Python: Join multiple components to build a URL

Using join

Have you tried simply "/".join(url_join_items). Does not http always use the forward slash? You might have to manually setup the prefix "https://" and the suffix, though.

Something like:

url = "https://{}.json".format("/".join(url_join_items))

Using reduce and urljoin

Here is a related question on SO that explains to some degree the thinking behind the implementation of urljoin. Your use case does not appear to be the best fit.

When using reduce and urljoin, I'm not sure it will do what the question intends, which is semantically like os.path.join, but for urls. Consider the following:

from urllib.parse import urljoin
from functools import reduce

parts_1 = ["a","b","c","d"]
parts_2 = ["https://","server.com","somedir","somefile.json"]
parts_3 = ["https://","server.com/","somedir/","somefile.json"]

out1 = reduce(urljoin, parts_1)
print(out1)

d

out2 = reduce(urljoin, parts_2)
print(out2)

https:///somefile.json

out3 = reduce(urljoin, parts_3)
print(out3)

https:///server.com/somedir/somefile.json

Note that with the exception of the extra "/" after the https prefix, the third output is probably closest to what the asker intends, except we've had to do all the work of formatting the parts with the separator.

I also needed something similar and came up with this solution:

from urllib.parse import urljoin, quote_plus

def multi_urljoin(*parts):
    return urljoin(parts[0], "/".join(quote_plus(part.strip("/"), safe="/") for part in parts[1:]))

print(multi_urljoin("https://server.com", "path/to/some/dir/", "2019", "4", "17", "some_random_string", "image.jpg"))

This prints 'https://server.com/path/to/some/dir/2019/4/17/some_random_string/image.jpg'

Here's a bit silly but workable solution, given that parts is a list of URL parts in order

my_url = '/'.join(parts).replace('//', '/').replace(':/', '://')

I wish replace would have a from option but it does not hence the second one is to recover https:// double slash

Nice thing is you don't have to worry about parts already having (or not having) any slashes