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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use md5::{Digest, Md5};
use url::{Host, Url};
pub type UrlHash = [u8; 16];
/// Given a URL, extract the part of it that we want to use to identify it.
///
/// We currently use the final 3 components of the URL domain.
///
/// TODO: decide if this should be 3 or 3 components.
pub fn url_hash_source(url: &str) -> Option<String> {
let url = Url::parse(url).ok()?;
let domain = match url.host() {
Some(Host::Domain(d)) => d,
_ => return None,
};
// This will store indexes of `.` chars as we search backwards.
let mut pos = domain.len();
for _ in 0..3 {
match domain[0..pos].rfind('.') {
Some(p) => pos = p,
// The domain has less than 3 dots, return it all
None => return Some(domain.to_owned()),
}
}
Some(domain[pos + 1..].to_owned())
}
pub fn hash_url(url: &str) -> Option<UrlHash> {
url_hash_source(url).map(|hash_source| {
let mut hasher = Md5::new();
hasher.update(hash_source);
let result = hasher.finalize();
result.into()
})
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn test_url_hash_source() {
let table = [
("http://example.com/some-path", Some("example.com")),
("http://foo.example.com/some-path", Some("foo.example.com")),
(
"http://foo.bar.baz.example.com/some-path",
Some("baz.example.com"),
),
("http://foo.com.uk/some-path", Some("foo.com.uk")),
("http://amazon.com/some-path", Some("amazon.com")),
("http://192.168.0.1/some-path", None),
];
for (url, expected) in table {
assert_eq!(url_hash_source(url).as_deref(), expected)
}
}
}
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