VAR'))
         self.assertTypeAndValue(str, 'foo\nbar', self.env.str('MULTILINE_STR_VAR', multiline=True))
 
+    def test_re(self):
+        self.assertTypeAndValue(str, '1.0.0', self.env.re('STR_RE_VAR', r'\d+.\d+.\d+'))
+        self.assertTypeAndValue(str, 'foo', self.env.re('MULTILINE_STR_VAR', r'\w+'))
+        self.assertTypeAndValue(str, 'bar', self.env.re('STR_VAR', r'\d+'))
+
     def test_bytes(self):
         self.assertTypeAndValue(bytes, b'bar', self.env.bytes('STR_VAR'))
 
@@ -395,7 +400,7 @@ def test_memory_sqlite_url(self):
 
         self.assertEqual(url['ENGINE'], 'django.db.backends.sqlite3')
         self.assertEqual(url['NAME'], ':memory:')
-        
+
     def test_memory_sqlite_url_warns_about_netloc(self):
         url = 'sqlite://missing-slash-path'
         with warnings.catch_warnings(record=True) as w:

environ/test_env.txt

@@ -22,6 +22,7 @@ EMPTY_LIST=
 INT_VAR=42
 STR_LIST_WITH_SPACES= foo,  bar
 STR_VAR=bar
+STR_RE_VAR=bar-1.0.0
 MULTILINE_STR_VAR=foo\nbar
 INT_LIST=42,33
 CYRILLIC_VAR=фуубар