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I'm generating a URL (in string) that depends on 3 optional parameters, file, user and active.

From a base url: /hey I want to generate the endpoint, this means:

• If file is specificied, my desired output would is: /hey?file=example
  


• If file and user is specified, my desired output is: /hey?file=example&user=boo
  


• If user and active are specified, my desired output is: /hey?user=boo&active=1


• If no optional parameters are specified, my desired output is: /hey
  


• and so on with all the combinations...

My code, which is working correctly, is as follows (change the None's at the top if you want to test it):

file = None

user = None

active = 1



ep = "/hey"

isFirst = True



if file:

  if isFirst:

    ep+= "?file=" + file;

    isFirst = False;

  else: ep += "&file=" + file;



if user:

  if isFirst:

    ep+= "?user=" + user;

    isFirst = False;

  else: ep += "&user=" + user;



if active:

  if isFirst:

    ep+= "?active=" + str(active);

    isFirst = False;

  else: ep += "&active=" + str(active);



print ep

Can someone give me a more python implementation for this? I can't use modules as requests.

Thanks in advance.

The most Pythonic version of this depends a bit on what you do with that URL afterwards. If you are using the requests module (which you probably should), this is already built-in by specifying the params keyword:

import requests



URL = "https://example.com/hey"



r1 = requests.get(URL, params={"file": "example"})

print(r1.url)

# https://example.com/hey?file=example



r2 = requests.get(URL, params={"file": "example", "user": "boo"})

print(r2.url)

# https://example.com/hey?file=example&user=boo



r3 = requests.get(URL, params={"user": "boo", "active": 1})

print(r3.url)

# https://example.com/hey?user=boo&active=1



r4 = requests.get(URL, params={})

print(r4.url)

# https://example.com/hey

If you do need a pure Python solution without any imports, this is what I would do:

def get_url(base_url, **kwargs):

    if not kwargs:

        return base_url

    params = "&".join(f"{key}={value}" for key, value in kwargs.items())

    return base_url + "?" + params

Of course this does not urlencode the keys and values and may therefore be a security risk or fail unexpectedly, but neither does your code.

Example usage:

print(get_url("/hey", file="example"))

# /hey?file=example



print(get_url("/hey", file="example", user="boo"))

# /hey?file=example&user=boo



print(get_url("/hey", user="boo", active=1))

# /hey?user=boo&active=1



print(get_url("/hey"))

# /hey

You're pretty much reinventing urllib.parse.urlencode:

from urllib.parse import urlencode





def prepare_query_string(**kwargs):

    return urlencode([(key, value) for key, value in kwargs.items() if value is not None])

Usage being:

>>> prepare_query_string(active=1)

'active=1'

>>> prepare_query_string(active=1, user=None)

'active=1'

>>> prepare_query_string(active=1, user='bob')

'active=1&user=bob'

>>> prepare_query_string(file='foo.tar.gz', user='bob')

'file=foo.tar.gz&user=bob'

>>> prepare_query_string(file='foo.tar.gz', user='bob', active=None)

'file=foo.tar.gz&user=bob'

>>> prepare_query_string(file='foo.tar.gz', user='bob', active=1)

'file=foo.tar.gz&user=bob&active=1'