Fix URLs with '@' parsing as emails (#177)

* Fix URLs with '@' parsing as emails

Only consider a link an email if it fails to parse as URL.

Also use a proper email validation instead of a simple '@' check.

This uses the fast_chemail crate which parses email links according
to the HTML specification (which is much more practical than checking
for RFC 5322 formatted emails).  It's also worth noting that
fast_chemail is used internally (albeit indirectly) by the
check_if_email_exists crate.  This means that email addresses
not considered valid by fast_chemail wouldn't pass link checks
anyway.

* Fix comment in test

Cargo.lock

@@ -1381,6 +1381,7 @@ dependencies = [
  "deadpool",
  "derive_builder",
  "doc-comment",
+ "fast_chemail",
  "futures",
  "glob",
  "headers",

Cargo.toml

@@ -26,7 +26,7 @@ hubcaps = { git="https://github.com/softprops/hubcaps.git" }
 linkify = "0.5.0"
 regex = "1.4.4"
 url = "2.2.1"
-# Switch back to version on crates.io after 
+# Switch back to version on crates.io after
 # https://github.com/async-email/async-smtp/pull/36
 # is merged and a new version of check-if-email-exists is released
 check-if-email-exists = { git="https://github.com/reacherhq/check-if-email-exists.git" }
@@ -53,6 +53,7 @@ serde_json = "1.0.64"
 ring = "0.16.19"
 pad = "0.1.6"
 console = "0.14.0"
+fast_chemail = "0.9.6"
 
 [dependencies.reqwest]
 features = ["gzip"]

src/extract.rs

@@ -498,4 +498,27 @@ mod test {
 
         assert_eq!(links, expected_links);
     }
+
+    #[test]
+    fn test_extract_urls_with_at_sign_properly() {
+        // note that these used to parse as emails
+        let input = "https://example.com/@test/test http://otherdomain.com/test/@test".to_string();
+        let links: HashSet<Uri> = extract_links(
+            &InputContent::from_string(&input, FileType::Plaintext),
+            None,
+        )
+        .into_iter()
+        .map(|r| r.uri)
+        .collect();
+
+        let expected_links = [
+            website("https://example.com/@test/test"),
+            website("http://otherdomain.com/test/@test"),
+        ]
+        .iter()
+        .cloned()
+        .collect();
+
+        assert_eq!(links, expected_links);
+    }
 }

src/uri.rs

@@ -1,4 +1,5 @@
 use anyhow::{bail, Result};
+use fast_chemail::is_valid_email;
 use serde::{Deserialize, Serialize};
 use std::net::IpAddr;
 use std::{convert::TryFrom, fmt::Display};
@@ -56,12 +57,12 @@ impl TryFrom<&str> for Uri {
         // Remove the `mailto` scheme if it exists
         // to avoid parsing it as a website URL.
         let s = s.trim_start_matches("mailto:");
-        if s.contains('@') & !is_link_internal {
-            return Ok(Uri::Mail(s.to_string()));
-        }
+
         if let Ok(uri) = Url::parse(s) {
             return Ok(Uri::Website(uri));
-        };
+        } else if !is_link_internal && is_valid_email(&s) {
+            return Ok(Uri::Mail(s.to_string()));
+        }
         bail!("Cannot convert to Uri")
     }
 }
@@ -86,6 +87,10 @@ mod test {
             Uri::try_from("http://example.org").unwrap(),
             website("http://example.org")
         );
+        assert_eq!(
+            Uri::try_from("http://example.org/@test/testing").unwrap(),
+            website("http://example.org/@test/testing")
+        );
         assert_eq!(
             Uri::try_from("mail@example.org").unwrap(),
             Uri::Mail("mail@example.org".to_string())