尝试并捕获Python中的异常以打开和上载PDF文件

Question

我开发了一个Python模块，用于将PDF文件上传到我的Parse.com项目。我使用了＆＃34;请求＆＃34;用于与https Parse.com服务器通信。这些代码试图涵盖与Parse通信时可能遇到的所有可能异常，因为我有一个公司防火墙。

import env
import json
import requests

def uploadFile(fileFullPath):
    result = False

    print "Attempting to upload file: " + fileFullPath

    headers = {"X-Parse-Application-Id": env.X_Parse_Application_Id,
            "X-Parse-REST-API-Key": env.X_Parse_REST_API_Key,
            "Content-Type": "application/json"}
    try:
        f = open(fileFullPath, 'r')
        files = {'file': f}
        r = requests.post(env.PARSE_HOSTNAME + env.PARSE_FILES_ENDPOINT + "/" + env.PARSE_UPLOADED_FILE_NAME, files=files, headers=headers)
        jsonResult = r.json()

        if 'error' in jsonResult:
            print "An error occurred while trying to upload the file to Parse.com. Details: " + (jsonResult["error"])
        else:
            print jsonResult["name"]
            print jsonResult["url"]

        print "Completed uploading the file."
        result = True

    # Unable to open the file
    except IOError as ex:
        print 'IOError thrown. Details: ' + ' %s' % ex
        # If file cannot be opened, IOError is thrown as well, so exit the function to avoid calling "f.close()" in "finally"

    # In the event of a network problem (e.g. DNS failure, refused connection, etc)
    except ConnectionError as ex:
        print 'ConnectionError thrown. Details: ' + ' %s' % ex

    # In the event of an invalid HTTP response
    except HTTPError as ex:
        print 'HTTPError thrown. Details: ' + ' %s' % ex

    # If time-out occurs
    except Timeout as ex:
        print 'Timeout exception thrown. Details: ' + ' %s' % ex

    # If a request exceeds the configured number of maximum redirections
    except TooManyRedirects as ex:
        print 'TooManyRedirects exception thrown. Details: ' + ' %s' % ex

    # All other exceptions
    except Exception as ex:
        print 'Unexpected error. Details:' + ' %s' % ex
    else:
        f.close()
    finally:
        return result

if __name__ == "__main__":
    myFilePath = r'D:/myfile.pdf'
    print uploadFile(myFilePath)

我的问题是这些例外的顺序是否正确。 IOError是否总是取代任何其他错误？