Question

我在python堆栈中设置了API的最基本结构

flask - connexion - flaskInjector

根据下面显示的代码。运行API并初始化FlaskInjector时，它将失败并显示错误消息：

injector.CallError：调用RequestScope。 init （）失败： init （）缺少1个必需的位置参数：'injector'（注入堆栈：[]）< / p>

我的系统是Ubuntu 18.04，在conda环境中的软件包如下：

conda列表中的相关摘录：

# Name                    Version                   Build  Channel
...
connexion                 2.2.0                    pypi_0    pypi
...
elasticsearch             7.0.1                    pypi_0    pypi
fastavro                  0.21.23                  pypi_0    pypi
flask                     1.0.2                    pypi_0    pypi
flask-cors                3.0.7                    pypi_0    pypi
flask-injector            0.12.0                   pypi_0    pypi
flask-opentracing         1.0.0                    pypi_0    pypi
flask-restplus            0.9.2                    pypi_0    pypi
flask-script              2.0.6                    pypi_0    pypi
flask-sqlalchemy          2.3.2                    pypi_0    pypi
...
injector                  0.12.0                   pypi_0    pypi
...
swagger-ui-bundle         0.0.3                    pypi_0    pypi
...

该项目的组织方式如下：

./ app.py：

from injector import Binder
from flask_injector import FlaskInjector
from connexion.resolver import RestyResolver
import connexion
from providers.provider import ItemsProvider


def configure(binder: Binder) -> Binder:
    binder.bind(
        ItemsProvider,
        ItemsProvider([{'Name': 'Test 1'}])
    )
    return binder


if __name__ == '__main__':
    app = connexion.App(__name__, specification_dir='./swagger/')
    app.add_api('app.yaml', resolver=RestyResolver('api'))
    FlaskInjector(app=app.app, modules=[configure])
    app.run(port=9090, debug=True)

./ api / items.py：

from flask_injector import inject
from providers.provider import ItemsProvider


@inject(data_provider=ItemsProvider)
def search(data_provider) -> list:
    return data_provider.get()

./ providers / provider.py：

class ItemsProvider(object):
    def __init__(self, items: list = []):
        self._items = items

    def get(self, number_of_items: int = 5) -> list:
        if not self._items:
            return []

        if number_of_items > len(self._items):
            number_of_items = len(self._items)

        return self._items[0:number_of_items]

./ swagger / app.yaml：

swagger: "2.0"

info:
  title: "My first API"
  version: "1.0"

basePath: /api

paths:
  /items/:
    get:
      responses:
        '200':
          description: 'Fetch a list of items'
          schema:
            type: array
            items:
              $ref: '#/definitions/Item'

definitions:
  Item:
    type: object
    properties:
      id:
        type: integer
        format: int64
      name: { type: string }

使用python app.py运行应用程序时，api服务器将按预期方式启动：

 * Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on http://0.0.0.0:9090/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 498-670-595

但是，在浏览器中寻址服务器或项目终结点时，会出现以下故障堆栈：

127.0.0.1 - - [21/May/2019 08:16:31] "GET / HTTP/1.1" 500 -
Traceback (most recent call last):
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 2309, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 1811, in full_dispatch_request
    rv = self.preprocess_request()
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask/app.py", line 2087, in preprocess_request
    rv = func()
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/flask_injector.py", line 327, in reset_request_scope_before
    injector_not_null.get(request_scope_class).prepare()
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/injector.py", line 738, in get
    result = scope_instance.get(key, binding.provider).get(self)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/injector.py", line 144, in get
    return injector.create_object(self._cls)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/injector.py", line 789, in create_object
    (), additional_kwargs, e, self._stack,)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/injector.py", line 73, in reraise
    raise exception.with_traceback(tb)
  File "/home/christian/.conda/envs/miccroservice/lib/python3.6/site-packages/injector.py", line 782, in create_object
    init(instance, **additional_kwargs)
injector.CallError: Call to RequestScope.__init__() failed: __init__() missing 1 required positional argument: 'injector' (injection stack: [])
127.0.0.1 - - [21/May/2019 08:16:31] "GET /?__debugger__=yes&cmd=resource&f=style.css HTTP/1.1" 200 -
127.0.0.1 - - [21/May/2019 08:16:31] "GET /?__debugger__=yes&cmd=resource&f=debugger.js HTTP/1.1" 200 -
127.0.0.1 - - [21/May/2019 08:16:31] "GET /?__debugger__=yes&cmd=resource&f=jquery.js HTTP/1.1" 200 -
127.0.0.1 - - [21/May/2019 08:16:31] "GET /?__debugger__=yes&cmd=resource&f=console.png HTTP/1.1" 200 -

Answer 1

将进样器版本从进样器0.12.0升级到进样器0.17.0解决了我的问题。

Answer 2

感谢您的回答。同时，我提出了一个可行的解决方案。 @inject def search(dataprovider=ItemsProvider_()) -> list: data = dataprovider.get(0) return data装饰器至少在当前版本中不能与参数一起使用。如果我将功能更改为：

class MyStreamWidget extends StatefulWidget {
  @override
  _MyStreamWidgetState createState() => _MyStreamWidgetState();
}

class _MyStreamWidgetState extends State<MyStreamWidget> {
  StreamBuilder _widget;
  // TODO your stream
  var myStream;

  @override
  void initState() {
    super.initState();
    _widget = StreamBuilder(
      stream: myStream,
        builder: (context, snapshot) {
          // TODO create widget
          return Container();
        })
  }

  @override
  Widget build(BuildContext context) {
    return _widget;
  }
}

谢谢！

Answer 3

在以下情况下出现此错误：

我在模块中定义了要注入的类，在其中实例化烧瓶应用程序并配置注入器：

app.py

class MyClass:
    def __init__(bar)
        self.bar = bar
# ... instantiate flask app and injector

我将类注入其他模块：

controller.py

from app import MyClass

@inject
def foo(my_object: MyClass):
    return 'Something'

对我来说，解决方案是创建一个单独的模块，在其中定义MyClass与实例化注入器的模块不同。

在python flask API应用程序启动时如何处理FlaskInjector错误？

3 个答案: