registration

I want to hook into the registration module. I already have a database of 50000 users who use my old website. Now I am migrating to Drupal. I still haven't migrated the entries to drupal database. I will be checking against my old database. When a user tries to register in Drupal, I need to check whether the username he gave is already present in that list of 50000 (and growing) entries. If it exists, I need to cancel the registration showing an error msg saying username exists.. Which hook should I use? If my code figures that the validation failed, How can I tell drupal to display an error

I have developed the XMPP Chat client for iOS and now I'm researching for how to do a new user registration from iOS itself. Can anyone help with the methods used to register a new user. As it needs to communicate with the Server and store the username and password to the server database. Please help I'm searching it from 2 days. This solution HAS WORKED for me NSString *username = @"rohit@XMPP_SERVER_IP_HERE"; // OR [NSString stringWithFormat:@"%@@%@",username,XMPP_BASE_URL]] NSString *password = @"SOME_PASSWORD"; AppDelegate *del = (AppDelegate *)[[UIApplication sharedApplication] delegate];

I'm trying to make a validation process for a password reset, what i've used are two values: the epoch time, and i want to use the users's old password (pbkdf2) as a key, Since i dont want to get non ASCII characters, i've used SimpleEncode library because it's fast since it's only a BASE64 with a key used, but the problem is that the password is too long (196 chars) so i get a long key! What i've done is split the result code = simpleencode.encode(key,asci)[::30] , but this will not be unique! To get an idea how it works, i've tried Facebook reset process, but what is given is a number! so

I'm developing a website with using struts2 and jsp pages. In many sites after you sign-up, a link will be sent to your email and after clicking on that the registration is complete. I want this feature on my webstie, but I don't have any idea how to do this and how is this working? Should I save user's information on my database until he/she is verified or not? I searched web but there is learning for php forms. any tutorial? Thanks in advance. The algorithm is something like this: Save the user's info, marking it with a pending status. Generate a token that contains some info related to the

I've written an application and I'd like to add a registration key/serial number to it (I'm big on minimum inconvinience - ala #4 at this Eric Sink article ). My question is about where to store the "activation" once the application has been registered. As I understand it, I have a trade-off between storing the key in a public place, where all users can read it (but which requires admin rights to save there) and storing a per-user activation (but then each user on the computer will have to activate independantly). That gives me two choices: Some user, with local admin rights, activates the