...

Author: tomoikey

src/rule/string.rs

@@ -1,3 +1,5 @@
 mod alphabet;
+mod email;
 
 pub use alphabet::{Alphabet, AlphabetRule};
+pub use email::{Email, EmailRule};

src/rule/string/email.rs

@@ -0,0 +1,50 @@
+use crate::result::Error;
+use crate::rule::Rule;
+use crate::Refined;
+use regex::Regex;
+
+pub type Email = Refined<EmailRule>;
+
+pub struct EmailRule;
+
+impl Rule for EmailRule {
+    type Item = String;
+
+    fn validate(target: Self::Item) -> Result<Self::Item, Error<Self::Item>> {
+        let regex =
+            Regex::new(r"^[a-zA-Z0-9_.+-]+@([a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]*\.)+[a-zA-Z]{2,}$")
+                .unwrap();
+        if regex.is_match(&target) {
+            Ok(target)
+        } else {
+            Err(Error::new(
+                format!("{target} is not a valid email format"),
+                target,
+            ))
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::rule::string::email::EmailRule;
+    use crate::rule::Rule;
+
+    #[test]
+    fn test_valid_email() {
+        let valid = "[email protected]".to_string();
+        assert!(EmailRule::validate(valid).is_ok())
+    }
+
+    #[test]
+    fn test_invalid_email_1() {
+        let invalid = "example.com".to_string();
+        assert!(EmailRule::validate(invalid).is_err())
+    }
+
+    #[test]
+    fn test_invalid_email_2() {
+        let invalid = "@".to_string();
+        assert!(EmailRule::validate(invalid).is_err())
+    }
+}