Email validation with third-party library

Cargo.toml

@@ -73,6 +73,7 @@ binascii = "0.1"
 axum = { version = "0.6.18", features = ["multipart"] }
 hyper = "0.14.26"
 tower-http = { version = "0.4.0", features = ["cors"] }
+email_address = "0.2.4"
 
 [dev-dependencies]
 rand = "0.8"

project-words.txt

@@ -15,11 +15,13 @@ Cyberneering
 datetime
 DATETIME
 Dont
+dotless
 Grünwald
 hasher
 Hasher
 hexlify
 httpseeds
+ICANN
 imagoodboy
 imdl
 indexadmin

src/services/user.rs

@@ -13,7 +13,7 @@ use crate::errors::ServiceError;
 use crate::mailer;
 use crate::mailer::VerifyClaims;
 use crate::models::user::{UserCompact, UserId, UserProfile};
-use crate::utils::regex::validate_email_address;
+use crate::utils::validation::validate_email_address;
 use crate::web::api::v1::contexts::user::forms::RegistrationForm;
 
 /// Since user email could be optional, we need a way to represent "no email"

src/utils/mod.rs

@@ -1,4 +1,4 @@
 pub mod clock;
 pub mod hex;
 pub mod parse_torrent;
-pub mod regex;
+pub mod validation;

src/utils/validation.rs

@@ -0,0 +1,79 @@
+use std::str::FromStr;
+
+use email_address::EmailAddress;
+use regex::Regex;
+
+const MIN_DOMAIN_LENGTH: usize = 4;
+
+/// Validates an email address.
+///
+/// # Panics
+///
+/// It panics if the email address is invalid. This should not happen
+/// because the email address is previously validated.
+#[must_use]
+pub fn validate_email_address(email_address_to_be_checked: &str) -> bool {
+    if !EmailAddress::is_valid(email_address_to_be_checked) {
+        return false;
+    }
+
+    let email = EmailAddress::from_str(email_address_to_be_checked).expect("Invalid email address");
+
+    // We reject anyway the email if it's a dotless domain name.
+    domain_has_extension(email.domain())
+}
+
+/// Returns true if the string representing a domain has an extension.
+///
+/// It does not check if the extension is valid.
+fn domain_has_extension(domain: &str) -> bool {
+    if domain.len() < MIN_DOMAIN_LENGTH {
+        return false;
+    }
+
+    Regex::new(r".*\..*").expect("Invalid regex").is_match(domain)
+}
+
+#[cfg(test)]
+mod tests {
+
+    mod for_email_validation {
+        use crate::utils::validation::validate_email_address;
+
+        #[test]
+        fn it_should_accept_valid_email_addresses() {
+            assert!(validate_email_address("[email protected]"));
+            assert!(validate_email_address("[email protected]"));
+        }
+
+        #[test]
+        fn it_should_not_accept_invalid_email_addresses() {
+            assert!(!validate_email_address("test"));
+            assert!(!validate_email_address("test@"));
+            assert!(!validate_email_address("test@torrust."));
+            assert!(!validate_email_address("test@."));
+            assert!(!validate_email_address("[email protected]"));
+
+            // Notice that local domain name with no TLD are valid,
+            // although ICANN highly discourages dotless email addresses
+            assert!(!validate_email_address("test@torrust"));
+        }
+    }
+
+    mod for_domain_validation {
+        use crate::utils::validation::domain_has_extension;
+
+        #[test]
+        fn it_should_accept_valid_domain_with_extension() {
+            assert!(domain_has_extension("a.io"));
+            assert!(domain_has_extension("a.com"));
+        }
+
+        #[test]
+        fn it_should_not_accept_dotless_domains() {
+            assert!(!domain_has_extension(""));
+            assert!(!domain_has_extension("."));
+            assert!(!domain_has_extension("a."));
+        }
+    }
+}