webpa-developer — This is where the discussion is held for the code development for WebPA

[Webpa-developer] Is this list still being used?

[Stephen P V. <Ste...@ed...>]

I have some comments and questions about the architecture of WebPA and 
thought that this might be the appropriate list in which to raise them. 
  However, I notice that it has not been used for over 18 months.  If 
anyone receives this email please could they let me know whether it has 
been superseded by another list, or if it is still an appropriate 
channel for technical-related issues.

Thanks,

Stephen

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

[Webpa-developer] Discussion held prior to list creation - related to login mechanisms

[Nicola W. <N.W...@lb...>]

Hi Nic,
 
I checked the SQL behind the get_student() and it is just selecting based on username so it works fine for both staff and students, I guess it would be better if there was a function called get_user() just in case at a later date it is altered to take account of the user status.
 
The good old shared secret, it works well and allows a lot of other stuff to use the same entry point.
 
I think it is better if this conversation is held in public so go ahead and create what you need to do in source forge.
 
I have to take a little break from the coding, other jobs piling up :(, but I will get back to it over the next couple of weeks.
 
John
 



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From: Nicola Wilkinson 
Sent: Tue 03/03/2009 17:22
To: John Tutchings
Subject: RE: 


Hi John,
 
I've gotten through my emails and gumph a bit faster than I thought. I had been on holiday last week (just forgot to turn on my out of office message again). I'm sorry the email begins to ramble from here on...
 
 
General comments - looks fine, my only concern is line 64 where you use the function get_student() from the /library/classes/class_engcis.php... how does it work with staff users? Do they get bumped to the login page? I know in theory that it should go through okay, but just wondered if you had tried it.
 
Why didn't I think of the shared secret! I can't see the wood for the trees anymore.
 
 
For the next steps you outlined you might be interested to know the following...
 
 
To add a user you will need the user class which can be found at /library/classes/class_user.php In this class you will find the function save_user()  At no point in this class is the user married up the the module code.
 
Were I have had to handle the module code and user information I have done stuff like... (from /admin/load/simple.php)

$sql = "SELECT user_id FROM user WHERE institutional_reference='{$entry['institutional_reference']}' AND email='{$entry['email']}'";

$user_id = $DB->fetch($sql);

$sql = "INSERT INTO user_module(user_id,module_id) VALUES ('{$user_id[0]['user_id']}','{$entry['module_code']}')";

$DB->execute($sql);

$SQL = "ALTER IGNORE TABLE user_module ADD UNIQUE KEY (user_id,module_id)";

$DB->execute($SQL);

Due to the data base structure and de-entanglement from Loughborough's SIS system I discovered that the classes don't necessarily relate to the OO way of coding (lacks constructors and destructors, often not even sensibly named and at times completely missing!) and in the process of the project, whenever I have tried to refactor anything I've completely trashed the system. Hence normally you would have thought that a class for module would be a good thing to have... but it doesn't exist.
 
When you get to the point of handling any groups.. any of the classes in the /library/classes/ folder that contains the word group you may well need. I'm afraid that it is a bit obvascated.. but in essence - anything with collection will relate to how the groups are collated to into a overall super group/cohort and how they are linked to an assessment/tutor. The others are for the sub groups of the super group/cohort - how they are constructed, the basic group class and the transverse of the super group.
 
Would you be comfortable if we conducted these conversations on a mailing list - I am happy to set one up in source forge for us to use. I think that it would be beneficial for this to be more publically conducted and then if we get anyone else who wants to contribute stuff in the future we won't have to type everything out again for them.
 
You also have to forgive the code and database... I'm afraid that I inherited these when the project started and although I have refactored some of it, I've had a nightmare with other bits. But just shout if you can't find anything or it doesn't make sense.
 
Cheers
 
Nic

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From: John Tutchings 
Sent: 25 February 2009 17:36
To: N.Wilkinson
Subject: 


Hi Nic,
 
Before you send me my post card saying that I was going to do a powerlink for Blackboard Vista here is my first cut.  I will be testing it in Coventry with several users.
 
It is just a proof of concept and the next one will be more comprehensive, this one just simulates the log in by using the idea of a shared secret.  The person's username, a time stamp (in seconds since the epoch) and a MAC is sent across to the script.  The script generates its own MAC using the parameters passed and compares it with the MAC coming in, if they match it then checks to see if the user is in the database, if they are then they are logged in, if they aren't then they get the log in page.
 
This script will work with any input as long as the MAC is generated by:
concating the username, timestamp and shared secret and then md5 hashing it, you then pass over the username, timestamp and MAC.  This means the script can be used to SSO in from Moodle etc.
 
In the next cut it if a member of staff clicks on the link it will also pass over the module/cohort code along with a text file with all the students that enrolled on that cohort so that they can all be added to the module in WebPA.  It may even pass over group membership but that could be the 3rd cut as it is more difficult to do.
 
I would like your feed back and I will need some help to find the functions to add a user and add membership before I can start the next bit.
 
John