Feature/image validator

.gitignore

@@ -35,3 +35,6 @@ nosetests.xml
 .mr.developer.cfg
 .project
 .pydevproject
+
+# PyCharm
+.idea

docs/index.rst

@@ -91,6 +91,13 @@ iban
 
 .. autofunction:: iban
 
+image
+-----
+
+.. module:: validators.image
+
+.. autofunction:: image
+
 ipv4
 ----
 

setup.py

@@ -28,7 +28,8 @@ def get_version():
     'test': [
         'pytest>=2.2.3',
         'flake8>=2.4.0',
-        'isort>=4.2.2'
+        'isort>=4.2.2',
+        'pillow>=3.4.2'
     ],
 }
 

tests/test_image.py

@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+import os
+
+import pytest
+from PIL import Image
+
+from validators import image, ValidationFailure
+
+
+@pytest.fixture()
+def image_file(tmpdir):
+    path = os.path.join(str(tmpdir), 'test.png')
+    img = Image.new('RGBA', (10, 10))
+    img.save(str(path), format='PNG')
+    return str(path)
+
+
+@pytest.fixture()
+def text_file(tmpdir):
+    path = os.path.join(str(tmpdir), 'test.txt')
+    f = open(path, 'w')
+    f.close()
+    return str(path)
+
+
+@pytest.mark.parametrize('address', [
+    u'https://i.imgur.com/DKUR9Tk.png',
+    u'https://i.imgur.com/DKUR9Tk.png?fb'
+])
+def test_returns_true_on_valid_image_url(address):
+    assert image(address)
+
+
+@pytest.mark.parametrize('address', [
+    u'http://www.google.com/'
+])
+def test_returns_false_on_invalid_image_url(address):
+    assert isinstance(image(address), ValidationFailure)
+
+
+def test_returns_true_on_valid_image_file(image_file):
+    assert image(image_file)
+
+
+def test_returns_false_on_invalid_image_file(text_file):
+    assert isinstance(image(text_file), ValidationFailure)

validators/__init__.py

@@ -4,6 +4,7 @@
 from .extremes import Max, Min  # noqa
 from .i18n import fi_business_id, fi_ssn  # noqa
 from .iban import iban  # noqa
+from .image import image  # noqa
 from .ip_address import ipv4, ipv6  # noqa
 from .length import length  # noqa
 from .mac_address import mac_address  # noqa

validators/image.py

@@ -0,0 +1,63 @@
+import imghdr  # isort:skip
+import os
+from io import BytesIO
+
+from .url import url
+from .utils import ValidationFailure, validator
+
+try:
+    from urllib2 import urlopen
+except ImportError:
+    from urllib.request import urlopen
+
+
+def _image_url(path):
+    result = False
+
+    try:
+        if url(path):
+            response = urlopen(path)
+            data = BytesIO(response.read())
+            if imghdr.what(data) is not None:
+                result = True
+            else:
+                result = False
+    except ValidationFailure:
+        result = False
+
+    return result
+
+
+def _image_file(path):
+    result = False
+
+    if os.path.exists(path):
+        if imghdr.what(path) is not None:
+            result = True
+        else:
+            result = False
+
+    return result
+
+
+@validator
+def image(path):
+    """
+    Return whether or not a file is a valid image type.
+
+    If the file is a valid image type this function returns ``True``, otherwise
+    :class:`~validators.utils.ValidationFailure`.
+
+    :param path: The path to the file to evaluate.
+    """
+
+    result = False
+
+    if _image_url(path):
+        result = True
+    elif _image_file(path):
+        result = True
+    else:
+        result = False
+
+    return result