Test if String is E-Mail Address

I need to test if a string is an e-mail address (not whether a string is the address of a valid e-mail account; just whether a string will be accepted by a mail server for attempted delivery to the address). I've written a simple function for doing this and would appreciate it if anyone has comments on how to make it more robust, more efficient, etc.

Here's the function:

integer IsEmailAddr(string test)
{
list testlist = llParseString2List(test,[" "],[]); // check for spaces
if ( llGetListLength(testlist) > 1 ) return FALSE;
testlist = llParseString2List(test,["@"],[]); // check for just one '@'
if ( llGetListLength(testlist) < 2 ) return FALSE;
if ( llGetListLength(testlist) > 2 ) return FALSE;
list testlist2 = llParseString2List((string)llList2List(testlist,1,1),["."],[]); // check for '.'
if ( llGetListLength(testlist2) < 2 ) return FALSE;
else return TRUE;
}

Then, anywhere in the code I wish to test whether a string is an e-mail address, I call the function with: "if ( IsEmailAddr(message) )" (in this case, the variable 'message' is the message returned by a listen; I'm checking whether what a user types into chat is an e-mail address). The code following this if statement only executes if the IsEmailAddr function returns TRUE.

How it works:

First, I check whether the string contains any spaces. If it contains spaces, then it's not an e-mail address.

Then, I check to see if the string contains a '@' and there is text on either side of the '@' by using the '@' to parse the list. If this returns a list with two elements, then I know there's one @ somewhere in the middle of the string. If testlist has only one element, or more than two elements, then it has more than one '@' and could not be a valid e-mail address.

Next, I check the part that appears after the '@' to see if it contains at least one '.'. If it does, then it looks like it's got the right formatting elements to be accepted by an e-mail server.

I realize there are some string combinations that might return false positives and that there's no way to check if an address belongs to a valid account until e-mail is actually sent, but, this is the best I can come up with. I'm sure a gazillion ways to check whether input is an e-mail address have cropped up over the years; what's best for use in SL?

but this was my thought. if you have a server, you can run a whois query to make sure the domain is registered. Perhaps there is even a way to query a registry from within SL. I do not have the skillz...



integer IsEmailAddr(string test)
{
//I call upon the string sorting power of llSubStringIndex()
//which may or may not be a cheaper operation than sorting to lists.
//all i do here is make sure that first there are no spaces, and
// then that there is an "@" followed by a "."
if (llSubStringIndex(test, " " != -1){return FALSE;}
integer whereatis = llSubStringIndex(test, "@";
integer wheredotis = llSubStringIndex(test, ".";
integer minimumatvalue = -1; // you can up this number if
// you want to assume minimum length of address.
else if (whereatis < wheredotis && whereatis > minimumatvalue){return TRUE;}
}

hrm .. llSubStringIndex .. that's the kind of command I was looking for .. probably faster to execute and makes the code simpler. will test & compare. however 'wheredotis < whereatis' will fail if an e-mail address contains a dot in the first part, as in [email]Jane.Doe@mydomain.com[/email] as some e-mail addresses have.

You may want to strengthen the function by making sure that the remaining string length after the . is 2-3 characters only.

my own email addresses have [dot]s before [@]s! Why didn't I think of that. I ph33r I never will be truly l33t. Good call on the 2-3chars after the [.]

[email]kurzweil.sleeper@gmail.com[/email]

I would add TLD checking. Go ahead and do the dot split; the last element then must be a valid TLD or country code. If it's a country code, the element before it must be a valid country TLD (e.g. [email]address@domain.co.uk[/email])

list lstGeneralTLDs = [
"com", "net", "org", "edu", "gov", "mil", "int",
"arpa", "aero", "biz", "coop", "info", "museum",
"name"
];

list lstCountryCodes = [
"ad", "ae", "af", "ag", "ai", "al", "am", "an", "ao", "aq",
"ar", "as", "at", "au", "aw", "az", "ba", "bb", "bd", "be",
"bf", "bg", "bh", "bi", "bj", "bm", "bn", "bo", "br", "bs",
"bt", "bv", "bw", "by", "bz", "ca", "cc", "cf", "cd", "cg",
"ch", "ci", "ck", "cl", "cm", "cn", "co", "cr", "cs", "cu",
"cv", "cx", "cy", "cz", "de", "dj", "dk", "dm", "do", "dz",
"ec", "ee", "eg", "eh", "er", "es", "et", "fi", "fj", "fk",
"fm", "fo", "fr", "fx", "ga", "gb", "gd", "ge", "gf", "gh",
"gi", "gl", "gm", "gn", "gp", "gq", "gr", "gs", "gt", "gu",
"gw", "gy", "hk", "hm", "hn", "hr", "ht", "hu", "id", "ie",
"il", "in", "io", "iq", "ir", "is", "it", "jm", "jo", "jp",
"ke", "kg", "kh", "ki", "km", "kn", "kp", "kr", "kw", "ky",
"kz", "la", "lb", "lc", "li", "lk", "lr", "ls", "lt", "lu",
"lv", "ly", "ma", "mc", "md", "mg", "mh", "mk", "ml", "mm",
"mn", "mo", "mp", "mq", "mr", "ms", "mt", "mu", "mv", "mw",
"mx", "my", "mz", "na", "nc", "ne", "nf", "ng", "ni", "nl",
"no", "np", "nr", "nt", "nu", "nz", "om", "pa", "pe", "pf",
"pg", "ph", "pk", "pl", "pm", "pn", "pr", "pt", "pw", "py",
"qa", "re", "ro", "ru", "rw", "sa", "sb", "sc", "sd", "se",
"sg", "sh", "si", "sj", "sk", "sl", "sm", "sn", "so", "sr",
"st", "su", "sv", "sy", "sz", "tc", "td", "tf", "tg", "th",
"tj", "tk", "tm", "tn", "to", "tp", "tr", "tt", "tv", "tw",
"tz", "ua", "ug", "uk", "um", "us", "uy", "uz", "va", "vc",
"ve", "vg", "vi", "vn", "vu", "wf", "ws", "ye", "yt", "yu",
"za", "zm", "zr", "zw"
];

list lstCountryTLDs = [
"com", "net", "org", "edu", "gov", "mil", "co", "ne", "or",
"ed", "go", "mi", "aero", "biz", "coop", "info", "museum",
"name"
];