From 8fc9c3789ea58f2fa9d9cb3f6ee0574b4c555061 Mon Sep 17 00:00:00 2001
From: Axmacher <Jeremy.Axmacher@ca.com>
Date: Mon, 30 Jan 2017 16:36:04 -0500
Subject: [PATCH] Add support for marshmallow Regexp validator

---
 marshmallow_jsonschema/base.py       |  4 +++-
 marshmallow_jsonschema/validation.py | 26 ++++++++++++++++++++++++++
 tests/__init__.py                    |  1 +
 tests/test_dump.py                   |  7 +++++++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/marshmallow_jsonschema/base.py b/marshmallow_jsonschema/base.py
index fbda2aa..6e4c6ed 100644
--- a/marshmallow_jsonschema/base.py
+++ b/marshmallow_jsonschema/base.py
@@ -6,7 +6,8 @@
 from marshmallow.class_registry import get_class
 from marshmallow.compat import text_type, binary_type, basestring
 
-from .validation import handle_length, handle_one_of, handle_range
+from .validation import (handle_length, handle_one_of, handle_range,
+                         handle_regexp)
 
 
 __all__ = ['JSONSchema']
@@ -73,6 +74,7 @@
     validate.Length: handle_length,
     validate.OneOf: handle_one_of,
     validate.Range: handle_range,
+    validate.Regexp: handle_regexp
 }
 
 
diff --git a/marshmallow_jsonschema/validation.py b/marshmallow_jsonschema/validation.py
index 4a40b61..36c023e 100644
--- a/marshmallow_jsonschema/validation.py
+++ b/marshmallow_jsonschema/validation.py
@@ -104,3 +104,29 @@ def handle_range(schema, field, validator, parent_schema):
         schema['exclusiveMaximum'] = True
 
     return schema
+
+
+def handle_regexp(schema, field, validator, parent_schema):
+    """Adds validation logic for ``marshmallow.validate.Regexp``, setting the
+    values appropriately for ``fields.String`` and its subclasses.
+
+    Args:
+        schema (dict): The original JSON schema we generated. This is what we
+            want to post-process.
+        field (fields.Field): The field that generated the original schema and
+            who this post-processor belongs to.
+        validator (marshmallow.validate.Regexp): The validator attached to the
+            passed in field.
+        parent_schema (marshmallow.Schema): The Schema instance that the field
+            belongs to.
+
+    Returns:
+        dict: A, possibly, new JSON Schema that has been post processed and
+            altered.
+    """
+    if not isinstance(field, fields.String):
+        return schema
+
+    if validator.regex and getattr(validator.regex, 'pattern', None):
+        schema['pattern'] = validator.regex.pattern
+    return schema
diff --git a/tests/__init__.py b/tests/__init__.py
index cdaae84..3a153e0 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -43,6 +43,7 @@ class UserSchema(Schema):
                               validate=validate.Length(min=1, max=3))
     github = fields.Nested(GithubProfile)
     const = fields.String(validate=validate.Length(equal=50))
+    hex_number = fields.String(validate=validate.Regexp('^[a-fA-F0-9]+$'))
 
 
 class BaseTest(unittest.TestCase):
diff --git a/tests/test_dump.py b/tests/test_dump.py
index 039c72f..95a21d8 100644
--- a/tests/test_dump.py
+++ b/tests/test_dump.py
@@ -192,3 +192,10 @@ class UserSchema(Schema):
     json_schema = JSONSchema()
     dumped = json_schema.dump(schema).data
     assert dumped['properties']['favourite_colour'] == {'type': 'string'}
+
+def test_regexp_validator():
+    schema = UserSchema()
+    json_schema = JSONSchema()
+    dumped = json_schema.dump(schema).data
+    _validate_schema(dumped)
+    assert dumped['properties']['hex_number']['pattern'] == '^[a-fA-F0-9]+$'