Added path-based validation.

- isdir(): verifies if the specified path exists and is a directory.
- isfile(): verifies if the specified path exists and is a file.
- path_exists(): verifies if the specified path exists.

1 files changed, 31 insertions, 0 deletions

diff --git a/voluptuous.py b/voluptuous.py
index b377560..be450a8 100644
--- a/voluptuous.py
+++ b/voluptuous.py
@@ -82,6 +82,7 @@ Validate like so:
                               'Users': {'snmp_community': 'monkey'}}}}
 """
 
+import os
 import re
 import string
 import types
@@ -630,6 +631,36 @@ def url(msg=None):
     return f
 
 
+def isfile(msg=None):
+    """Verify the file exists."""
+    def f(v):
+        if os.path.isfile(v):
+            return v
+        else:
+            raise Invalid(msg or 'not a file')
+    return f
+
+
+def isdir(msg=None):
+    """Verify the directory exists."""
+    def f(v):
+        if os.path.isdir(v):
+            return v
+        else:
+            raise Invalid(msg or 'not a directory')
+    return f
+
+
+def path_exists(msg=None):
+    """Verify the path exists, regardless of its type."""
+    def f(v):
+        if os.path.exists(v):
+            return v
+        else:
+            raise Invalid(msg or 'path does not exist')
+    return f
+
+
 def range(min=None, max=None, msg=None):
     """Limit a value to a range.