CODEWITHSUNDEEP
pythonurl-parsing
summerNight
summerNight

Reputation: 1506

Python: Join multiple components to build a URL

I am trying to build a URL by joining some dynamic components. I thought of using something like os.path.join() BUT for URLs in my case. From research I found urlparse.urljoin() does the same thing. However, it looks like it only take two arguments at one time.

I have the following so far which works but looks repetitive:

    a = urlparse.urljoin(environment, schedule_uri)
    b = urlparse.urljoin(a, str(events_to_hours))
    c = urlparse.urljoin(b, str(events_from_date))
    d = urlparse.urljoin(c, str(api_version))
    e = urlparse.urljoin(d, str(id))
    url = e + '.json'

Output = http://example.com/schedule/12/20160322/v1/1.json

The above works and I tried to make it shorter this way:

url_join_items = [environment, schedule_uri, str(events_to_hours),
                  str(events_from_date), str(api_version), str(id), ".json"]
new_url = ""
for url_items in url_join_items:
    new_url = urlparse.urljoin(new_url, url_items)

Output: http://example.com/schedule/.json

But the second implementation does not work. Please suggest me how to fix this or the better way of doing it.

EDIT 1: The output from the reduce solution looks like this (unfortunately): Output: http://example.com/schedule/.json

Upvotes: 21

Views: 25268

Answers (5)

Artur Barseghyan
Artur Barseghyan

Reputation: 14272

This is what worked for me all the best:

def join_url_parts(base: str, parts: list[str], allow_fragments: bool = True) -> str:
    """Join multiple URL parts together.

    See the examples below. All of them would produce the same result:
    `https://example.com/api/v1/users/`

        print(join_url_parts("https://example.com", ["api", "v1", "users"]))
        print(join_url_parts("https://example.com", ["api", "v1/", "users"]))
        print(join_url_parts("https://example.com/", ["api/", "v1/", "users/"]))
        print(join_url_parts("https://example.com/", ["/api/", "/v1/", "users/"]))
    """
    url = "/".join(map(lambda x: str(x).strip("/"), parts)) + "/"
    return urljoin(base, url, allow_fragments)

This basically replicates the standard urljoin but allows the second arguments to be parts (list of strings).

Upvotes: 0

dzav
dzav

Reputation: 554

Simple solution will be:

def url_join(*parts: str) -> str:
    import re

    line = '/'.join(parts)
    line = re.sub('/{2,}', '/', line)
    return re.sub(':/', '://', line)

Upvotes: 2

Bostone
Bostone

Reputation: 37154

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

Upvotes: 0

Klemen Tusar
Klemen Tusar

Reputation: 9709

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'

Upvotes: 9

svohara
svohara

Reputation: 2199

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.

Upvotes: 25

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