Question

In one of my projects users are allowed to edit the same file. It is group work and max number of users in group is 4. It is rare that they will be editing at the same time but there is possibility of it. I am using ckeditor which displays the content. how I can lock the content while it is being edited?
For the above case what will happen if one users open the content for editing and then never saves and leave window open. Is it possible to save the content, release the lock for editing by another users? If first user comes back to desk they should see the message that “content has been changed, please refresh”.

I am using php, mysql.

Thanks

Answer 1

You sort of need three parts to make this work.

1. You need to add a field to your database to indicate when the file is being edited. Create a field called something like “LastUsed” and record a timestamp for when the file was opened for editing. When someone tries to open the file, check the timestamp, if the timestamp is recent (say last 5 minutes) don’t allow it to be opened by a second user.

2. On the page that allows the file to be edited have an ajax request run every few minutes. All it needs to do is update the timestamp for the file being edited to the current date and time.

3. You could then have a timer running that once it reaches a certain point the ajax requests are stopped so the timestamp in the database can expire. However have that timer reset every time the user takes an action. That way as long as the user is doing something, the timer is reset, and the ajax request is allowed to continue updating the timestamp in the database. If the user doesn’t do something for a given time, the timer runs up, the ajax request is stopped, the timestamp expires, and someone else can open it for editing. You could also use that same timer to show your message that the editing session has expired or whatever.

It basically works like this:

• When users is editing a file an ajax request is continually updating the “LastUsed” timestamp.

• As long as that page is open to edit the file the ajax request will keep the timestamp in the database up to date.

• If the person leaves the page open but is not doing anything the timer will run up and stop the ajax requests, which will allow someone else to edit the file.

• Once the person leaves the page the ajax request will not be able to update the timestamp any longer. That way if a person just leaves the page others will be able to edit the file.

• So when the second user tries to edit the file if the “LastUsed” timestamp is within the last 5 minutes you know someone else is editing the file. if the timestamp is greater than 5 minutes you know that nobody currently has the file open for editing, so the second user can edit it.