tornado下解决restful api 无法测试读取json

测试用例如下

class AuthTest(AsyncTestCase):
    @gen_test
    def test_http_fetch(self):
        client = AsyncHTTPClient(self.io_loop)
        data = {
            'type':'nomal',
            'phone_num':'1322********',
            'password':'******'
        }
        headers = {'Content-Type': 'application/json; charset=UTF-8'}

        request = HTTPRequest(
            url=BASE_URL + '/v1.0/auth',
            method='POST',
            body=json_encode(data),
            headers=headers
        )
        response = yield client.fetch(request)
        # Test contents of response
        self.assertIn("ok", response.body)

但是无法通过测试，原因在于tornado 的get_body_argument(),get_argument()等函数并没有解析json的共轭呢过

以下是4.0下tornado.httputil中的部分代码

def parse_body_arguments(content_type, body, arguments, files, headers=None):
    """Parses a form request body.

    Supports ``application/x-www-form-urlencoded`` and
    ``multipart/form-data``.  The ``content_type`` parameter should be
    a string and ``body`` should be a byte string.  The ``arguments``
    and ``files`` parameters are dictionaries that will be updated
    with the parsed contents.
    """
    if headers and 'Content-Encoding' in headers:
        gen_log.warning("Unsupported Content-Encoding: %s",
                        headers['Content-Encoding'])
        return
    if content_type.startswith("application/x-www-form-urlencoded"):
        try:
            uri_arguments = parse_qs_bytes(native_str(body), keep_blank_values=True)
        except Exception as e:
            gen_log.warning('Invalid x-www-form-urlencoded body: %s', e)
            uri_arguments = {}
        for name, values in uri_arguments.items():
            if values:
                arguments.setdefault(name, []).extend(values)
    elif content_type.startswith("multipart/form-data"):
        try:
            fields = content_type.split(";")
            for field in fields:
                k, sep, v = field.strip().partition("=")
                if k == "boundary" and v:
                    parse_multipart_form_data(utf8(v), body, arguments, files)
                    break
            else:
                raise ValueError("multipart boundary not found")
        except Exception as e:
            gen_log.warning("Invalid multipart/form-data: %s", e)

可以看到并没有解析json

于是我们可以自己在基类中定义一个

class BassHandler(tornado.web.RequestHandler):
    def get_json_argument(self, name, default = None):
        args = json_decode(self.request.body)
        name = to_unicode(name)
        if name in args:
            return args[name]
        elif default is not None:
            return default
        else:
            raise MissingArgumentError(name)

测试通过