python - 访问 API 时的错误处理

Question

我正在尝试通过 python 访问 API（Scopus），在下面的 for 循环中下载多个摘要：

for t in eid:
    url = "http://api.elsevier.com/content/abstract/eid/"+str(t)+"?view=FULL"
    #    url = "http://api.elsevier.com/content/abstract/eid/2-s2.0-84934272190?view=FULL"
    resp2 = requests.get(url,
                         headers={'Accept':'application/json',
                         'X-ELS-APIKey': MYAPIKEY})

    retrieval = resp2.json()

    dep = retrieval['abstracts-retrieval-response']['item']['bibrecord']['head']['author-group']
    sub = retrieval['abstracts-retrieval-response']['subject-areas']['subject-area']
    iD = retrieval['abstracts-retrieval-response']['coredata']['intid']
    date = retrieval['abstracts-retrieval-response']['coredata']['prism:coverDate']

    department.append(dep)
    subj.append(sub)
    ident.append(iD)
    dates.append(date)

但是，这样做后，我不断收到以下错误（也总是在 for 循环的不同点）。有人告诉我错误处理是解决这个问题的一种方法，但是作为 Python 新手，我不知道这是什么。任何人都可以帮忙吗？谢谢

编辑：这是整个错误消息，其中应包含所有正确信息（对不起，它很长）

Traceback (most recent call last):
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connection.py", line 142, in _new_conn
    (self.host, self.port), self.timeout, **extra_kw)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\util\connection.py", line 91, in create_connection
    raise err
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\util\connection.py", line 81, in create_connection
    sock.connect(sa)
ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connectionpool.py", line 578, in urlopen
    chunked=chunked)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connectionpool.py", line 362, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "C:\Users\User\Anaconda3\lib\http\client.py", line 1106, in request
    self._send_request(method, url, body, headers)
  File "C:\Users\User\Anaconda3\lib\http\client.py", line 1151, in _send_request
    self.endheaders(body)
  File "C:\Users\User\Anaconda3\lib\http\client.py", line 1102, in endheaders
    self._send_output(message_body)
  File "C:\Users\User\Anaconda3\lib\http\client.py", line 934, in _send_output
    self.send(msg)
  File "C:\Users\User\Anaconda3\lib\http\client.py", line 877, in send
    self.connect()
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connection.py", line 167, in connect
    conn = self._new_conn()
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connection.py", line 151, in _new_conn
    self, "Failed to establish a new connection: %s" % e)
requests.packages.urllib3.exceptions.NewConnectionError: <requests.packages.urllib3.connection.HTTPConnection object at 0x000002058C7E1C18>: Failed to establish a new connection: [WinError 10053] An established connection was aborted by the software in your host machine

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\adapters.py", line 403, in send
    timeout=timeout
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\connectionpool.py", line 623, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\packages\urllib3\util\retry.py", line 281, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
requests.packages.urllib3.exceptions.MaxRetryError: HTTPConnectionPool(host='api.elsevier.com', port=80): Max retries exceeded with url: /content/abstract/eid/2-s2.0-84978766692?view=FULL (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0x000002058C7E1C18>: Failed to establish a new connection: [WinError 10053] An established connection was aborted by the software in your host machine',))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 5, in <module>
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\api.py", line 71, in get
    return request('get', url, params=params, **kwargs)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\api.py", line 57, in request
    return session.request(method=method, url=url, **kwargs)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\sessions.py", line 475, in request
    resp = self.send(prep, **send_kwargs)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\sessions.py", line 585, in send
    r = adapter.send(request, **kwargs)
  File "C:\Users\User\Anaconda3\lib\site-packages\requests\adapters.py", line 467, in send
    raise ConnectionError(e, request=request)
requests.exceptions.ConnectionError: HTTPConnectionPool(host='api.elsevier.com', port=80): Max retries exceeded with url: /content/abstract/eid/2-s2.0-84978766692?view=FULL (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0x000002058C7E1C18>: Failed to establish a new connection: [WinError 10053] An established connection was aborted by the software in your host machine',))

Answer 1

不幸的是，您没有包含输出中提到的“上述异常”。

但一般来说，当一段代码执行过程中出现异常情况，比如错误，你可以捕捉到该异常并进行处理。一个例外是一个对象，其中包含有关问题所在的信息。一般来说，异常处理是一个大主题，您可以从以下位置开始阅读：https ://docs.python.org/3/tutorial/errors.html

处理异常的一个例子就是报告情况和异常。这已经可以让您深入了解出了什么问题：

for t in eid:
    try:
        url = "http://api.elsevier.com/content/abstract/eid/"+str(t)+"?view=FULL"
        #    url = "http://api.elsevier.com/content/abstract/eid/2-s2.0-84934272190?view=FULL"
        resp2 = requests.get(url,
                             headers={'Accept':'application/json',
                             'X-ELS-APIKey': MYAPIKEY})

        retrieval = resp2.json()

        dep = retrieval['abstracts-retrieval-response']['item']['bibrecord']['head']['author-group']
        sub = retrieval['abstracts-retrieval-response']['subject-areas']['subject-area']
        iD = retrieval['abstracts-retrieval-response']['coredata']['intid']
        date = retrieval['abstracts-retrieval-response']['coredata']['prism:coverDate']

        department.append(dep)
        subj.append(sub)
        ident.append(iD)
        dates.append(date)
    except Exception as exception:
        print (url) # 'print' will only work on a console
        print (exception)

[编辑]

我查看了错误消息，您尝试连接的服务器似乎关闭了连接。另请参阅为什么主机中止连接？尽管原因可能完全不同。试试上面的代码，看看这种情况是一直发生还是只发生在某些 URL 上

[/编辑]

要构建一些重试，请使用：

import time

nrOfTries = 10

for t in eid:
    for count in range (nrOfTries):
        try:
            url = "http://api.elsevier.com/content/abstract/eid/"+str(t)+"?view=FULL"
            #    url = "http://api.elsevier.com/content/abstract/eid/2-s2.0-84934272190?view=FULL"
            resp2 = requests.get(url,
                                 headers={'Accept':'application/json',
                                 'X-ELS-APIKey': MYAPIKEY})

            retrieval = resp2.json()

            dep = retrieval['abstracts-retrieval-response']['item']['bibrecord']['head']['author-group']
            sub = retrieval['abstracts-retrieval-response']['subject-areas']['subject-area']
            iD = retrieval['abstracts-retrieval-response']['coredata']['intid']
            date = retrieval['abstracts-retrieval-response']['coredata']['prism:coverDate']

            department.append(dep)
            subj.append(sub)
            ident.append(iD)
            dates.append(date)

            break   # Don't do the else

        except Exception as exception:
            print ('Problem accessing: {}' .format (url))
            print (exception)
            time.sleep (2)  # Seconds
    else:   # Done after for-loop exhausted, but not if 'break' was encountered
        print ('Gave up accessing: {}' .format (url))

注意我没有对此进行测试，但它应该传达一般的想法。“睡眠”是为了让服务器喘口气……