fix valid email address

Author: lyqio

src/string/.idea/.gitignore

@@ -3,26 +3,31 @@ const MAX_DOMAIN_LENGTH: u32 = 255;
 const CHARACTERS: &str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz1234567890";
 const SYMBOLS: &str = "!#$%&'*+-/=?^_`{|}~";
 
-/// Returns true if email address is valid, otherwise returns false
-///
-/// A valid email address is made up of two parts, the local-part, and
-/// the domain.
-///
-/// The local-part may contain the following:
-///     - uppercase & lowercase latin letters
-///     - digits 0-9
-///     - characters !#$%&'*+-/=?^_`{|}~
-///     - non consecutive dots ('.') not located at start or end of local-part
-///
-/// The domain may contain the following:
-///     - uppercase & lowercase latin letters
-///     - digits 0-9
-///     - dash ('-') as long as not at start or end of domain
-///
-/// The local-part and domain must be separated by an '@'
-/// The local-part must not contain more than 64 characters
-/// The domain must not contain more than 255 characters
-pub fn is_valid_email_address(email_address: &str) -> bool {
+fn clear_quotes(input: &str) -> String {
+    let mut quote_count = input.starts_with('"') as u32;
+    let mut new_local_part: String = String::from(input.chars().next().unwrap());
+    for i in 1..input.len() {
+        if input.chars().nth(i).unwrap() == '"' && input.chars().nth(i - 1).unwrap() != '\\' {
+            quote_count += 1;
+
+            if !new_local_part.starts_with('"') && quote_count != 1 {
+                new_local_part.push('"');
+            }
+        }
+
+        if quote_count % 2 == 0 {
+            new_local_part.push(input.chars().nth(i).unwrap());
+        }
+    }
+
+    new_local_part
+}
+
+/// Follows email address rules as listed:
+/// https://en.wikipedia.org/wiki/Email_address#Examples
+pub fn is_valid_email_address(input_email_address: &str) -> bool {
+    let email_address = clear_quotes(input_email_address);
+
     let parts: Vec<String> = email_address
         .split('@')
         .map(|x| x.to_string())
@@ -42,31 +47,43 @@ pub fn is_valid_email_address(email_address: &str) -> bool {
         return false;
     }
 
-    // (3)  validate the dots in the local part
+    // (3)  check quote dots
+    for i in 1..local_part.len() {
+        if local_part.chars().nth(i - 1).unwrap() == '"'
+            && local_part.chars().nth(i).unwrap() == '"'
+        {
+            let proceeding_quote = local_part.chars().nth(i + 1);
+            if proceeding_quote.is_some() && proceeding_quote.unwrap() != '.' {
+                return false;
+            }
+        }
+    }
+
+    // (4)  validate the dots in the local part
     if local_part.starts_with('.') || local_part.ends_with('.') || local_part.contains("..") {
         return false;
     }
 
-    // (4)  check that the characters in the local part are valid
+    // (5)  check that the characters in the local part are valid
     for item in local_part.chars() {
-        if !CHARACTERS.contains(item) && !SYMBOLS.contains(item) && item != '.' {
+        if !CHARACTERS.contains(item) && !SYMBOLS.contains(item) && item != '.' && item != '"' {
             return false;
         }
     }
 
-    // (5)  check that the domain contains valid characters
+    // (6)  check that the domain contains valid characters
     for item in domain.chars() {
-        if !CHARACTERS.contains(item) && item != '-' && item != '.' {
+        if !CHARACTERS.contains(item) && item != '-' && item != '.' && !"[]:".contains(item) {
             return false;
         }
     }
 
-    // (6)  validate the dots in the domain
+    // (7)  validate the dots in the domain
     if domain.starts_with('.') || domain.ends_with('.') || domain.contains("..") {
         return false;
     }
 
-    // (7)  validate the dashes in the domain
+    // (8)  validate the dashes in the domain
     if domain.starts_with('-') || domain.ends_with('-') {
         return false;
     }
@@ -91,22 +108,32 @@ mod tests {
     }
 
     test_is_valid_email_address! {
-        normal_email: ("[email protected]", true),
-        email_with_dots: ("[email protected]", true),
-        dots_with_symbols: ("[email protected]", true),
-        dash_test: ("[email protected]", true),
-        short_local_part: ("[email protected]", true),
-        multiple_dash: ("[email protected]", true),
-        extreme_valid: ("longlonglonglonglonglonglonglonglonglonglonglonglonglonglonglon@example.com",true),
-        extreme_invalid: ("longlonglonglonglonglonglonglonglonglonglonglonglonglonglonglongl@example.com",false),
-        invalid_at: ("where.is.at", false),
-        multiple_ats: ("too@[email protected]", false),
-        consecutive_dots: ("[email protected]", false),
-        invalid_underscore: ("wrong@no_underscore_here", false),
-        dash_start: ("[email protected]", false),
-        dash_end: ("also-dont-put@here-", false),
-        dot_start: (".not_at_start@dont", false),
-        dot_end: ("or-at-end@here.", false),
-        dot_start_end: ("[email protected].", false),
+        basic: ("[email protected]", true),
+        basic_2: ("[email protected]", true),
+        cases: ("[email protected]", true),
+        one_letter_local: ("[email protected]", true),
+        long_email_subdomains: ("[email protected]", true),
+        tags: ("[email protected]", true),
+        slashes: ("name/[email protected]", true),
+        no_tld: ("admin@example", true),
+        tld: ("[email protected]", true),
+        quotes_with_space: ("\" \"@example.org", true),
+        quoted_double_dot: ("\"john..doe\"@example.org", true),
+        host_route: ("[email protected]", true),
+        quoted_non_letters: (r#""very.(),:;<>[]\".VERY.\"very@\\ \"very\".unusual"@strange.example.com"#, true),
+        percent_symbol: ("user%[email protected]", true),
+        local_end_symbol: ("[email protected]", true),
+        ip_address: ("postmaster@[123.123.123.123]", true),
+        other_ip: ("postmaster@[IPv6:2001:0db8:85a3:0000:0000:8a2e:0370:7334]", true),
+        begin_with_underscore: ("_test@[IPv6:2001:0db8:85a3:0000:0000:8a2e:0370:7334]", true),
+
+        no_at: ("abc.example.com", false),
+        multiple_ats: ("a@b@[email protected]", false),
+        bad_local_characters: ("a\"b(c)d,e:f;g<h>i[j\\k][email protected]", false),
+        bad_local_string: ("just\"not\"[email protected]", false),
+        bad_backslash: ("this is\"not\\[email protected]", false),
+        escaped_backslash: ("this\\ still\\\"not\\\\[email protected]", false),
+        long_local_part: ("1234567890123456789012345678901234567890123456789012345678901234+x@example.com", false),
+        domain_underscore: ("i.like.underscores@but_they_are_not_allowed_in_this_part", false),
     }
 }