Python POST request to retrieve base64 encode File - python-3.x

Question

Im trying to POST request using Python to retreive a specific File. Since the URL is behind a server with authorized access theres no use posting it here
However the form data contains a field called base64 and lengthy which I cant figure out if its a form data value or base64 encoding of post request
Here are browser parameters
General:
Request URL: http://exampleapi.com/api/Document/Export
Request Method: POST
Status Code: 200 OK
Remote Address: XX.XXX.XXX.XX:XX
Referrer Policy: no-referrer-when-downgrade
Response Headers:
Access-Control-Allow-Origin: http://example.com
Cache-Control: no-cache
Content-Disposition: attachment; filename=location-downloads.xlsx
Content-Length: 7148
Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
Date: Tue, 23 Jul 2019 21:00:18 GMT
Expires: -1
Pragma: no-cache
Server: Microsoft-IIS/7.5
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Request Headers :
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Cache-Control: max-age=0
Connection: keep-alive
Content-Length: 10162
Content-Type: application/x-www-form-urlencoded
Cookie: abcConnection=!UA7tkC3iZCmVNGRUyRpDWARVBWk/lY6SZvgxLlaygsQKk+vuwA1NxvhwE9ph4i+3NZlKeepIfuHhUvyQjl68fhhrT9ueqMx/3mBKUDcT
DNT: 1
Host: exampleapi.com
Origin: http://example.com
Referer: http://example.com/
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36
Form Data:
fileName: location-downloads.xlsx
contentType: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
base64: UEsDBAoAAAAAAAh4904AAAAAAAAAAAAAAAAJAAAAZG9jUHJvcHMvUEsDBAoAAAAIAAh490(shortened for simplicity)
Here is what I tried
url='http://example.com'
urllib3.disable_warnings()
headers = {
"Content-Type": "application/x-www-form-urlencoded",
"User-Agent": "Mozilla/5.0",
}
with requests.session() as s:
r=s.get(url,headers={"User-Agent":"Mozilla/5.0"},verify=False)
data=r.content
soup=BeautifulSoup(data,'html.parser')
form_data = {
"fileName":"location-downloads.xlsx",
"contentType":"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
}
r2=s.post('http://exampleapi.com/api/Document/Export',data=json.dumps(form_data,ensure_ascii=True).encode('utf-8'),headers=headers,verify=False)
print(r2.status_code)
Any idea how i should proceed. My status code also shows 500 for the post here