Downloading Excel Reports From a Secure Mail Center

New programmer who has been coding scripts to automate work responsibilities.

Scope of Problem:
I get bi-monthly excel reports from an outside vendor sent via email. This vendor uses ZixMail for encryption in which my company does not leverage. As a result, I have to access these emails via a Secure Mail Center with my username and password to log on this Mail Center website. I am trying to establish a connection to this server and download the attachment files.

What I have tried:

• Tried a IMAP connection into the "server" (I am not sure if the website is a mail server)

  • Struck out many times, as I could never get a connection (If there are suggestions to try please share)

• Accessing the site via HTTP using sessions.
  

  • I am able to connect to the site but when I go to .get and .write the file my excel file returns blank and corrupted.
    
  • On the Mail Center/website when I click the link/url it automatically downloads the file. I am not sure why this has to be so challenging?

The source code from the website where you download the file looks like:
a rel="external" href="/s/attachment?name=Random Letters and Numbers=emdeon" title="File Title.xlsx"

the href looks nothing like a normal URL and does not end in a .xlsx or any other type of file like most of the examples I have seen.

I guess I am just really looking for any ideas, thoughts, helps solutions.

Here is my HTTP connection code

import requests
import urllib.request
import shutil
import os

#Fill in your details here to be posted to the login form.
payload = {
    'em': 'Username',
    'passphrase': 'Password',
    'validationKey': 'Key'
}

#This reads your URL and returns if the file is downloadable
def is_downloadable(URL_D):
    h = requests.head(URL_D, allow_redirects=True)
    header = h.headers
    content_type = header.get('content-type')
    if 'text' in content_type.lower():
        return False
    if 'html' in content_type.lower():
        return False
    return True

def download_file(URL_D):
    with requests.get(URL_D, stream=True) as r:
        r.raise_for_status()
        with open(FileName, 'wb') as f:
            for chunk in r.iter_content(chunk_size=None): 
                if chunk: 
                    f.write(chunk)
        f.close()
    return FileName

def Main():
    with requests.Session() as s:
        p = s.post(URL, data=payload, allow_redirects=True )
        print(is_downloadable(URL_D))
        download_file(URL_D)


if __name__ == '__main__':
    Path = "<path>"
    FileName = os.path.join(Path,"Testing File.xlsx")
    URL = 'login URL'
    URL_D = 'Attachment URL"
    Main()

is_downloadable(URL_D) returns as false and the excel file is empty and corrupted

Here is my code for the IMAP attempt:

import email
import imaplib
import os 

class FetchEmail():

    connection = None
    error = None
    

    def __init__(self, mail_server, username, password):
        self.connection = imaplib.IMAP4_SSL(mail_server,port=993)
        self.connection.login(username, password)
        self.connection.select('inbox',readonly=False) # so we can mark mails as read

    def close_connection(self):
        """
        Close the connection to the IMAP server
        """
        self.connection.close()

    def save_attachment(self, msg, download_folder):

        att_path = "No attachment found."
        for part in msg.walk():
            if part.get_content_maintype() == 'multipart':
                continue
            if part.get('Content-Disposition') is None:
                continue

            filename = part.get_filename()
            att_path = os.path.join(download_folder, filename)

            if not os.path.isfile(att_path):
                fp = open(att_path, 'wb')
                fp.write(part.get_payload(decode=True))
                fp.close()
        return att_path

    def fetch_messages(self):
    
        emails = []
        (result, messages) = self.connection.search(None, "(ON 20-Nov-2020)")
        if result == "OK":
            for message in messages[0].split(' '):
                try: 
                    ret, data = self.connection.fetch(message,'(RFC822)')
                except:
                    print ("No emails to read for date.")
                    self.close_connection()
                    exit()

                msg = email.message_from_bytes(data[0][1])
                if isinstance(msg, str) == False:
                    emails.append(msg)
                response, data = self.connection.store(message, '+FLAGS','\\Seen')

            return emails

        self.error = "Failed to retreive emails."
        return emails

def Main():
    p = FetchEmail(mail_server,username,password)
    msg = p.fetch_messages()
    p.save_attachment(msg, download_folder)
    p.close_connection()

if __name__ == "__main__":
    mail_server = "Server"
    username = "username"
    password = "password"
    download_folder= Path
    Main()

Error Message: TimeoutError: [WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond

Even if I wrote the IMAP script wrong, I tried to IMAP connect via cmd prompt and same results.

To recap all I am looking for is some pointers and ideas to solve this problem. Thank You!