Stop multiple sessions accessing the same file simultaneously
- by Pablo
Is it possible to lock a file to stop it being opened while GD library is accessing it?
What I am looking to achieve is similar to a database 'serialzable' level of isolation... I want to ensure that only one session/user can access an image at a time to stop a 'dirty read'.
May application allows users to add an image of choice to a bigger image.
for example
the big image is empty
Raj & Janet upload their images
Raj's session opens the big image.
1 ms later Janet's session
opens the big image.
Raj's session add's his image and
saves the big image
1 ms later Janet's session
adds his image and saves its version
of the big image.
As a result Raj's image is not in
the final image as Janet's version
overwrote it.
I hope that makes it clear enough.
