Allow users to remove their account

Question

I am developing a gallery which allows users to post photos, comments, vote and do many other tasks.

Now I think that it is correct to allow users to unsubscribe and remove all their data if they want to. However it is difficult to allow such a thing because you run the risk to break your application (e.g. what should I do when a comment has many replies? what should I do with pages that have many revisions by different users?).

Photos can be easily removed, but for other data (i.e. comments, revisions...) I thought that there are three possibilities:

• assign it to the admin
• assign it to a user called "removed-user"
• mantain the current associations (i.e. the user ID) and only rename user's data (e.g. assign a new username such as "removed-user-24" and a non-existent e-mail such as "noreply-removed-user-24@mysite.com"

What are the best practices to follow when we allow users to remove their accounts? How do you implement them (particularly in Rails)?

Answer 1

Ideally in a system you would not want to "hard delete" data. The best way I know of and that we have implemented in past is "soft delete". Maintain a status column in all your data tables which ideally refers to the fact whether the row is active or not. Any row when created is "Active" by default; however as entries are deleted; they are made inactive.

All select queries which display data on screen filter results for only "active records". This way you get following advantages: 1. Data Recovery is possible. 2. You can have a scheduled task on database level, which can take care of hard deletes of once in a way; if really needed. (Like a SQL procedure or something) 3. You can have an admin screen to be able to decide which accounts, entries etc you'd really want to mark for deletion 4. A temperory disabling of account can also be implemented with same solution.

In prod environments where I have worked on, a hard delete is a strict No-No. Infact audits are maintained for deletes also. But if application is really small; it'd be upto user.

I would still suggest a "virtual delete" or a "soft delete" with periodic cleanup on db level; which will be faster efficient and optimized way of cleaning up.

Answer 2

I've typically solved this type of problem by having an active flag on user, and simply setting active to false when the user is deleted. That way I maintain referential integrity throughout the system even if a user is "deleted". In the business layer I always validate a user is active before allowing them to perform operations. I also filter inactive users when retrieving data.

Answer 3

The usual thing to do is instead of deleting them from a database, add a boolean flag field and have it be true for valid users and false for invalid users. You will have to add code to filter on the flag. You should also remove all relevant data from the user that you can. The primary purpose of this flag is to keep the links intact. It is a variant of the renaming the user's data, but the flag will be easier to check.

Answer 4

I generally don't like to delete anything and instead opt to mark records as deleted/unpublished using states (with AASM i.e. acts as state machine).

I prefer states and events to just using flags as you can use events to update attributes and send emails etc. in one foul swoop. Then check states to decide what to do later on.

HTH.

Answer 5

I would recommend putting in a delete date field that contains the date/time the user unsubscribed - not only to the user record, but to all information related to that user. The app should check the field prior to displaying anything. You can then run a hard delete for all records 30 days (your choice of time) after the delete date. This will allow the information not to be shown (you will probably need to update the app in a few places), time to allow the user to re-subscribe (accidental or rethinking) and a scheduled process to delete old data. I would remove ALL information about the member and any related comments about the member or their prior published data (photos, etc.)