使用Python请求从本地网址获取文件? [英] Fetch a file from a local url with Python requests?

问题描述

我在我的应用程序的一种方法中使用Python的请求库.该方法的主体如下所示:

I am using Python's requests library in one method of my application. The body of the method looks like this:

def handle_remote_file(url, **kwargs):
    response = requests.get(url, ...)
    buff = StringIO.StringIO()
    buff.write(response.content)
    ...
    return True

我想为该方法编写一些单元测试，但是，我想做的是传递一个伪造的本地URL，例如:

I'd like to write some unit tests for that method, however, what I want to do is to pass a fake local url such as:

class RemoteTest(TestCase):
    def setUp(self):
        self.url = 'file:///tmp/dummy.txt'

    def test_handle_remote_file(self):
        self.assertTrue(handle_remote_file(self.url))

当我使用本地网址调用 requests.get 时，出现了以下 KeyError 异常:

When I call requests.get with a local url, I got the KeyError exception below:

requests.get('file:///tmp/dummy.txt')

/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/requests/packages/urllib3/poolmanager.pyc in connection_from_host(self, host, port, scheme)
76 
77         # Make a fresh ConnectionPool of the desired type
78         pool_cls = pool_classes_by_scheme[scheme]
79         pool = pool_cls(host, port, **self.connection_pool_kw)
80 

KeyError: 'file'

问题是如何将本地URL传递给 requests.get ?

The question is how can I pass a local url to requests.get?

PS:我整理了上面的示例.它可能包含许多错误.

PS: I made up the above example. It possibly contains many errors.

推荐答案

如@WooParadog所述，请求库不知道如何处理本地文件.尽管当前版本允许定义运输适配器.

As @WooParadog explained requests library doesn't know how to handle local files. Although, current version allows to define transport adapters.

因此，您只需定义自己的适配器即可处理本地文件，例如:

Therefore you can simply define you own adapter which will be able to handle local files, e.g.:

from requests_testadapter import Resp

class LocalFileAdapter(requests.adapters.HTTPAdapter):
    def build_response_from_file(self, request):
        file_path = request.url[7:]
        with open(file_path, 'rb') as file:
            buff = bytearray(os.path.getsize(file_path))
            file.readinto(buff)
            resp = Resp(buff)
            r = self.build_response(request, resp)

            return r

    def send(self, request, stream=False, timeout=None,
             verify=True, cert=None, proxies=None):

        return self.build_response_from_file(request)

requests_session = requests.session()
requests_session.mount('file://', LocalFileAdapter())
requests_session.get('file://<some_local_path>')

在上面的示例中，我正在使用 requests-testadapter 模块.

I'm using requests-testadapter module in the above example.

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