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Merge pull request #2489 from Pylons/feature/json_exceptions
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Feature: JSON exceptions
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@mmerickel
mmerickel committed Apr 14, 2016
2 parents 8863785 + aac7a47 commit 4bb2095
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Showing 3 changed files with 153 additions and 25 deletions.
7 changes: 7 additions & 0 deletions CHANGES.txt
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Original file line number Diff line number Diff line change
@@ -1,6 +1,13 @@
unreleased
==========

- Pyramid HTTPExceptions will now take into account the best match for the
clients Accept header, and depending on what is requested will return
text/html, application/json or text/plain. The default for */* is still
text/html, but if application/json is explicitly mentioned it will now
receive a valid JSON response. See:
https://github.com/Pylons/pyramid/pull/2489

- (Deprecation) Support for Python 3.3 will be removed in Pyramid 1.8.
https://github.com/Pylons/pyramid/issues/2477

Expand Down
50 changes: 42 additions & 8 deletions pyramid/httpexceptions.py
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Original file line number Diff line number Diff line change
Expand Up @@ -123,12 +123,14 @@
field. Reflecting this, these subclasses have one additional keyword argument:
``location``, which indicates the location to which to redirect.
"""
import json

from string import Template

from zope.interface import implementer

from webob import html_escape as _html_escape
from webob.acceptparse import MIMEAccept

from pyramid.compat import (
class_types,
Expand Down Expand Up @@ -214,7 +216,7 @@ class HTTPException(Response, Exception):
empty_body = False

def __init__(self, detail=None, headers=None, comment=None,
body_template=None, **kw):
body_template=None, json_formatter=None, **kw):
status = '%s %s' % (self.code, self.title)
Response.__init__(self, status=status, **kw)
Exception.__init__(self, detail)
Expand All @@ -225,6 +227,8 @@ def __init__(self, detail=None, headers=None, comment=None,
if body_template is not None:
self.body_template = body_template
self.body_template_obj = Template(body_template)
if json_formatter is not None:
self._json_formatter = json_formatter

if self.empty_body:
del self.content_type
Expand All @@ -233,18 +237,48 @@ def __init__(self, detail=None, headers=None, comment=None,
def __str__(self):
return self.detail or self.explanation

def _json_formatter(self, status, body, title, environ):
return {'message': body,
'code': status,
'title': self.title}

def prepare(self, environ):
if not self.body and not self.empty_body:
html_comment = ''
comment = self.comment or ''
accept = environ.get('HTTP_ACCEPT', '')
if accept and 'html' in accept or '*/*' in accept:
accept_value = environ.get('HTTP_ACCEPT', '')
accept = MIMEAccept(accept_value)
# Attempt to match text/html or application/json, if those don't
# match, we will fall through to defaulting to text/plain
match = accept.best_match(['text/html', 'application/json'])

if match == 'text/html':
self.content_type = 'text/html'
escape = _html_escape
page_template = self.html_template_obj
br = '<br/>'
if comment:
html_comment = '<!-- %s -->' % escape(comment)
elif match == 'application/json':
self.content_type = 'application/json'
self.charset = None
escape = _no_escape
br = '\n'
if comment:
html_comment = escape(comment)

class JsonPageTemplate(object):
def __init__(self, excobj):
self.excobj = excobj

def substitute(self, status, body):
jsonbody = self.excobj._json_formatter(
status=status,
body=body, title=self.excobj.title,
environ=environ)
return json.dumps(jsonbody)

page_template = JsonPageTemplate(self)
else:
self.content_type = 'text/plain'
escape = _no_escape
Expand All @@ -253,11 +287,11 @@ def prepare(self, environ):
if comment:
html_comment = escape(comment)
args = {
'br':br,
'br': br,
'explanation': escape(self.explanation),
'detail': escape(self.detail or ''),
'comment': escape(comment),
'html_comment':html_comment,
'html_comment': html_comment,
}
body_tmpl = self.body_template_obj
if HTTPException.body_template_obj is not body_tmpl:
Expand All @@ -274,7 +308,7 @@ def prepare(self, environ):
body = body_tmpl.substitute(args)
page = page_template.substitute(status=self.status, body=body)
if isinstance(page, text_type):
page = page.encode(self.charset)
page = page.encode(self.charset if self.charset else 'UTF-8')
self.app_iter = [page]
self.body = page

Expand Down Expand Up @@ -1001,8 +1035,8 @@ class HTTPInternalServerError(HTTPServerError):
code = 500
title = 'Internal Server Error'
explanation = (
'The server has either erred or is incapable of performing '
'the requested operation.')
'The server has either erred or is incapable of performing '
'the requested operation.')

class HTTPNotImplemented(HTTPServerError):
"""
Expand Down
121 changes: 104 additions & 17 deletions pyramid/tests/test_httpexceptions.py
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Original file line number Diff line number Diff line change
Expand Up @@ -28,9 +28,9 @@ def test_status_201(self):
self.assertTrue(isinstance(self._callFUT(201), HTTPCreated))

def test_extra_kw(self):
resp = self._callFUT(404, headers=[('abc', 'def')])
resp = self._callFUT(404, headers=[('abc', 'def')])
self.assertEqual(resp.headers['abc'], 'def')

class Test_default_exceptionresponse_view(unittest.TestCase):
def _callFUT(self, context, request):
from pyramid.httpexceptions import default_exceptionresponse_view
Expand Down Expand Up @@ -129,7 +129,7 @@ def test_ctor_extends_headers(self):
def test_ctor_sets_body_template_obj(self):
exc = self._makeOne(body_template='${foo}')
self.assertEqual(
exc.body_template_obj.substitute({'foo':'foo'}), 'foo')
exc.body_template_obj.substitute({'foo': 'foo'}), 'foo')

def test_ctor_with_empty_body(self):
cls = self._getTargetSubclass(empty_body=True)
Expand Down Expand Up @@ -160,7 +160,7 @@ def test_ctor_with_body_sets_default_app_iter_html(self):
self.assertTrue(b'200 OK' in body)
self.assertTrue(b'explanation' in body)
self.assertTrue(b'detail' in body)

def test_ctor_with_body_sets_default_app_iter_text(self):
cls = self._getTargetSubclass()
exc = cls('detail')
Expand All @@ -173,7 +173,7 @@ def test__str__detail(self):
exc = self._makeOne()
exc.detail = 'abc'
self.assertEqual(str(exc), 'abc')

def test__str__explanation(self):
exc = self._makeOne()
exc.explanation = 'def'
Expand Down Expand Up @@ -212,6 +212,9 @@ def test__default_app_iter_no_comment_plain(self):
environ = _makeEnviron()
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/plain; charset=UTF-8')
self.assertEqual(body, b'200 OK\n\nexplanation\n\n\n\n\n')

def test__default_app_iter_with_comment_plain(self):
Expand All @@ -220,26 +223,78 @@ def test__default_app_iter_with_comment_plain(self):
environ = _makeEnviron()
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/plain; charset=UTF-8')
self.assertEqual(body, b'200 OK\n\nexplanation\n\n\n\ncomment\n')

def test__default_app_iter_no_comment_html(self):
cls = self._getTargetSubclass()
exc = cls()
environ = _makeEnviron()
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/plain; charset=UTF-8')
self.assertFalse(b'<!-- ' in body)

def test__default_app_iter_with_comment_html(self):
def test__content_type(self):
cls = self._getTargetSubclass()
exc = cls(comment='comment & comment')
exc = cls()
environ = _makeEnviron()
start_response = DummyStartResponse()
exc(environ, start_response)
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/plain; charset=UTF-8')

def test__content_type_default_is_html(self):
cls = self._getTargetSubclass()
exc = cls()
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = '*/*'
start_response = DummyStartResponse()
exc(environ, start_response)
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/html; charset=UTF-8')

def test__content_type_text_html(self):
cls = self._getTargetSubclass()
exc = cls()
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = 'text/html'
start_response = DummyStartResponse()
exc(environ, start_response)
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/html; charset=UTF-8')

def test__content_type_application_json(self):
cls = self._getTargetSubclass()
exc = cls()
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = 'application/json'
start_response = DummyStartResponse()
exc(environ, start_response)
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'application/json')

def test__default_app_iter_with_comment_ampersand(self):
cls = self._getTargetSubclass()
exc = cls(comment='comment & comment')
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = 'text/html'
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
for header in start_response.headerlist:
if header[0] == 'Content-Type':
self.assertEqual(header[1], 'text/html; charset=UTF-8')
self.assertTrue(b'<!-- comment &amp; comment -->' in body)

def test__default_app_iter_with_comment_html2(self):
def test__default_app_iter_with_comment_html(self):
cls = self._getTargetSubclass()
exc = cls(comment='comment & comment')
environ = _makeEnviron()
Expand All @@ -248,6 +303,38 @@ def test__default_app_iter_with_comment_html2(self):
body = list(exc(environ, start_response))[0]
self.assertTrue(b'<!-- comment &amp; comment -->' in body)

def test__default_app_iter_with_comment_json(self):
cls = self._getTargetSubclass()
exc = cls(comment='comment & comment')
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = 'application/json'
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
import json
retval = json.loads(body.decode('UTF-8'))
self.assertEqual(retval['code'], '200 OK')
self.assertEqual(retval['title'], 'OK')

def test__default_app_iter_with_custom_json(self):
def json_formatter(status, body, title, environ):
return {'message': body,
'code': status,
'title': title,
'custom': environ['CUSTOM_VARIABLE']
}
cls = self._getTargetSubclass()
exc = cls(comment='comment', json_formatter=json_formatter)
environ = _makeEnviron()
environ['HTTP_ACCEPT'] = 'application/json'
environ['CUSTOM_VARIABLE'] = 'custom!'
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
import json
retval = json.loads(body.decode('UTF-8'))
self.assertEqual(retval['code'], '200 OK')
self.assertEqual(retval['title'], 'OK')
self.assertEqual(retval['custom'], 'custom!')

def test_custom_body_template(self):
cls = self._getTargetSubclass()
exc = cls(body_template='${REQUEST_METHOD}')
Expand All @@ -261,7 +348,8 @@ def test_custom_body_template_with_custom_variable_doesnt_choke(self):
exc = cls(body_template='${REQUEST_METHOD}')
environ = _makeEnviron()
class Choke(object):
def __str__(self): raise ValueError
def __str__(self): # pragma nocover
raise ValueError
environ['gardentheory.user'] = Choke()
start_response = DummyStartResponse()
body = list(exc(environ, start_response))[0]
Expand Down Expand Up @@ -293,7 +381,7 @@ def _doit(self, content_type):
self.assertTrue(bytes_(exc.status) in result)
L.append(result)
self.assertEqual(len(L), len(status_map))

def test_it_plain(self):
self._doit('text/plain')

Expand Down Expand Up @@ -367,12 +455,11 @@ class DummyStartResponse(object):
def __call__(self, status, headerlist):
self.status = status
self.headerlist = headerlist

def _makeEnviron(**kw):
environ = {'REQUEST_METHOD':'GET',
'wsgi.url_scheme':'http',
'SERVER_NAME':'localhost',
'SERVER_PORT':'80'}
environ = {'REQUEST_METHOD': 'GET',
'wsgi.url_scheme': 'http',
'SERVER_NAME': 'localhost',
'SERVER_PORT': '80'}
environ.update(kw)
return environ

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