Support jsonschema >= 3.0.0 (#1050)

* setup.py: Support jsonschema >= 3.0.0

Other projects have started using jsonschema >= 3.0.0, and modern python
packaging tools such as poetry now fail to install projects using both
connexion and a different dependency if they depend on different
versions of jsonschema.

Allow jsonschema versions >= 3.0.0 to avoid this problem.

See: python-poetry/poetry#697

* Avoid warning when using jsonschema >= 3.0

jsonschema 3.0.0 changed the API to deprecate the types parameter of the
jsonschema.IValidator constructor and now raises a warning when using
it.

Avoid the warning by checking the jsonschema version and switching to
the new way to implement this when it is >= 3.0. Note that while
jsonschema 2.x did have jsonschema.validators.extend, it did not support
the type_checker argument, so the same code cannot be used with
jsonschema 2.x.

connexion/decorators/validation.py

@@ -4,8 +4,10 @@
 import logging
 import sys
 
+import pkg_resources
 import six
 from jsonschema import Draft4Validator, ValidationError, draft4_format_checker
+from jsonschema.validators import extend
 from werkzeug.datastructures import FileStorage
 
 from ..exceptions import ExtraParameterProblem
@@ -14,6 +16,10 @@
 from ..problem import problem
 from ..utils import all_json, boolean, is_json_mimetype, is_null, is_nullable
 
+_jsonschema_3_or_newer = pkg_resources.parse_version(
+        pkg_resources.get_distribution("jsonschema").version) >= \
+    pkg_resources.parse_version("3.0.0")
+
 logger = logging.getLogger('connexion.decorators.validation')
 
 TYPE_MAP = {
@@ -261,10 +267,19 @@ def validate_parameter(parameter_type, value, param, param_name=None):
                 del param['required']
             try:
                 if parameter_type == 'formdata' and param.get('type') == 'file':
-                    Draft4Validator(
-                        param,
-                        format_checker=draft4_format_checker,
-                        types={'file': FileStorage}).validate(converted_value)
+                    if _jsonschema_3_or_newer:
+                        extend(
+                            Draft4Validator,
+                            type_checker=Draft4Validator.TYPE_CHECKER.redefine(
+                                "file",
+                                lambda checker, instance: isinstance(instance, FileStorage)
+                            )
+                        )(param, format_checker=draft4_format_checker).validate(converted_value)
+                    else:
+                        Draft4Validator(
+                            param,
+                            format_checker=draft4_format_checker,
+                            types={'file': FileStorage}).validate(converted_value)
                 else:
                     Draft4Validator(
                         param, format_checker=draft4_format_checker).validate(converted_value)

setup.py

@@ -22,7 +22,7 @@ def read_version(package):
 
 install_requires = [
     'clickclick>=1.2',
-    'jsonschema>=2.5.1,<3.0.0',
+    'jsonschema>=2.5.1',
     'PyYAML>=5.1',
     'requests>=2.9.1',
     'six>=1.9',