Ability to remove a query value while retaining others

[apmorton]

Is your feature request related to a problem?

I have a situation where I would like to get a query parameter, do something with it, and then pass the URL onto a lower layer without that single query param.

The current API is awkward for this.

Describe the solution you'd like

It would be nice to be able to pass kwargs to update_query with None value and have that remove those specific query params.

actual = URL('http://test.com/path?a=1&b=2').update_query(a=None)
expected = URL('http://test.com/path?b=2')
assert actual == expected

Today this throws a TypeError

Describe alternatives you've considered

Today you can accomplish this, but its somewhat awkward:

url = URL('http://test.com/path?a=1&b=2')
query = url.query.copy()
del query['a']
actual = url.with_query(query)
expected = URL('http://test.com/path?b=2')
assert actual == expected

Additional context

No response

Code of Conduct

• I agree to follow the aio-libs Code of Conduct

[webknjaz]

None seems ambiguous. Its semantics can be misinterpreted. JS would use null in it's place and that would be transmitted over the wire as a string, for example.
The None- check is correct.
I think you could just use an empty string and semantically it'd be the same as an unset value, usually.
But if you want to really exclude it, I'd recommend going for a separate method for deleting the param rather than setting it to a magical sentinel value which would mean "instead of updating, remove".
If you want to take a stab at it — send a PR with tests for review.

[apmorton]

Assigning an argument to none None seems logical and consistent to me given the existing behavior of passing None to with_query and update_query.

A separate method is fine too, but given None explicitly has no meaning now (by way of TypeError) it seemed a good fit.

A single method is definitely more convenient - imagine the use case of mutating and renaming an existing query parameter.

url.update_query(old=None, new=func(url.query['old']))

vs

url.update_query(new=func(url.query['old'])).remove_query('old')

Either is an improvement, but I think the first is more ergonomic.

[webknjaz]

Assigning an argument to none None seems logical and consistent to me given the existing behavior of passing None to with_query and update_query.

I disagree: for with_query(), the value of None can have the semantics of "no query" as it works with complex mappings. When working with a value of a param, the value is a primitive. None is ambiguous in this case.

As for update_query(), I think allowing None was a design mistake in that context since it's advertised as a way to patch individual params and this magic sentinel just removes them all.

[webknjaz]

I also stumbled upon an earlier discussion mentioning the ambiguity of None in this very same context: #307 (comment).