How to implement unsubscribe feature for website?

Question

Hai This is my task Example:when we upload our resume to naukri.com we get mails some companys regarding job openings so at the bottom we see a link if you want to unscribe please click the link button so actually this is my task when customer doesnt want to receive mails from our product if he wants to unscribe when he clicks the link button he has to unsubscribe from our website plz help me what logic i have to write which services i have to use plz help me Thanks Karthik

Zoran Horvat · Answer

Create Web page which executes unsubscribe feature. This Web page should accept parameter as part of URL (not as part of POSTed form). I'll call this parameter Token. Now whenever your customer subscribes to mailing list you update his customer record in your database and store Token there. Token should be a relatively long string which is randomly generated and unique. Unsubscribing page then finds customer with Token found in URL and updates his customer record in the dabase to set Token to NULL. With this solution only those customers having non-NULL Token field are actually subscribed to the mailing list. All that have NULL value are not subscribed. Zoran

karthik parcha · Answer

hie zoran i check it has correct answer for this post and my previous post thanks karthik

Anil Kumar · Answer

Karthik if your query is resolved mark Zoran's answer as 'Answered'.

karthik parcha · Answer

Ya sure Zoran iam working now if their any doubts i will contact u

Zoran Horvat · Answer

Please don't forget to check This is correct answer for the post which helped you solve the problem. Thanks Zoran

karthik parcha · Answer

thanq zoran thanq very much

Zoran Horvat · Answer

rnd.Next(26) would generate random integer in range 0 to 25 inclusive. Now adding 'A' to that (actually adding ASCII code for 'A') would make 'A' from value 0 'B' from 1 ...  'Z' from 25. In that way I'm appending one letter at a time to the string builder and all letters are randomly generated. Zoran

karthik parcha · Answer

hie thanq awesome explanation Now that this is done remaining length - sb.Length characters are completely randomly generated: while (sb.Length sb.Append((char)(rnd.Next(26) + 'A')); can u explain this line

Zoran Horvat · Answer

First I'm creating a string which contains current UTC timestamp up to 1/10000 seconds: string ts = DateTime.UtcNow.ToString(yyyyMMddHHmmssffff); This would produce output: 201107261016464723  which is year 2011 month 07 day 26 hour 10 minute 16 second 46 and part of the second 4723 Now this string which consists of digits is converted to letters so that 0 becomes A 1 becomes B ... 9 becomes I: for (int i = 0; i sb.Append((char)(ts[i] - '0' + 'A')); Now that this is done remaining length - sb.Length characters are completely randomly generated: while (sb.Length sb.Append((char)(rnd.Next(26) + 'A')); In this way you get string of required length which consists of current UTC timestamp and random part e.g.: CABBAHCGBABIEAAHBHPSYWUJYKHIYY This should always be unique (unless you have more than 16 new customers per second as clock changes 15-16 times per second). Zoran

karthik parcha · Answer

hie thanq thanq very much i will try it if their any doubts i will contact you zoran yesterday i tried your storedprocedure its working now hie can u explain this code plz dont mind private string GenerateToken(int length) { Random rnd = new Random(); StringBuilder sb = new StringBuilder(); string ts = DateTime.UtcNow.ToString(yyyyMMddHHmmssffff); for (int i = 0; i sb.Append((char)(ts[i] - '0' + 'A')); while (sb.Length sb.Append((char)(rnd.Next(26) + 'A')); return sb.ToString(); }

Zoran Horvat · Answer

I don't have ready to use code but it should not be too complicated to implement. Function which generates token can look like this: private string GenerateToken(int length) { Random rnd = new Random(); StringBuilder sb = new StringBuilder(); string ts = DateTime.UtcNow.ToString(yyyyMMddHHmmssffff); for (int i = 0; i sb.Append((char)(ts[i] - '0' + 'A')); while (sb.Length sb.Append((char)(rnd.Next(26) + 'A')); return sb.ToString(); } private string GenerateToken() { return GenerateToken(40); } You can use GenerateToken() function and that will generate 40 characters long tokens. First part of the token is created from current timestamp which guarantees uniqueness. Now suppose that you have a customers table like this: CREATE TABLE Customer( CustomerID INT PRIMARY KEY IDENTITY(1 1) UserName VARCHAR(100) MailingListToken CHAR(40) ); In this case you can create Subscribe and Unsubscribe stored procedures: CREATE PROCEDURE Subscribe @CustomerID INT @Token CHAR(40) AS BEGIN UPDATE Customer SET MailingListToken=@Token WHERE CustomerID=@CustomerID END GO CREATE PROCEDURE Unsubscribe @Token CHAR(40) AS BEGIN UPDATE Customer SET MailingListToken=NULL WHERE MailingListToken=@Token END GO You can extract the list of subscribed customers like this: SELECT CustomerID UserName FROM Customer WHERE MailingListToken IS NOT NULL; Zoran

karthik parcha · Answer

hie Zoran What you said i understand But How to write code for this Token should be a relatively long string which is randomly generated and unique If you know can u write code for me If you have any example application or just sample overview regarding this task will you post for me