Don't check Twitter URLs (#1147)

Twitter completely locked down and requires
a login to read tweets. (Temporarily) disable all
Twitter URLs to avoid false-positives.

For context:
zedeus/nitter#919
https://news.ycombinator.com/item?id=36540957
https://techcrunch.com/2023/06/30/twitter-now-requires-an-account-to-view-tweets/

Fixes #1108

lychee-bin/tests/cli.rs

@@ -241,8 +241,10 @@ mod cli {
     }
 
     #[test]
-    #[ignore = "Twitter quirk works locally but is flaky on Github (timeout)"]
-    fn test_twitter_quirk() {
+    // Exclude Twitter links because they require login to view tweets.
+    // https://techcrunch.com/2023/06/30/twitter-now-requires-an-account-to-view-tweets/
+    // https://github.com/zedeus/nitter/issues/919
+    fn test_ignored_hosts() {
         let url = "https://twitter.com/zarfeblong/status/1339742840142872577";
 
         main_command()
@@ -253,7 +255,7 @@ mod cli {
             .assert()
             .success()
             .stdout(contains("1 Total"))
-            .stdout(contains("1 OK"));
+            .stdout(contains("1 Excluded"));
     }
 
     #[tokio::test]

lychee-lib/src/filter/mod.rs

@@ -21,6 +21,14 @@ static EXAMPLE_DOMAINS: Lazy<HashSet<&'static str>> =
 #[cfg(any(test, feature = "check_example_domains"))]
 static EXAMPLE_DOMAINS: Lazy<HashSet<&'static str>> = Lazy::new(HashSet::new);
 
+static UNSUPPORTED_DOMAINS: Lazy<HashSet<&'static str>> = Lazy::new(|| {
+    HashSet::from_iter([
+        // Twitter requires an account to view tweets
+        // https://news.ycombinator.com/item?id=36540957
+        "twitter.com",
+    ])
+});
+
 /// Pre-defined exclusions for known false-positives
 const FALSE_POSITIVE_PAT: &[&str] = &[
     r"^https?://schemas.openxmlformats.org",
@@ -70,6 +78,20 @@ pub fn is_example_domain(uri: &Uri) -> bool {
     res
 }
 
+#[inline]
+#[must_use]
+/// Check if the host belongs to a known unsupported domain
+pub fn is_unsupported_domain(uri: &Uri) -> bool {
+    if let Some(domain) = uri.domain() {
+        // It is not enough to use `UNSUPPORTED_DOMAINS.contains(domain)` here
+        // as this would not include checks for subdomains, such as
+        // `foo.example.com`
+        UNSUPPORTED_DOMAINS.iter().any(|tld| domain.ends_with(tld))
+    } else {
+        false
+    }
+}
+
 /// A generic URI filter
 /// Used to decide if a given URI should be checked or skipped
 #[allow(clippy::struct_excessive_bools)]
@@ -179,6 +201,7 @@ impl Filter {
             || self.is_host_excluded(uri)
             || self.is_scheme_excluded(uri)
             || is_example_domain(uri)
+            || is_unsupported_domain(uri)
         {
             return true;
         }

lychee-lib/src/quirks/mod.rs

@@ -5,8 +5,6 @@ use regex::Regex;
 use reqwest::{Request, Url};
 use std::collections::HashMap;
 
-static TWITTER_PATTERN: Lazy<Regex> =
-    Lazy::new(|| Regex::new(r"^(https?://)?(www\.)?twitter.com").unwrap());
 static CRATES_PATTERN: Lazy<Regex> =
     Lazy::new(|| Regex::new(r"^(https?://)?(www\.)?crates.io").unwrap());
 static YOUTUBE_PATTERN: Lazy<Regex> =
@@ -33,13 +31,6 @@ pub(crate) struct Quirks {
 impl Default for Quirks {
     fn default() -> Self {
         let quirks = vec![
-            Quirk {
-                pattern: &TWITTER_PATTERN,
-                rewrite: |mut request| {
-                    request.url_mut().set_host(Some("nitter.net")).unwrap();
-                    request
-                },
-            },
             Quirk {
                 pattern: &CRATES_PATTERN,
                 rewrite: |mut request| {
@@ -118,34 +109,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn test_twitter_request() {
-        let cases = vec![
-            (
-                "https://twitter.com/search?q=rustlang",
-                "https://nitter.net/search?q=rustlang",
-            ),
-            ("http://twitter.com/jack", "http://nitter.net/jack"),
-            (
-                "https://twitter.com/notifications",
-                "https://nitter.net/notifications",
-            ),
-        ];
-
-        for (input, output) in cases {
-            let url = Url::parse(input).unwrap();
-            let expected = Url::parse(output).unwrap();
-
-            let request = Request::new(Method::GET, url.clone());
-            let modified = Quirks::default().apply(request);
-
-            assert_eq!(
-                MockRequest(modified),
-                MockRequest::new(Method::GET, expected)
-            );
-        }
-    }
-
     #[test]
     fn test_cratesio_request() {
         let url = Url::parse("https://crates.io/crates/lychee").unwrap();