Pretty-print format all JSON response bodies

Flask-RESTful automatically converts a response body to JSON when it
creates the Response object. The Flask app configuration option
RESTFUL_JSON is added by this commit to appropriately modify how the
JSON body is constructed.

response_filter has been modified so that it returns a tuple of
information that Flask-RESTful will use to create an appropriately
formatted response.

Resource.error_response is creating the Response object itself and so
has been modified to format the JSON in the same way as Flask-RESTful.
Ideally, error_response would not create a separate Response object
however addressing this is a separate issue.

Change-Id: I02eafaf48d7c6e2ceab0add2f78cf6aa1b890f18
Closes-bug: 1664328

craton/api/__init__.py

@@ -1,6 +1,7 @@
+from datetime import date
 import os
 from paste import deploy
-from flask import Flask
+from flask import Flask, json
 
 
 from oslo_config import cfg
@@ -48,10 +49,27 @@ def create_app(global_config, **local_config):
     return setup_app()
 
 
+class JSONEncoder(json.JSONEncoder):
+
+    def default(self, o):
+        if isinstance(o, date):
+            return o.isoformat()
+        return json.JSONEncoder.default(self, o)
+
+
+RESTFUL_JSON = {
+    "indent": 2,
+    "sort_keys": True,
+    "cls": JSONEncoder,
+    "separators": (",", ": "),
+}
+
+
 def setup_app(config=None):
     app = Flask(__name__, static_folder=None)
     app.config.update(
-        PROPAGATE_EXCEPTIONS=True
+        PROPAGATE_EXCEPTIONS=True,
+        RESTFUL_JSON=RESTFUL_JSON,
     )
     app.register_blueprint(v1.bp, url_prefix='/v1')
     return app

craton/api/v1/base.py

@@ -1,5 +1,6 @@
 import functools
 import inspect
+import json
 import re
 import urllib.parse as urllib
 
@@ -8,6 +9,7 @@ import decorator
 import flask
 import flask_restful as restful
 
+from craton import api
 from craton.api.v1.validators import ensure_project_exists
 from craton.api.v1.validators import request_validate
 from craton.api.v1.validators import response_filter
@@ -22,10 +24,14 @@ class Resource(restful.Resource):
                          response_filter]
 
     def error_response(self, status_code, message):
-        resp = flask.jsonify({
-            'status': status_code,
-            'message': message
-            })
+        body = json.dumps(
+            {
+                'status': status_code,
+                'message': message
+            },
+            **api.RESTFUL_JSON,
+        )
+        resp = flask.make_response("{body}\n".format(body=body))
         resp.status_code = status_code
         return resp
 

craton/api/v1/validators.py

@@ -1,11 +1,10 @@
 # The code is auto generated, your change will be overwritten by
 # code generating.
 
-from datetime import date
 from functools import wraps
 
 from werkzeug.datastructures import MultiDict, Headers
-from flask import request, current_app, json
+from flask import request, current_app
 from flask_restful import abort
 from flask_restful.utils import unpack
 from jsonschema import Draft4Validator
@@ -143,14 +142,6 @@ def normalize(schema, data, required_defaults=None):
     return _normalize(schema, data), errors
 
 
-class JSONEncoder(json.JSONEncoder):
-
-    def default(self, o):
-        if isinstance(o, date):
-            return o.isoformat()
-        return json.JSONEncoder.default(self, o)
-
-
 class FlaskValidatorAdaptor(object):
 
     def __init__(self, schema):
@@ -282,13 +273,7 @@ def response_filter(view):
         if errors:
             abort(500, message='Expectation Failed', errors=errors)
 
-        return current_app.response_class(
-            json.dumps(resp, cls=JSONEncoder) + '\n',
-            status=status,
-            headers=headers,
-            mimetype='application/json'
-        )
-
+        return resp, status, headers
     return wrapper
 
 

craton/tests/functional/__init__.py

@@ -1,5 +1,6 @@
 import contextlib
 import docker
+import json
 import requests
 from retrying import retry
 from sqlalchemy import create_engine
@@ -220,28 +221,49 @@ class TestCase(testtools.TestCase):
     def assertBadRequest(self, response):
         self.assertEqual(requests.codes.BAD_REQUEST, response.status_code)
 
+    def assertJSON(self, response):
+        if response.text:
+            try:
+                data = json.loads(response.text)
+            except json.JSONDecodeError:
+                self.fail("Response data is not JSON.")
+            else:
+                reference = "{formatted_data}\n".format(
+                    formatted_data=json.dumps(
+                        data, indent=2, sort_keys=True, separators=(',', ': ')
+                    )
+                )
+                self.assertEqual(
+                    reference,
+                    response.text
+                )
+
     def get(self, url, headers=None, **params):
         resp = self.session.get(
             url, verify=False, headers=headers, params=params,
         )
+        self.assertJSON(resp)
         return resp
 
     def post(self, url, headers=None, data=None):
         resp = self.session.post(
             url, verify=False, headers=headers, json=data,
         )
+        self.assertJSON(resp)
         return resp
 
     def put(self, url, headers=None, data=None):
         resp = self.session.put(
             url, verify=False, headers=headers, json=data,
         )
+        self.assertJSON(resp)
         return resp
 
     def delete(self, url, headers=None, body=None):
         resp = self.session.delete(
             url, verify=False, headers=headers, json=body,
         )
+        self.assertJSON(resp)
         return resp
 
     def create_cloud(self, name, variables=None):