deno add - support http: and https: specifiers

[bartlomieju]

Currently deno add only works with jsr: and npm: specifiers.

We should add an ability to do deno add https://deno.land/x/foo/bar.ts.

To do this, we should leverage existing infer_name_from_url() helper, that is already used in deno install and deno compile

deno/cli/tools/installer.rs

Lines 131 to 185 in d3d3582

	pub async fn infer_name_from_url(url: &Url) -> Option<String> {
	// If there's an absolute url with no path, eg. https://my-cli.com
	// perform a request, and see if it redirects another file instead.
	let mut url = url.clone();
	if url.path() == "/" {
	let client = HttpClient::new(None, None);
	if let Ok(res) = client.get_redirected_response(url.clone()).await {
	url = res.url().clone();
	}
	}
	if let Ok(npm_ref) = NpmPackageReqReference::from_specifier(&url) {
	let npm_ref = npm_ref.into_inner();
	if let Some(sub_path) = npm_ref.sub_path {
	if !sub_path.contains('/') {
	return Some(sub_path);
	}
	}
	if !npm_ref.req.name.contains('/') {
	return Some(npm_ref.req.name);
	}
	return None;
	}
	let percent_decode = percent_encoding::percent_decode(url.path().as_bytes());
	#[cfg(unix)]
	let path = {
	use std::os::unix::prelude::OsStringExt;
	PathBuf::from(std::ffi::OsString::from_vec(
	percent_decode.collect::<Vec<u8>>(),
	))
	};
	#[cfg(windows)]
	let path = PathBuf::from(percent_decode.decode_utf8_lossy().as_ref());
	let mut stem = path.file_stem()?.to_string_lossy();
	if matches!(stem.as_ref(), "main" | "mod" | "index" | "cli") {
	if let Some(parent_name) = path.parent().and_then(|p| p.file_name()) {
	stem = parent_name.to_string_lossy();
	}
	}
	// if atmark symbol appears in the index other than 0 (e.g. `foo@bar`) we use
	// the former part as the inferred name because the latter part is most likely
	// a version number.
	match stem.find('@') {
	Some(at_index) if at_index > 0 => {
	stem = stem.split_at(at_index).0.to_string().into();
	}
	_ => {}
	}
	Some(stem.to_string())
	}

[dsherret]

Note that there is #23144 for aliases

[tristanisham]

This would require modifying https://github.com/denoland/deno_semver.

[dsherret]

@tristanisham why?

[tristanisham]

@tristanisham why?

I believe that's where all the code for specifiers is. If the goal is to add "http(s):" that's the package where the actual structs and implementation details reside.

[tristanisham]

For the record:

Had a discussion about adding the feature to the deno_semver crate, but concluded that it would be better implemented here.

[jmj0502]

@bartlomieju @tristanisham Can I take this issue? I may have some questions regarding certain internals of the project but I would like to give it a shot c:

[tristanisham]

Be my guess. I haven't finished my PR.