Python 3 urllib produces TypeError: POST data should be bytes or an iterable of bytes. It cannot be of type str

Question

I am trying to convert working Python 2.7 code into Python 3 code and I am receiving a type error from the urllib request module.

I used the inbuilt 2to3 Python tool

Answer 1

Try this:

url = 'https://www.customdomain.com'
d = dict(parameter1="value1", parameter2="value2")

f = urllib.parse.urlencode(d)
f = f.encode('utf-8')

req = urllib.request.Request(url, f)

Your problem lies in the way you were handling the dictionary.

Answer 2

I used python requests module with ZOHO CRM API V2. It worked without any issues. Here is a sample working code with GET request:

import json
import requests

# API methods - https://www.zoho.com/crm/developer/docs/api/api-methods.html
# getrecords API Call
module_name = 'Deals'
authtoken = '*****'
api_url = "https://crm.zoho.com/crm/private/json/"+module_name+"/getRecords?authtoken="+authtoken+"&scope=crmapi&fromIndex=1&toIndex=2"

# GET Request
request_response = requests.get(
    url=api_url
    )
print(json.dumps(json.loads(request_response.text), sort_keys=True, indent=4, separators=(",", ": ")))
json_response = json.loads(request_response.text)

Answer 3

From the docs Note that params output from urlencode is encoded to bytes before it is sent to urlopen as data:

data = urllib.parse.urlencode(d).encode("utf-8")
req = urllib.request.Request(url)
with urllib.request.urlopen(req,data=data) as f:
    resp = f.read()
    print(resp)